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Sample records for selectively encodes aversive

  1. Motivated encoding selectively promotes memory for future inconsequential semantically-related events.

    Science.gov (United States)

    Oyarzún, Javiera P; Packard, Pau A; de Diego-Balaguer, Ruth; Fuentemilla, Lluis

    2016-09-01

    Neurobiological models of long-term memory explain how memory for inconsequential events fades, unless these happen before or after other relevant (i.e., rewarding or aversive) or novel events. Recently, it has been shown in humans that retrospective and prospective memories are selectively enhanced if semantically related events are paired with aversive stimuli. However, it remains unclear whether motivating stimuli, as opposed to aversive, have the same effect in humans. Here, participants performed a three phase incidental encoding task where one semantic category was rewarded during the second phase. A memory test 24h after, but not immediately after encoding, revealed that memory for inconsequential items was selectively enhanced only if items from the same category had been previously, but not subsequently, paired with rewards. This result suggests that prospective memory enhancement of reward-related information requires, like previously reported for aversive memories, of a period of memory consolidation. The current findings provide the first empirical evidence in humans that the effects of motivated encoding are selectively and prospectively prolonged over time. Copyright © 2016 Elsevier Inc. All rights reserved.

  2. Choice by value encoding and value construction : processes of loss aversion

    NARCIS (Netherlands)

    Willemsen, M.C.; Boeckenholt, U.; Johnson, E.J.

    2011-01-01

    Loss aversion and reference dependence are 2 keystones of behavioral theories of choice, but little is known about their underlying cognitive processes. We suggest an additional account for loss aversion that supplements the current account of the value encoding of attributes as gains or losses

  3. Choice by Value Encoding and Value Construction: Processes of Loss Aversion

    Science.gov (United States)

    Willemsen, Martijn C.; Bockenholt, Ulf; Johnson, Eric J.

    2011-01-01

    Loss aversion and reference dependence are 2 keystones of behavioral theories of choice, but little is known about their underlying cognitive processes. We suggest an additional account for loss aversion that supplements the current account of the value encoding of attributes as gains or losses relative to a reference point, introducing a value…

  4. Determinants of Propranolol's Selective Effect on Loss Aversion.

    Science.gov (United States)

    Sokol-Hessner, Peter; Lackovic, Sandra F; Tobe, Russell H; Camerer, Colin F; Leventhal, Bennett L; Phelps, Elizabeth A

    2015-07-01

    Research on emotion and decision making has suggested that arousal mediates risky decisions, but several distinct and often confounded processes drive such choices. We used econometric modeling to separate and quantify the unique contributions of loss aversion, risk attitudes, and choice consistency to risky decision making. We administered the beta-blocker propranolol in a double-blind, placebo-controlled within-subjects study, targeting the neurohormonal basis of physiological arousal. Matching our intervention's pharmacological specificity with a quantitative model delineating decision-making components allowed us to identify the causal relationships between arousal and decision making that do and do not exist. Propranolol selectively reduced loss aversion in a baseline- and dose-dependent manner (i.e., as a function of initial loss aversion and body mass index), and did not affect risk attitudes or choice consistency. These findings provide evidence for a specific, modulatory, and causal relationship between precise components of emotion and risky decision making. © The Author(s) 2015.

  5. Determinants of propranolol’s selective effect on loss aversion

    Science.gov (United States)

    Sokol-Hessner, Peter; Lackovic, Sandra F.; Tobe, Russell H.; Camerer, Colin F.; Leventhal, Bennett L.; Phelps, Elizabeth A.

    2015-01-01

    Research on emotion and decision-making has suggested that arousal mediates risky decisions (e.g., Bechara et al., 1997), but several distinct and often confounded processes drive such choices. Here, we used econometric modeling to separate and quantify the unique contributions of loss aversion, risk sensitivity and choice consistency to risky decision-making. We administered the beta-blocker propranolol in a double-blind, placebo-controlled within-subjects study, targeting the neurohormonal basis of physiological arousal. Matching our intervention’s pharmacological specificity with a quantitative model delineating decision-making components allowed us to identify the causal relationships between arousal and decision-making that do and do not exist. Propranolol selectively reduced loss aversion in a baseline- and dose-dependent manner (i.e. as a function of initial loss aversion and body-mass index), and did not affect risk sensitivity or choice consistency. These findings provide evidence for a specific, modulatory, and causal relationship between precise components of both emotion and risky decision-making. PMID:26063441

  6. ERP Correlates of Encoding Success and Encoding Selectivity in Attention Switching

    Science.gov (United States)

    Yeung, Nick

    2016-01-01

    Long-term memory encoding depends critically on effective processing of incoming information. The degree to which participants engage in effective encoding can be indexed in electroencephalographic (EEG) data by studying event-related potential (ERP) subsequent memory effects. The current study investigated ERP correlates of memory success operationalised with two different measures—memory selectivity and global memory—to assess whether previously observed ERP subsequent memory effects reflect focused encoding of task-relevant information (memory selectivity), general encoding success (global memory), or both. Building on previous work, the present study combined an attention switching paradigm—in which participants were presented with compound object-word stimuli and switched between attending to the object or the word across trials—with a later recognition memory test for those stimuli, while recording their EEG. Our results provided clear evidence that subsequent memory effects resulted from selective attentional focusing and effective top-down control (memory selectivity) in contrast to more general encoding success effects (global memory). Further analyses addressed the question of whether successful encoding depended on similar control mechanisms to those involved in attention switching. Interestingly, differences in the ERP correlates of attention switching and successful encoding, particularly during the poststimulus period, indicated that variability in encoding success occurred independently of prestimulus demands for top-down cognitive control. These results suggest that while effects of selective attention and selective encoding co-occur behaviourally their ERP correlates are at least partly dissociable. PMID:27907075

  7. Medial amygdala lesions selectively block aversive Pavlovian-instrumental transfer in rats.

    Directory of Open Access Journals (Sweden)

    Margaret Grace McCue

    2014-09-01

    Full Text Available Pavlovian conditioned stimuli (CSs play an important role in the reinforcement and motivation of instrumental active avoidance (AA. Conditioned threats can also invigorate ongoing AA responding (aversive Pavlovian-instrumental transfer or PIT. The neural circuits mediating AA are poorly understood, although lesion studies suggest that lateral, basal and central amygdala nuclei, as well as infralimbic prefrontal cortex, make key, and sometimes opposing, contributions. We recently completed an extensive analysis of brain c-Fos expression in good vs. poor avoiders following an AA test (Martinez et al 2013, Learning and Memory. This analysis identified medial amygdala (MeA as a potentially important region for Pavlovian motivation of instrumental actions. MeA is known to mediate defensive responding to innate threats as well as social behaviors, but its role in mediating aversive Pavlovian-instrumental interactions is unknown. We evaluated the effect of MeA lesions on Pavlovian conditioning, Sidman two-way AA conditioning (shuttling and aversive PIT in rats. Mild footshocks served as the unconditioned stimulus in all conditioning phases. MeA lesions had no effect on AA but blocked the expression of aversive PIT and 22 kHz ultrasonic vocalizations in the AA context. Interestingly, MeA lesions failed to affect Pavlovian freezing to discrete threats but reduced freezing to contextual threats when assessed outside of the AA chamber. These findings differentiate MeA from lateral and central amygdala, as lesions of these nuclei disrupt Pavlovian freezing and aversive PIT, but have opposite effects on AA performance. Taken together, these results suggest that MeA plays a selective role in the motivation of instrumental avoidance by general or uncertain Pavlovian threats.

  8. Thinking like a trader selectively reduces individuals' loss aversion.

    Science.gov (United States)

    Sokol-Hessner, Peter; Hsu, Ming; Curley, Nina G; Delgado, Mauricio R; Camerer, Colin F; Phelps, Elizabeth A

    2009-03-31

    Research on emotion regulation has focused upon observers' ability to regulate their emotional reaction to stimuli such as affective pictures, but many other aspects of our affective experience are also potentially amenable to intentional cognitive regulation. In the domain of decision-making, recent work has demonstrated a role for emotions in choice, although such work has generally remained agnostic about the specific role of emotion. Combining psychologically-derived cognitive strategies, physiological measurements of arousal, and an economic model of behavior, this study examined changes in choices (specifically, loss aversion) and physiological correlates of behavior as the result of an intentional cognitive regulation strategy. Participants were on average more aroused per dollar to losses relative to gains, as measured with skin conductance response, and the difference in arousal to losses versus gains correlated with behavioral loss aversion across subjects. These results suggest a specific role for arousal responses in loss aversion. Most importantly, the intentional cognitive regulation strategy, which emphasized "perspective-taking," uniquely reduced both behavioral loss aversion and arousal to losses relative to gains, largely by influencing arousal to losses. Our results confirm previous research demonstrating loss aversion while providing new evidence characterizing individual differences and arousal correlates and illustrating the effectiveness of intentional regulation strategies in reducing loss aversion both behaviorally and physiologically.

  9. Selecting Operations for Assembler Encoding

    Directory of Open Access Journals (Sweden)

    Tomasz Praczyk

    2010-04-01

    Full Text Available Assembler Encoding is a neuro-evolutionary method in which a neural network is represented in the form of a simple program called Assembler Encoding Program. The task of the program is to create the so-called Network Definition Matrix which maintains all the information necessary to construct the network. To generate Assembler Encoding Programs and the subsequent neural networks evolutionary techniques are used.
    The performance of Assembler Encoding strongly depends on operations used in Assembler Encoding Programs. To select the most effective operations, experiments in the optimization and the predator-prey problem were carried out. In the experiments, Assembler Encoding Programs equipped with different types of operations were tested. The results of the tests are presented at the end of the paper.

  10. Serotonin selectively influences moral judgment and behavior through effects on harm aversion.

    Science.gov (United States)

    Crockett, Molly J; Clark, Luke; Hauser, Marc D; Robbins, Trevor W

    2010-10-05

    Aversive emotional reactions to real or imagined social harms infuse moral judgment and motivate prosocial behavior. Here, we show that the neurotransmitter serotonin directly alters both moral judgment and behavior through increasing subjects' aversion to personally harming others. We enhanced serotonin in healthy volunteers with citalopram (a selective serotonin reuptake inhibitor) and contrasted its effects with both a pharmacological control treatment and a placebo on tests of moral judgment and behavior. We measured the drugs' effects on moral judgment in a set of moral 'dilemmas' pitting utilitarian outcomes (e.g., saving five lives) against highly aversive harmful actions (e.g., killing an innocent person). Enhancing serotonin made subjects more likely to judge harmful actions as forbidden, but only in cases where harms were emotionally salient. This harm-avoidant bias after citalopram was also evident in behavior during the ultimatum game, in which subjects decide to accept or reject fair or unfair monetary offers from another player. Rejecting unfair offers enforces a fairness norm but also harms the other player financially. Enhancing serotonin made subjects less likely to reject unfair offers. Furthermore, the prosocial effects of citalopram varied as a function of trait empathy. Individuals high in trait empathy showed stronger effects of citalopram on moral judgment and behavior than individuals low in trait empathy. Together, these findings provide unique evidence that serotonin could promote prosocial behavior by enhancing harm aversion, a prosocial sentiment that directly affects both moral judgment and moral behavior.

  11. The strength of aversive and appetitive associations and maladaptive behaviors.

    Science.gov (United States)

    Itzhak, Yossef; Perez-Lanza, Daniel; Liddie, Shervin

    2014-08-01

    Certain maladaptive behaviors are thought to be acquired through classical Pavlovian conditioning. Exaggerated fear response, which can develop through Pavlovian conditioning, is associated with acquired anxiety disorders such as post-traumatic stress disorders (PTSDs). Inflated reward-seeking behavior, which develops through Pavlovian conditioning, underlies some types of addictive behavior (e.g., addiction to drugs, food, and gambling). These maladaptive behaviors are dependent on associative learning and the development of long-term memory (LTM). In animal models, an aversive reinforcer (fear conditioning) encodes an aversive contextual and cued LTM. On the other hand, an appetitive reinforcer results in conditioned place preference (CPP) that encodes an appetitive contextual LTM. The literature on weak and strong associative learning pertaining to the development of aversive and appetitive LTM is relatively scarce; thus, this review is particularly focused on the strength of associative learning. The strength of associative learning is dependent on the valence of the reinforcer and the salience of the conditioned stimulus that ultimately sways the strength of the memory trace. Our studies suggest that labile (weak) aversive and appetitive LTM may share similar signaling pathways, whereas stable (strong) aversive and appetitive LTM is mediated through different pathways. In addition, we provide some evidence suggesting that extinction of aversive fear memory and appetitive drug memory is likely to be mediated through different signaling molecules. We put forward the importance of studies aimed to investigate the molecular mechanisms underlying the development of weak and strong memories (aversive and appetitive), which would ultimately help in the development of targeted pharmacotherapies for the management of maladaptive behaviors that arise from classical Pavlovian conditioning. © 2014 International Union of Biochemistry and Molecular Biology.

  12. Chronic stress triggers social aversion via glucocorticoid receptor in dopaminoceptive neurons.

    Science.gov (United States)

    Barik, Jacques; Marti, Fabio; Morel, Carole; Fernandez, Sebastian P; Lanteri, Christophe; Godeheu, Gérard; Tassin, Jean-Pol; Mombereau, Cédric; Faure, Philippe; Tronche, François

    2013-01-18

    Repeated traumatic events induce long-lasting behavioral changes that are key to organism adaptation and that affect cognitive, emotional, and social behaviors. Rodents subjected to repeated instances of aggression develop enduring social aversion and increased anxiety. Such repeated aggressions trigger a stress response, resulting in glucocorticoid release and activation of the ascending dopamine (DA) system. We bred mice with selective inactivation of the gene encoding the glucocorticoid receptor (GR) along the DA pathway, and exposed them to repeated aggressions. GR in dopaminoceptive but not DA-releasing neurons specifically promoted social aversion as well as dopaminergic neurochemical and electrophysiological neuroadaptations. Anxiety and fear memories remained unaffected. Acute inhibition of the activity of DA-releasing neurons fully restored social interaction in socially defeated wild-type mice. Our data suggest a GR-dependent neuronal dichotomy for the regulation of emotional and social behaviors, and clearly implicate GR as a link between stress resiliency and dopaminergic tone.

  13. Amygdala activity related to enhanced memory for pleasant and aversive stimuli.

    Science.gov (United States)

    Hamann, S B; Ely, T D; Grafton, S T; Kilts, C D

    1999-03-01

    Pleasant or aversive events are better remembered than neutral events. Emotional enhancement of episodic memory has been linked to the amygdala in animal and neuropsychological studies. Using positron emission tomography, we show that bilateral amygdala activity during memory encoding is correlated with enhanced episodic recognition memory for both pleasant and aversive visual stimuli relative to neutral stimuli, and that this relationship is specific to emotional stimuli. Furthermore, data suggest that the amygdala enhances episodic memory in part through modulation of hippocampal activity. The human amygdala seems to modulate the strength of conscious memory for events according to emotional importance, regardless of whether the emotion is pleasant or aversive.

  14. The origin of risk aversion.

    Science.gov (United States)

    Zhang, Ruixun; Brennan, Thomas J; Lo, Andrew W

    2014-12-16

    Risk aversion is one of the most basic assumptions of economic behavior, but few studies have addressed the question of where risk preferences come from and why they differ from one individual to the next. Here, we propose an evolutionary explanation for the origin of risk aversion. In the context of a simple binary-choice model, we show that risk aversion emerges by natural selection if reproductive risk is systematic (i.e., correlated across individuals in a given generation). In contrast, risk neutrality emerges if reproductive risk is idiosyncratic (i.e., uncorrelated across each given generation). More generally, our framework implies that the degree of risk aversion is determined by the stochastic nature of reproductive rates, and we show that different statistical properties lead to different utility functions. The simplicity and generality of our model suggest that these implications are primitive and cut across species, physiology, and genetic origins.

  15. ARE PEOPLE INEQUALITY AVERSE OR JUST RISK AVERSE?

    OpenAIRE

    Carlsson, Fredrik; Daruvala, Dinky; Johansson-Stenman, Olof

    2001-01-01

    Individuals’ preferences for risk and inequality are measured through experimental choices between hypothetical societies and lotteries. The median relative risk aversion, which is often seen to reflect social inequality aversion, is between 2 and 3. We also estimate the individual inequality aversion, reflecting individuals’ willingness to pay for living in a more equal society. Left-wing voters and women are both more risk- and inequality averse than others. The model allows for non-monoton...

  16. Selective Memories: Infants' Encoding Is Enhanced in Selection via Suppression

    Science.gov (United States)

    Markant, Julie; Amso, Dima

    2013-01-01

    The present study examined the hypothesis that inhibitory visual selection mechanisms play a vital role in memory by limiting distractor interference during item encoding. In Experiment 1a we used a modified spatial cueing task in which 9-month-old infants encoded multiple category exemplars in the contexts of an attention orienting mechanism…

  17. The Betrayal Aversion Elicitation Task: An Individual Level Betrayal Aversion Measure.

    Science.gov (United States)

    Aimone, Jason; Ball, Sheryl; King-Casas, Brooks

    2015-01-01

    Research on betrayal aversion shows that individuals' response to risk depends not only on probabilities and payoffs, but also on whether the risk includes a betrayal of trust. While previous studies focus on measuring aggregate levels of betrayal aversion, the connection between an individual's own betrayal aversion and other individually varying factors, including risk preferences, are currently unexplored. This paper develops a new task to elicit an individual's level of betrayal aversion that can then be compared to individual characteristics. We demonstrate the feasibility of our new task and show that our aggregate individual results are consistent with previous studies. We then use this classification to ask whether betrayal aversion is correlated with risk aversion. While we find risk aversion and betrayal aversion have no significant relationship, we do observe that risk aversion is correlated with non-social risk preferences, but not the social, betrayal related, risk component of the new task.

  18. Impact of perennial energy crops income variability on the crop selection of risk averse farmers

    International Nuclear Information System (INIS)

    Alexander, Peter; Moran, Dominic

    2013-01-01

    The UK Government policy is for the area of perennial energy crops in the UK to expand significantly. Farmers need to choose these crops in preference to conventional rotations for this to be achievable. This paper looks at the potential level and variability of perennial energy crop incomes and the relation to incomes from conventional arable crops. Assuming energy crop prices are correlated to oil prices the results suggests that incomes from them are not well correlated to conventional arable crop incomes. A farm scale mathematical programming model is then used to attempt to understand the affect on risk averse farmers crop selection. The inclusion of risk reduces the energy crop price required for the selection of these crops. However yields towards the highest of those predicted in the UK are still required to make them an optimal choice, suggesting only a small area of energy crops within the UK would be expected to be chosen to be grown. This must be regarded as a tentative conclusion, primarily due to high sensitivity found to crop yields, resulting in the proposal for further work to apply the model using spatially disaggregated data. - Highlights: ► Energy crop and conventional crop incomes suggested as uncorrelated. ► Diversification effect of energy crops investigated for a risk averse farmer. ► Energy crops indicated as optimal selection only on highest yielding UK sites. ► Large establishment grant rates to substantially alter crop selections.

  19. Interoceptive ability predicts aversion to losses.

    Science.gov (United States)

    Sokol-Hessner, Peter; Hartley, Catherine A; Hamilton, Jeffrey R; Phelps, Elizabeth A

    2015-01-01

    Emotions have been proposed to inform risky decision-making through the influence of affective physiological responses on subjective value. The ability to perceive internal body states, or "interoception" may influence this relationship. Here, we examined whether interoception predicts participants' degree of loss aversion, which has been previously linked to choice-related arousal responses. Participants performed both a heartbeat-detection task indexing interoception and a risky monetary decision-making task, from which loss aversion, risk attitudes and choice consistency were parametrically measured. Interoceptive ability correlated selectively with loss aversion and was unrelated to the other value parameters. This finding suggests that specific and separable component processes underlying valuation are shaped not only by our physiological responses, as shown in previous findings, but also by our interoceptive access to such signals.

  20. Diminished Neural Processing of Aversive and Rewarding Stimuli During Selective Serotonin Reuptake Inhibitor Treatment

    Science.gov (United States)

    McCabe, Ciara; Mishor, Zevic; Cowen, Philip J.; Harmer, Catherine J.

    2010-01-01

    Background Selective serotonin reuptake inhibitors (SSRIs) are popular medications for anxiety and depression, but their effectiveness, particularly in patients with prominent symptoms of loss of motivation and pleasure, has been questioned. There are few studies of the effect of SSRIs on neural reward mechanisms in humans. Methods We studied 45 healthy participants who were randomly allocated to receive the SSRI citalopram, the noradrenaline reuptake inhibitor reboxetine, or placebo for 7 days in a double-blind, parallel group design. We used functional magnetic resonance imaging to measure the neural response to rewarding (sight and/or flavor of chocolate) and aversive stimuli (sight of moldy strawberries and/or an unpleasant strawberry taste) on the final day of drug treatment. Results Citalopram reduced activation to the chocolate stimuli in the ventral striatum and the ventral medial/orbitofrontal cortex. In contrast, reboxetine did not suppress ventral striatal activity and in fact increased neural responses within medial orbitofrontal cortex to reward. Citalopram also decreased neural responses to the aversive stimuli conditions in key “punishment” areas such as the lateral orbitofrontal cortex. Reboxetine produced a similar, although weaker effect. Conclusions Our findings are the first to show that treatment with SSRIs can diminish the neural processing of both rewarding and aversive stimuli. The ability of SSRIs to decrease neural responses to reward might underlie the questioned efficacy of SSRIs in depressive conditions characterized by decreased motivation and anhedonia and could also account for the experience of emotional blunting described by some patients during SSRI treatment. PMID:20034615

  1. Alcohol-Aversion Therapy: Relation Between Strength of Aversion and Abstinence.

    Science.gov (United States)

    Cannon, Dale S.; And Others

    1986-01-01

    Assessed degree of alcohol aversion in 60 alcoholics who received emetic alcohol-aversion therapy. Results revealed changes in response to alcoholic, but not to nonalcoholic, flavors, including decreased consumption in taste tests, more negative flavor ratings, overt behavioral indicants of aversion and increased tachycardiac response. (Author/NB)

  2. How does economic risk aversion affect biodiversity?

    Science.gov (United States)

    Mouysset, L; Doyen, L; Jiguet, F

    2013-01-01

    Significant decline of biodiversity in farmlands has been reported for several decades. To limit the negative impact of agriculture, many agro-environmental schemes have been implemented, but their effectiveness remains controversial. In this context, the study of economic drivers is helpful to understand the role played by farming on biodiversity. The present paper analyzes the impact of risk aversion on farmland biodiversity. Here "risk aversion" means a cautious behavior of farmers facing uncertainty. We develop a bio-economic model that articulates bird community dynamics and representative farmers selecting land uses within an uncertain macro-economic context. It is specialized and calibrated at a regional scale for France through national databases. The influence of risk aversion is assessed on ecological, agricultural, and economic outputs through projections at the 2050 horizon. A high enough risk aversion appears sufficient to both manage economic risk and promote ecological performance. This occurs through a diversification mechanism on regional land uses. However, economic calibration leads to a weak risk-aversion parameter, which is consistent with the current decline of farmland birds. Spatial disparities however suggest that public incentives could be necessary to reinforce the diversification and bio-economic effectiveness.

  3. Task-selective memory effects for successfully implemented encoding strategies.

    Science.gov (United States)

    Leshikar, Eric D; Duarte, Audrey; Hertzog, Christopher

    2012-01-01

    Previous behavioral evidence suggests that instructed strategy use benefits associative memory formation in paired associate tasks. Two such effective encoding strategies--visual imagery and sentence generation--facilitate memory through the production of different types of mediators (e.g., mental images and sentences). Neuroimaging evidence suggests that regions of the brain support memory reflecting the mental operations engaged at the time of study. That work, however, has not taken into account self-reported encoding task success (i.e., whether participants successfully generated a mediator). It is unknown, therefore, whether task-selective memory effects specific to each strategy might be found when encoding strategies are successfully implemented. In this experiment, participants studied pairs of abstract nouns under either visual imagery or sentence generation encoding instructions. At the time of study, participants reported their success at generating a mediator. Outside of the scanner, participants further reported the quality of the generated mediator (e.g., images, sentences) for each word pair. We observed task-selective memory effects for visual imagery in the left middle occipital gyrus, the left precuneus, and the lingual gyrus. No such task-selective effects were observed for sentence generation. Intriguingly, activity at the time of study in the left precuneus was modulated by the self-reported quality (vividness) of the generated mental images with greater activity for trials given higher ratings of quality. These data suggest that regions of the brain support memory in accord with the encoding operations engaged at the time of study.

  4. Encoding negative events under stress: high subjective arousal is related to accurate emotional memory despite misinformation exposure.

    Science.gov (United States)

    Hoscheidt, Siobhan M; LaBar, Kevin S; Ryan, Lee; Jacobs, W Jake; Nadel, Lynn

    2014-07-01

    Stress at encoding affects memory processes, typically enhancing, or preserving, memory for emotional information. These effects have interesting implications for eyewitness accounts, which in real-world contexts typically involve encoding an aversive event under stressful conditions followed by potential exposure to misinformation. The present study investigated memory for a negative event encoded under stress and subsequent misinformation endorsement. Healthy young adults participated in a between-groups design with three experimental sessions conducted 48 h apart. Session one consisted of a psychosocial stress induction (or control task) followed by incidental encoding of a negative slideshow. During session two, participants were asked questions about the slideshow, during which a random subgroup was exposed to misinformation. Memory for the slideshow was tested during the third session. Assessment of memory accuracy across stress and no-stress groups revealed that stress induced just prior to encoding led to significantly better memory for the slideshow overall. The classic misinformation effect was also observed - participants exposed to misinformation were significantly more likely to endorse false information during memory testing. In the stress group, however, memory accuracy and misinformation effects were moderated by arousal experienced during encoding of the negative event. Misinformed-stress group participants who reported that the negative slideshow elicited high arousal during encoding were less likely to endorse misinformation for the most aversive phase of the story. Furthermore, these individuals showed better memory for components of the aversive slideshow phase that had been directly misinformed. Results from the current study provide evidence that stress and high subjective arousal elicited by a negative event act concomitantly during encoding to enhance emotional memory such that the most aversive aspects of the event are well remembered and

  5. Complexity and competition in appetitive and aversive neural circuits

    Directory of Open Access Journals (Sweden)

    Crista L. Barberini

    2012-11-01

    Full Text Available Decision-making often involves using sensory cues to predict possible rewarding or punishing reinforcement outcomes before selecting a course of action. Recent work has revealed complexity in how the brain learns to predict rewards and punishments. Analysis of neural signaling during and after learning in the amygdala and orbitofrontal cortex, two brain areas that process appetitive and aversive stimuli, reveals a dynamic relationship between appetitive and aversive circuits. Specifically, the relationship between signaling in appetitive and aversive circuits in these areas shifts as a function of learning. Furthermore, although appetitive and aversive circuits may often drive opposite behaviors – approaching or avoiding reinforcement depending upon its valence – these circuits can also drive similar behaviors, such as enhanced arousal or attention; these processes also may influence choice behavior. These data highlight the formidable challenges ahead in dissecting how appetitive and aversive neural circuits interact to produce a complex and nuanced range of behaviors.

  6. Task-selective memory effects for successfully implemented encoding strategies.

    Directory of Open Access Journals (Sweden)

    Eric D Leshikar

    Full Text Available Previous behavioral evidence suggests that instructed strategy use benefits associative memory formation in paired associate tasks. Two such effective encoding strategies--visual imagery and sentence generation--facilitate memory through the production of different types of mediators (e.g., mental images and sentences. Neuroimaging evidence suggests that regions of the brain support memory reflecting the mental operations engaged at the time of study. That work, however, has not taken into account self-reported encoding task success (i.e., whether participants successfully generated a mediator. It is unknown, therefore, whether task-selective memory effects specific to each strategy might be found when encoding strategies are successfully implemented. In this experiment, participants studied pairs of abstract nouns under either visual imagery or sentence generation encoding instructions. At the time of study, participants reported their success at generating a mediator. Outside of the scanner, participants further reported the quality of the generated mediator (e.g., images, sentences for each word pair. We observed task-selective memory effects for visual imagery in the left middle occipital gyrus, the left precuneus, and the lingual gyrus. No such task-selective effects were observed for sentence generation. Intriguingly, activity at the time of study in the left precuneus was modulated by the self-reported quality (vividness of the generated mental images with greater activity for trials given higher ratings of quality. These data suggest that regions of the brain support memory in accord with the encoding operations engaged at the time of study.

  7. Least-squares reverse time migration of marine data with frequency-selection encoding

    KAUST Repository

    Dai, Wei

    2013-06-24

    The phase-encoding technique can sometimes increase the efficiency of the least-squares reverse time migration (LSRTM) by more than one order of magnitude. However, traditional random encoding functions require all the encoded shots to share the same receiver locations, thus limiting the usage to seismic surveys with a fixed spread geometry. We implement a frequency-selection encoding strategy that accommodates data with a marine streamer geometry. The encoding functions are delta functions in the frequency domain, so that all the encoded shots have unique nonoverlapping frequency content, and the receivers can distinguish the wavefield from each shot with a unique frequency band. Because the encoding functions are orthogonal to each other, there will be no crosstalk between different shots during modeling and migration. With the frequency-selection encoding method, the computational efficiency of LSRTM is increased so that its cost is comparable to conventional RTM for the Marmousi2 model and a marine data set recorded in the Gulf of Mexico. With more iterations, the LSRTM image quality is further improved by suppressing migration artifacts, balancing reflector amplitudes, and enhancing the spatial resolution. We conclude that LSRTM with frequency-selection is an efficient migration method that can sometimes produce more focused images than conventional RTM. © 2013 Society of Exploration Geophysicists.

  8. Least-squares reverse time migration of marine data with frequency-selection encoding

    KAUST Repository

    Dai, Wei

    2013-08-20

    The phase-encoding technique can sometimes increase the efficiency of the least-squares reverse time migration (LSRTM) by more than one order of magnitude. However, traditional random encoding functions require all the encoded shots to share the same receiver locations, thus limiting the usage to seismic surveys with a fixed spread geometry. We implement a frequency-selection encoding strategy that accommodates data with a marine streamer geometry. The encoding functions are delta functions in the frequency domain, so that all the en- coded shots have unique non-overlapping frequency content, and the receivers can distinguish the wavefield from each shot with a unique frequency band. Since the encoding functions are orthogonal to each other, there will be no crosstalk between different shots during modeling and migration. With the frequency-selection encoding method, the computational efficiency of LSRTM is increased so that its cost is compara- ble to conventional RTM for both the Marmousi2 model and a marine data set recorded in the Gulf of Mexico. With more iterations, the LSRTM image quality is further improved. We conclude that LSRTM with frequency-selection is an efficient migration method that can sometimes produce more focused images than conventional RTM.

  9. Drugs and taste aversion

    International Nuclear Information System (INIS)

    Rondeau, D.B.; Jolicoeur, F.B.; Merkel, A.D.; Wayner, M.J.

    1981-01-01

    The literature on the effects of drugs on the acquisition and the magnitude of taste aversion is reviewed and discussed. Then, the results of a series of experiments on the effects of phenobarbital and related drugs on taste aversion are reported. A standard taste aversion model was used in all experiments; test drugs were injected prior to drinking in a one bottle situation on the first test day following the taste aversion treatment. Phenobarbital in doses ranging from 20 to 80 mg/kg significantly attenuated taste aversion induced by lithium chloride (LiCl) and x-radiation, the maximal effect occurred with the 60 mg/kg dose. The attenuating effect was found to be dependent upon the magnitude of the aversion to the sapid solution. Phenobarbital completely abolished aversion produced by 0.375 mEq LiCl while the attenuation effect decreased linearly with higher doses of LiCl. Results also indicate that phenobarbital's attenuating effect cannot be solely attributed to its dipsogenic characteristic or to its state dependent learning effect. Attenuation of LiCl aversion to a saccharin solution was also observed following single doses of amobarbital, 30 mg/kg, pentobarbital, 15 mg/kg, and chloropromazine, 0.75 mg/kg. Taste aversion was not affected by other doses of those drugs or by hexobarbital, barbital, and chlordiazepoxide. Phenobarbital's attenuating effect on taste aversion is discussed in relation to other known behavioral and neurophysiological effects of the drug

  10. Narp regulates long-term aversive effects of morphine withdrawal

    Science.gov (United States)

    Reti, Irving M.; Crombag, Hans S.; Takamiya, Kogo; Sutton, Jeffrey M.; Guo, Ning; Dinenna, Megan L.; Huganir, Richard L.; Holland, Peter C.; Baraban, Jay M.

    2008-01-01

    Although long-lasting effects of drug withdrawal are thought to play a key role in motivating continued drug use, the mechanisms mediating this type of drug-induced plasticity are unclear. As Narp is an immediate early gene product that is secreted at synaptic sites and binds to AMPA receptors, it has been implicated in mediating enduring forms of synaptic plasticity. In previous studies, we found that Narp is selectively induced by morphine withdrawal in the extended amygdala, a group of limbic nuclei that mediate aversive behavioral responses. Accordingly, in this study, we evaluated whether long-term aversive effects of morphine withdrawal are altered in Narp KO mice. We found that acute physical signs of morphine withdrawal are unaffected by Narp deletion. However, Narp KO mice acquire and sustain more aversive responses to the environment conditioned with morphine withdrawal than WT controls. Paradoxically, Narp KO mice undergo accelerated extinction of this heightened aversive response. Taken together, these studies suggest that Narp modulates both acquisition and extinction of aversive responses to morphine withdrawal and, therefore, may regulate plasticity processes underlying drug addiction. PMID:18729628

  11. Enhanced Risk Aversion, But Not Loss Aversion, in Unmedicated Pathological Anxiety.

    Science.gov (United States)

    Charpentier, Caroline J; Aylward, Jessica; Roiser, Jonathan P; Robinson, Oliver J

    2017-06-15

    Anxiety disorders are associated with disruptions in both emotional processing and decision making. As a result, anxious individuals often make decisions that favor harm avoidance. However, this bias could be driven by enhanced aversion to uncertainty about the decision outcome (e.g., risk) or aversion to negative outcomes (e.g., loss). Distinguishing between these possibilities may provide a better cognitive understanding of anxiety disorders and hence inform treatment strategies. To address this question, unmedicated individuals with pathological anxiety (n = 25) and matched healthy control subjects (n = 23) completed a gambling task featuring a decision between a gamble and a safe (certain) option on every trial. Choices on one type of gamble-involving weighing a potential win against a potential loss (mixed)-could be driven by both loss and risk aversion, whereas choices on the other type-featuring only wins (gain only)-were exclusively driven by risk aversion. By fitting a computational prospect theory model to participants' choices, we were able to reliably estimate risk and loss aversion and their respective contribution to gambling decisions. Relative to healthy control subjects, pathologically anxious participants exhibited enhanced risk aversion but equivalent levels of loss aversion. Individuals with pathological anxiety demonstrate clear avoidance biases in their decision making. These findings suggest that this may be driven by a reduced propensity to take risks rather than a stronger aversion to losses. This important clarification suggests that psychological interventions for anxiety should focus on reducing risk sensitivity rather than reducing sensitivity to negative outcomes per se. Copyright © 2017 Society of Biological Psychiatry. Published by Elsevier Inc. All rights reserved.

  12. Loss Aversion and Individual Characteristics

    DEFF Research Database (Denmark)

    Hjorth, Katrine; Fosgerau, Mogens

    2011-01-01

    Many studies have shown that loss aversion affects the valuation of non-market goods. Using stated choice data, this paper presents an empirical investigation of how individual-level loss aversion varies with observable personal characteristics and with the choice context. We investigate loss...... aversion with respect to travel time and money, and find significant loss aversion in both dimensions. The degree of loss aversion in the time dimension is larger than in the money dimension, and depends on age and education. Subjects tend to be more loss averse when the reference is well established....

  13. Dine or dash? Turbulence inhibits blue crab navigation in attractive-aversive odor plumes by altering signal structure encoded by the olfactory pathway.

    Science.gov (United States)

    Weissburg, Marc; Atkins, Lorin; Berkenkamp, Kimberly; Mankin, Danielle

    2012-12-01

    Blue crabs can distinguish and navigate to attractive (food) odors even when aversive odors (injured crab metabolites) are released nearby. Blue crabs in these conditions detect the aversive odor and avoid it, but find the attractive source with nearly the same success rate as when the attractive source is presented alone. Spatially and temporally distinct odor filaments appear to signal to foragers that the two odor sources are not co-located, and hence navigating to the attractive odor entails an acceptable risk of predation. However, environmentally produced turbulence suppresses tracking by homogenizing the two odors; blue crabs fail to track to the attractive source when the aversive source is present, even though turbulence does not substantially inhibit tracking to the attractive source alone. Removal of sensory input from aesthetascs on the antennules, but not chemosensors on the legs, rescues navigation to attractive-aversive dual plumes in turbulent conditions. These results suggest that mixing in the natural environment may amplify the effects of predators by suppressing tracking to food odors when aversive cues are present, and that the olfactory pathway mediates the response.

  14. Understanding Loan Aversion in Education

    Directory of Open Access Journals (Sweden)

    Angela Boatman

    2017-01-01

    Full Text Available Although prior research has suggested that some students may be averse to taking out loans to finance their college education, there is little empirical evidence showing the extent to which loan aversion exists or how it affects different populations of students. This study provides the first large-scale quantitative evidence of levels of loan aversion in the United States. Using survey data collected on more than 6,000 individuals, we examine the frequency of loan aversion in three distinct populations. Depending on the measure, between 20 and 40% of high school seniors exhibit loan aversion with lower rates among community college students and adults not in college. Women are less likely to express loan-averse attitudes than men, and Hispanic respondents are more likely to be loan averse than White respondents.

  15. Anticipation of high arousal aversive and positive movie clips engages common and distinct neural substrates.

    Science.gov (United States)

    Greenberg, Tsafrir; Carlson, Joshua M; Rubin, Denis; Cha, Jiook; Mujica-Parodi, Lilianne

    2015-04-01

    The neural correlates of anxious anticipation have been primarily studied with aversive and neutral stimuli. In this study, we examined the effect of valence on anticipation by using high arousal aversive and positive stimuli and a condition of uncertainty (i.e. either positive or aversive). The task consisted of predetermined cues warning participants of upcoming aversive, positive, 'uncertain' (either aversive or positive) and neutral movie clips. Anticipation of all affective clips engaged common regions including the anterior insula, dorsal anterior cingulate cortex, thalamus, caudate, inferior parietal and prefrontal cortex that are associated with emotional experience, sustained attention and appraisal. In contrast, the nucleus accumbens and medial prefrontal cortex, regions implicated in reward processing, were selectively engaged during anticipation of positive clips (depicting sexually explicit content) and the mid-insula, which has been linked to processing aversive stimuli, was selectively engaged during anticipation of aversive clips (depicting graphic medical procedures); these three areas were also activated during anticipation of 'uncertain' clips reflecting a broad preparatory response for both aversive and positive stimuli. These results suggest that a common circuitry is recruited in anticipation of affective clips regardless of valence, with additional areas preferentially engaged depending on whether expected stimuli are negative or positive. © The Author (2014). Published by Oxford University Press. For Permissions, please email: journals.permissions@oup.com.

  16. Economic decision biases and fundamental motivations: how mating and self-protection alter loss aversion.

    Science.gov (United States)

    Li, Yexin Jessica; Kenrick, Douglas T; Griskevicius, Vladas; Neuberg, Steven L

    2012-03-01

    Much research shows that people are loss averse, meaning that they weigh losses more heavily than gains. Drawing on an evolutionary perspective, we propose that although loss aversion might have been adaptive for solving challenges in the domain of self-protection, this may not be true for men in the domain of mating. Three experiments examine how loss aversion is influenced by mating and self-protection motives. Findings reveal that mating motives selectively erased loss aversion in men. In contrast, self-protective motives led both men and women to become more loss averse. Overall, loss aversion appears to be sensitive to evolutionarily important motives, suggesting that it may be a domain-specific bias operating according to an adaptive logic of recurring threats and opportunities in different evolutionary domains.

  17. The Role of Risk Aversion in Predicting Individual Behaviours

    OpenAIRE

    Guiso, Luigi; Paiella, Monica

    2004-01-01

    We use household survey data to construct a direct measure of absolute risk aversion based on the maximum price a consumer is willing to pay to buy a risky asset. We relate this measure to a set of consumers’ decisions that in theory should vary with attitude towards risk. We find that elicited risk aversion has considerable predictive power for a number of key household decisions such as choice of occupation, portfolio selection, moving decisions and exposure to chronic diseases in ways cons...

  18. The Role of Risk Aversion in Predicting Individual Behaviour

    OpenAIRE

    Monica Paiella; Luigi Guiso

    2004-01-01

    We use household survey data to construct a direct measure of absolute risk aversion based on the maximum price a consumer is willing to pay to buy a risky asset. We relate this measure to a set of consumers' decisions that in theory should vary with attitude towards risk. We find that elicited risk aversion has considerable predictive power for a number of key household decisions such as choice of occupation, portfolio selection, moving decisions and exposure to chronic diseases in ways cons...

  19. Pain and disgust: the facial signaling of two aversive bodily experiences.

    Directory of Open Access Journals (Sweden)

    Miriam Kunz

    Full Text Available The experience of pain and disgust share many similarities, given that both are aversive experiences resulting from bodily threat and leading to defensive reactions. The aim of the present study was to investigate whether facial expressions are distinct enough to encode the specific quality of pain and disgust or whether they just encode the similar negative valence and arousal level of both states. In sixty participants pain and disgust were induced by heat stimuli and pictures, respectively. Facial responses (Facial Action Coding System as well as subjective responses were assessed. Our main findings were that nearly the same single facial actions were elicited during pain and disgust experiences. However, these single facial actions were displayed with different strength and were differently combined depending on whether pain or disgust was experienced. Whereas pain was mostly encoded by contraction of the muscles surrounding the eyes (by itself or in combination with contraction of the eyebrows; disgust was mainly accompanied by contraction of the eyebrows and--in contrast to pain--by raising of the upper lip as well as the combination of upper lip raise and eyebrow contraction. Our data clearly suggests that facial expressions seem to be distinct enough to encode not only the general valence and arousal associated with these two bodily aversive experiences, namely pain and disgust, but also the specific origin of the threat to the body. This implies that the differential decoding of these two states by an observer is possible without additional verbal or contextual information, which is of special interest for clinical practice, given that raising awareness in observers about these distinct differences could help to improve the detection of pain in patients who are not able to provide a self-report of pain (e.g., patients with dementia.

  20. Loss Aversion in the Laboratory

    OpenAIRE

    Morrison, William G.; Oxoby, Robert J.

    2014-01-01

    We report the results of a laboratory experiment testing for the existence of loss aversion in a standard risk aversion protocol (Holt and Laury, 2002). In our experiment, participants earn and retain money for a week before using it in an incentivized risk preference elicitation task. We find loss aversion, distinct from risk aversion, has a significant effect on behavior resulting in participants requiring higher compensation to bear risk.

  1. Duration of inhibition of ventral tegmental area dopamine neurons encodes a level of conditioned fear.

    Science.gov (United States)

    Mileykovskiy, Boris; Morales, Marisela

    2011-05-18

    It is widely accepted that midbrain dopamine (DA) neurons encode actual and expected reward values by phasic alterations in firing rate. However, how DA neurons encode negative events in the environment is still unclear because some DA neurons appear to be depressed and others excited by aversive stimuli. Here, we show that exposing fear-conditioned rats to stimuli predicting electrical shock elicited three types of biphasic responses, each of which contained an inhibitory pause, in neurochemically identified ventral tegmental area (VTA) DA neurons. The duration of the inhibitory pause in these responses of VTA DA neurons was in direct proportion to the increase in respiratory rate reflecting the level of conditioned fear. Our results suggest that the duration of inhibition of VTA DA neurons encodes negative emotional values of signals predicting aversive events in the environment.

  2. THE ROLE OF RISK AVERSION IN PREDICTING INDIVIDUAL BEHAVIOR

    OpenAIRE

    Luigi Guiso; Monica Paiella

    2005-01-01

    We use household survey data to construct a direct measure of absolute risk aversion based on the maximum price a consumer is willing to pay to buy a risky asset. We relate this measure to a set of consumers� decisions that in theory should vary with attitude towards risk. We find that elicited risk aversion has considerable predictive power for a number of key household decisions such as choice of occupation, portfolio selection, moving decisions and exposure to chronic diseases in ways co...

  3. The importance of risk-aversion as a measurable psychological parameter governing risk-taking behaviour

    International Nuclear Information System (INIS)

    Thomas, P J

    2013-01-01

    A utility function with risk-aversion as its sole parameter is developed and used to examine the well-known psychological phenomenon, whereby risk averse people adopt behavioural strategies that are extreme and apparently highly risky. The pioneering work of the psychologist, John W. Atkinson, is revisited, and utility theory is used to extend his mathematical model. His explanation of the psychology involved is improved by regarding risk-aversion not as a discrete variable with three possible states: risk averse, risk neutral and risk confident, but as continuous and covering a large range. A probability distribution is derived, the m otivational density , to describe the process of selecting tasks of different degrees of difficulty. An assessment is then made of practicable methods for measuring risk-aversion

  4. The importance of risk-aversion as a measurable psychological parameter governing risk-taking behaviour

    Science.gov (United States)

    Thomas, P. J.

    2013-09-01

    A utility function with risk-aversion as its sole parameter is developed and used to examine the well-known psychological phenomenon, whereby risk averse people adopt behavioural strategies that are extreme and apparently highly risky. The pioneering work of the psychologist, John W. Atkinson, is revisited, and utility theory is used to extend his mathematical model. His explanation of the psychology involved is improved by regarding risk-aversion not as a discrete variable with three possible states: risk averse, risk neutral and risk confident, but as continuous and covering a large range. A probability distribution is derived, the "motivational density", to describe the process of selecting tasks of different degrees of difficulty. An assessment is then made of practicable methods for measuring risk-aversion.

  5. The ontogeny of ethanol aversion.

    Science.gov (United States)

    Saalfield, Jessica; Spear, Linda

    2016-03-15

    Recent work has suggested separate developmental periods within the broader framework of adolescence, with data suggesting distinct alterations and vulnerabilities within these intervals. While previous research has suggested reduced sensitivity to the aversive effects of alcohol in adolescence relative to adults, a more detailed ontogeny of this effect has yet to be conducted. The adolescent brain undergoes significant transitions throughout adolescence, including in regions linked with drug reward and aversion. The current study aimed to determine the ontogeny of ethanol aversion by utilizing a conditioned taste aversion procedure at six different ages to test the hypothesis that the transitions into, through, and out of adolescence are associated with ontogenetic alterations in sensitivity to the aversive properties of ethanol. Non-deprived animals given Boost® as the conditioned stimulus (CS) were used in Experiment 1, whereas Experiment 2 used water-restricted animals provided with a saccharin/sucrose solution as the CS. In both experiments, an attenuated sensitivity to the aversive properties of ethanol was evident in adolescents compared to adults, although more age differences were apparent in water deprived animals than when a highly palatable CS was given to ad libitum animals. Overall, the data suggest an attenuated sensitivity to the aversive properties of ethanol that is most pronounced during pre- and early adolescence, declining thereafter to reach the enhanced aversive sensitivity of adults. Copyright © 2016 Elsevier Inc. All rights reserved.

  6. Loss aversion in schizophrenia.

    Science.gov (United States)

    Trémeau, Fabien; Brady, Melissa; Saccente, Erica; Moreno, Alexis; Epstein, Henry; Citrome, Leslie; Malaspina, Dolores; Javitt, Daniel

    2008-08-01

    Loss aversion in decision-making refers to a higher sensitivity to losses than to gains. Loss aversion is conceived as an affective interference in cognitive processes such as judgment and decision-making. Loss aversion in non-risky choices has not been studied in schizophrenia. Forty-two individuals with schizophrenia and 42 non-patient control subjects, matched by gender and age, were randomized to two different scenarios (a buying scenario and a selling scenario). Subjects were asked to evaluate the price of a decorated mug. Schizophrenia subjects were re-tested four weeks later with the other scenario. Contrary to non-patient controls, schizophrenia subjects did not show loss aversion. In the schizophrenia group, absence of loss aversion was correlated with age, duration of illness, number of months in State hospitals, and poorer performance in the Wisconsin Card Sorting Test, but not with current psychopathology and two domains of emotional experience. Absence of loss aversion in schizophrenia represents a deficit in the processing of emotional information during decision-making. It can be interpreted as a lack of integration between the emotional and the cognitive systems, or to a more diffuse and de-differentiated impact of emotional information on decision-making. Future studies should bring more clarity to this question.

  7. An Index of Loss Aversion

    NARCIS (Netherlands)

    Köbberling, V.; Wakker, P.P.

    2005-01-01

    To a considerable extent, risk aversion as it is commonly observed is caused by loss aversion. Several indexes of loss aversion have been proposed in the literature. The one proposed in this paper leads to a clear decomposition of risk attitude into three distinct components: basic utility,

  8. An Index of Loss Aversion

    NARCIS (Netherlands)

    V. Köbberling (Veronika); P.P. Wakker (Peter)

    2005-01-01

    textabstractTo a considerable extent, risk aversion as it is commonly observed is caused by loss aversion. Several indexes of loss aversion have been proposed in the literature. The one proposed in this paper leads to a clear decomposition of risk attitude into three distinct components: basic

  9. How to make loss aversion disappear and reverse: tests of the decision by sampling origin of loss aversion.

    Science.gov (United States)

    Walasek, Lukasz; Stewart, Neil

    2015-02-01

    One of the most robust empirical findings in the behavioral sciences is loss aversion--the finding that losses loom larger than gains. We offer a new psychological explanation of the origins of loss aversion in which loss aversion emerges from differences in the distribution of gains and losses people experience. In 4 experiments, we tested this proposition by manipulating the range of gains and losses that individuals saw during the process of eliciting their loss aversion. We were able to find loss aversion, loss neutrality, and even the reverse of loss aversion.

  10. The role of risk aversion in non-conscious decision making.

    Science.gov (United States)

    Wang, Shuo; Krajbich, Ian; Adolphs, Ralph; Tsuchiya, Naotsugu

    2012-01-01

    To what extent can people choose advantageously without knowing why they are making those choices? This hotly debated question has capitalized on the Iowa Gambling Task (IGT), in which people often learn to choose advantageously without appearing to know why. However, because the IGT is unconstrained in many respects, this finding remains debated and other interpretations are possible (e.g., risk aversion, ambiguity aversion, limits of working memory, or insensitivity to reward/punishment can explain the finding of the IGT). Here we devised an improved variant of the IGT in which the deck-payoff contingency switches after subjects repeatedly choose from a good deck, offering the statistical power of repeated within-subject measures based on learning the reward contingencies associated with each deck. We found that participants exhibited low confidence in their choices, as probed with post-decision wagering, despite high accuracy in selecting advantageous decks in the task, which is putative evidence for non-conscious decision making. However, such a behavioral dissociation could also be explained by risk aversion, a tendency to avoid risky decisions under uncertainty. By explicitly measuring risk aversion for each individual, we predicted subjects' post-decision wagering using Bayesian modeling. We found that risk aversion indeed does play a role, but that it did not explain the entire effect. Moreover, independently measured risk aversion was uncorrelated with risk aversion exhibited during our version of the IGT, raising the possibility that the latter risk aversion may be non-conscious. Our findings support the idea that people can make optimal choices without being fully aware of the basis of their decision. We suggest that non-conscious decision making may be mediated by emotional feelings of risk that are based on mechanisms distinct from those that support cognitive assessment of risk.

  11. Role for the Rostromedial Tegmental Nucleus in Signaling the Aversive Properties of Alcohol.

    Science.gov (United States)

    Glover, Elizabeth J; McDougle, Molly J; Siegel, Griffin S; Jhou, Thomas C; Chandler, L Judson

    2016-08-01

    While the rewarding effects of alcohol contribute significantly to its addictive potential, it is becoming increasingly appreciated that alcohol's aversive properties also play an important role in the propensity to drink. Despite this, the neurobiological mechanism for alcohol's aversive actions is not well understood. The rostromedial tegmental nucleus (RMTg) was recently characterized for its involvement in aversive signaling and has been shown to encode the aversive properties of cocaine, yet its involvement in alcohol's aversive actions have not been elucidated. Adult male and female Long-Evans rats underwent conditioned taste aversion (CTA) procedures where exposure to a novel saccharin solution was paired with intraperitoneal administration of saline, lithium chloride (LiCl), or ethanol (EtOH). Control rats underwent the same paradigm except that drug and saccharin exposure were explicitly unpaired. Saccharin consumption was measured on test day in the absence of drug administration, and rats were sacrificed 90 to 105 minutes following access to saccharin. Brains were subsequently harvested and processed for cFos immunohistochemistry. The number of cFos-labeled neurons was counted in the RMTg and the lateral habenula (LHb)-a region that sends prominent glutamatergic input to the RMTg. In rats that received paired drug and saccharin exposure, EtOH and LiCl induced significant CTA compared to saline to a similar degree in males and females. Both EtOH- and LiCl-induced CTA significantly enhanced cFos expression in the RMTg and LHb but not the hippocampus. Similar to behavioral measures, no significant effect of sex on CTA-induced cFos expression was observed. cFos expression in both the RMTg and LHb was significantly correlated with CTA magnitude with greater cFos being associated with more pronounced CTA. In addition, cFos expression in the RMTg was positively correlated with LHb cFos. These data suggest that the RMTg and LHb are involved in the expression of

  12. Risk-Averse Evolutionary Game Model of Aviation Joint Emergency Response

    Directory of Open Access Journals (Sweden)

    Wei Pan

    2016-01-01

    Full Text Available We study effects of risk-averse attitude of both participators in aviation joint emergency response on the coevolution of cooperation mechanisms and individual preferences between airport and nonprofit organization. First, based on the current aviation joint emergency mechanism in China, we put forward two mechanisms to select the joint nonprofit organization, including reputation cooperation and bidding competition. Meanwhile, we consider two preferences including altruism and selfishness. Then we build replicator dynamics equations using the theory of conditional value-at-risk (CVaR taking risk aversion attitude into account. Finally, we introduce the factor of government and give all participators some suggestions. We show that the risk-averse attitude of the other game participator affects the one participator’s decision and the effects subject to some parameters.

  13. Myopic loss aversion revisited

    OpenAIRE

    Blavatskyy, Pavlo; Pogrebna, Ganna

    2009-01-01

    In this paper we reexamine several experimental papers on myopic loss aversion by analyzing individual rather than aggregate choice patterns. We find that the behavior of the majority of subjects is inconsistent with the hypothesis of myopic loss aversion.

  14. Linking Measured Risk Aversion to Individual Characteristics.

    NARCIS (Netherlands)

    Hartog, J.; Ferrer-i-Carbonell, A.; Jonker, N.

    2002-01-01

    From the stated price of a specified lottery in three unrelated surveys we deduce individuals' Arrow-Pratt measure of risk aversion. We find that risk aversion indeed falls with income and wealth. Entrepreneurs are less risk averse than employees, civil servants are more risk averse than private

  15. Optimal portfolio choice under loss aversion

    NARCIS (Netherlands)

    A.B. Berkelaar (Arjan); R.R.P. Kouwenberg (Roy)

    2000-01-01

    textabstractProspect theory and loss aversion play a dominant role in behavioral finance. In this paper we derive closed-form solutions for optimal portfolio choice under loss aversion. When confronted with gains a loss averse investor behaves similar to a portfolio insurer. When confronted with

  16. Colour Separation and Aversion

    Directory of Open Access Journals (Sweden)

    Sarah M Haigh

    2012-05-01

    Full Text Available Aversion to achromatic patterns is well documented but relatively little is known about discomfort from chromatic patterns. Large colour differences are uncommon in the natural environment and deviation from natural statistics makes images uncomfortable (Fernandez and Wilkins 2008, Perception, 37(7, 1098–113; Juricevic et al 2010, Perception, 39(7, 884–899. We report twelve studies documenting a linear increase in aversion to chromatic square-wave gratings as a function of the separation in UCS chromaticity between the component bars, independent of their luminance contrast. Two possible explanations for the aversion were investigated: (1 accommodative response, or (2 cortical metabolic demand. We found no correlation between chromaticity separation and accommodative lag or variance in lag, measured using an open-field autorefractor. However, near infrared spectroscopy of the occipital cortex revealed a larger oxyhaemoglobin response to patterns with large chromaticity separation. The aversion may be cortical in origin and does not appear to be due to accommodation.

  17. Mathematical Modeling for Risk Averse Firm Facing Loss Averse Customer’s Stochastic Uncertainty

    Directory of Open Access Journals (Sweden)

    Seungbeom Kim

    2017-01-01

    Full Text Available To optimize the firm’s profit during a finite planning horizon, a dynamic programming model is used to make joint pricing and inventory replenishment decision assuming that customers are loss averse and the firm is risk averse. We model the loss averse customer’s demand using the multinomial choice model. In this choice model, we consider the acquisition and transition utilities widely used by a mental accounting theory which also incorporate the reference price and actual price. Then, we show that there is an optimal inventory policy which is base-stock policy depending on the accumulated wealth in each period.

  18. Visual Aversive Learning Compromises Sensory Discrimination.

    Science.gov (United States)

    Shalev, Lee; Paz, Rony; Avidan, Galia

    2018-03-14

    Aversive learning is thought to modulate perceptual thresholds, which can lead to overgeneralization. However, it remains undetermined whether this modulation is domain specific or a general effect. Moreover, despite the unique role of the visual modality in human perception, it is unclear whether this aspect of aversive learning exists in this modality. The current study was designed to examine the effect of visual aversive outcomes on the perception of basic visual and auditory features. We tested the ability of healthy participants, both males and females, to discriminate between neutral stimuli, before and after visual learning. In each experiment, neutral stimuli were associated with aversive images in an experimental group and with neutral images in a control group. Participants demonstrated a deterioration in discrimination (higher discrimination thresholds) only after aversive learning. This deterioration was measured for both auditory (tone frequency) and visual (orientation and contrast) features. The effect was replicated in five different experiments and lasted for at least 24 h. fMRI neural responses and pupil size were also measured during learning. We showed an increase in neural activations in the anterior cingulate cortex, insula, and amygdala during aversive compared with neutral learning. Interestingly, the early visual cortex showed increased brain activity during aversive compared with neutral context trials, with identical visual information. Our findings imply the existence of a central multimodal mechanism, which modulates early perceptual properties, following exposure to negative situations. Such a mechanism could contribute to abnormal responses that underlie anxiety states, even in new and safe environments. SIGNIFICANCE STATEMENT Using a visual aversive-learning paradigm, we found deteriorated discrimination abilities for visual and auditory stimuli that were associated with visual aversive stimuli. We showed increased neural

  19. The effect of accountability on loss aversion.

    Science.gov (United States)

    Vieider, Ferdinand M

    2009-09-01

    This paper investigates the effect of accountability-the expectation on the side of the decision maker of having to justify his/her decisions to somebody else-on loss aversion. Loss aversion is commonly thought to be the strongest component of risk aversion. Accountability is found to reduce the bias of loss aversion. This effect is explained by the higher cognitive effort induced by accountability, which triggers a rational check on emotional reactions at the base of loss aversion, leading to a reduction of the latter. Connections to dual-processing models are discussed.

  20. Peer effects in risk aversion.

    Science.gov (United States)

    Balsa, Ana I; Gandelman, Néstor; González, Nicolás

    2015-01-01

    We estimate peer effects in risk attitudes in a sample of high school students. Relative risk aversion is elicited from surveys administered at school. Identification of peer effects is based on parents not being able to choose the class within the school of their choice, and on the use of instrumental variables conditional on school-grade fixed effects. We find a significant and quantitatively large impact of peers' risk attitudes on a male individual's coefficient of risk aversion. Specifically, a one standard deviation increase in the group's coefficient of risk aversion increases an individual's risk aversion by 43%. Our findings shed light on the origin and stability of risk attitudes and, more generally, on the determinants of economic preferences. © 2014 Society for Risk Analysis.

  1. Rewarding and aversive effects of nicotine are segregated within the nucleus accumbens.

    Science.gov (United States)

    Sellings, Laurie H L; Baharnouri, Golriz; McQuade, Lindsey E; Clarke, Paul B S

    2008-07-01

    Forebrain dopamine plays a critical role in motivated behavior. According to the classic view, mesolimbic dopamine selectively guides behavior motivated by positive reinforcers. However, this has been challenged in favor of a wider role encompassing aversively motivated behavior. This controversy is particularly striking in the case of nicotine, with opposing claims that either the rewarding or the aversive effect of nicotine is critically dependent on mesolimbic dopamine transmission. In the present study, the effects of 6-hydroxydopamine lesions of nucleus accumbens core vs. medial shell on intravenous nicotine conditioned place preference and conditioned taste aversion were examined in male adult rats. Dopaminergic denervation in accumbens medial shell was associated with decreased nicotine conditioned place preference. Conversely, denervation in accumbens core was associated with an increase in conditioned place preference. In addition, dopaminergic denervation of accumbens core but not medial shell abolished conditioned taste aversion for nicotine. We conclude that nucleus accumbens core and medial shell dopaminergic innervation exert segregated effects on rewarding and aversive effects of nicotine. More generally, our findings indicate that dopaminergic transmission may mediate or enable opposing motivational processes within functionally distinct domains of the accumbens.

  2. Risk Aversion and Job Mobility

    OpenAIRE

    van Huizen, T.M.; Alessie, Rob

    2016-01-01

    Job mobility is inherently risky as workers have limited ex ante information about the quality of outside jobs. Using a large longitudinal Dutch dataset, which includes data on risk preferences elicited through (incentivized) experiments, we examine the relation between risk aversion and job mobility. The results for men show that risk averse workers are less likely to move to other jobs. For women, the evidence that risk aversion affects job mobility is weak. Our empirical findings indicate ...

  3. The Role of Executive Control of Attention and Selective Encoding for Preschoolers' Learning

    Science.gov (United States)

    Roderer, Thomas; Krebs, Saskia; Schmid, Corinne; Roebers, Claudia M.

    2012-01-01

    Selectivity in encoding, aspects of attentional control and their contribution to learning performance were explored in a sample of preschoolers. While the children are performing a learning task, their encoding of relevant and attention towards irrelevant information was recorded through an eye-tracking device. Recognition of target items was…

  4. Incidental fear cues increase monetary loss aversion.

    Science.gov (United States)

    Schulreich, Stefan; Gerhardt, Holger; Heekeren, Hauke R

    2016-04-01

    In many everyday decisions, people exhibit loss aversion-a greater sensitivity to losses relative to gains of equal size. Loss aversion is thought to be (at least partly) mediated by emotional--in particular, fear-related--processes. Decision research has shown that even incidental emotions, which are unrelated to the decision at hand, can influence decision making. The effect of incidental fear on loss aversion, however, is thus far unclear. In two studies, we experimentally investigated how incidental fear cues, presented during (Study 1) or before (Study 2) choices to accept or reject mixed gambles over real monetary stakes, influence monetary loss aversion. We find that the presentation of fearful faces, relative to the presentation of neutral faces, increased risk aversion-an effect that could be attributed to increased loss aversion. The size of this effect was moderated by psychopathic personality: Fearless dominance, in particular its interpersonal facet, but not self-centered impulsivity, attenuated the effect of incidental fear cues on loss aversion, consistent with reduced fear reactivity. Together, these results highlight the sensitivity of loss aversion to the affective context. (c) 2016 APA, all rights reserved).

  5. Unpleasant odors increase aversion to monetary losses.

    Science.gov (United States)

    Stancak, Andrej; Xie, Yuxin; Fallon, Nicholas; Bulsing, Patricia; Giesbrecht, Timo; Thomas, Anna; Pantelous, Athanasios A

    2015-04-01

    Loss aversion is the tendency to prefer avoiding losses over acquiring gains of equal nominal values. Unpleasant odors not only influence affective state but have also been shown to activate brain regions similar to those mediating loss aversion. Therefore, we hypothesized a stronger loss aversion in a monetary gamble task if gambles were associated with an unpleasant as opposed to pleasant odor. In thirty human subjects, unpleasant (methylmercaptan), pleasant (jasmine), and neutral (clean air) odors were presented for 4 s. At the same time, uncertain gambles offering an equal chance of gain or loss of a variable amount of money, or a prospect of an assured win were displayed. One hundred different gambles were presented three times, each time paired with a different odor. Loss aversion, risk aversion, and logit sensitivity were evaluated using non-linear fitting of individual gamble decisions. Loss aversion was larger when prospects were displayed in the presence of methylmercaptan compared to jasmine or clean air. Moreover, individual differences in changes in loss aversion to the unpleasant as compared to pleasant odor correlated with odor pleasantness but not with odor intensity. Skin conductance responses to losses during the outcome period were larger when gambles were associated with methylmercaptan compared to jasmine. Increased loss aversion while perceiving an unpleasant odor suggests a dynamic adjustment of loss aversion toward greater sensitivity to losses. Given that odors are biological signals of hazards, such adjustment of loss aversion may have adaptive value in situations entailing threat or danger. Copyright © 2015 Elsevier B.V. All rights reserved.

  6. Effects of pharmacological manipulation of the kappa opioid receptors on the aversive effects of nicotine.

    Science.gov (United States)

    Ward, Melissa; Norman, Haval; D'Souza, Manoranjan S

    2018-02-15

    Nicotine, an addictive component of tobacco smoke, produces both rewarding and aversive effects. Increasing the aversive effects of nicotine may help in promoting smoking cessation. However, neural targets mediating the aversive effects of nicotine have not been fully identified. In this study, we evaluated the role of kappa opioid receptors (KORs) in the aversive effects of nicotine (0.4 mg/kg, base; s.c.) using the nicotine-induced conditioned taste aversion (CTA) model in Wistar rats. The KORs were activated using the selective KOR agonist (±)U-50,488H (0, 0.03, 0.15 & 0.3mg/kg; s.c.) and inhibited using the KOR antagonist nor-binaltorphimine (nor-BNI; 0, 15 & 30mg/kg; s.c.) in separate groups of rats using a between-subjects design. Pretreatment with the KOR agonist (±)U-50,488H (0.3mg/kg) significantly increased aversion for the nicotine-associated solution. Additionally, (±)U-50,488H (0.3mg/kg) on its own induced aversion to the flavored solution associated with it even in the absence of nicotine, suggesting that the KOR agonist induced increase in nicotine-induced aversion was an additive effect. Interestingly, administration of the KOR antagonist nor-BNI (30mg/kg) prior to conditioning with nicotine/saline, but not after conditioning with nicotine/saline, attenuated nicotine-induced aversive effects compared to saline controls. Taken together, these data suggest a role for KORs in the aversive effects of nicotine. Copyright © 2017 Elsevier B.V. All rights reserved.

  7. Overcoming Learning Aversion in Evaluating and Managing Uncertain Risks.

    Science.gov (United States)

    Cox, Louis Anthony Tony

    2015-10-01

    Decision biases can distort cost-benefit evaluations of uncertain risks, leading to risk management policy decisions with predictably high retrospective regret. We argue that well-documented decision biases encourage learning aversion, or predictably suboptimal learning and premature decision making in the face of high uncertainty about the costs, risks, and benefits of proposed changes. Biases such as narrow framing, overconfidence, confirmation bias, optimism bias, ambiguity aversion, and hyperbolic discounting of the immediate costs and delayed benefits of learning, contribute to deficient individual and group learning, avoidance of information seeking, underestimation of the value of further information, and hence needlessly inaccurate risk-cost-benefit estimates and suboptimal risk management decisions. In practice, such biases can create predictable regret in selection of potential risk-reducing regulations. Low-regret learning strategies based on computational reinforcement learning models can potentially overcome some of these suboptimal decision processes by replacing aversion to uncertain probabilities with actions calculated to balance exploration (deliberate experimentation and uncertainty reduction) and exploitation (taking actions to maximize the sum of expected immediate reward, expected discounted future reward, and value of information). We discuss the proposed framework for understanding and overcoming learning aversion and for implementing low-regret learning strategies using regulation of air pollutants with uncertain health effects as an example. © 2015 Society for Risk Analysis.

  8. Inequity aversion and the evolution of cooperation

    Science.gov (United States)

    Ahmed, Asrar; Karlapalem, Kamalakar

    2014-02-01

    Evolution of cooperation is a widely studied problem in biology, social science, economics, and artificial intelligence. Most of the existing approaches that explain cooperation rely on some notion of direct or indirect reciprocity. These reciprocity based models assume agents recognize their partner and know their previous interactions, which requires advanced cognitive abilities. In this paper we are interested in developing a model that produces cooperation without requiring any explicit memory of previous game plays. Our model is based on the notion of inequity aversion, a concept introduced within behavioral economics, whereby individuals care about payoff equality in outcomes. Here we explore the effect of using income inequality to guide partner selection and interaction. We study our model by considering both the well-mixed and the spatially structured population and present the conditions under which cooperation becomes dominant. Our results support the hypothesis that inequity aversion promotes cooperative relationship among nonkin.

  9. Aversive racism in Spain: testing the theory

    NARCIS (Netherlands)

    Wojcieszak, M.

    2015-01-01

    This study applies the aversive racism framework to Spain and tests whether aversive racism depends on intergroup contact. Relying on a 3 (qualifications) by 3 (ethnicity) experiment, this study finds that aversive racism is especially pronounced against the Mexican job applicant, and emerges among

  10. Suboptimal nutrient balancing despite dietary choice in glucose-averse German cockroaches, Blattella germanica.

    Science.gov (United States)

    Jensen, Kim; Schal, Coby; Silverman, Jules

    2015-10-01

    Insects have evolved fine-tuned gustatory and post-ingestive physiological mechanisms that enable them to self-select an optimal composition of macronutrients. Their ability to forage optimally among multiple food sources and maximize fitness parameters depends on their ability not only to taste and perceive the nutritional value of potential foods but also to avoid deleterious components; the strength of such avoidance should reflect the severity of the perceived hazard. In German cockroaches (Blattella germanica), glucose aversion has evolved in some populations in response to anthropogenic selection with glucose-containing insecticidal baits. In four feeding treatments, we gave newly eclosed glucose-averse female cockroaches free choice to feed from two artificial, nutritionally complementary foods varying in protein and carbohydrate composition, with glucose or fructose as the sole carbohydrate source in either food. After 6days of feeding, we measured diet consumption and the length of basal oocytes as an estimate of sexual maturation. The females did not compromise on their aversion to glucose in order to balance their protein and carbohydrate intake, and experienced lower sexual maturation rates as a consequence. Nutrient specific hunger via feedback mechanisms, and adjustments to gustatory sensitivity thus do not override the deterrence of glucose, likely due to strong selection against ingesting even small amounts of toxin associated with glucose in baits. In the absence of baits, glucose aversion would be expected to incur a fitness cost compared to wild-type individuals due to lower overall food availability but also to larger difficulty in attaining a nutritionally balanced diet. Copyright © 2015 Elsevier Ltd. All rights reserved.

  11. Alcohol reduces aversion to ambiguity

    Directory of Open Access Journals (Sweden)

    Tadeusz eTyszka

    2015-01-01

    Full Text Available Several years ago, Cohen, Dearnaley, and Hansel [1] demonstrated that under the influence of alcohol drivers became more risk prone, although their risk perception remained unchanged. Research shows that ambiguity aversion is to some extent positively correlated with risk aversion, though not very highly [2]. The question addressed by the present research is whether alcohol reduces ambiguity aversion. Our research was conducted in a natural setting (a restaurant bar, where customers with differing levels of alcohol intoxication were offered a choice between a risky and an ambiguous lottery. We found that alcohol reduced ambiguity aversion and that the effect occurred in men but not women. We interpret these findings in terms of the risk-as-value hypothesis, according to which, people in Western culture tend to value risk, and suggest that alcohol consumption triggers adherence to socially and culturally valued patterns of conduct different for men and women.

  12. Alcohol reduces aversion to ambiguity.

    Science.gov (United States)

    Tyszka, Tadeusz; Macko, Anna; Stańczak, Maciej

    2014-01-01

    Several years ago, Cohen et al. (1958) demonstrated that under the influence of alcohol drivers became more risk prone, although their risk perception remained unchanged. Research shows that ambiguity aversion is to some extent positively correlated with risk aversion, though not very highly (Camerer and Weber, 1992). The question addressed by the present research is whether alcohol reduces ambiguity aversion. Our research was conducted in a natural setting (a restaurant bar), where customers with differing levels of alcohol intoxication were offered a choice between a risky and an ambiguous lottery. We found that alcohol reduced ambiguity aversion and that the effect occurred in men but not women. We interpret these findings in terms of the risk-as-value hypothesis, according to which, people in Western culture tend to value risk, and suggest that alcohol consumption triggers adherence to socially and culturally valued patterns of conduct different for men and women.

  13. Small Stakes Risk Aversion in the Laboratory

    DEFF Research Database (Denmark)

    Harrison, Glenn W.; Lau, Morten I.; Ross, Don

    2017-01-01

    Evidence of risk aversion in laboratory settings over small stakes leads to a priori implausible levels of risk aversion over large stakes under certain assumptions. One core assumption in statements of this calibration puzzle is that small-stakes risk aversion is observed over all levels of wealth...

  14. Quantization selection in the high-throughput H.264/AVC encoder based on the RD

    Science.gov (United States)

    Pastuszak, Grzegorz

    2013-10-01

    In the hardware video encoder, the quantization is responsible for quality losses. On the other hand, it allows the reduction of bit rates to the target one. If the mode selection is based on the rate-distortion criterion, the quantization can also be adjusted to obtain better compression efficiency. Particularly, the use of Lagrangian function with a given multiplier enables the encoder to select the most suitable quantization step determined by the quantization parameter QP. Moreover, the quantization offset added before discarding the fraction value after quantization can be adjusted. In order to select the best quantization parameter and offset in real time, the HD/SD encoder should be implemented in the hardware. In particular, the hardware architecture should embed the transformation and quantization modules able to process the same residuals many times. In this work, such an architecture is used. Experimental results show what improvements in terms of compression efficiency are achievable for Intra coding.

  15. Assessing appetitive, aversive, and negative ethanol-mediated reinforcement through an immature rat model.

    Science.gov (United States)

    Pautassi, Ricardo M; Nizhnikov, Michael E; Spear, Norman E

    2009-06-01

    The motivational effects of drugs play a key role during the transition from casual use to abuse and dependence. Ethanol reinforcement has been successfully studied through Pavlovian and operant conditioning in adult rats and mice genetically selected for their ready acceptance of ethanol. Another model for studying ethanol reinforcement is the immature (preweanling) rat, which consumes ethanol and exhibits the capacity to process tactile, odor and taste cues and transfer information between different sensorial modalities. This review describes the motivational effects of ethanol in preweanling, heterogeneous non-selected rats. Preweanlings exhibit ethanol-mediated conditioned taste avoidance and conditioned place aversion. Ethanol's appetitive effects, however, are evident when using first- and second-order conditioning and operant procedures. Ethanol also devalues the motivational representation of aversive stimuli, suggesting early negative reinforcement. It seems that preweanlings are highly sensitive not only to the aversive motivational effects of ethanol but also to its positive and negative (anti-anxiety) reinforcement potential. The review underscores the advantages of using a developing rat to evaluate alcohol's motivational effects.

  16. Risk aversion and social networks

    NARCIS (Netherlands)

    Kovářík, J.; van der Leij, M.J.

    2014-01-01

    This paper first investigates empirically the relationship between risk aversion and social network structure in a large group of undergraduate students. We find that risk aversion is strongly correlated to local network clustering, that is, the probability that one has a social tie to friends of

  17. Loss aversion and rent-seeking: An experimental study

    OpenAIRE

    Kong, Xiaojing

    2008-01-01

    We report an experiment designed to evaluate the impact of loss aversion on rent-seeking contests. We find, as theoretically predicted, a negative relationship between rent-seeking expenditures and loss aversion. However, for any degree of loss aversion, levels of rent-seeking expenditure are higher than predicted. Moreover, we find that the effect of loss aversion becomes weaker with repetition of the contest.

  18. Interactions between radiation and amphetamine in taste aversion learning and the role of the area postrema in amphetamine-induced conditioned taste aversions

    International Nuclear Information System (INIS)

    Rabin, B.M.; Hunt, W.A.; Lee, J.

    1987-01-01

    Three experiments were run to assess the role of the area postrema in taste aversion learning resulting from combined treatment with subthreshold unconditioned stimuli and in the acquisition of an amphetamine-induced taste aversion. In the first experiment, it was shown that combined treatment with subthreshold radiation (15 rad) and subthreshold amphetamine (0.5 mg/kg, IP) resulted in the acquisition of a taste aversion. The second experiment showed that lesions of the area postrema blocked taste aversion learning produced by two subthreshold doses of amphetamine. In the third experiment, which looked at the dose-response curve for amphetamine-induced taste aversion learning in intact rats and rats with area postrema lesions, it was shown that both groups of rats acquired taste aversions following injection of amphetamine, although the rats with lesions showed a less severe aversion than the intact rats. The results are interpreted as indicating that amphetamine-induced taste aversion learning may involve area postrema-mediated mechanisms, particularly at the lower doses, but that an intact area postrema is not a necessary condition for the acquisition of an amphetamine-induced taste aversion

  19. Social influences on inequity aversion in children.

    Directory of Open Access Journals (Sweden)

    Katherine McAuliffe

    Full Text Available Adults and children are willing to sacrifice personal gain to avoid both disadvantageous and advantageous inequity. These two forms of inequity aversion follow different developmental trajectories, with disadvantageous inequity aversion emerging around 4 years and advantageous inequity aversion emerging around 8 years. Although inequity aversion is assumed to be specific to situations where resources are distributed among individuals, the role of social context has not been tested in children. Here, we investigated the influence of two aspects of social context on inequity aversion in 4- to 9-year-old children: (1 the role of the experimenter distributing rewards and (2 the presence of a peer with whom rewards could be shared. Experiment 1 showed that children rejected inequity at the same rate, regardless of whether the experimenter had control over reward allocations. This indicates that children's decisions are based upon reward allocations between themselves and a peer and are not attempts to elicit more favorable distributions from the experimenter. Experiment 2 compared rejections of unequal reward allocations in children interacting with or without a peer partner. When faced with a disadvantageous distribution, children frequently rejected a smaller reward when a larger reward was visible, even if no partner would obtain the larger reward. This suggests that nonsocial factors partly explain disadvantageous inequity rejections. However, rejections of disadvantageous distributions were higher when the larger amount would go to a peer, indicating that social context enhances disadvantageous inequity aversion. By contrast, children rejected advantageous distributions almost exclusively in the social context. Therefore, advantageous inequity aversion appears to be genuinely social, highlighting its potential relevance for the development of fairness concerns. By comparing social and nonsocial factors, this study provides a detailed picture of

  20. Excitation of lateral habenula neurons as a neural mechanism underlying ethanol-induced conditioned taste aversion.

    Science.gov (United States)

    Tandon, Shashank; Keefe, Kristen A; Taha, Sharif A

    2017-02-15

    The lateral habenula (LHb) has been implicated in regulation of drug-seeking behaviours through aversion-mediated learning. In this study, we recorded neuronal activity in the LHb of rats during an operant task before and after ethanol-induced conditioned taste aversion (CTA) to saccharin. Ethanol-induced CTA caused significantly higher baseline firing rates in LHb neurons, as well as elevated firing rates in response to cue presentation, lever press and saccharin taste. In a separate cohort of rats, we found that bilateral LHb lesions blocked ethanol-induced CTA. Our results strongly suggest that excitation of LHb neurons is required for ethanol-induced CTA, and point towards a mechanism through which LHb firing may regulate voluntary ethanol consumption. Ethanol, like other drugs of abuse, has both rewarding and aversive properties. Previous work suggests that sensitivity to ethanol's aversive effects negatively modulates voluntary alcohol intake and thus may be important in vulnerability to developing alcohol use disorders. We previously found that rats with lesions of the lateral habenula (LHb), which is implicated in aversion-mediated learning, show accelerated escalation of voluntary ethanol consumption. To understand neural encoding in the LHb contributing to ethanol-induced aversion, we recorded neural firing in the LHb of freely behaving, water-deprived rats before and after an ethanol-induced (1.5 g kg -1 20% ethanol, i.p.) conditioned taste aversion (CTA) to saccharin taste. Ethanol-induced CTA strongly decreased motivation for saccharin in an operant task to obtain the tastant. Comparison of LHb neural firing before and after CTA induction revealed four main differences in firing properties. First, baseline firing after CTA induction was significantly higher. Second, firing evoked by cues signalling saccharin availability shifted from a pattern of primarily inhibition before CTA to primarily excitation after CTA induction. Third, CTA induction reduced

  1. The Neural Basis of Aversive Pavlovian Guidance during Planning.

    Science.gov (United States)

    Lally, Níall; Huys, Quentin J M; Eshel, Neir; Faulkner, Paul; Dayan, Peter; Roiser, Jonathan P

    2017-10-18

    Important real-world decisions are often arduous as they frequently involve sequences of choices, with initial selections affecting future options. Evaluating every possible combination of choices is computationally intractable, particularly for longer multistep decisions. Therefore, humans frequently use heuristics to reduce the complexity of decisions. We recently used a goal-directed planning task to demonstrate the profound behavioral influence and ubiquity of one such shortcut, namely aversive pruning, a reflexive Pavlovian process that involves neglecting parts of the decision space residing beyond salient negative outcomes. However, how the brain implements this important decision heuristic and what underlies individual differences have hitherto remained unanswered. Therefore, we administered an adapted version of the same planning task to healthy male and female volunteers undergoing functional magnetic resonance imaging (fMRI) to determine the neural basis of aversive pruning. Through both computational and standard categorical fMRI analyses, we show that when planning was influenced by aversive pruning, the subgenual cingulate cortex was robustly recruited. This neural signature was distinct from those associated with general planning and valuation, two fundamental cognitive components elicited by our task but which are complementary to aversive pruning. Furthermore, we found that individual variation in levels of aversive pruning was associated with the responses of insula and dorsolateral prefrontal cortices to the receipt of large monetary losses, and also with subclinical levels of anxiety. In summary, our data reveal the neural signatures of an important reflexive Pavlovian process that shapes goal-directed evaluations and thereby determines the outcome of high-level sequential cognitive processes. SIGNIFICANCE STATEMENT Multistep decisions are complex because initial choices constrain future options. Evaluating every path for long decision sequences

  2. The Neural Basis of Aversive Pavlovian Guidance during Planning

    Science.gov (United States)

    Faulkner, Paul

    2017-01-01

    Important real-world decisions are often arduous as they frequently involve sequences of choices, with initial selections affecting future options. Evaluating every possible combination of choices is computationally intractable, particularly for longer multistep decisions. Therefore, humans frequently use heuristics to reduce the complexity of decisions. We recently used a goal-directed planning task to demonstrate the profound behavioral influence and ubiquity of one such shortcut, namely aversive pruning, a reflexive Pavlovian process that involves neglecting parts of the decision space residing beyond salient negative outcomes. However, how the brain implements this important decision heuristic and what underlies individual differences have hitherto remained unanswered. Therefore, we administered an adapted version of the same planning task to healthy male and female volunteers undergoing functional magnetic resonance imaging (fMRI) to determine the neural basis of aversive pruning. Through both computational and standard categorical fMRI analyses, we show that when planning was influenced by aversive pruning, the subgenual cingulate cortex was robustly recruited. This neural signature was distinct from those associated with general planning and valuation, two fundamental cognitive components elicited by our task but which are complementary to aversive pruning. Furthermore, we found that individual variation in levels of aversive pruning was associated with the responses of insula and dorsolateral prefrontal cortices to the receipt of large monetary losses, and also with subclinical levels of anxiety. In summary, our data reveal the neural signatures of an important reflexive Pavlovian process that shapes goal-directed evaluations and thereby determines the outcome of high-level sequential cognitive processes. SIGNIFICANCE STATEMENT Multistep decisions are complex because initial choices constrain future options. Evaluating every path for long decision sequences

  3. Heterogeneity of Loss Aversion in Pathological Gambling.

    Science.gov (United States)

    Takeuchi, Hideaki; Kawada, Ryosaku; Tsurumi, Kosuke; Yokoyama, Naoto; Takemura, Ariyoshi; Murao, Takuro; Murai, Toshiya; Takahashi, Hidehiko

    2016-12-01

    Pathological gambling (PG) is characterized by continual repeated gambling behavior despite negative consequences. PG is considered to be a disorder of altered decision-making under risk, and behavioral economics tools were utilized by studies on decision-making under risk. At the same time, PG was suggested to be a heterogeneous disorder in terms of personality traits as well as risk attitude. We aimed to examine the heterogeneity of PG in terms of loss aversion, which means that a loss is subjectively felt to be larger than the same amount of gain. Thirty-one male PG subjects and 26 male healthy control (HC) subjects underwent a behavioral economics task for estimation of loss aversion and personality traits assessment. Although loss aversion in PG subjects was not significantly different from that in HC subjects, distributions of loss aversion differed between PG and HC subjects. HC subjects were uniformly classified into three levels (low, middle, high) of loss aversion, whereas PG subjects were mostly classified into the two extremes, and few PG subjects were classified into the middle range. PG subjects with low and high loss aversion showed a significant difference in anxiety, excitement-seeking and craving intensity. Our study suggested that PG was a heterogeneous disorder in terms of loss aversion. This result might be useful for understanding cognitive and neurobiological mechanisms and the establishment of treatment strategies for PG.

  4. On the descriptive value of loss aversion in decisions under risk: Six clarifications

    Directory of Open Access Journals (Sweden)

    Eyal Ert

    2013-05-01

    Full Text Available Previous studies of loss aversion in decisions under risk have led to mixed results. Losses appear to loom larger than gains in some settings, but not in others. The current paper clarifies these results by highlighting six experimental manipulations that tend to increase the likelihood of the behavior predicted by loss aversion. These manipulations include: (1 framing of the safe alternative as the status quo; (2 ensuring that the choice pattern predicted by loss aversion maximizes the probability of positive (rather than zero or negative outcomes; (3 the use of high nominal (numerical payoffs; (4 the use of high stakes; (5 the inclusion of highly attractive risky prospects that creates a contrast effect; and (6 the use of long experiments in which no feedback is provided and in which the computation of the expected values is difficult. In addition, the results suggest the possibility of learning in the absence of feedback: The tendency to select simple strategies, like ``maximize the worst outcome'' which implies ``loss aversion'', increases when this behavior is not costly. Theoretical and practical implications are discussed.

  5. Cue-elicited food seeking is eliminated with aversive outcomes following outcome devaluation.

    Science.gov (United States)

    Eder, Andreas B; Dignath, David

    2016-01-01

    In outcome-selective Pavlovian-to-instrumental transfer (PIT), stimuli that are predictive of specific outcomes prime instrumental responses that are associated with these outcomes. Previous human studies yielded mixed evidence in respect to whether the PIT effect is affected by a posttraining devaluation of an outcome, with the PIT effect being preserved after a devaluation of a primary reinforcer (food, drugs) but not following the devaluation of a secondary reinforcer (money). The present research examined whether outcome-selective transfer is eliminated when the devaluation of a primary (liquid) reinforcer is strong and aversive. Experiment 1 confirmed these expectations following a devaluation with bad tasting Tween 20. However, outcome-selective transfer was still observed when the earned (devalued) outcome was not consumed immediately after each test (Experiment 2). These results suggest that the capacity of a Pavlovian cue to motivate a specific response is affected by the incentive value of the shared outcome only when the devaluation yields an aversive outcome that is consumed immediately.

  6. Impact of childhood trauma and cognitive emotion regulation strategies on risk-aversive and loss-aversive patterns of decision-making in patients with depression.

    Science.gov (United States)

    Huh, Hyu Jung; Baek, Kwangyeol; Kwon, Jae-Hyung; Jeong, Jaeseung; Chae, Jeong-Ho

    2016-11-01

    Although poor decision-making ultimately impairs quality of life in depression, few studies describe the clinical characteristics of patients suffering from dysfunctional decision-making. This study aims to delineate the effect of childhood trauma and other personality factors on risk-aversive and loss-aversive patterns of decision-making in patients with depression. A total of 50 depressive patients completed surveys for the measurement of sociodemographic factors, trauma loads and other clinical characteristics, including depression, anxiety, and strategies for emotion regulation. Risk aversion and loss aversion were quantified using probability discounting task and a 50:50 gamble on monetary decision-making task under specified risks. Stepwise multiple regression analysis was performed to determine the factors, predicting risk aversion or loss aversion in depression. Childhood trauma was the most prominent factor predicting loss aversion in patients with depressive disorders. Overall maladaptive emotion regulation strategies were associated with risk aversion. Childhood trauma and specific strategies of emotion regulation contribute to risk or loss aversion in patients with depression. These findings may provide useful insight into elaborative evaluation and interventions to improve decision-making and quality of life in patients with depression.

  7. Deciding for Future Selves Reduces Loss Aversion

    Directory of Open Access Journals (Sweden)

    Qiqi Cheng

    2017-09-01

    Full Text Available In this paper, we present an incentivized experiment to investigate the degree of loss aversion when people make decisions for their current selves and future selves under risk. We find that when participants make decisions for their future selves, they are less loss averse compared to when they make decisions for their current selves. This finding is consistent with the interpretation of loss aversion as a bias in decision-making driven by emotions, which are reduced when making decisions for future selves. Our findings endorsed the external validity of previous studies on the impact of emotion on loss aversion in a real world decision-making environment.

  8. Deciding for Future Selves Reduces Loss Aversion.

    Science.gov (United States)

    Cheng, Qiqi; He, Guibing

    2017-01-01

    In this paper, we present an incentivized experiment to investigate the degree of loss aversion when people make decisions for their current selves and future selves under risk. We find that when participants make decisions for their future selves, they are less loss averse compared to when they make decisions for their current selves. This finding is consistent with the interpretation of loss aversion as a bias in decision-making driven by emotions, which are reduced when making decisions for future selves. Our findings endorsed the external validity of previous studies on the impact of emotion on loss aversion in a real world decision-making environment.

  9. Aversion substance(s) of the rat coagulating glands

    Science.gov (United States)

    Gawienowski, Anthony M.; Berry, Iver J.; Kennelly, James J.

    1982-01-01

    The aversive substance(s) present in adult male urine were not found in castrate rat urine. Removal of the coagulating glands also resulted in a loss of the aversion compounds. The aversion substances were restored to the urine after androgen treatment of the castrate rats.

  10. Aversive Learning and Trait Aggression Influence Retaliatory Behavior.

    Science.gov (United States)

    Molapour, Tanaz; Lindström, Björn; Olsson, Andreas

    2016-01-01

    In two experiments (n = 35, n = 34), we used a modified fear-conditioning paradigm to investigate the role of aversive learning in retaliatory behavior in social context. Participants first completed an initial aversive learning phase in which the pairing of a neutral conditioned stimulus (CS; i.e., neutral face) with a naturally aversive unconditioned stimulus (US; electric shock) was learned. Then they were given an opportunity to interact (i.e., administer 0-2 shocks) with the same faces again, during a Test phase. In Experiment 2, we used the same paradigm with the addition of online trial-by-trial ratings (e.g., US expectancy and anger) to examine the role of aversive learning, anger, and the learned expectancy of receiving punishment more closely. Our results indicate that learned aversions influenced future retaliation in a social context. In both experiments, participants showed largest skin conductance responses (SCRs) to the faces paired with one or two shocks, demonstrating successful aversive learning. Importantly, participants administered more shocks to the faces paired with the most number of shocks when the opportunity was given during test. Also, our results revealed that aggressive traits (Buss and Perry Aggression scale) were associated with retaliation only toward CSs associated with aversive experiences. These two experiments show that aggressive traits, when paired with aversive learning experiences enhance the likelihood to act anti-socially toward others.

  11. An Aversion-Desensitization Treatment for Alcoholism

    Science.gov (United States)

    Primo, Richard V.; And Others

    1972-01-01

    A six-to nine-month interview follow-up showed that five of the seven traceable Ss given the interpersonal aversion-systematic desensitization treatment had been abstinent, compared with only one of seven treated by the interpersonal aversion-control procedure. (Author)

  12. Neural mechanisms underlying paradoxical performance for monetary incentives are driven by loss aversion.

    Science.gov (United States)

    Chib, Vikram S; De Martino, Benedetto; Shimojo, Shinsuke; O'Doherty, John P

    2012-05-10

    Employers often make payment contingent on performance in order to motivate workers. We used fMRI with a novel incentivized skill task to examine the neural processes underlying behavioral responses to performance-based pay. We found that individuals' performance increased with increasing incentives; however, very high incentive levels led to the paradoxical consequence of worse performance. Between initial incentive presentation and task execution, striatal activity rapidly switched between activation and deactivation in response to increasing incentives. Critically, decrements in performance and striatal deactivations were directly predicted by an independent measure of behavioral loss aversion. These results suggest that incentives associated with successful task performance are initially encoded as a potential gain; however, when actually performing a task, individuals encode the potential loss that would arise from failure. Copyright © 2012 Elsevier Inc. All rights reserved.

  13. Discovery of Potent and Selective Inhibitors for ADAMTS-4 through DNA-Encoded Library Technology (ELT).

    Science.gov (United States)

    Ding, Yun; O'Keefe, Heather; DeLorey, Jennifer L; Israel, David I; Messer, Jeffrey A; Chiu, Cynthia H; Skinner, Steven R; Matico, Rosalie E; Murray-Thompson, Monique F; Li, Fan; Clark, Matthew A; Cuozzo, John W; Arico-Muendel, Christopher; Morgan, Barry A

    2015-08-13

    The aggrecan degrading metalloprotease ADAMTS-4 has been identified as a novel therapeutic target for osteoarthritis. Here, we use DNA-encoded Library Technology (ELT) to identify novel ADAMTS-4 inhibitors from a DNA-encoded triazine library by affinity selection. Structure-activity relationship studies based on the selection information led to the identification of potent and highly selective inhibitors. For example, 4-(((4-(6,7-dimethoxy-3,4-dihydroisoquinolin-2(1H)-yl)-6-(((4-methylpiperazin-1-yl)methyl)amino)-1,3,5-triazin-2-yl)amino)methyl)-N-ethyl-N-(m-tolyl)benzamide has IC50 of 10 nM against ADAMTS-4, with >1000-fold selectivity over ADAMT-5, MMP-13, TACE, and ADAMTS-13. These inhibitors have no obvious zinc ligand functionality.

  14. Are Teams Less Inequality Averse than Individuals?

    OpenAIRE

    He, Haoran; Villeval, Marie Claire

    2014-01-01

    We compare inequality aversion in individuals and teams by means of both within- and between-subject experimental designs, and we investigate how teams aggregate individual preferences. We find that team decisions reveal less inequality aversion than individual initial proposals in team decision-making. However, teams are no more selfish than individuals who decide in isolation. Individuals express strategically more inequality aversion in their initial proposals in team decision-making becau...

  15. Multiattribute Utility Theory, Intertemporal Utility and Correlation Aversion

    DEFF Research Database (Denmark)

    Andersen, Steffen; Harrison, Glenn W.; Lau, Morten

    2018-01-01

    Convenient assumptions about qualitative properties of the intertemporal utility function have generated counterintuitive implications for the relationship between atemporal risk aversion and the intertemporal elasticity of substitution. If the intertemporal utility function is additively separable...... aversion. Our results show that subjects are correlation averse over lotteries with intertemporal income profiles....

  16. How to Make Loss Aversion Disappear and Reverse: Tests of the Decision by Sampling Origin of Loss Aversion

    OpenAIRE

    Walasek, Lukasz; Stewart, Neil

    2014-01-01

    One of the most robust empirical findings in the behavioral sciences is loss aversion—the finding that losses loom larger than gains. We offer a new psychological explanation of the origins of loss aversion in which loss aversion emerges from differences in the distribution of gains and losses people experience. In 4 experiments, we tested this proposition by manipulating the range of gains and losses that individuals saw during the process of eliciting their loss aversion. We were able to fi...

  17. Reference-dependent preferences and loss aversion

    Directory of Open Access Journals (Sweden)

    Einat Neuman

    2008-02-01

    Full Text Available This study employs a Discrete Choice Experiment (DCE in the health-care sector to test the loss aversion theory that is derived from reference-dependent preferences: The absolute subjective value of a deviation from a reference point is generally greater when the deviation represents a loss than when the same-sized change is perceived as a gain. As far as is known, this paper is the first to use a DCE to test the loss aversion theory. A DCE is a highly suitable tool for such testing because it estimates the marginal valuations of attributes, based onextit{ deviations from a reference point} (a constant scenario. Moreover, loss aversion can be examined for extit{each attribute separately}. Another advantage of a DCE is that is can be applied toextit{ non-traded goods with non-tangible attributes}. A health-care event is used for empirical illustration: The loss aversion theory is tested within the context of preference structures for maternity-ward attributes, estimated using data gathered from 3850 observations made by a sample of 542 women who had recently given birth. Seven hypotheses are presented and tested. Overall, significant support for behavioral loss aversion theories was found. %JEL codes: D01, D12, I19

  18. Coping with Loss Aversion in the Newsvendor Model

    Directory of Open Access Journals (Sweden)

    Jianwu Sun

    2015-01-01

    Full Text Available We introduce loss aversion into the decision framework of the newsvendor model. By introducing the loss aversion coefficient λ, we propose a novel utility function for the loss-averse newsvendor. First, we obtain the optimal order quantity to maximize the expected utility for the loss-averse newsvendor who is risk-neutral. It is found that this optimal order quantity is smaller than the expected profit maximization order quantity in the classical newsvendor model, which may help to explain the decision bias in the classical newsvendor model. Then, to reduce the risk which originates from the fluctuation in the market demand, we achieve the optimal order quantity to maximize CVaR about utility for the loss-averse newsvendor who is risk-averse. We find that this optimal order quantity is smaller than the optimal order quantity to maximize the expected utility above and is decreasing in the confidence level α. Further, it is proved that the expected utility under this optimal order quantity is decreasing in the confidence level α, which verifies that low risk implies low return. Finally, a numerical example is given to illustrate the obtained results and some management insights are suggested for the loss-averse newsvendor model.

  19. Amygdala damage eliminates monetary loss aversion.

    Science.gov (United States)

    De Martino, Benedetto; Camerer, Colin F; Adolphs, Ralph

    2010-02-23

    Losses are a possibility in many risky decisions, and organisms have evolved mechanisms to evaluate and avoid them. Laboratory and field evidence suggests that people often avoid risks with losses even when they might earn a substantially larger gain, a behavioral preference termed "loss aversion." The cautionary brake on behavior known to rely on the amygdala is a plausible candidate mechanism for loss aversion, yet evidence for this idea has so far not been found. We studied two rare individuals with focal bilateral amygdala lesions using a series of experimental economics tasks. To measure individual sensitivity to financial losses we asked participants to play a variety of monetary gambles with possible gains and losses. Although both participants retained a normal ability to respond to changes in the gambles' expected value and risk, they showed a dramatic reduction in loss aversion compared to matched controls. The findings suggest that the amygdala plays a key role in generating loss aversion by inhibiting actions with potentially deleterious outcomes.

  20. Narrative Aversion: Challenges for the Illness Narrative Advocate.

    Science.gov (United States)

    Behrendt, Kathy

    2017-02-01

    Engaging in self-narrative is often touted as a powerful antidote to the bad effects of illness. However, there are various examples of what may broadly be termed "aversion" to illness narrative. I group these into three kinds: aversion to certain types of illness narrative; aversion to illness narrative as a whole; and aversion to illness narrative as an essentially therapeutic endeavor. These aversions can throw into doubt the advantages claimed for the illness narrator, including the key benefits of repair to the damage illness does to identity and life-trajectory. Underlying these alleged benefits are two key presuppositions: that it is the whole of one's life that is narratively unified, and that one's identity is inextricably bound up with narrative. By letting go of these assumptions, illness narrative advocates can respond to the challenges of narrative aversions. © The Author 2016. Published by Oxford University Press, on behalf of The Journal of Medicine and Philosophy Inc. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  1. Inequality Aversion and Voting on Redistribution

    DEFF Research Database (Denmark)

    Höchtl, Wolfgang; Sausgruber, Rupert; Tyran, Jean-Robert

    of income classes. We experimentally study voting on redistribution between two income classes and show that the effect of inequality aversion is asymmetric. Inequality aversion is more likely to matter if the “rich” are in majority. With a “poor” majority, we find that redistribution outcomes look...

  2. Inequality aversion and voting on redistribution

    DEFF Research Database (Denmark)

    Höchtl, Wolfgang; Sausgruber, Rupert; Tyran, Jean-Robert Karl

    2012-01-01

    of income classes. We experimentally study voting on redistribution between two income classes and show that the effect of inequality aversion is asymmetric. Inequality aversion is more likely to matter if the “rich” are in majority. With a “poor” majority, we find that redistribution outcomes look...

  3. Ethanol-induced conditioned taste aversion in Warsaw Alcohol High-Preferring (WHP) and Warsaw Alcohol Low-Preferring (WLP) rats.

    Science.gov (United States)

    Dyr, Wanda; Wyszogrodzka, Edyta; Paterak, Justyna; Siwińska-Ziółkowska, Agnieszka; Małkowska, Anna; Polak, Piotr

    2016-03-01

    The aversive action of the pharmacological properties of ethanol was studied in selectively bred Warsaw Alcohol High-Preferring (WHP) and Warsaw Alcohol Low-Preferring (WLP) rats. For this study, a conditioned-taste aversion test was used. Male WHP and WLP rats were submitted to daily 20-min sessions for 5 days, in which a saccharin solution (1.0 g/L) was available (pre-conditioning phase). Next, this drinking was paired with the injection of ethanol (0, 0.5, 1.0 g/kg), intraperitoneally [i.p.] immediately after removal of the saccharin bottle (conditioning phase). Afterward, the choice between the saccharin solution and water was extended for 18 subsequent days for 20-min daily sessions (post-conditioning phase). Both doses of ethanol did not produce an aversion to saccharin in WLP and WHP rats in the conditioning phase. However, injection of the 1.0 g/kg dose of ethanol produced an aversion in WLP rats that was detected by a decrease in saccharin intake at days 1, 3, 7, and 10 of the post-conditioning phase, with a decrease in saccharin preference for 16 days of the post-conditioning phase. Conditioned taste aversion, measured as a decrease in saccharin intake and saccharin preference, was only visible in WHP rats at day 1 and day 3 of the post-conditioning phase. This difference between WLP and WHP rats was apparent despite similar blood ethanol levels in both rat lines following injection of 0.5 and 1.0 g/kg of ethanol. These results may suggest differing levels of aversion to the post-ingestional effects of ethanol between WLP and WHP rats. These differing levels of aversion may contribute to the selected line difference in ethanol preference in WHP and WLP rats. Copyright © 2016 Elsevier Inc. All rights reserved.

  4. Brief Report: Risk-Aversion and Rationality in Autism Spectrum Disorders.

    Science.gov (United States)

    Gosling, Corentin J; Moutier, Sylvain

    2018-05-30

    Risk-aversion and rationality have both been highlighted as core features of decision making in individuals with Autism Spectrum Disorders (ASD). This study tested whether risk-aversion is related to rational decision-making in ASD individuals. ASD and matched control adults completed a decision-making task that discriminated between the use of risk-averse and rational strategies. Results showed that overall, ASD participants were more risk-averse than control participants. Specifically, both groups made similar choices when risk-aversion was the less rational strategy but ASD participants chose more rational options than control participants when risk-aversion was the most rational strategy. This study confirmed that risk-aversion is a core feature of ASD and revealed that ASD individuals can switch their decision-making strategy adaptively to avoid negative consequences.

  5. Schizophrenia illness severity is associated with reduced loss aversion.

    Science.gov (United States)

    Currie, James; Buruju, Dheeraj; Perrin, Jennifer S; Reid, Ian C; Steele, J Douglas; Feltovich, Nick

    2017-06-01

    Loss aversion, whereby losses weigh more heavily than equal-sized gains, has been demonstrated in many decision-making settings. Previous research has suggested reduced loss aversion in schizophrenia, but with little evidence of a link between loss aversion and schizophrenia illness severity. In this study, 20 individuals with schizophrenia and 16 control participants, matched by age and sex, played two versions of the Iterated Prisoners' Dilemma, one version with only positive payoffs and another version in which negative payoffs were possible, with the second version being derived from the first by subtracting a constant value from all payoffs. The control group demonstrated significantly lower cooperation rates under negative payoffs, compared with the version with only positive payoffs, indicative of loss aversion. The patient group on average showed no loss aversion response. Moreover, the extent of loss aversion in patients was found to be negatively correlated with schizophrenia illness severity, with less ill patients showing loss aversion more similar to controls. Results were found to be robust to the inclusion of potential confounding factors as covariates within rigorous probit regression analyses. Reduced loss aversion is a feature of schizophrenia and related to illness severity. Copyright © 2017. Published by Elsevier B.V.

  6. Mechanisms of radiation-induced conditioned taste aversion learning

    International Nuclear Information System (INIS)

    Rabin, B.M.; Hunt, W.A.

    1986-01-01

    The literature on taste aversion learning is reviewed and discussed, with particular emphasis on those studies that have used exposure to ionizing radiation as an unconditioned stimulus to produce a conditioned taste aversion. The primary aim of the review is to attempt to define the mechanisms that lead to the initiation of the taste aversion response following exposure to ionizing radiation. Studies using drug treatments to produce a taste aversion have been included to the extent that they are relevant to understanding the mechanisms by which exposure to ionizing radiation can affect the behavior of the organism. 141 references

  7. Risk aversion and compliance in markets for pollution control.

    Science.gov (United States)

    Stranlund, John K

    2008-07-01

    This paper examines the effects of risk aversion on compliance choices in markets for pollution control. A firm's decision to be compliant or not is independent of its manager's risk preference. However, non-compliant firms with risk-averse managers will have lower violations than otherwise identical firms with risk-neutral managers. The violations of non-compliant firms with risk-averse managers are independent of differences in their profit functions and their initial allocations of permits if and only if their managers' utility functions exhibit constant absolute risk aversion. However, firm-level characteristics do impact violation choices when managers have coefficients of absolute risk aversion that are increasing or decreasing in profit levels. Finally, in the equilibrium of a market for emissions rights with widespread non-compliance, risk aversion is associated with higher permit prices, better environmental quality, and lower aggregate violations.

  8. Time-varying risk aversion. An application to energy hedging

    Energy Technology Data Exchange (ETDEWEB)

    Cotter, John [Centre for Financial Markets, School of Business, University College Dublin, Blackrock, Co. Dublin (Ireland); Hanly, Jim [School of Accounting and Finance, Dublin Institute of Technology, Dublin 2 (Ireland)

    2010-03-15

    Risk aversion is a key element of utility maximizing hedge strategies; however, it has typically been assigned an arbitrary value in the literature. This paper instead applies a GARCH-in-Mean (GARCH-M) model to estimate a time-varying measure of risk aversion that is based on the observed risk preferences of energy hedging market participants. The resulting estimates are applied to derive explicit risk aversion based optimal hedge strategies for both short and long hedgers. Out-of-sample results are also presented based on a unique approach that allows us to forecast risk aversion, thereby estimating hedge strategies that address the potential future needs of energy hedgers. We find that the risk aversion based hedges differ significantly from simpler OLS hedges. When implemented in-sample, risk aversion hedges for short hedgers outperform the OLS hedge ratio in a utility based comparison. (author)

  9. Time-varying risk aversion. An application to energy hedging

    International Nuclear Information System (INIS)

    Cotter, John; Hanly, Jim

    2010-01-01

    Risk aversion is a key element of utility maximizing hedge strategies; however, it has typically been assigned an arbitrary value in the literature. This paper instead applies a GARCH-in-Mean (GARCH-M) model to estimate a time-varying measure of risk aversion that is based on the observed risk preferences of energy hedging market participants. The resulting estimates are applied to derive explicit risk aversion based optimal hedge strategies for both short and long hedgers. Out-of-sample results are also presented based on a unique approach that allows us to forecast risk aversion, thereby estimating hedge strategies that address the potential future needs of energy hedgers. We find that the risk aversion based hedges differ significantly from simpler OLS hedges. When implemented in-sample, risk aversion hedges for short hedgers outperform the OLS hedge ratio in a utility based comparison. (author)

  10. Acceptable losses: the debatable origins of loss aversion.

    Science.gov (United States)

    Yechiam, Eldad

    2018-04-16

    It is often claimed that negative events carry a larger weight than positive events. Loss aversion is the manifestation of this argument in monetary outcomes. In this review, we examine early studies of the utility function of gains and losses, and in particular the original evidence for loss aversion reported by Kahneman and Tversky (Econometrica  47:263-291, 1979). We suggest that loss aversion proponents have over-interpreted these findings. Specifically, the early studies of utility functions have shown that while very large losses are overweighted, smaller losses are often not. In addition, the findings of some of these studies have been systematically misrepresented to reflect loss aversion, though they did not find it. These findings shed light both on the inability of modern studies to reproduce loss aversion as well as a second literature arguing strongly for it.

  11. Risk Aversion Relates to Cognitive Ability

    DEFF Research Database (Denmark)

    Andersson, Ola; Holm, Håkan J.; Tyran, Jean-Robert Karl

    2016-01-01

    Recent experimental studies suggest that risk aversion is negatively related to cognitive ability. In this paper we report evidence that this relation might be spurious. We recruit a large subject pool drawn from the general Danish population for our experiment. By presenting subjects with choice...... tasks that vary the bias induced by random choices, we are able to generate both negative and positive correlations between risk aversion and cognitive ability. Structural estimation allowing for heterogeneity of noise yields no significant relation between risk aversion and cognitive ability. Our...... results suggest that cognitive ability is related to random decision making, rather than to risk preferences....

  12. Risk aversion relates to cognitive ability

    DEFF Research Database (Denmark)

    Andersson, Ola; Holm, Håkan J.; Tyran, Jean-Robert Karl

    Recent experimental studies suggest that risk aversion is negatively related to cognitive ability. In this paper we report evidence that this relation might be spurious. We recruit a large subject pool drawn from the general Danish population for our experiment. By presenting subjects with choice...... tasks that vary the bias induced by random choices, we are able to generate both negative and positive correlations between risk aversion and cognitive ability. Structural estimation allowing for heterogeneity of noise yields no significant relation between risk aversion and cognitive ability. Our...... results suggest that cognitive ability is related to random decision making rather than to risk preferences....

  13. Ambiguity aversion in rhesus macaques

    Directory of Open Access Journals (Sweden)

    Benjamin eHayden

    2010-09-01

    Full Text Available People generally prefer risky options, which have fully specified outcome probabilities, to ambiguous options, which have unspecified probabilities. This preference, formalized in economics, is strong enough that people will reliably prefer a risky option to an ambiguous option with a greater expected value. Explanations for ambiguity aversion often invoke uniquely human faculties like language, self-justification, or a desire to avoid public embarrassment. Challenging these ideas, here we demonstrate that a preference for unambiguous options is shared with rhesus macaques. We trained four monkeys to choose between pairs of options that both offered explicitly cued probabilities of large and small juice outcomes. We then introduced occasional trials where one of the options was obscured and examined their resulting preferences; we ran humans in a parallel experiment on a nearly identical task. We found that monkeys reliably preferred risky options to ambiguous ones, even when this bias was costly, closely matching the behavior of humans in the analogous task. Notably, ambiguity aversion varied parametrically with the extent of ambiguity. As expected, ambiguity aversion gradually declined as monkeys learned the underlying probability distribution of rewards. These data indicate that ambiguity aversion reflects fundamental cognitive biases shared with other animals rather than uniquely human factors guiding decisions.

  14. Visual attention and emotional memory: recall of aversive pictures is partially mediated by concurrent task performance.

    Science.gov (United States)

    Pottage, Claire L; Schaefer, Alexandre

    2012-02-01

    The emotional enhancement of memory is often thought to be determined by attention. However, recent evidence using divided attention paradigms suggests that attention does not play a significant role in the formation of memories for aversive pictures. We report a study that investigated this question using a paradigm in which participants had to encode lists of randomly intermixed negative and neutral pictures under conditions of full attention and divided attention followed by a free recall test. Attention was divided by a highly demanding concurrent task tapping visual processing resources. Results showed that the advantage in recall for aversive pictures was still present in the DA condition. However, mediation analyses also revealed that concurrent task performance significantly mediated the emotional enhancement of memory under divided attention. This finding suggests that visual attentional processes play a significant role in the formation of emotional memories. PsycINFO Database Record (c) 2012 APA, all rights reserved

  15. Probabilistic Sophistication, Second Order Stochastic Dominance, and Uncertainty Aversion

    OpenAIRE

    Simone Cerreia-Vioglio; Fabio Maccheroni; Massimo Marinacci; Luigi Montrucchio

    2010-01-01

    We study the interplay of probabilistic sophistication, second order stochastic dominance, and uncertainty aversion, three fundamental notions in choice under uncertainty. In particular, our main result, Theorem 2, characterizes uncertainty averse preferences that satisfy second order stochastic dominance, as well as uncertainty averse preferences that are probabilistically sophisticated.

  16. Selective attention to phonology dynamically modulates initial encoding of auditory words within the left hemisphere.

    Science.gov (United States)

    Yoncheva, Yuliya; Maurer, Urs; Zevin, Jason D; McCandliss, Bruce D

    2014-08-15

    Selective attention to phonology, i.e., the ability to attend to sub-syllabic units within spoken words, is a critical precursor to literacy acquisition. Recent functional magnetic resonance imaging evidence has demonstrated that a left-lateralized network of frontal, temporal, and posterior language regions, including the visual word form area, supports this skill. The current event-related potential (ERP) study investigated the temporal dynamics of selective attention to phonology during spoken word perception. We tested the hypothesis that selective attention to phonology dynamically modulates stimulus encoding by recruiting left-lateralized processes specifically while the information critical for performance is unfolding. Selective attention to phonology was captured by manipulating listening goals: skilled adult readers attended to either rhyme or melody within auditory stimulus pairs. Each pair superimposed rhyming and melodic information ensuring identical sensory stimulation. Selective attention to phonology produced distinct early and late topographic ERP effects during stimulus encoding. Data-driven source localization analyses revealed that selective attention to phonology led to significantly greater recruitment of left-lateralized posterior and extensive temporal regions, which was notably concurrent with the rhyme-relevant information within the word. Furthermore, selective attention effects were specific to auditory stimulus encoding and not observed in response to cues, arguing against the notion that they reflect sustained task setting. Collectively, these results demonstrate that selective attention to phonology dynamically engages a left-lateralized network during the critical time-period of perception for achieving phonological analysis goals. These findings suggest a key role for selective attention in on-line phonological computations. Furthermore, these findings motivate future research on the role that neural mechanisms of attention may

  17. Selective attention to phonology dynamically modulates initial encoding of auditory words within the left hemisphere

    Science.gov (United States)

    Yoncheva; Maurer, Urs; Zevin, Jason; McCandliss, Bruce

    2015-01-01

    Selective attention to phonology, i.e., the ability to attend to sub-syllabic units within spoken words, is a critical precursor to literacy acquisition. Recent functional magnetic resonance imaging evidence has demonstrated that a left-lateralized network of frontal, temporal, and posterior language regions, including the visual word form area, supports this skill. The current event-related potential (ERP) study investigated the temporal dynamics of selective attention to phonology during spoken word perception. We tested the hypothesis that selective atten tion to phonology dynamically modulates stimulus encoding by recruiting left-lateralized processes specifically while the information critical for performance is unfolding. Selective attention to phonology was captured by ma nipulating listening goals: skilled adult readers attended to either rhyme or melody within auditory stimulus pairs. Each pair superimposed rhyming and melodic information ensuring identical sensory stimulation. Selective attention to phonology produced distinct early and late topographic ERP effects during stimulus encoding. Data- driven source localization analyses revealed that selective attention to phonology led to significantly greater re cruitment of left-lateralized posterior and extensive temporal regions, which was notably concurrent with the rhyme-relevant information within the word. Furthermore, selective attention effects were specific to auditory stimulus encoding and not observed in response to cues, arguing against the notion that they reflect sustained task setting. Collectively, these results demonstrate that selective attention to phonology dynamically engages a left-lateralized network during the critical time-period of perception for achieving phonological analysis goals. These findings support the key role of selective attention to phonology in the development of literacy and motivate future research on the neural bases of the interaction between phonological

  18. The effects of area postrema lesions and selective vagotomy on motion-induced conditioned taste aversion

    Science.gov (United States)

    Fox, Robert A.; Sutton, R. L.; Mckenna, Susan

    1991-01-01

    Conditioned taste aversion (CTA) is one of several behaviors which was suggested as a putative measure of motion sickness in rats. A review is made of studies which used surgical disruption of area postrema or the vagus nerve to investigate whether CTA and vomiting induced by motion may depend on common neural pathways or structures. When the chemoreceptive function of the area postrema (AP) is destroyed by complete ablation, rats develop CTA and cats and monkeys develop CTA and vomit. Thus the AP is not crucially involved in either CTA or vomiting induced by motion. However, after complete denervation of the stomach or after labyrinthectomy rats do not develop CTA when motion is used as the unconditioned stimulus. Studies of brainstem projections of the vagus nerve, the area postrema, the periaqueductal grey, and the vestibular system are used as the basis for speculation about regions which could mediate both motion-induced vomiting and behavioral food aversion.

  19. Small Stakes Risk Aversion in the Laboratory

    DEFF Research Database (Denmark)

    Harrison, Glenn W.; Lau, Morten; Ross, Don

    Evidence of risk aversion in laboratory settings over small stakes leads to a priori implausible levels of risk aversion over large stakes under certain assumptions. One core assumption in standard statements of this calibration puzzle is that individuals define utility over terminal wealth......, and that terminal wealth is defined as the sum of extra-lab wealth and any wealth accumulated in the lab. This assumption is often used in Expected Utility Theory, as well as popular alternatives such as RankDependent Utility theory. Another core assumption is that the small-stakes risk aversion is observed over...... all levels of wealth, or over a “sufficiently large” range of wealth. Although this second assumption if often viewed as self-evident from the vast experimental literature showing risk aversion over laboratory stakes, it actually requires that lab wealth be varied for a given subject as one takes...

  20. Risk aversion affects economic values of blue fox breeding scheme.

    Science.gov (United States)

    Peura, J; Kempe, R; Strandén, I; Rydhmer, L

    2016-12-01

    The profit and production of an average Finnish blue fox farm was simulated using a deterministic bio-economic farm model. Risk was included using Arrow-Prat absolute risk aversion coefficient and profit variance. Risk-rated economic values were calculated for pregnancy rate, litter loss, litter size, pelt size, pelt quality, pelt colour clarity, feed efficiency and eye infection. With high absolute risk aversion, economic values were lower than with low absolute risk aversion. Economic values were highest for litter loss (18.16 and 26.42 EUR), litter size (13.27 and 19.40 EUR), pregnancy (11.99 and 18.39 EUR) and eye infection (12.39 and 13.81 EUR). Sensitivity analysis showed that selection pressure for improved eye health depended strongly on proportion of culled animals among infected animals and much less on the proportion of infected animals. The economic value of feed efficiency was lower than expected (6.06 and 8.03 EUR). However, it was almost the same magnitude as pelt quality (7.30 and 7.30 EUR) and higher than the economic value of pelt size (3.37 and 5.26 EUR). Risk factors should be considered in blue fox breeding scheme because they change the relative importance of traits. © 2016 Blackwell Verlag GmbH.

  1. Risk aversion in medical decision making: a survey

    OpenAIRE

    Liliana Chicaíza; Mario García; Giancarlo Romano

    2011-01-01

    This article surveys the literature on risk aversion in medical decision making. The search covered Econlit, Jstor Science Direct and Springer Link since 1985. The results are classified in three topics: Risk aversion in the frameworks of Expected Utility and Rank Dependent Expected Utility theories, and the methodologies for measuring risk aversion and its applications to clinical situations from the points of view of economics and psychology. It was found that, despite conceptual and method...

  2. Risk Aversion, Price Uncertainty and Irreversible Investments

    NARCIS (Netherlands)

    van den Goorbergh, R.W.J.; Huisman, K.J.M.; Kort, P.M.

    2003-01-01

    This paper generalizes the theory of irreversible investment under uncertainty by allowing for risk averse investors in the absence of com-plete markets.Until now this theory has only been developed in the cases of risk neutrality, or risk aversion in combination with complete markets.Within a

  3. Sodium butyrate into the insular cortex during conditioned taste-aversion acquisition delays aversive taste memory extinction.

    Science.gov (United States)

    Núñez-Jaramillo, Luis; Reyes-López, Julian; Miranda, María Isabel

    2014-04-16

    Histone acetylation is one mechanism that promotes gene expression, and it increases during learning of various tasks. Specifically, novel taste consumption produces an increased acetylation of histone lysine residues in the insular cortex (IC), where protein synthesis is crucial during memory consolidation of conditioned taste aversion (CTA). However, the role of this elevated histone acetylation during CTA learning has not been examined directly. Thus, the present study investigated the effects of sodium butyrate (NaBu), a histone deacetylase inhibitor, injected into the IC during CTA acquisition. Male Wistar rats, IC bilaterally implanted, were injected 60 min before saccharine presentation, with a total volume of 0.5 µl of NaBu solution (100, 500, and 10 µg/0.5 µl) or saline; 30 min later animals were injected intraperitoneally with lithium chloride, a malaise-inducing drug. The next day, CTA retrieval was tested. No effects of NaBu were observed during acquisition or retrieval, but during extinction trials, a significant delay in aversive memory extinction was observed in the group injected with the lowest NaBu dose. This result indicates that NaBu in the IC strengthens CTA and delays aversive memory extinction, and suggests that histone acetylation could increase long-term taste-aversive memory strength.

  4. Estimation of Esfarayen Farmers Risk Aversion Coefficient and Its Influencing Factors (Nonparametric Approach

    Directory of Open Access Journals (Sweden)

    Z. Nematollahi

    2016-03-01

    Full Text Available Introduction: Due to existence of the risk and uncertainty in agriculture, risk management is crucial for management in agriculture. Therefore the present study was designed to determine the risk aversion coefficient for Esfarayens farmers. Materials and Methods: The following approaches have been utilized to assess risk attitudes: (1 direct elicitation of utility functions, (2 experimental procedures in which individuals are presented with hypothetical questionnaires regarding risky alternatives with or without real payments and (3: Inference from observation of economic behavior. In this paper, we focused on approach (3: inference from observation of economic behavior, based on this assumption of existence of the relationship between the actual behavior of a decision maker and the behavior predicted from empirically specified models. A new non-parametric method and the QP method were used to calculate the coefficient of risk aversion. We maximized the decision maker expected utility with the E-V formulation (Freund, 1956. Ideally, in constructing a QP model, the variance-covariance matrix should be formed for each individual farmer. For this purpose, a sample of 100 farmers was selected using random sampling and their data about 14 products of years 2008- 2012 were assembled. The lowlands of Esfarayen were used since within this area, production possibilities are rather homogeneous. Results and Discussion: The results of this study showed that there was low correlation between some of the activities, which implies opportunities for income stabilization through diversification. With respect to transitory income, Ra, vary from 0.000006 to 0.000361 and the absolute coefficient of risk aversion in our sample were 0.00005. The estimated Ra values vary considerably from farm to farm. The results showed that the estimated Ra for the subsample existing of 'non-wealthy' farmers was 0.00010. The subsample with farmers in the 'wealthy' group had an

  5. Repeatable aversion across threat types is linked with life-history traits but is dependent on how aversion is measured.

    Science.gov (United States)

    Davidson, Gabrielle L; Reichert, Michael S; Crane, Jodie M S; O'Shea, William; Quinn, John L

    2018-02-01

    Personality research suggests that individual differences in risk aversion may be explained by links with life-history variation. However, few empirical studies examine whether repeatable differences in risk avoidance behaviour covary with life-history traits among individuals in natural populations, or how these links vary depending on the context and the way risk aversion is measured. We measured two different risk avoidance behaviours (latency to enter the nest and inspection time) in wild great tits ( Parus major ) in two different contexts-response to a novel object and to a predator cue placed at the nest-box during incubation---and related these behaviours to female reproductive success and condition. Females responded equally strongly to both stimuli, and although both behaviours were repeatable, they did not correlate. Latency to enter was negatively related to body condition and the number of offspring fledged. By contrast, inspection time was directly explained by whether incubating females had been flushed from the nest before the trial began. Thus, our inferences on the relationship between risk aversion and fitness depend on how risk aversion was measured. Our results highlight the limitations of drawing conclusions about the relevance of single measures of a personality trait such as risk aversion.

  6. Risk Attitudes, Sample Selection and Attrition in a Longitudinal Field Experiment

    DEFF Research Database (Denmark)

    Harrison, Glenn W.; Lau, Morten Igel

    with respect to risk attitudes. Our design builds in explicit randomization on the incentives for participation. We show that there are significant sample selection effects on inferences about the extent of risk aversion, but that the effects of subsequent sample attrition are minimal. Ignoring sample...... selection leads to inferences that subjects in the population are more risk averse than they actually are. Correcting for sample selection and attrition affects utility curvature, but does not affect inferences about probability weighting. Properly accounting for sample selection and attrition effects leads...... to findings of temporal stability in overall risk aversion. However, that stability is around different levels of risk aversion than one might naively infer without the controls for sample selection and attrition we are able to implement. This evidence of “randomization bias” from sample selection...

  7. Spatially dynamic recurrent information flow across long-range dorsal motor network encodes selective motor goals.

    Science.gov (United States)

    Yoo, Peter E; Hagan, Maureen A; John, Sam E; Opie, Nicholas L; Ordidge, Roger J; O'Brien, Terence J; Oxley, Thomas J; Moffat, Bradford A; Wong, Yan T

    2018-03-08

    Performing voluntary movements involves many regions of the brain, but it is unknown how they work together to plan and execute specific movements. We recorded high-resolution ultra-high-field blood-oxygen-level-dependent signal during a cued ankle-dorsiflexion task. The spatiotemporal dynamics and the patterns of task-relevant information flow across the dorsal motor network were investigated. We show that task-relevant information appears and decays earlier in the higher order areas of the dorsal motor network then in the primary motor cortex. Furthermore, the results show that task-relevant information is encoded in general initially, and then selective goals are subsequently encoded in specifics subregions across the network. Importantly, the patterns of recurrent information flow across the network vary across different subregions depending on the goal. Recurrent information flow was observed across all higher order areas of the dorsal motor network in the subregions encoding for the current goal. In contrast, only the top-down information flow from the supplementary motor cortex to the frontoparietal regions, with weakened recurrent information flow between the frontoparietal regions and bottom-up information flow from the frontoparietal regions to the supplementary cortex were observed in the subregions encoding for the opposing goal. We conclude that selective motor goal encoding and execution rely on goal-dependent differences in subregional recurrent information flow patterns across the long-range dorsal motor network areas that exhibit graded functional specialization. © 2018 Wiley Periodicals, Inc.

  8. Effective return, risk aversion and drawdowns

    Science.gov (United States)

    Dacorogna, Michel M.; Gençay, Ramazan; Müller, Ulrich A.; Pictet, Olivier V.

    2001-01-01

    We derive two risk-adjusted performance measures for investors with risk averse preferences. Maximizing these measures is equivalent to maximizing the expected utility of an investor. The first measure, Xeff, is derived assuming a constant risk aversion while the second measure, Reff, is based on a stronger risk aversion to clustering of losses than of gains. The clustering of returns is captured through a multi-horizon framework. The empirical properties of Xeff, Reff are studied within the context of real-time trading models for foreign exchange rates and their properties are compared to those of more traditional measures like the annualized return, the Sharpe Ratio and the maximum drawdown. Our measures are shown to be more robust against clustering of losses and have the ability to fully characterize the dynamic behaviour of investment strategies.

  9. Risk Aversion and Engagement in the Sharing Economy

    Directory of Open Access Journals (Sweden)

    Jessica Santana

    2015-10-01

    Full Text Available The sharing economy is a new online community that has important implications for offline behavior. This study evaluates whether engagement in the sharing economy is associated with an actor’s aversion to risk. Using a web-based survey and a field experiment, we apply an adaptation of Holt and Laury’s (2002 risk lottery game to a representative sample of sharing economy participants. We find that frequency of activity in the sharing economy predicts risk aversion, but only in interaction with satisfaction. While greater satisfaction with sharing economy websites is associated with a decrease in risk aversion, greater frequency of usage is associated with greater risk aversion. This analysis shows the limitations of a static perspective on how risk attitudes relate to participation in the sharing economy.

  10. Empirical analysis of time preferences and risk aversion

    NARCIS (Netherlands)

    Tu, Q.

    2005-01-01

    One of the important contributions is that a structural model with the reference point and loss aversion for intertemporal choice was developed to estimate the coefficient of loss aversion and the reference points of individuals.

  11. Excitation of lateral habenula neurons as a neural mechanism underlying ethanol‐induced conditioned taste aversion

    Science.gov (United States)

    Keefe, Kristen A.; Taha, Sharif A.

    2016-01-01

    Key points The lateral habenula (LHb) has been implicated in regulation of drug‐seeking behaviours through aversion‐mediated learning.In this study, we recorded neuronal activity in the LHb of rats during an operant task before and after ethanol‐induced conditioned taste aversion (CTA) to saccharin.Ethanol‐induced CTA caused significantly higher baseline firing rates in LHb neurons, as well as elevated firing rates in response to cue presentation, lever press and saccharin taste.In a separate cohort of rats, we found that bilateral LHb lesions blocked ethanol‐induced CTA.Our results strongly suggest that excitation of LHb neurons is required for ethanol‐induced CTA, and point towards a mechanism through which LHb firing may regulate voluntary ethanol consumption. Abstract Ethanol, like other drugs of abuse, has both rewarding and aversive properties. Previous work suggests that sensitivity to ethanol's aversive effects negatively modulates voluntary alcohol intake and thus may be important in vulnerability to developing alcohol use disorders. We previously found that rats with lesions of the lateral habenula (LHb), which is implicated in aversion‐mediated learning, show accelerated escalation of voluntary ethanol consumption. To understand neural encoding in the LHb contributing to ethanol‐induced aversion, we recorded neural firing in the LHb of freely behaving, water‐deprived rats before and after an ethanol‐induced (1.5 g kg−1 20% ethanol, i.p.) conditioned taste aversion (CTA) to saccharin taste. Ethanol‐induced CTA strongly decreased motivation for saccharin in an operant task to obtain the tastant. Comparison of LHb neural firing before and after CTA induction revealed four main differences in firing properties. First, baseline firing after CTA induction was significantly higher. Second, firing evoked by cues signalling saccharin availability shifted from a pattern of primarily inhibition before CTA to primarily excitation after CTA

  12. Differences in Risk Aversion between Young and Older Adults.

    Science.gov (United States)

    Albert, Steven M; Duffy, John

    2012-01-15

    Research on decision-making strategies among younger and older adults suggests that older adults may be more risk averse than younger people in the case of potential losses. These results mostly come from experimental studies involving gambling paradigms. Since these paradigms involve substantial demands on memory and learning, differences in risk aversion or other features of decision-making attributed to age may in fact reflect age-related declines in cognitive abilities. In the current study, older and younger adults completed a simpler, paired lottery choice task used in the experimental economics literature to elicit risk aversion. A similar approach was used to elicit participants' discount rates. The older adult group was more risk averse than younger adults (p Risk aversion and implied discount rates were weakly correlated. It may be valuable to investigate developmental changes in neural correlates of decision-making across the lifespan.

  13. Reducing constraints on quantum computer design by encoded selective recoupling

    International Nuclear Information System (INIS)

    Lidar, D.A.; Wu, L.-A.

    2002-01-01

    The requirement of performing both single-qubit and two-qubit operations in the implementation of universal quantum logic often leads to very demanding constraints on quantum computer design. We show here how to eliminate the need for single-qubit operations in a large subset of quantum computer proposals: those governed by isotropic and XXZ , XY -type anisotropic exchange interactions. Our method employs an encoding of one logical qubit into two physical qubits, while logic operations are performed using an analogue of the NMR selective recoupling method

  14. Ambiguity aversion and household portfolio choice puzzles: Empirical evidence*

    Science.gov (United States)

    Dimmock, Stephen G.; Kouwenberg, Roy; Mitchell, Olivia S.; Peijnenburg, Kim

    2017-01-01

    We test the relation between ambiguity aversion and five household portfolio choice puzzles: nonparticipation in equities, low allocations to equity, home-bias, own-company stock ownership, and portfolio under-diversification. In a representative US household survey, we measure ambiguity preferences using custom-designed questions based on Ellsberg urns. As theory predicts, ambiguity aversion is negatively associated with stock market participation, the fraction of financial assets in stocks, and foreign stock ownership, but it is positively related to own-company stock ownership. Conditional on stock ownership, ambiguity aversion is related to portfolio under-diversification, and during the financial crisis, ambiguity-averse respondents were more likely to sell stocks. PMID:28458446

  15. Ambiguity aversion and household portfolio choice puzzles: Empirical evidence.

    Science.gov (United States)

    Dimmock, Stephen G; Kouwenberg, Roy; Mitchell, Olivia S; Peijnenburg, Kim

    2016-03-01

    We test the relation between ambiguity aversion and five household portfolio choice puzzles: nonparticipation in equities, low allocations to equity, home-bias, own-company stock ownership, and portfolio under-diversification. In a representative US household survey, we measure ambiguity preferences using custom-designed questions based on Ellsberg urns. As theory predicts, ambiguity aversion is negatively associated with stock market participation, the fraction of financial assets in stocks, and foreign stock ownership, but it is positively related to own-company stock ownership. Conditional on stock ownership, ambiguity aversion is related to portfolio under-diversification, and during the financial crisis, ambiguity-averse respondents were more likely to sell stocks.

  16. A Moist Crevice for Word Aversion: In Semantics Not Sounds.

    Directory of Open Access Journals (Sweden)

    Paul H Thibodeau

    Full Text Available Why do people self-report an aversion to words like "moist"? The present studies represent an initial scientific exploration into the phenomenon of word aversion by investigating its prevalence and cause. Results of five experiments indicate that about 10-20% of the population is averse to the word "moist." This population often speculates that phonological properties of the word are the cause of their displeasure. However, data from the current studies point to semantic features of the word-namely, associations with disgusting bodily functions-as a more prominent source of peoples' unpleasant experience. "Moist," for averse participants, was notable for its valence and personal use, rather than imagery or arousal-a finding that was confirmed by an experiment designed to induce an aversion to the word. Analyses of individual difference measures suggest that word aversion is more prevalent among younger, more educated, and more neurotic people, and is more commonly reported by females than males.

  17. An evolutionarily conserved gene family encodes proton-selective ion channels.

    Science.gov (United States)

    Tu, Yu-Hsiang; Cooper, Alexander J; Teng, Bochuan; Chang, Rui B; Artiga, Daniel J; Turner, Heather N; Mulhall, Eric M; Ye, Wenlei; Smith, Andrew D; Liman, Emily R

    2018-03-02

    Ion channels form the basis for cellular electrical signaling. Despite the scores of genetically identified ion channels selective for other monatomic ions, only one type of proton-selective ion channel has been found in eukaryotic cells. By comparative transcriptome analysis of mouse taste receptor cells, we identified Otopetrin1 (OTOP1), a protein required for development of gravity-sensing otoconia in the vestibular system, as forming a proton-selective ion channel. We found that murine OTOP1 is enriched in acid-detecting taste receptor cells and is required for their zinc-sensitive proton conductance. Two related murine genes, Otop2 and Otop3 , and a Drosophila ortholog also encode proton channels. Evolutionary conservation of the gene family and its widespread tissue distribution suggest a broad role for proton channels in physiology and pathophysiology. Copyright © 2018 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works.

  18. Risk-Averse Newsvendor Model with Strategic Consumer Behavior

    Directory of Open Access Journals (Sweden)

    Tie Wang

    2013-01-01

    Full Text Available The classic newsvendor problem focuses on maximizing the expected profit or minimizing the expected cost when the newsvendor faces myopic customers. However, it ignores the customer’s bargain-hunting behavior and risk preference measure of the newsvendor. As a result, we carry out the rational expectation (RE equilibrium analysis for risk-averse newsvendor facing forward-looking customers who anticipate future sales and choose purchasing timing to maximize their expected surplus. We propose the equations satisfied by the RE equilibrium price and quantity for the risk-averse retailer in general setting and the explicit equilibrium decisions for the case where demand follows the uniform distribution and utility is a general power function. We identify the impacts of the system parameters on the RE equilibrium for this specific situation. In particular, we show that the RE equilibrium price for some risk-averse newsvendors is lower than for a risk-neutral retailer and the RE equilibrium stocking quantity for some risk-averse newsvendors is higher than for a risk-neutral retailer. We also find that the RE equilibrium sale price for a risk-averse newsvendor is decreasing in salvage price in some situations.

  19. Optimal Consumption and Investment under Time-Varying Relative Risk Aversion

    DEFF Research Database (Denmark)

    Steffensen, Mogens

    2011-01-01

    We consider the continuous time consumption-investment problem originally formalized and solved by Merton in case of constant relative risk aversion. We present a complete solution for the case where relative risk aversion with respect to consumption varies with time, having in mind an investor...... with age-dependent risk aversion. This provides a new motivation for life-cycle investment rules. We study the optimal consumption and investment rules, in particular in the case where the relative risk aversion with respect to consumption is increasing with age....

  20. Self-Other Decision Making and Loss Aversion

    Science.gov (United States)

    Polman, Evan

    2012-01-01

    In eight studies, we tested the prediction that making choices for others involves less loss aversion than making choices for the self. We found that loss aversion is significantly lessened among people choosing for others in scenarios describing riskless choice (Study 1), gambling (Studies 2 and 3), and social aspects of life, such as likeably…

  1. Aversive smell associations shape social judgment

    OpenAIRE

    Homan, Philipp; Ely, Benjamin A.; Yuan, May; Brosch, Tobias; Ng, John; Trope, Yaacov; Schiller, Daniela

    2017-01-01

    Once associating another person with an unpleasant smell, how do we perceive and judge this person from that moment on? Here, we used aversive olfactory conditioning followed by a social attribution task during functional magnetic resonance imaging to address this question. After conditioning, where one of two faces was repeatedly paired with an aversive smell, the participants reported negative affect when viewing the smell-conditioned but not the neutral face. When subsequently confronted w...

  2. Memory reconsolidation in aversive and appetitive settings

    Directory of Open Access Journals (Sweden)

    Amy Claire Reichelt

    2013-09-01

    Full Text Available Memory reconsolidation has been observed across species and in a number of behavioural paradigms. The majority of memory reconsolidation studies have been carried out in pavlovian fear conditioning and other aversive memory settings, with potential implications for the treatment of post-traumatic stress disorder. However, there is a growing literature on memory reconsolidation in appetitive reward-related memory paradigms, including translational models of drug addiction. While there appears to be substantial similarity in the basic phenomenon and underlying mechanisms of memory reconsolidation across unconditioned stimulus valence, there are also notable discrepancies. These arise both when comparing aversive to appetitive paradigms and also across different paradigms within the same valence of memory. We review the demonstration of memory reconsolidation across different aversive and appetitive memory paradigms, the commonalities and differences in underlying mechanisms and the conditions under which each memory undergoes reconsolidation. We focus particularly on whether principles derived from the aversive literature are applicable to appetitive settings, and also whether the expanding literature in appetitive paradigms is informative for fear memory reconsolidation.

  3. Characterizing the genetic influences on risk aversion.

    Science.gov (United States)

    Harrati, Amal

    2014-01-01

    Risk aversion has long been cited as an important factor in retirement decisions, investment behavior, and health. Some of the heterogeneity in individual risk tolerance is well understood, reflecting age gradients, wealth gradients, and similar effects, but much remains unexplained. This study explores genetic contributions to heterogeneity in risk aversion among older Americans. Using over 2 million genetic markers per individual from the U.S. Health and Retirement Study, I report results from a genome-wide association study (GWAS) on risk preferences using a sample of 10,455 adults. None of the single-nucleotide polymorphisms (SNPs) are found to be statistically significant determinants of risk preferences at levels stricter than 5 × 10(-8). These results suggest that risk aversion is a complex trait that is highly polygenic. The analysis leads to upper bounds on the number of genetic effects that could exceed certain thresholds of significance and still remain undetected at the current sample size. The findings suggest that the known heritability in risk aversion is likely to be driven by large numbers of genetic variants, each with a small effect size.

  4. Decision-Making in Suicidal Behavior: The Protective Role of Loss Aversion.

    Science.gov (United States)

    Hadlaczky, Gergö; Hökby, Sebastian; Mkrtchian, Anahit; Wasserman, Danuta; Balazs, Judit; Machín, Núria; Sarchiapone, Marco; Sisask, Merike; Carli, Vladimir

    2018-01-01

    Loss aversion is a central and well operationalized trait behavior that describes the tendency for humans to strongly prefer avoiding losses to making equivalent gains. Human decision-making is thus biased toward safer choices. The aim of this study was to explore the relationship between loss aversion and suicidal behavior in a large cohort of adolescents recruited in 30 schools of seven European countries for a longitudinal study (Current Controlled Trials ISRCTN65120704). We hypothesized that individuals with higher loss aversion would be less likely to attempt suicide. A mixed monetary gamble task was used to generate loss aversion scores for each participant. Logistic regression was used to estimate the cross-sectional association between loss aversion and life-time suicide attempts in the baseline sample ( N  = 2,158; 156 attempters), and incident attempts were predicted in a 4-month prospective model ( N  = 1,763; 75 attempters). Multiple regression was used to estimate the association between loss aversion and suicidal ideation. Loss aversion was a significant predictor of attempted suicide in both the cross-sectional (OR = 0.79; P  = 0.005) and prospective analysis (OR = 0.81; P  = 0.040), adjusting for depression, anxiety, stress, and sex. The correlation between pre and post measures of loss aversion was r  = 0.52 ( P  loss aversion was not (cross-sectional model: P  = 0.092; Prospective model: P  = 0.390). This suggests that the concept of loss aversion may be useful in understanding the transition from suicidal thoughts to attempts. This and previous studies suggest that altered decision-making is involved in suicide attempts. In our study, we show the involvement of loss aversion in particular, and propose that individuals high in loss aversion are discouraged from carrying out the suicide attempt because of a greater focus on the negative consequences of the decision.

  5. Loss aversion and 5HTT gene variants in adolescent anxiety

    Directory of Open Access Journals (Sweden)

    Monique Ernst

    2014-04-01

    Full Text Available Loss aversion, a well-documented behavioral phenomenon, characterizes decisions under risk in adult populations. As such, loss aversion may provide a reliable measure of risky behavior. Surprisingly, little is known about loss aversion in adolescents, a group who manifests risk-taking behavior, or in anxiety disorders, which are associated with risk-avoidance. Finally, loss aversion is expected to be modulated by genotype, particularly the serotonin transporter (SERT gene variant, based on its role in anxiety and impulsivity. This genetic modulation may also differ between anxious and healthy adolescents, given their distinct propensities for risk taking. The present work examines the modulation of loss aversion, an index of risk-taking, and reaction-time to decision, an index of impulsivity, by the serotonin-transporter-gene-linked polymorphisms (5HTTLPR in healthy and clinically anxious adolescents. Findings show that loss aversion (1 does manifest in adolescents, (2 does not differ between healthy and clinically anxious participants, and (3, when stratified by SERT genotype, identifies a subset of anxious adolescents who are high SERT-expressers, and show excessively low loss-aversion and high impulsivity. This last finding may serve as preliminary evidence for 5HTTLPR as a risk factor for the development of comorbid disorders associated with risk-taking and impulsivity in clinically anxious adolescents.

  6. Health shocks and risk aversion.

    Science.gov (United States)

    Decker, Simon; Schmitz, Hendrik

    2016-12-01

    We empirically assess whether a health shock influences individual risk aversion. We use grip strength data to obtain an objective health shock indicator. In order to account for the non-random nature of our data regression-adjusted matching is employed. Risk preferences are traditionally assumed to be constant. However, we find that a health shock increases individual risk aversion. The finding is robust to a series of sensitivity analyses and persists for at least four years after the shock. Income changes do not seem to be the driving mechanism. Copyright © 2016 Elsevier B.V. All rights reserved.

  7. Probability Weighting and Loss Aversion in Futures Hedging

    NARCIS (Netherlands)

    Mattos, F.; Garcia, P.; Pennings, J.M.E.

    2008-01-01

    We analyze how the introduction of probability weighting and loss aversion in a futures hedging model affects decision making. Analytical findings indicate that probability weighting alone always affects optimal hedge ratios, while loss and risk aversion only have an impact when probability

  8. Feasible sets, comparative risk aversion, and comparative uncertainty aversion in bargaining

    NARCIS (Netherlands)

    Driesen, B.W.I.; Lombardi, M.; Peters, H.J.M.

    2015-01-01

    We study feasible sets of the bargaining problem under two different assumptions: the players are subjective expected utility maximizers or the players are Choquet expected utility maximizers. For the latter case, we consider the effects on bargaining solutions when players become more risk averse

  9. Combined Effects of Glucocorticoid and Noradrenergic Activity on Loss Aversion.

    Science.gov (United States)

    Margittai, Zsofia; Nave, Gideon; Van Wingerden, Marijn; Schnitzler, Alfons; Schwabe, Lars; Kalenscher, Tobias

    2018-01-01

    Loss aversion is a well-known behavioral regularity in financial decision making, describing humans' tendency to overweigh losses compared to gains of the same amount. Recent research indicates that stress and associated hormonal changes affect loss aversion, yet the underlying neuroendocrine mechanisms are still poorly understood. Here, we investigated the causal influence of two major stress neuromodulators, cortisol and noradrenaline, on loss aversion during financial decision making. In a double-blind, placebo-controlled between-subject design, we orally administered either the α2-adrenergic antagonist yohimbine (increasing noradrenergic stimulation), hydrocortisone, both substances, or a placebo to healthy young men. We tested the treatments' influence on a financial decision-making task measuring loss aversion and risk attitude. We found that both drugs combined, relative to either drug by itself, reduced loss aversion in the absence of an effect on risk attitude or choice consistency. Our data suggest that concurrent glucocorticoid and noradrenergic activity prompts an alignment of reward- with loss-sensitivity, and thus diminishes loss aversion. Our results have implications for the understanding of the susceptibility to biases in decision making.

  10. Does ambiguity aversion survive in experimental asset markets?

    NARCIS (Netherlands)

    Füllbrunn, Sascha; Rau, Holger A.; Weitzel, Utz

    2014-01-01

    Although a number of theoretical studies explain empirical puzzles in finance with ambiguity aversion, it is not a given that individual ambiguity attitudes survive in markets. In fact, despite ample evidence of ambiguity aversion in individual decision making, most studies find no or only limited

  11. Inequity aversion revisted

    NARCIS (Netherlands)

    Yang, Y.; Onderstal, S.; Schram, A.

    2012-01-01

    We provide the first systematic study of the robustness of parameter estimates for the Fehr-Schmidt (1999) model of inequity aversion with respect to (i) the occurrence of efficiency concerns; (ii) the scale of payoffs; and (iii) the game used (i.e., cross-game consistency). Moreover, we provide

  12. Risk Aversion and Expected-Utility Theory: A Calibration Theorem.

    OpenAIRE

    Matthew Rabin.

    2000-01-01

    Within the expected-utility framework, the only explanation for risk aversion is that the utility function for wealth is concave: A person has lower marginal utility for additional wealth when she is wealthy than when she is poor. This paper provides a theorem showing that expected-utility theory is an utterly implausible explanation for appreciable risk aversion over modest stakes: Within expected-utility theory, for any concave utility function, even very little risk aversion over modest st...

  13. Loss aversion and 5HTT gene variants in adolescent anxiety.

    Science.gov (United States)

    Ernst, Monique; Plate, Rista C; Carlisi, Christina O; Gorodetsky, Elena; Goldman, David; Pine, Daniel S

    2014-04-01

    Loss aversion, a well-documented behavioral phenomenon, characterizes decisions under risk in adult populations. As such, loss aversion may provide a reliable measure of risky behavior. Surprisingly, little is known about loss aversion in adolescents, a group who manifests risk-taking behavior, or in anxiety disorders, which are associated with risk-avoidance. Finally, loss aversion is expected to be modulated by genotype, particularly the serotonin transporter (SERT) gene variant, based on its role in anxiety and impulsivity. This genetic modulation may also differ between anxious and healthy adolescents, given their distinct propensities for risk taking. The present work examines the modulation of loss aversion, an index of risk-taking, and reaction-time to decision, an index of impulsivity, by the serotonin-transporter-gene-linked polymorphisms (5HTTLPR) in healthy and clinically anxious adolescents. Findings show that loss aversion (1) does manifest in adolescents, (2) does not differ between healthy and clinically anxious participants, and (3), when stratified by SERT genotype, identifies a subset of anxious adolescents who are high SERT-expressers, and show excessively low loss-aversion and high impulsivity. This last finding may serve as preliminary evidence for 5HTTLPR as a risk factor for the development of comorbid disorders associated with risk-taking and impulsivity in clinically anxious adolescents. Copyright © 2013 The Authors. Published by Elsevier Ltd.. All rights reserved.

  14. Myopic loss aversion: Potential causes of replication failures

    Directory of Open Access Journals (Sweden)

    Alexander Klos

    2013-09-01

    Full Text Available This paper presents two studies on narrow bracketing and myopic loss aversion. The first study shows that the tendency to segregate multiple gambles is eliminated if subjects face a certainty equivalent or a probability equivalent task instead of a binary choice. The second study argues that the behavioral differences previously attributed entirely to myopic loss aversion are partly because long-term return properties are simply easier to grasp if the return information is already provided in the form of long-term returns rather than one-year returns. Both results may be related to recent failures to replicate myopic loss aversion. When the choice situation is structured in such a way that it draws respondents' attention to the final outcome distribution and/or if severe misestimations of long-term returns based on short-term return information are unlikely, behavioral differences consistent with myopic loss aversion are less likely to be observed.

  15. Loss Aversion Reflects Information Accumulation, Not Bias: A Drift-Diffusion Model Study.

    Science.gov (United States)

    Clay, Summer N; Clithero, John A; Harris, Alison M; Reed, Catherine L

    2017-01-01

    Defined as increased sensitivity to losses, loss aversion is often conceptualized as a cognitive bias. However, findings that loss aversion has an attentional or emotional regulation component suggest that it may instead reflect differences in information processing. To distinguish these alternatives, we applied the drift-diffusion model (DDM) to choice and response time (RT) data in a card gambling task with unknown risk distributions. Loss aversion was measured separately for each participant. Dividing the participants into terciles based on loss aversion estimates, we found that the most loss-averse group showed a significantly lower drift rate than the other two groups, indicating overall slower uptake of information. In contrast, neither the starting bias nor the threshold separation (barrier) varied by group, suggesting that decision thresholds are not affected by loss aversion. These results shed new light on the cognitive mechanisms underlying loss aversion, consistent with an account based on information accumulation.

  16. Visual encoding and fixation target selection in free viewing: presaccadic brain potentials

    Directory of Open Access Journals (Sweden)

    Andrey R Nikolaev

    2013-06-01

    Full Text Available In scrutinizing a scene, the eyes alternate between fixations and saccades. During a fixation, two component processes can be distinguished: visual encoding and selection of the next fixation target. We aimed to distinguish the neural correlates of these processes in the electrical brain activity prior to a saccade onset. Participants viewed color photographs of natural scenes, in preparation for a change detection task. Then, for each participant and each scene we computed an image heat map, with temperature representing the duration and density of fixations. The temperature difference between the start and end points of saccades was taken as a measure of the expected task-relevance of the information concentrated in specific regions of a scene. Visual encoding was evaluated according to whether subsequent change was correctly detected. Saccades with larger temperature difference were more likely to be followed by correct detection than ones with smaller temperature differences. The amplitude of presaccadic activity over anterior brain areas was larger for correct detection than for detection failure. This difference was observed for short scrutinizing but not for long explorative saccades, suggesting that presaccadic activity reflects top-down saccade guidance. Thus, successful encoding requires local scanning of scene regions which are expected to be task-relevant. Next, we evaluated fixation target selection. Saccades moving up in temperature were preceded by presaccadic activity of higher amplitude than those moving down. This finding suggests that presaccadic activity reflects attention deployed to the following fixation location. Our findings illustrate how presaccadic activity can elucidate concurrent brain processes related to the immediate goal of planning the next saccade and the larger-scale goal of constructing a robust representation of the visual scene.

  17. Choice Behavior Guided by Learned, But Not Innate, Taste Aversion Recruits the Orbitofrontal Cortex.

    Science.gov (United States)

    Ramírez-Lugo, Leticia; Peñas-Rincón, Ana; Ángeles-Durán, Sandybel; Sotres-Bayon, Francisco

    2016-10-12

    The ability to select an appropriate behavioral response guided by previous emotional experiences is critical for survival. Although much is known about brain mechanisms underlying emotional associations, little is known about how these associations guide behavior when several choices are available. To address this, we performed local pharmacological inactivations of several cortical regions before retrieval of an aversive memory in choice-based versus no-choice-based conditioned taste aversion (CTA) tasks in rats. Interestingly, we found that inactivation of the orbitofrontal cortex (OFC), but not the dorsal or ventral medial prefrontal cortices, blocked retrieval of choice CTA. However, OFC inactivation left retrieval of no-choice CTA intact, suggesting its role in guiding choice, but not in retrieval of CTA memory. Consistently, OFC activity increased in the choice condition compared with no-choice, as measured with c-Fos immunolabeling. Notably, OFC inactivation did not affect choice behavior when it was guided by innate taste aversion. Consistent with an anterior insular cortex (AIC) involvement in storing taste memories, we found that AIC inactivation impaired retrieval of both choice and no-choice CTA. Therefore, this study provides evidence for OFC's role in guiding choice behavior and shows that this is dissociable from AIC-dependent taste aversion memory. Together, our results suggest that OFC is required and recruited to guide choice selection between options of taste associations relayed from AIC. Survival and mental health depend on being able to choose stimuli not associated with danger. This is particularly important when danger is associated with stimuli that we ingest. Although much is known about the brain mechanisms that underlie associations with dangerous taste stimuli, very little is known about how these stored emotional associations guide behavior when it involves choice. By combining pharmacological and immunohistochemistry tools with taste

  18. Children do not exhibit ambiguity aversion despite intact familiarity bias.

    Science.gov (United States)

    Li, Rosa; Brannon, Elizabeth M; Huettel, Scott A

    2014-01-01

    The phenomenon of ambiguity aversion, in which risky gambles with known probabilities are preferred over ambiguous gambles with unknown probabilities, has been thoroughly documented in adults but never measured in children. Here, we use two distinct tasks to investigate ambiguity preferences of children (8- to 9-year-olds) and a comparison group of adults (19- to 27-year-olds). Across three separate measures, we found evidence for significant ambiguity aversion in adults but not in children and for greater ambiguity aversion in adults compared to children. As ambiguity aversion in adults has been theorized to result from a preference to bet on the known and avoid the unfamiliar, we separately measured familiarity bias and found that children, like adults, are biased towards the familiar. Our findings indicate that ambiguity aversion emerges across the course of development between childhood and adolescence, while a familiarity bias is already present in childhood.

  19. Further evidence for conditioned taste aversion induced by forced swimming.

    Science.gov (United States)

    Masaki, Takahisa; Nakajima, Sadahiko

    2005-01-31

    A series of experiments with rats reported that aversion to a taste solution can be established by forced swimming in a water pool. Experiment 1 demonstrated that correlation of taste and swimming is a critical factor for this phenomenon, indicating associative (i.e., Pavlovian) nature of this learning. Experiment 2 showed that this learning obeys the Pavlovian law of strength, by displaying a positive relationship between the duration of water immersion in training and the taste aversion observed in subsequent testing. Experiment 3 revealed that swimming rather than being wet is the critical agent, because a water shower did not endow rats with taste aversion. Experiment 4 found that taste aversion was a positive function of water level of the pools in training (0, 12 or 32 cm). These results, taken together, suggest that energy expenditure caused by physical exercise might be involved in the development of taste aversion.

  20. Loss-Averse Retailer’s Optimal Ordering Policies for Perishable Products with Customer Returns

    Directory of Open Access Journals (Sweden)

    Xu Chen

    2014-01-01

    Full Text Available We investigate the loss-averse retailer’s ordering policies for perishable product with customer returns. With the introduction of the segmental loss utility function, we depict the retailer’s loss aversion decision bias and establish the loss-averse retailer’s ordering policy model. We derive that the loss-averse retailer’s optimal order quantity with customer returns exists and is unique. By comparison, we obtain that both the risk-neutral and the loss-averse retailer’s optimal order quantities depend on the inventory holding cost and the marginal shortage cost. Through the sensitivity analysis, we also discuss the effect of loss-averse coefficient and the ratio of return on the loss-averse retailer’s optimal order quantity with customer returns.

  1. Anxiety and spatial attention moderate the electrocortical response to aversive pictures.

    Science.gov (United States)

    MacNamara, Annmarie; Hajcak, Greg

    2009-11-01

    Aversive stimuli capture attention and elicit increased neural activity, as indexed by behavioral, electrocortical and hemodynamic measures; moreover, individual differences in anxiety relate to a further increased sensitivity to threatening stimuli. Evidence has been mixed, however, as to whether aversive pictures elicit increased neural response when presented in unattended spatial locations. In the current study, ERP and behavioral data were recorded from 49 participants as aversive and neutral pictures were simultaneously presented in spatially attended and unattended locations; on each trial, participants made same/different judgments about pictures presented in attended locations. Aversive images presented in unattended locations resulted in increased error rate and reaction time. The late positive potential (LPP) component of the ERP was only larger when aversive images were presented in attended locations, and this increase was positively correlated with self-reported state anxiety. Findings are discussed in regard to the sensitivity of ERP and behavioral responses to aversive distracters, and in terms of increased neural processing of threatening stimuli in anxiety.

  2. Loss Aversion Reflects Information Accumulation, Not Bias: A Drift-Diffusion Model Study

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    Summer N. Clay

    2017-10-01

    Full Text Available Defined as increased sensitivity to losses, loss aversion is often conceptualized as a cognitive bias. However, findings that loss aversion has an attentional or emotional regulation component suggest that it may instead reflect differences in information processing. To distinguish these alternatives, we applied the drift-diffusion model (DDM to choice and response time (RT data in a card gambling task with unknown risk distributions. Loss aversion was measured separately for each participant. Dividing the participants into terciles based on loss aversion estimates, we found that the most loss-averse group showed a significantly lower drift rate than the other two groups, indicating overall slower uptake of information. In contrast, neither the starting bias nor the threshold separation (barrier varied by group, suggesting that decision thresholds are not affected by loss aversion. These results shed new light on the cognitive mechanisms underlying loss aversion, consistent with an account based on information accumulation.

  3. Risk Aversion, Loss Aversion, and the Demand for Insurance

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    Louis Eeckhoudt

    2018-05-01

    Full Text Available In this paper we analyze insurance demand when the utility function depends both upon final wealth and the level of losses or gains relative to a reference point. Besides some comparative statics results, we discuss the links with first-order risk aversion, with the Omega measure, and with a tendency to over-insure modest risks that has been been extensively documented in real insurance markets.

  4. RELATIONSHIP BETWEEN THE TASK AVERSIVENESS AND ACADEMIC PROCRASTINATION

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    Magvirasari Lestari Linra

    2016-12-01

    Full Text Available Academic procrastination occurs when certain tasks are considered unpleasant, an unpleasant task and the usual delayed them is the task of writing, reading, studying for the exam, meetings, and administrative. The purpose of this study was to determine the relationship of the task aversiveness with academic procrastination. Subject of the study were 100 students out of a population of 516 students of the Faculty of Psychology class of 2012-2014. The method used in this research is quantitative by using Spearman rho as data analysis techniques. The research instrument consists of academic procrastination scale and the scale of the task aversiveness. Based on the results of correlation is known that there is a positive relationship between task aversiveness with academic procrastination with a correlation coefficient r = 0.508; p = 0.000. The results showed that of the 100 students of the Faculty of Psychology University of Makassar has a degree of relationship between task aversiveness with academic procrastination is on the very low category (25, 8%. Area / types of tasks delayed is not necessarily an unpleasant task and otherwise unpleasant task may not be postponed. Area task the highest level of aversive and delays are areas the task of writing and reading. This study illustrates that academic procrastination can be lowered by a change in the mindset of an unpleasant task.

  5. Cognitive function is associated with risk aversion in community-based older persons.

    Science.gov (United States)

    Boyle, Patricia A; Yu, Lei; Buchman, Aron S; Laibson, David I; Bennett, David A

    2011-09-11

    Emerging data from younger and middle-aged persons suggest that cognitive ability is negatively associated with risk aversion, but this association has not been studied among older persons who are at high risk of experiencing loss of cognitive function. Using data from 369 community-dwelling older persons without dementia from the Rush Memory and Aging Project, an ongoing longitudinal epidemiologic study of aging, we examined the correlates of risk aversion and tested the hypothesis that cognition is negatively associated with risk aversion. Global cognition and five specific cognitive abilities were measured via detailed cognitive testing, and risk aversion was measured using standard behavioral economics questions in which participants were asked to choose between a certain monetary payment ($15) versus a gamble in which they could gain more than $15 or gain nothing; potential gamble gains ranged from $21.79 to $151.19 with the gain amounts varied randomly over questions. We first examined the bivariate associations of age, education, sex, income and cognition with risk aversion. Next, we examined the associations between cognition and risk aversion via mixed models adjusted for age, sex, education, and income. Finally, we conducted sensitivity analyses to ensure that our results were not driven by persons with preclinical cognitive impairment. In bivariate analyses, sex, education, income and global cognition were associated with risk aversion. However, in a mixed effect model, only sex (estimate = -1.49, standard error (SE) = 0.39, p risk aversion. Thus, a lower level of global cognitive function and female sex were associated with greater risk aversion. Moreover, performance on four out of the five cognitive domains was negatively related to risk aversion (i.e., semantic memory, episodic memory, working memory, and perceptual speed); performance on visuospatial abilities was not. A lower level of cognitive ability and female sex are associated with greater

  6. Gender differences in financial risk aversion and career choices are affected by testosterone.

    Science.gov (United States)

    Sapienza, Paola; Zingales, Luigi; Maestripieri, Dario

    2009-09-08

    Women are generally more risk averse than men. We investigated whether between- and within-gender variation in financial risk aversion was accounted for by variation in salivary concentrations of testosterone and in markers of prenatal testosterone exposure in a sample of >500 MBA students. Higher levels of circulating testosterone were associated with lower risk aversion among women, but not among men. At comparably low concentrations of salivary testosterone, however, the gender difference in risk aversion disappeared, suggesting that testosterone has nonlinear effects on risk aversion regardless of gender. A similar relationship between risk aversion and testosterone was also found using markers of prenatal testosterone exposure. Finally, both testosterone levels and risk aversion predicted career choices after graduation: Individuals high in testosterone and low in risk aversion were more likely to choose risky careers in finance. These results suggest that testosterone has both organizational and activational effects on risk-sensitive financial decisions and long-term career choices.

  7. Enhanced striatal sensitivity to aversive reinforcement in adolescents versus adults.

    Science.gov (United States)

    Galván, Adriana; McGlennen, Kristine M

    2013-02-01

    Neurodevelopmental changes in mesolimbic regions are associated with adolescent risk-taking behavior. Numerous studies have shown exaggerated activation in the striatum in adolescents compared with children and adults during reward processing. However, striatal sensitivity to aversion remains elusive. Given the important role of the striatum in tracking both appetitive and aversive events, addressing this question is critical to understanding adolescent decision-making, as both positive and negative factors contribute to this behavior. In this study, human adult and adolescent participants performed a task in which they received squirts of appetitive or aversive liquid while undergoing fMRI, a novel approach in human adolescents. Compared with adults, adolescents showed greater behavioral and striatal sensitivity to both appetitive and aversive stimuli, an effect that was exaggerated in response to delivery of the aversive stimulus. Collectively, these findings contribute to understanding how neural responses to positive and negative outcomes differ between adolescents and adults and how they may influence adolescent behavior.

  8. Are group members less inequality averse than individual decision makers?

    OpenAIRE

    He, Haoran; Villeval, Marie Claire

    2017-01-01

    International audience; We compare inequality aversion in individuals and teams by means of both within- and between-subject experimental designs, and we investigate how teams aggregate individual preferences. We find that team decisions reveal less inequality aversion than individual initial proposals in team decision-making. However, teams are no more selfish than individuals who decide in isolation. Individuals express strategically more inequality aversion in their initial proposals in te...

  9. Risk Aversion and Emotions

    NARCIS (Netherlands)

    Nguyen, Y.; Noussair, C.N.

    2013-01-01

    Abstract: We consider the relationship between emotions and decision-making under risk. Specifically, we examine the emotional correlates of risk-averse decisions. In our experiment, individuals' facial expressions are monitored with facereading software, as they are presented with risky lotteries.

  10. Can natural selection encode Bayesian priors?

    Science.gov (United States)

    Ramírez, Juan Camilo; Marshall, James A R

    2017-08-07

    The evolutionary success of many organisms depends on their ability to make decisions based on estimates of the state of their environment (e.g., predation risk) from uncertain information. These decision problems have optimal solutions and individuals in nature are expected to evolve the behavioural mechanisms to make decisions as if using the optimal solutions. Bayesian inference is the optimal method to produce estimates from uncertain data, thus natural selection is expected to favour individuals with the behavioural mechanisms to make decisions as if they were computing Bayesian estimates in typically-experienced environments, although this does not necessarily imply that favoured decision-makers do perform Bayesian computations exactly. Each individual should evolve to behave as if updating a prior estimate of the unknown environment variable to a posterior estimate as it collects evidence. The prior estimate represents the decision-maker's default belief regarding the environment variable, i.e., the individual's default 'worldview' of the environment. This default belief has been hypothesised to be shaped by natural selection and represent the environment experienced by the individual's ancestors. We present an evolutionary model to explore how accurately Bayesian prior estimates can be encoded genetically and shaped by natural selection when decision-makers learn from uncertain information. The model simulates the evolution of a population of individuals that are required to estimate the probability of an event. Every individual has a prior estimate of this probability and collects noisy cues from the environment in order to update its prior belief to a Bayesian posterior estimate with the evidence gained. The prior is inherited and passed on to offspring. Fitness increases with the accuracy of the posterior estimates produced. Simulations show that prior estimates become accurate over evolutionary time. In addition to these 'Bayesian' individuals, we also

  11. Are team members less inequality averse than individual decision makers?

    OpenAIRE

    Haoran He; Marie Claire Villeval

    2014-01-01

    révision Août 2015; We compare inequality aversion in individuals and teams by means of both within- and between-subject experimental designs, and we investigate how teams aggregate individual preferences. We find that team decisions reveal less inequality aversion than individual initial proposals in team decision-making. However, teams are no more selfish than individuals who decide in isolation. Individuals express strategically more inequality aversion in their initial proposals in team d...

  12. Common brain activations for painful and non-painful aversive stimuli

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    Hayes Dave J

    2012-06-01

    Full Text Available Abstract Background Identification of potentially harmful stimuli is necessary for the well-being and self-preservation of all organisms. However, the neural substrates involved in the processing of aversive stimuli are not well understood. For instance, painful and non-painful aversive stimuli are largely thought to activate different neural networks. However, it is presently unclear whether there is a common aversion-related network of brain regions responsible for the basic processing of aversive stimuli. To help clarify this issue, this report used a cross-species translational approach in humans (i.e. meta-analysis and rodents (i.e. systematic review of functional neuroanatomy. Results Animal and human data combined to show a core aversion-related network, consisting of similar cortical (i.e. MCC, PCC, AI, DMPFC, RTG, SMA, VLOFC; see results section or abbreviation section for full names and subcortical (i.e. Amyg, BNST, DS, Hab, Hipp/Parahipp, Hyp, NAc, NTS, PAG, PBN, raphe, septal nuclei, Thal, LC, midbrain regions. In addition, a number of regions appeared to be more involved in pain-related (e.g. sensory cortex or non-pain-related (e.g. amygdala aversive processing. Conclusions This investigation suggests that aversive processing, at the most basic level, relies on similar neural substrates, and that differential responses may be due, in part, to the recruitment of additional structures as well as the spatio-temporal dynamic activity of the network. This network perspective may provide a clearer understanding of why components of this circuit appear dysfunctional in some psychiatric and pain-related disorders.

  13. PKMζ maintains drug reward and aversion memory in the basolateral amygdala and extinction memory in the infralimbic cortex.

    Science.gov (United States)

    He, Ying-Ying; Xue, Yan-Xue; Wang, Ji-Shi; Fang, Qin; Liu, Jian-Feng; Xue, Li-Fen; Lu, Lin

    2011-09-01

    The intense associative memories that develop between drug-paired contextual cues and rewarding stimuli or the drug withdrawal-associated aversive feeling have been suggested to contribute to the high rate of relapse. Various studies have elucidated the mechanisms underlying the formation and expression of drug-related cue memories, but how this mechanism is maintained is unknown. Protein kinase M ζ (PKMζ) was recently shown to be necessary and sufficient for long-term potentiation maintenance and memory storage. In the present study, we used conditioned place preference (CPP) and aversion (CPA) to examine whether PKMζ maintains both morphine-associated reward memory and morphine withdrawal-associated aversive memory in the basolateral amygdala (BLA). We also investigate the role of PKMζ in the infralimbic cortex in the extinction memory of morphine reward-related cues and morphine withdrawal-related aversive cues. We found that intra-BLA but not central nucleus of the amygdala injection of the selective PKMζ inhibitor ZIP 1 day after CPP and CPA training impaired the expression of CPP and CPA 1 day later, and the effect of ZIP on memory lasted at least 2 weeks. Inhibiting PKMζ activity in the infralimbic cortex, but not prelimbic cortex, disrupted the expression of the extinction memory of CPP and CPA. These results indicate that PKMζ in the BLA is required for the maintenance of associative morphine reward memory and morphine withdrawal-associated aversion memory, and PKMζ in the infralimbic cortex is required for the maintenance of extinction memory of morphine reward-related cues and morphine withdrawal-related aversive cues.

  14. Decomposing Self-Control:Individual Differences in Goal Pursuit Despite Interfering Aversion, Temptation, and Distraction

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    Rosa eSteimke

    2016-04-01

    Full Text Available Self-control can be defined as the ability to exert control over ones impulses. Currently, most research in the area relies on self-report. Focusing on attentional control processes involved in self-control, we modified a spatial selective attentional cueing task to test three domains of self-control experimentally in one task using aversive, tempting, and neutral picture-distractors. The aims of the study were (1 to investigate individual differences in the susceptibility to aversive, tempting and neutral distraction within one paradigm and (2 to test the association of these three self-control domains to conventional measures of self-control including self-report. The final sample consisted of 116 participants. The task required participants to identify target letters E or F presented at a cued target location while the distractors were presented. Behavioral and eyetracking data were obtained during the performance of the task. High task performance was encouraged via monetary incentives. In addition to the attentional self-control task, self-reported self-control was assessed and participants performed a color Stroop task, an unsolvable anagram task and a delay of gratification task using chocolate sweets. We found that aversion, temptation, and neutral distraction were associated with significantly increased error rates, reaction times and gaze pattern deviations. Overall task performance on our task correlated with self-reported self-control ability. Measures of aversion, temptation, and distraction showed moderate split-half reliability, but did not correlate with each other across participants. Additionally, participants who made a self-controlled decision in the delay of gratification task were less distracted by temptations in our task than participants who made an impulsive choice. Our individual differences analyses suggest that (1 the ability to endure aversion, resist temptations and ignore neutral distractions are independent of

  15. Decomposing Self-Control: Individual Differences in Goal Pursuit Despite Interfering Aversion, Temptation, and Distraction

    Science.gov (United States)

    Steimke, Rosa; Stelzel, Christine; Gaschler, Robert; Rothkirch, Marcus; Ludwig, Vera U.; Paschke, Lena M.; Trempler, Ima; Kathmann, Norbert; Goschke, Thomas; Walter, Henrik

    2016-01-01

    Self-control can be defined as the ability to exert control over ones impulses. Currently, most research in the area relies on self-report. Focusing on attentional control processes involved in self-control, we modified a spatial selective attentional cueing task to test three domains of self-control experimentally in one task using aversive, tempting, and neutral picture-distractors. The aims of the study were (1) to investigate individual differences in the susceptibility to aversive, tempting, and neutral distraction within one paradigm and (2) to test the association of these three self-control domains to conventional measures of self-control including self-report. The final sample consisted of 116 participants. The task required participants to identify target letters “E” or “F” presented at a cued target location while the distractors were presented. Behavioral and eyetracking data were obtained during the performance of the task. High task performance was encouraged via monetary incentives. In addition to the attentional self-control task, self-reported self-control was assessed and participants performed a color Stroop task, an unsolvable anagram task and a delay of gratification task using chocolate sweets. We found that aversion, temptation, and neutral distraction were associated with significantly increased error rates, reaction times and gaze pattern deviations. Overall task performance on our task correlated with self-reported self-control ability. Measures of aversion, temptation, and distraction showed moderate split-half reliability, but did not correlate with each other across participants. Additionally, participants who made a self-controlled decision in the delay of gratification task were less distracted by temptations in our task than participants who made an impulsive choice. Our individual differences analyses suggest that (1) the ability to endure aversion, resist temptations and ignore neutral distractions are independent of each

  16. Loss Aversion under Prospect Theory: a Parameter-Free Measurement

    NARCIS (Netherlands)

    H. Bleichrodt (Han); M. Abdellaoui (Mohammed); C. Paraschiv (Corina)

    2007-01-01

    textabstractA growing body of qualitative evidence shows that loss aversion, a phenomenon formalized in prospect theory, can explain a variety of field and experimental data. Quantifications of loss aversion are, however, hindered by the absence of a general preference-based method to elicit the

  17. Aversive counterconditioning attenuates reward signalling in the ventral striatum

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    Anne Marije Kaag

    2016-08-01

    Full Text Available Appetitive conditioning refers to the process of learning cue-reward associations and is mediated by the mesocorticolimbic system. Appetitive conditioned responses are difficult to extinguish, especially for highly salient rewards such as food and drugs. We investigate whether aversive counterconditioning can alter reward reinstatement in the ventral striatum in healthy volunteers using functional Magnetic Resonance Imaging (fMRI. In the initial conditioning phase, two different stimuli were reinforced with a monetary reward. In the subsequent counterconditioning phase, one of these stimuli was paired with an aversive shock to the wrist. In the following extinction phase, none of the stimuli were reinforced. In the final reinstatement phase, reward was reinstated by informing the participants that the monetary gain could be doubled. Our fMRI data revealed that reward signalling in the ventral striatum and ventral tegmental area following reinstatement was smaller for the stimulus that was counterconditioned with an electrical shock, compared to the non-counterconditioned stimulus. A functional connectivity analysis showed that aversive counterconditioning strengthened striatal connectivity with the hippocampus and insula. These results suggest that reward signalling in the ventral striatum can be attenuated through aversive counterconditioning, possibly by concurrent retrieval of the aversive association through enhanced connectivity with hippocampus and insula.

  18. Differences in risk aversion between young and older adults

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    Albert SM

    2012-02-01

    Full Text Available Steven M Albert1, John Duffy21Department of Behavioral and Community Health Sciences, 2Department of Economics, University of Pittsburgh, Pittsburgh, PA, USAAbstract: Research on decision-making strategies among younger and older adults suggests that older adults may be more risk averse than younger people in the case of potential losses. These results mostly come from experimental studies involving gambling paradigms. Since these paradigms involve substantial demands on memory and learning, differences in risk aversion or other features of decision making attributed to age may in fact reflect age-related declines in cognitive abilities. In the current study, older and younger adults completed a simpler, paired lottery choice task used in the experimental economics literature to elicit risk aversion. A similar approach was used to elicit participants' discount rates. The older adult group was more risk averse than the younger (P < 0.05 and had a higher discount rate (15.6%–21.0% versus 10.3%–15.5%, P < 0.01, indicating lower expected utility from future income. Risk aversion and implied discount rates were weakly correlated. It may be valuable to investigate developmental changes in neural correlates of decision making across the lifespan.Keywords: aging, decision making, risk, time preference, behavioral economics

  19. Coordination of a Random Yield Supply Chain with a Loss-Averse Supplier

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    Jiarong Luo

    2015-01-01

    Full Text Available This paper investigates the coordination of a supply chain consisting of a loss-averse supplier and a risk-neutral buyer who orders products from the supplier who suffers from random yield to meet a deterministic demand. We derive the risk-neutral buyer’s optimal order policy and the loss-averse supplier’s optimal production policy under shortage-penalty-surplus-subsidy (SPSS contracts. We also analyze the impacts of loss aversion on the loss-averse supplier’s production decision making and find that the loss-averse supplier may produce less than, equal to, or more than the risk-neutral supplier. Then, we provide explicit conditions on which the random yield supply chain with a loss-averse supplier can be coordinated under SPSS contracts. Finally, adopting numerical examples, we find that when the shortage penalty is low, the buyer’s optimal order quantity will increase, while the supplier’s optimal production quantity will first decrease and then increase as the loss aversion level increases. When the shortage penalty is high, the buyer’s optimal order quantity will decrease but the supplier’s optimal production quantity will always increase as the loss aversion level increases. Furthermore, the numerical examples provide strong evidence for the view that SPSS contracts can effectively improve the performance of the whole supply chain.

  20. Genotype Modulates Age-Related Alterations in Sensitivity to the Aversive Effects of Ethanol: An 8 Inbred Strain Analysis of Conditioned Taste Aversion

    Science.gov (United States)

    Moore, Eileen M.; Forrest, Robert D.; Boehm, Stephen L.

    2012-01-01

    Adolescent individuals display altered behavioral sensitivity to ethanol, which may contribute to the increased ethanol consumption seen in this age-group. However, genetics also exert considerable influence on both ethanol intake and sensitivity. Thus far there is little research assessing the combined influence of developmental and genetic alcohol sensitivities. Sensitivity to the aversive effects of ethanol using a conditioned taste aversion (CTA) procedure was measured during both adolescence (P30) and adulthood (P75) in 8 inbred mouse strains (C57BL/6J, DBA/2J, 129S1/SvImJ, A/J, BALB/cByJ, BTBR T+tf/J, C3H/HeJ, and FVB/NJ). Adolescent and adult mice were water deprived, and subsequently provided with access to 0.9% (v/v) NaCl solution for 1h. Immediately following access mice were administered ethanol (0, 1.5, 2.25, 3g/kg, ip). This procedure was repeated in 72h intervals for a total of 5 CTA trials. Sensitivity to the aversive effects of ethanol was highly dependent upon both strain and age. Within an inbred strain, adolescent animals were consistently less sensitive to the aversive effects of ethanol than their adult counterparts. However, the dose of ethanol required to produce an aversion response differed as a function of both age and strain. PMID:23171343

  1. Neurocognitive development of risk aversion from early childhood to adulthood

    Directory of Open Access Journals (Sweden)

    David ePaulsen

    2012-01-01

    Full Text Available Human adults tend to avoid risk. In behavioral economic studies, risk aversion is manifest as a preference for sure gains over uncertain gains. However, children tend to be less averse to risk than adults. Given that many of the brain regions supporting decision making under risk do not reach maturity until late adolescence or beyond it is possible that mature risk-averse behavior may emerge from the development of decision-making circuitry. To explore this hypothesis, we tested 6- to 8-year-old children, 14- to 16-year-old adolescents, and young adults in a risky-decision task during functional magnetic resonance imaging (fMRI data acquisition. We found a number of decision-related brain regions to increase in activation with age during decision making, including areas associated with contextual memory retrieval and the incorporation of prior outcomes into the current decision-making strategy, e.g. insula, hippocampus and amygdala. Further, children who were more risk averse showed increased activation during decision making in vmPFC and ventral striatum. Our findings indicate that the emergence of adult levels of risk aversion co-occurs with the recruitment of regions supporting decision making under risk, including the integration of prior outcomes into current decision-making behavior. This pattern of results suggests that individual differences in the development of risk aversion may reflect differences in the maturation of these neural processes.

  2. Shared risk aversion in spontaneous and induced abortion.

    Science.gov (United States)

    Catalano, Ralph; Bruckner, Tim A; Karasek, Deborah; Adler, Nancy E; Mortensen, Laust H

    2016-05-01

    Does the incidence of spontaneous abortion correlate positively over conception cohorts with the incidence of non-clinically indicated induced abortion as predicted by shared risk aversion? We find that the number of spontaneous and non-clinically indicated induced abortions correlates in conception cohorts, suggesting that risk aversion affects both the conscious and non-conscious mechanisms that control parturition. Much literature speculates that natural selection conserved risk aversion because the trait enhanced Darwinian fitness. Risk aversion, moreover, supposedly influences all decisions including those that individuals can and cannot report making. We argue that these circumstances, if real, would manifest in conscious and non-conscious decisions to invest in prospective offspring, and therefore affect incidence of induced and spontaneous abortion over time. Using data from Denmark, we test the hypothesis that monthly conception cohorts yielding unexpectedly many non-clinically indicated induced abortions also yield unexpectedly many spontaneous abortions. The 180 month test period (January 1995 through December 2009), yielded 1 351 800 gestations including 156 780 spontaneous as well as 233 280 induced abortions 9100 of which were clinically indicated. We use Box-Jenkins transfer functions to adjust the incidence of spontaneous and non-clinically indicated induced abortions for autocorrelation (including seasonality), cohort size, and fetal as well as gestational anomalies over the 180-month test period. We use cross-correlation to test our hypothesized association. We find a positive association between spontaneous and non-clinically indicated induced abortions. This suggests, consistent with our theory, that mothers of conception cohorts that yielded more spontaneous abortions than expected opted more frequently than expected for non-clinically indicated induced abortion. Limitations of our work include that even the world's best registration system

  3. The Selectivity of Aversive Memory Reconsolidation and Extinction Processes Depends on the Initial Encoding of the Pavlovian Association

    Science.gov (United States)

    Debiec, Jacek; Diaz-Mataix, Lorenzo; Bush, David E. A.; Doyère, Valérie; LeDoux, Joseph E.

    2013-01-01

    In reconsolidation studies, memories are typically retrieved by an exposure to a single conditioned stimulus (CS). We have previously demonstrated that reconsolidation processes are CS-selective, suggesting that memories retrieved by the CS exposure are discrete and reconsolidate separately. Here, using a compound stimulus in which two distinct…

  4. Reappraising social insect behavior through aversive responsiveness and learning.

    Science.gov (United States)

    Roussel, Edith; Carcaud, Julie; Sandoz, Jean-Christophe; Giurfa, Martin

    2009-01-01

    The success of social insects can be in part attributed to their division of labor, which has been explained by a response threshold model. This model posits that individuals differ in their response thresholds to task-associated stimuli, so that individuals with lower thresholds specialize in this task. This model is at odds with findings on honeybee behavior as nectar and pollen foragers exhibit different responsiveness to sucrose, with nectar foragers having higher response thresholds to sucrose concentration. Moreover, it has been suggested that sucrose responsiveness correlates with responsiveness to most if not all other stimuli. If this is the case, explaining task specialization and the origins of division of labor on the basis of differences in response thresholds is difficult. To compare responsiveness to stimuli presenting clear-cut differences in hedonic value and behavioral contexts, we measured appetitive and aversive responsiveness in the same bees in the laboratory. We quantified proboscis extension responses to increasing sucrose concentrations and sting extension responses to electric shocks of increasing voltage. We analyzed the relationship between aversive responsiveness and aversive olfactory conditioning of the sting extension reflex, and determined how this relationship relates to division of labor. Sucrose and shock responsiveness measured in the same bees did not correlate, thus suggesting that they correspond to independent behavioral syndromes, a foraging and a defensive one. Bees which were more responsive to shock learned and memorized better aversive associations. Finally, guards were less responsive than nectar foragers to electric shocks, exhibiting higher tolerance to low voltage shocks. Consequently, foragers, which are more sensitive, were the ones learning and memorizing better in aversive conditioning. Our results constitute the first integrative study on how aversive responsiveness affects learning, memory and social

  5. Reappraising social insect behavior through aversive responsiveness and learning.

    Directory of Open Access Journals (Sweden)

    Edith Roussel

    Full Text Available The success of social insects can be in part attributed to their division of labor, which has been explained by a response threshold model. This model posits that individuals differ in their response thresholds to task-associated stimuli, so that individuals with lower thresholds specialize in this task. This model is at odds with findings on honeybee behavior as nectar and pollen foragers exhibit different responsiveness to sucrose, with nectar foragers having higher response thresholds to sucrose concentration. Moreover, it has been suggested that sucrose responsiveness correlates with responsiveness to most if not all other stimuli. If this is the case, explaining task specialization and the origins of division of labor on the basis of differences in response thresholds is difficult.To compare responsiveness to stimuli presenting clear-cut differences in hedonic value and behavioral contexts, we measured appetitive and aversive responsiveness in the same bees in the laboratory. We quantified proboscis extension responses to increasing sucrose concentrations and sting extension responses to electric shocks of increasing voltage. We analyzed the relationship between aversive responsiveness and aversive olfactory conditioning of the sting extension reflex, and determined how this relationship relates to division of labor.Sucrose and shock responsiveness measured in the same bees did not correlate, thus suggesting that they correspond to independent behavioral syndromes, a foraging and a defensive one. Bees which were more responsive to shock learned and memorized better aversive associations. Finally, guards were less responsive than nectar foragers to electric shocks, exhibiting higher tolerance to low voltage shocks. Consequently, foragers, which are more sensitive, were the ones learning and memorizing better in aversive conditioning.Our results constitute the first integrative study on how aversive responsiveness affects learning, memory and

  6. Black Faces, White Spaces: Adjusting Self to Manage Aversive ...

    African Journals Online (AJOL)

    This article focuses on conversations in which South Africans speak about their experiences of aversive racism in 'raced' spaces. The article interrogates experiences of aversive racism and argues that, for various reasons, racial segregation and less overt forms of racism remain entrenched in South Africa. Presently, those ...

  7. Climate policy: Risk-averse governments

    Science.gov (United States)

    Harris, Paul G.

    2014-04-01

    Relative to the scale of the problem, climate policies worldwide have failed. Now research explains why policy innovations are often inadequate, routinely reflecting the aversion of policymakers to the risk of failure.

  8. Endogenous time-varying risk aversion and asset returns.

    Science.gov (United States)

    Berardi, Michele

    2016-01-01

    Stylized facts about statistical properties for short horizon returns in financial markets have been identified in the literature, but a satisfactory understanding for their manifestation is yet to be achieved. In this work, we show that a simple asset pricing model with representative agent is able to generate time series of returns that replicate such stylized facts if the risk aversion coefficient is allowed to change endogenously over time in response to unexpected excess returns under evolutionary forces. The same model, under constant risk aversion, would instead generate returns that are essentially Gaussian. We conclude that an endogenous time-varying risk aversion represents a very parsimonious way to make the model match real data on key statistical properties, and therefore deserves careful consideration from economists and practitioners alike.

  9. Neurocognitive development of risk aversion from early childhood to adulthood.

    Science.gov (United States)

    Paulsen, David J; Carter, R McKell; Platt, Michael L; Huettel, Scott A; Brannon, Elizabeth M

    2011-01-01

    Human adults tend to avoid risk. In behavioral economic studies, risk aversion is manifest as a preference for sure gains over uncertain gains. However, children tend to be less averse to risk than adults. Given that many of the brain regions supporting decision-making under risk do not reach maturity until late adolescence or beyond it is possible that mature risk-averse behavior may emerge from the development of decision-making circuitry. To explore this hypothesis, we tested 5- to 8-year-old children, 14- to 16-year-old adolescents, and young adults in a risky-decision task during functional magnetic resonance imaging (fMRI) data acquisition. To our knowledge, this is the youngest sample of children in an fMRI decision-making task. We found a number of decision-related brain regions to increase in activation with age during decision-making, including areas associated with contextual memory retrieval and the incorporation of prior outcomes into the current decision-making strategy, e.g., insula, hippocampus, and amygdala. Further, children who were more risk-averse showed increased activation during decision-making in ventromedial prefrontal cortex and ventral striatum. Our findings indicate that the emergence of adult levels of risk aversion co-occurs with the recruitment of regions supporting decision-making under risk, including the integration of prior outcomes into current decision-making behavior. This pattern of results suggests that individual differences in the development of risk aversion may reflect differences in the maturation of these neural processes.

  10. Aversive tension in female adolescents with Anorexia Nervosa: a controlled ecological momentary assessment using smartphones.

    Science.gov (United States)

    Kolar, David R; Hammerle, Florian; Jenetzky, Ekkehart; Huss, Michael; Bürger, Arne

    2016-04-12

    Current models of Anorexia Nervosa (AN) emphasize the role of emotion regulation. Aversive tension, described as a state of intense arousal and negative valence, is considered to be a link between emotional events and disordered eating. Recent research focused only on adult patients, and mainly general emotion regulation traits were studied. However, the momentary occurrence of aversive tension, particularly in adolescents with AN, has not been previously studied. 20 female adolescents with AN in outpatient treatment and 20 healthy adolescents aged 12 to 19 years participated in an ecological momentary assessment using their smartphones. Current states of aversive tension and events were assessed hourly for two consecutive weekdays. Mean and maximum values of aversive tension were compared. Multilevel analyses were computed to test the influence of time and reported events on aversive tension. The effect of reported events on subsequent changes of aversive tension in patients with AN were additionally tested in a multilevel model. AN patients showed higher mean and maximum levels of aversive tension. In a multilevel model, reported food intake was associated with higher levels of aversive tension in the AN group, whereas reported school or sport-related events were not linked to specific states of aversive tension. After food intake, subsequent increases of aversive tension were diminished and decreases of aversive tension were induced in adolescents with AN. Aversive tension may play a substantial role in the psychopathology of AN, particular in relation with food intake. Therefore, treatment should consider aversive tension as a possible intervening variable during refeeding. Our findings encourage further research on aversive tension and its link to disordered eating. German register of clinical trials (DRKS): DRKS00005228 (Date of registration: September 2, 2013).

  11. Genotype modulates age-related alterations in sensitivity to the aversive effects of ethanol: an eight inbred strain analysis of conditioned taste aversion.

    Science.gov (United States)

    Moore, E M; Forrest, R D; Boehm, S L

    2013-02-01

    Adolescent individuals display altered behavioral sensitivity to ethanol, which may contribute to the increased ethanol consumption seen in this age-group. However, genetics also exert considerable influence on both ethanol intake and sensitivity. Currently there is little research assessing the combined influence of developmental and genetic alcohol sensitivities. Sensitivity to the aversive effects of ethanol using a conditioned taste aversion (CTA) procedure was measured during both adolescence (P30) and adulthood (P75) in eight inbred mouse strains (C57BL/6J, DBA/2J, 129S1/SvImJ, A/J, BALB/cByJ, BTBR T(+) tf/J, C3H/HeJ and FVB/NJ). Adolescent and adult mice were water deprived, and subsequently provided with access to 0.9% (v/v) NaCl solution for 1 h. Immediately following access mice were administered ethanol (0, 1.5, 2.25 and 3 g/kg, ip). This procedure was repeated in 72 h intervals for a total of five CTA trials. Sensitivity to the aversive effects of ethanol was highly dependent upon both strain and age. Within an inbred strain, adolescent animals were consistently less sensitive to the aversive effects of ethanol than their adult counterparts. However, the dose of ethanol required to produce an aversion response differed as a function of both age and strain. © 2012 Blackwell Publishing Ltd and International Behavioural and Neural Genetics Society.

  12. On Loss Aversion, Level-1 Reasoning, and Betting

    OpenAIRE

    Ido Erev; Sharon Gilat-Yihyie; Davide Marchiori; Doron Sonsino

    2013-01-01

    Previous research suggests that human reaction to risky opportunities reflects two contradicting biases: Òloss aversion", and Òlimited level of reasoning" that leads to overconfidence. Rejection of attractive gambles is explained by loss aversion, while counterproductive risk seeking is attributed to limited level of reasoning. The current research highlights a shortcoming of this popular (but often implicit) "contradicting biases" assertion. Studies of "negative-sum betting games" reveal hig...

  13. Expressing negative emotions to children: Mothers' aversion sensitivity and children's adjustment.

    Science.gov (United States)

    Moed, Anat; Dix, Theodore; Anderson, Edward R; Greene, Shannon M

    2017-03-01

    Research is unclear about when expressing negative emotions to children performs valuable socialization and regulatory functions and when, instead, it undermines children's adjustment. In this study, we isolated 1 kind of negative expression to test the aversion sensitivity hypothesis: that rapid increases in mothers' negativity as a function of increases in the aversiveness of children's behavior are uniquely problematic for children. During multiple assessments of a divorcing sample over 2 years (N = 284), 12-min interactions between mothers and their 4- to 11-year-old children were recorded. Forty-seven observed child behaviors were ranked from low to high aversive. Within-dyad changes demonstrated that mothers' general negativity-their tendency to express negative emotion at high rates-was unrelated to children's adjustment. In contrast, mothers' aversion-focused negativity-their tendency to increase negative emotional expression rapidly as the aversiveness of children's behavior increased-predicted children's poor social competence, poor emotion regulation, and externalizing behavior problems at the next assessment. The findings suggest that negative expression that reflects mothers' affective sensitivity to aversive child behavior may promote interaction patterns and adaptations in children that are particularly likely to place children at risk for adjustment problems. (PsycINFO Database Record (c) 2017 APA, all rights reserved).

  14. Neural intrinsic connectivity networks associated with risk aversion in old age.

    Science.gov (United States)

    Han, S Duke; Boyle, Patricia A; Arfanakis, Konstantinos; Fleischman, Debra A; Yu, Lei; Edmonds, Emily C; Bennett, David A

    2012-02-01

    Risk aversion is associated with several important real world outcomes. Although the neurobiological correlates of risk aversion have been studied in young persons, little is known of the neurobiological correlates of risk aversion among older persons. Resting-state functional MRI data were collected on 134 non-demented participants of the Rush Memory and Aging Project, a community-based cohort study of aging. Risk aversion was measured using a series of standard questions in which participants were asked to choose between a certain monetary payment ($15) versus a gamble in which they could gain more than $15 or gain nothing, with potential gains varied across questions. Participants determined to be "high" (n=27) and "low" (n=27) in risk aversion were grouped accordingly. Using a spherical seed region of interest in the anterior cingulate cortex, voxel-wise functional connectivity network similarities were observed in bilateral frontal, anterior and posterior cingulate, insula, basal ganglia, temporal, parietal, and thalamic regions. Differences in functional connectivity were observed such that those low in risk aversion had greater connectivity to clusters in the superior, middle, and medial frontal regions, as well as cerebellar, parietal, occipital, and inferior temporal regions. Those high in risk aversion had greater connectivity to clusters in the inferior and orbital frontal, parahippocampal, and insula regions, as well as thalamic, parietal, precentral gyrus, postcentral gyrus, and middle temporal regions. Similarities and differences in functional connectivity patterns may reflect the historical recruitment of specific brain regions as a network in the active processing of risk in older adults. Copyright © 2011 Elsevier B.V. All rights reserved.

  15. Extinction of aversive classically conditioned human sexual response.

    Science.gov (United States)

    Brom, Mirte; Laan, Ellen; Everaerd, Walter; Spinhoven, Philip; Both, Stephanie

    2015-04-01

    Research has shown that acquired subjective likes and dislikes are quite resistant to extinction. Moreover, studies on female sexual response demonstrated that diminished genital arousal and positive affect toward erotic stimuli due to aversive classical conditioning did not extinguish during an extinction phase. Possible resistance to extinction of aversive conditioned sexual responses may have important clinical implications. However, resistance to extinction of aversive conditioned human sexual response has not been studied using extensive extinction trials. This article aims to study resistance to extinction of aversive conditioned sexual responses in sexually functional men and women. A differential conditioning experiment was conducted, with two erotic pictures as conditioned stimulus (CSs) and a painful stimulus as unconditioned stimuli (USs). Only one CS (the CS+) was followed by the US during the acquisition phase. Conditioned responses were assessed during the extinction phase. Penile circumference and vaginal pulse amplitude were assessed, and ratings of affective value and subjective sexual arousal were obtained. Also, a stimulus response compatibility task was included to assess automatic approach and avoidance tendencies. Men and women rated the CS+ more negative as compared with the CS-. During the first trials of the extinction phase, vaginal pulse amplitude was lower in response to the CS+ than in response to the CS-, and on the first extinction trial women rated the CS+ as less sexually arousing. Intriguingly, men did not demonstrate attenuated genital and subjective sexual response. Aversive conditioning, by means of painful stimuli, only affects sexual responses in women, whereas it does not in men. Although conditioned sexual likes and dislikes are relatively persistent, conditioned affect eventually does extinguish. © 2014 International Society for Sexual Medicine.

  16. Size doesn't really matter: ambiguity aversion in Ellsberg urns with few balls.

    Science.gov (United States)

    Pulford, Briony D; Colman, Andrew M

    2008-01-01

    When attempting to draw a ball of a specified color either from an urn containing 50 red balls and 50 black balls or from an urn containing an unknown ratio of 100 red and black balls, a majority of decision makers prefer the known-risk urn, and this ambiguity aversion effect violates expected utility theory. In an experimental investigation of the effect of urn size on ambiguity aversion, 149 participants showed similar levels of aversion when choosing from urns containing 2, 10, or 100 balls. The occurrence of a substantial and significant ambiguity aversion effect even in the smallest urn suggests that influential theoretical interpretations of ambiguity aversion may need to be reconsidered.

  17. Food Aversions and Cravings during Pregnancy on Yasawa Island, Fiji.

    Science.gov (United States)

    McKerracher, Luseadra; Collard, Mark; Henrich, Joseph

    2016-09-01

    Women often experience novel food aversions and cravings during pregnancy. These appetite changes have been hypothesized to work alongside cultural strategies as adaptive responses to the challenges posed by pregnancy (e.g., maternal immune suppression). Here, we report a study that assessed whether data from an indigenous population in Fiji are consistent with the predictions of this hypothesis. We found that aversions focus predominantly on foods expected to exacerbate the challenges of pregnancy. Cravings focus on foods that provide calories and micronutrients while posing few threats to mothers and fetuses. We also found that women who experience aversions to specific foods are more likely to crave foods that meet nutritional needs similar to those provided by the aversive foods. These findings are in line with the predictions of the hypothesis. This adds further weight to the argument that appetite changes may function in parallel with cultural mechanisms to solve pregnancy challenges.

  18. Medial prefrontal cortex dopamine controls the persistent storage of aversive memories

    Science.gov (United States)

    Gonzalez, María C.; Kramar, Cecilia P.; Tomaiuolo, Micol; Katche, Cynthia; Weisstaub, Noelia; Cammarota, Martín; Medina, Jorge H.

    2014-01-01

    Medial prefrontal cortex (mPFC) is essential for initial memory processing and expression but its involvement in persistent memory storage has seldom been studied. Using the hippocampus dependent inhibitory avoidance learning task and the hippocampus-independent conditioned taste aversion paradigm together with specific dopamine receptor agonists and antagonists we found that persistence but not formation of long-term aversive memories requires dopamine D1/D5 receptors activation in mPFC immediately after training and, depending on the task, between 6 and 12 h later. Our results indicate that besides its well-known participation in retrieval and early consolidation, mPFC also modulates the endurance of long-lasting aversive memories regardless of whether formation of the aversive mnemonic trace requires the participation of the hippocampus. PMID:25506318

  19. Loss Aversion, Team Relocations, and Major League Expansion

    OpenAIRE

    Humphreys, Brad; Zhou, Li

    2014-01-01

    Professional sports teams receive large public subsidies for new facility construction. Empirical research suggests that these subsidies cannot be justified by tangible or intangible economic benefits. We develop a model of bargaining between local governments and teams over subsidies that includes league expansion decisions. The model features loss aversion by fans that captures lost utility when a team leaves a city. The model predicts that teams exploit this loss aversion to extract larger...

  20. Neural markers of loss aversion in resting-state brain activity.

    Science.gov (United States)

    Canessa, Nicola; Crespi, Chiara; Baud-Bovy, Gabriel; Dodich, Alessandra; Falini, Andrea; Antonellis, Giulia; Cappa, Stefano F

    2017-02-01

    Neural responses in striatal, limbic and somatosensory brain regions track individual differences in loss aversion, i.e. the higher sensitivity to potential losses compared with equivalent gains in decision-making under risk. The engagement of structures involved in the processing of aversive stimuli and experiences raises a further question, i.e. whether the tendency to avoid losses rather than acquire gains represents a transient fearful overreaction elicited by choice-related information, or rather a stable component of one's own preference function, reflecting a specific pattern of neural activity. We tested the latter hypothesis by assessing in 57 healthy human subjects whether the relationship between behavioral and neural loss aversion holds at rest, i.e. when the BOLD signal is collected during 5minutes of cross-fixation in the absence of an explicit task. Within the resting-state networks highlighted by a spatial group Independent Component Analysis (gICA), we found a significant correlation between strength of activity and behavioral loss aversion in the left ventral striatum and right posterior insula/supramarginal gyrus, i.e. the very same regions displaying a pattern of neural loss aversion during explicit choices. Cross-study analyses confirmed that this correlation holds when voxels identified by gICA are used as regions of interest in task-related activity and vice versa. These results suggest that the individual degree of (neural) loss aversion represents a stable dimension of decision-making, which reflects in specific metrics of intrinsic brain activity at rest possibly modulating cortical excitability at choice. Copyright © 2016 Elsevier Inc. All rights reserved.

  1. The effects of nicotine on ethanol-induced conditioned taste aversions in Long-Evans rats.

    Science.gov (United States)

    Rinker, Jennifer A; Busse, Gregory D; Roma, Peter G; Chen, Scott A; Barr, Christina S; Riley, Anthony L

    2008-04-01

    Overall drug acceptability is thought to be a function of the balance between its rewarding and aversive effects, the latter of which is reportedly affected by polydrug use. Given that nicotine and alcohol are commonly co-used, the present experiments sought to assess nicotine's impact on ethanol's aversive effects within a conditioned taste aversion design. Experiment 1 examined various doses of nicotine (0, 0.4, 0.8, 1.2 mg/kg) to determine a behaviorally active dose, and experiment 2 examined various doses of ethanol (0, 0.5, 1.0, 1.5 g/kg) to determine a dose that produced intermediate aversions. Experiment 3 then examined the aversive effects of nicotine (0.8 mg/kg) and ethanol (1.0 g/kg) alone and in combination. Additionally, nicotine's effects on blood alcohol concentrations (BAC) and ethanol-induced hypothermia were examined. Nicotine and ethanol combined produced aversions significantly greater than those produced by either drug alone or the summed aversive effects of the individual compounds. These effects were unrelated to changes in BAC, but nicotine and ethanol combined produced a prolonged hypothermic effect which may contribute to the increased aversions induced by the combination. These data demonstrate that nicotine may interact with ethanol, increasing ethanol's aversive effects. Although the rewarding effects of concurrently administered nicotine and ethanol were not assessed, these data do indicate that the reported high incidence of nicotine and ethanol co-use is unlikely due to reductions in the aversiveness of ethanol with concurrently administered nicotine. It is more likely attributable to nicotine-related changes in ethanol's rewarding effects.

  2. Cognitive function is associated with risk aversion in community-based older persons

    Directory of Open Access Journals (Sweden)

    Buchman Aron S

    2011-09-01

    Full Text Available Abstract Background Emerging data from younger and middle-aged persons suggest that cognitive ability is negatively associated with risk aversion, but this association has not been studied among older persons who are at high risk of experiencing loss of cognitive function. Methods Using data from 369 community-dwelling older persons without dementia from the Rush Memory and Aging Project, an ongoing longitudinal epidemiologic study of aging, we examined the correlates of risk aversion and tested the hypothesis that cognition is negatively associated with risk aversion. Global cognition and five specific cognitive abilities were measured via detailed cognitive testing, and risk aversion was measured using standard behavioral economics questions in which participants were asked to choose between a certain monetary payment ($15 versus a gamble in which they could gain more than $15 or gain nothing; potential gamble gains ranged from $21.79 to $151.19 with the gain amounts varied randomly over questions. We first examined the bivariate associations of age, education, sex, income and cognition with risk aversion. Next, we examined the associations between cognition and risk aversion via mixed models adjusted for age, sex, education, and income. Finally, we conducted sensitivity analyses to ensure that our results were not driven by persons with preclinical cognitive impairment. Results In bivariate analyses, sex, education, income and global cognition were associated with risk aversion. However, in a mixed effect model, only sex (estimate = -1.49, standard error (SE = 0.39, p i.e., semantic memory, episodic memory, working memory, and perceptual speed; performance on visuospatial abilities was not. Conclusion A lower level of cognitive ability and female sex are associated with greater risk aversion in advanced age.

  3. Joint Inventory, Pricing, and Advertising Decisions with Surplus and Stockout Loss Aversions

    Directory of Open Access Journals (Sweden)

    Bing-Bing Cao

    2016-01-01

    Full Text Available The newsvendor models considering decision-makers’ behavioral factors remain a fruitful research area in operation management field in past decade. In this paper, we further extend the current literatures to look into joint inventory, pricing, and advertising decisions considering loss aversion effects under the newsvendor setting. The purpose is to explore how the loss aversions affect the optimal policy of order quantity, price, and advertising effort level. We present an integrated utility model to measure both economic payoff and loss aversion utility of the newsvendor, where surplus loss aversion and stockout loss aversion are first separately defined and quantified. Then, we analyze the optimal solution conditions of the integrated model under exogenous and endogenous price cases, respectively. Under exogenous price case, we find that the uniquely optimal policy exists and is presented in the closed form. Under endogenous price case, the optimal policy is determined under mild conditions; we also provide the solutions when order quantity factor or advertising effort level is fixed in this case. In addition, the sensitivity analysis shows that the loss aversions affect the optimal decisions of order quantity, price, and advertising effort level in a systematic way.

  4. Ambiguity aversion is not universal

    NARCIS (Netherlands)

    Kocher, M.G.; Lahno, Amrei; Trautmann, Stefan

    Assuming universal ambiguity aversion, an extensive theoretical literature studies how ambiguity can account for market anomalies from the perspective of expected utility-based theories. We provide a systematic experimental assessment of ambiguity attitudes in different likelihood ranges, and in the

  5. Human capital and risk aversion in relational incentive contracts

    International Nuclear Information System (INIS)

    Kvaloey, Ola

    2003-01-01

    This paper examines a self-enforced relational incentive contract between a risk neutral principal and a risk averse agent where the agent's human capital is essential in ex post realization of values. I analyse the effect of outside options on the optimal bonus level, showing how the presence of ex post outside options may impede desirable degrees of performance pay. The effect of risk aversion and incentive responsiveness is analysed by allowing for linear contracts. I show that the first order effect of these parameters are the same as in verifiable contracts, but second order effects show that the optimal bonus level's sensitivity to risk aversion and incentive responsiveness increases with the discount factor. The analysis has interesting implications on firm boundaries and specificity choices. (author)

  6. The risks of risk aversion in drug regulation.

    Science.gov (United States)

    Eichler, Hans-Georg; Bloechl-Daum, Brigitte; Brasseur, Daniel; Breckenridge, Alasdair; Leufkens, Hubert; Raine, June; Salmonson, Tomas; Schneider, Christian K; Rasi, Guido

    2013-12-01

    Drugs are approved by regulatory agencies on the basis of their assessment of whether the available evidence indicates that the benefits of the drug outweigh its risks. In recent years, regulatory agencies have been criticized both for being overly tolerant of risks or being excessively risk-averse, which reflects the challenge in determining an appropriate balance between benefit and risk with the limited data that is typically available before drug approval. The negative consequences of regulatory tolerance in allowing drugs onto the market that turn out to be unsafe are obvious, but the potential for adverse effects on public health owing to the absence of new drugs because of regulatory risk-aversion is less apparent. Here, we discuss the consequences of regulatory risk-aversion for public health and suggest what might be done to best align acceptance of risk and uncertainty by regulators with the interests of public health.

  7. Patient risk perceptions for carotid endarterectomy: which patients are strongly averse to surgery?

    Science.gov (United States)

    Bosworth, Hayden B; Stechuchak, Karen M; Grambow, Steven C; Oddone, Eugene Z

    2004-07-01

    Patient risk perception for surgery may be central to their willingness to undergo surgery. This study examined potential factors associated with patient aversion of surgery. This is a secondary data analysis of a prospective cohort study that examined patients referred for evaluation of carotid artery stenosis at five Veterans Affairs Medical Centers. The study collected demographic, clinical, and psychosocial information related to surgery. This analysis focused on patient response to a question assessing their aversion to surgery. Among the 1065 individuals, at the time of evaluation for carotid endarterectomy (CEA), 66% of patients had no symptoms, 16% had a transient ischemic attack, and 18% had stroke. Twelve percent of patients referred for CEA evaluation were averse to surgery. In adjusted analyses, increased age, black race, no previous surgery, lower level of chance locus of control, less trust of physicians, and less social support were significantly related to greater likelihood of surgery aversion among individuals referred for CEA evaluation. Patient degree of medical comorbidity and a validated measure of preoperative risk score were not associated with increased aversion to surgery. In previous work, aversion to CEA was associated with lack of receipt of CEA even after accounting for patient clinical appropriateness for surgery. We identified important patient characteristics associated with aversion to CEA. Interventions designed to assist patient decision making should focus on these more complex factors related to CEA aversion rather than the simple explanation of clinical usefulness.

  8. Increased ethanol consumption despite taste aversion in mice with a human tryptophan hydroxylase 2 loss of function mutation.

    Science.gov (United States)

    Lemay, Francis; Doré, François Y; Beaulieu, Jean-Martin

    2015-11-16

    Polymorphisms in the gene encoding the brain serotonin synthesis enzyme Tph2 have been identified in mental illnesses, with co-morbidity of substance use disorder. However, little is known about the impact of Tph2 gene variants on addiction. Mice expressing a human Tph2 loss of function variant were used to investigate consequences of aversive conditions on ethanol intake. Mice were familiarized either with ethanol or a solution containing both ethanol and the bittering agent quinine. Effect of familiarization to ethanol or an ethanol-quinine solution was then evaluated using a two-bottles preference test in Tph2-KI and control littermates. Mice from both genotypes displayed similar levels of ethanol consumption and quinine avoidance when habituated to ethanol alone. In contrast, addition of quinine to ethanol during the familiarization period resulted in a reduction of avoidance for the quinine-ethanol solution only in mutant mice. These results indicate that loss of function mutation in Tph2 results in greater motivation for ethanol consumption under aversive conditions and may confer enhanced sensitivity to alcohol use disorder. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

  9. Risk Aversion is Associated with Decision Making among Community-Based Older Persons.

    Science.gov (United States)

    Boyle, Patricia A; Yu, Lei; Buchman, Aron S; Bennett, David A

    2012-01-01

    Risk aversion is associated with many important decisions among younger and middle aged persons, but the association of risk aversion with decision making has not been well studied among older persons who face some of the most significant decisions of their lives. Using data from 606 community-dwelling older persons without dementia from the Rush Memory and Aging Project, an ongoing longitudinal epidemiologic study of aging, we examined the association of risk aversion with decision making. Risk aversion was measured using standard behavioral economics questions in which participants were asked to choose between a certain monetary payment ($15) versus a gamble in which they could gain more than $15 or gain nothing; potential gamble gains ranged from $20 to $300 with the gain amounts varied randomly over questions. Decision making was measured using a 12 item version of the Decision Making Competence Assessment Tool. In a linear regression model adjusted for age, sex, education, and income, greater risk aversion was associated with poorer decision making [estimate = -1.03, standard error (SE) = 0.35, p = 0.003]. Subsequent analyses showed that the association of risk aversion with decision making persisted after adjustment for global cognitive function as well as executive and non-executive cognitive abilities. Similar to findings from studies of younger persons, risk aversion is associated with poorer decision making among older persons who face a myriad of complex and influential decisions.

  10. Loss aversion and hypoxia: less loss aversion in oxygen-depleted environment.

    Science.gov (United States)

    Pighin, Stefania; Bonini, Nicolao; Savadori, Lucia; Hadjichristidis, Constantinos; Schena, Federico

    2014-03-01

    Hypoxia, the deprivation of adequate oxygen supply, constitutes a direct threat to survival by disrupting cardiovascular or respiratory homeostasis and eliciting a respiratory distress. Although hypoxia has been shown to increase brain vulnerability and impair basic cognitive functions, only one study has examined its effect on decision-making. The present study examined the effect of mild hypoxia on individual's loss aversion, that is, the tendency to be more affected by losses than equal sized gains. A sample of 26 participants were asked to either accept or reject a series of mixed gambles once in an oxygen-depleted environment (14.1% oxygen concentration) and once in a normoxic environment (20.9% oxygen concentration). Each gamble involved a 50-50 chance of winning or losing specified amounts of money. Mild hypoxia decreased loss aversion: on average in the normoxic condition participants accepted gambles if the gain was at least 2.4 times as large as the loss, whereas in the oxygen-depleted condition participants accepted gambles if the gain was at least 1.7 times as large as the loss. Mild hypoxia may push individuals to be less cautious in daily decisions that involve a trade-off between a gain and a loss.

  11. Loss Aversion and Time-Differentiated Electricity Pricing

    Energy Technology Data Exchange (ETDEWEB)

    Spurlock, C. Anna [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

    2015-06-01

    I develop a model of loss aversion over electricity expenditure, from which I derive testable predictions for household electricity consumption while on combination time-of-use (TOU) and critical peak pricing (CPP) plans. Testing these predictions results in evidence consistent with loss aversion: (1) spillover effects - positive expenditure shocks resulted in significantly more peak consumption reduction for several weeks thereafter; and (2) clustering - disproportionate probability of consuming such that expenditure would be equal between the TOUCPP or standard flat-rate pricing structures. This behavior is inconsistent with a purely neoclassical utility model, and has important implications for application of time-differentiated electricity pricing.

  12. The effects of cocaine, alcohol and cocaine/alcohol combinations in conditioned taste aversion learning.

    Science.gov (United States)

    Busse, Gregory D; Verendeev, Andrey; Jones, Jermaine; Riley, Anthony L

    2005-09-01

    We have recently reported that alcohol attenuates cocaine place preferences. Although the basis for this effect is unknown, alcohol may attenuate cocaine reward by potentiating its aversive effects. To examine this possibility, these experiments assessed the effects of alcohol on cocaine-induced taste aversions under conditions similar to those that resulted in attenuated place preferences. Specifically, Experiments 1 and 2 assessed the effects of alcohol (0.5 g/kg) on taste aversions induced by 20, 30 and 40 mg/kg cocaine. Experiment 3 examined the role of intertrial interval in the effects of alcohol (0.5 g/kg) on cocaine (30 mg/kg) taste aversions. In Experiments 1 and 2, cocaine was effective at conditioning aversions. Alcohol produced no measurable effect. Combining cocaine and alcohol produced no greater aversion than cocaine alone (and, in fact, weakened aversions at the lowest dose of cocaine). In Experiment 3, varying the intertrial interval from 3 days (as in the case of Experiments 1 and 2) to 1 day (a procedure identical to that in which alcohol attenuated cocaine place preferences) resulted in significant alcohol- and cocaine-induced taste aversions. Nonetheless, alcohol remained ineffective in potentiating cocaine aversions. Thus, under these conditions alcohol does not potentiate cocaine's aversiveness. These results were discussed in terms of their implication for the effects of alcohol on cocaine-induced place preferences. Further, the effects of alcohol on place preferences conditioned by cocaine were discussed in relation to other assessments of the effects of alcohol on the affective properties of cocaine and the implications of these interactions for alcohol and cocaine co-use.

  13. Appetitive and aversive visual learning in freely moving Drosophila

    Directory of Open Access Journals (Sweden)

    Christopher Schnaitmann

    2010-03-01

    Full Text Available To compare appetitive and aversive visual memories of the fruit fly Drosophila melanogaster, we developed a new paradigm for classical conditioning. Adult flies are trained en masse to differentially associate one of two visual conditioned stimuli (blue and green light as conditioned stimuli or CS with an appetitive or aversive chemical substance (unconditioned stimulus or US. In a test phase, flies are given a choice between the paired and the unpaired visual stimuli. Associative memory is measured based on altered visual preference in the test. If a group of flies has, for example, received a sugar reward with green light, they show a significantly higher preference for the green stimulus during the test than another group of flies having received the same reward with blue light. We demonstrate critical parameters for the formation of visual appetitive memory, such as training repetition, order of reinforcement, starvation, and individual conditioning. Furthermore, we show that formic acid can act as an aversive chemical reinforcer, yielding weak, yet significant, aversive memory. These results provide a basis for future investigations into the cellular and molecular mechanisms underlying visual memory and perception in Drosophila.

  14. Risk Aversion and Public Reporting. Part 2: Mitigation Strategies.

    Science.gov (United States)

    Shahian, David M; Jacobs, Jeffrey P; Badhwar, Vinay; D'Agostino, Richard S; Bavaria, Joseph E; Prager, Richard L

    2017-12-01

    Part 1 of this review summarizes the consequences of risk aversion and the observational studies and surveys relevant to this phenomenon, almost all of which are derived from cardiac surgery and interventional cardiology. In Part 2, we describe the root cause of risk aversion-the belief by providers that current risk adjustment is inadequate to account for the severity of their highest-risk patients, thereby prejudicing their publicly reported performance scores. Evidence supporting the robustness of current risk adjustment is presented, as well as nine potential strategies to further mitigate risk aversion: optimization of data source, risk models, and performance measures; exclusion of high-risk patients; exclusion of non-procedure-related end points; separate reporting of high-risk patients; reporting by condition or diagnosis rather than by procedures; reporting at the hospital or program level rather than the physician level; collaborative, cross-disciplinary decision making; active surveillance for risk aversion; and improved stakeholder education. Of these, the first is most desirable, widely applicable, and resistant to gaming. Copyright © 2017 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.

  15. Role of IL-4 in aversion induced by food allergy in mice.

    Science.gov (United States)

    Dourado, Luana Pereira Antunes; Saldanha, Janaína Cláudia da Silva; Gargiulo, Daniela Longo; Noviello, Maria de Lourdes Meirelles; Brant, Cláudia Caldeira; Reis, Maria Letícia Costa; Souza, Raphaela Mendes Fernandes de; Faria, Ana Maria Caetano; Souza, Danielle da Glória de; Cara, Denise Carmona

    2010-01-01

    To ascertain the role of IL-4 in aversion to antigen induced by food allergy, wild type and IL-4 deficient BALB/c mice were sensitized with ovalbumin and challenged orally with egg white. Sensitized wild type mice had increased production of IL-4 by spleen and mesenteric lymph node cells in vitro, higher levels of serum anti-ovalbumin IgE and IgG1, aversion to ingestion of the antigen and loss of body weight after continuous oral challenge. Intestinal changes in wild type sensitized mice included eosinophil infiltration and increased mucus production. The IL-4 deficiency impaired the development of food allergy and the aversion to antigen, suggesting the involvement of the antigen specific antibodies. When IL-4 deficient mice received serum from sensitized wild type donors, the aversion was restored. These results indicate that production of IL-4 and specific IgE/IgG1 antibodies correlate with aversion to antigen induced by food allergy in mice. Copyright 2009 Elsevier Inc. All rights reserved.

  16. Risk Aversion and Job Mobility

    NARCIS (Netherlands)

    van Huizen, T.M.; Alessie, Rob

    2016-01-01

    Job mobility is inherently risky as workers have limited ex ante information about the quality of outside jobs. Using a large longitudinal Dutch dataset, which includes data on risk preferences elicited through (incentivized) experiments, we examine the relation between risk aversion and job

  17. The Neural Foundations of Reaction and Action in Aversive Motivation.

    Science.gov (United States)

    Campese, Vincent D; Sears, Robert M; Moscarello, Justin M; Diaz-Mataix, Lorenzo; Cain, Christopher K; LeDoux, Joseph E

    2016-01-01

    Much of the early research in aversive learning concerned motivation and reinforcement in avoidance conditioning and related paradigms. When the field transitioned toward the focus on Pavlovian threat conditioning in isolation, this paved the way for the clear understanding of the psychological principles and neural and molecular mechanisms responsible for this type of learning and memory that has unfolded over recent decades. Currently, avoidance conditioning is being revisited, and with what has been learned about associative aversive learning, rapid progress is being made. We review, below, the literature on the neural substrates critical for learning in instrumental active avoidance tasks and conditioned aversive motivation.

  18. Risk Aversion and Sorting into Public Sector Employment

    OpenAIRE

    Pfeifer, Christian

    2008-01-01

    This research note uses two German data sets – the large-scale German Socio-Economic Panel and unique data from own student questionnaires – to analyse the relationship between risk aversion and the choice for public sector employment. Main results are: (1) more risk averse individuals sort into public sector employment, (2) the impact of career specific and unemployment risk attitudes is larger than the impact of general risk attitudes, and (3) risk taking is rewarded with higher wages in th...

  19. A Survey Data Response to the Teaching of Utility Curves and Risk Aversion

    Science.gov (United States)

    Hobbs, Jeffrey; Sharma, Vivek

    2011-01-01

    In many finance and economics courses as well as in practice, the concept of risk aversion is reduced to the standard deviation of returns, whereby risk-averse investors prefer to minimize their portfolios' standard deviations. In reality, the concept of risk aversion is richer and more interesting than this, and can easily be conveyed through…

  20. Acquisition of lithium chloride- and radiation-induced taste aversions in hypophysectomized rats

    International Nuclear Information System (INIS)

    Rabin, B.M.; Hunt, W.A.; Lee, J.

    1983-01-01

    The effects of hypophysectomy on the acquisition of conditioned taste aversions following injection of lithium chloride and following exposure to ionizing radiation were studied using a two-bottle preference test. Hypophysectomy did not disrupt the acquisition of a taste aversion following either treatment. The results are interpreted as: (a) suggesting that pituitary/adrenal hormones do not mediate the acquisition of a conditioned taste aversion following injections of lithium chloride or following exposure to ionizing radiation in a two-bottle preference test, and (b) consistent with other research suggesting that the involvement of pituitary/adrenal hormones in taste aversion learning may be related to the conflict induced by using a one-bottle test and not to the learning itself

  1. Methods for measuring risk-aversion: problems and solutions

    International Nuclear Information System (INIS)

    Thomas, P J

    2013-01-01

    Risk-aversion is a fundamental parameter determining how humans act when required to operate in situations of risk. Its general applicability has been discussed in a companion presentation, and this paper examines methods that have been used in the past to measure it and their attendant problems. It needs to be borne in mind that risk-aversion varies with the size of the possible loss, growing strongly as the possible loss becomes comparable with the decision maker's assets. Hence measuring risk-aversion when the potential loss or gain is small will produce values close to the risk-neutral value of zero, irrespective of who the decision maker is. It will also be shown how the generally accepted practice of basing a measurement on the results of a three-term Taylor series will estimate a limiting value, minimum or maximum, rather than the value utilised in the decision. A solution is to match the correct utility function to the results instead

  2. Methods for measuring risk-aversion: problems and solutions

    Science.gov (United States)

    Thomas, P. J.

    2013-09-01

    Risk-aversion is a fundamental parameter determining how humans act when required to operate in situations of risk. Its general applicability has been discussed in a companion presentation, and this paper examines methods that have been used in the past to measure it and their attendant problems. It needs to be borne in mind that risk-aversion varies with the size of the possible loss, growing strongly as the possible loss becomes comparable with the decision maker's assets. Hence measuring risk-aversion when the potential loss or gain is small will produce values close to the risk-neutral value of zero, irrespective of who the decision maker is. It will also be shown how the generally accepted practice of basing a measurement on the results of a three-term Taylor series will estimate a limiting value, minimum or maximum, rather than the value utilised in the decision. A solution is to match the correct utility function to the results instead.

  3. Managing Risk Aversion for Low-Carbon Supply Chains with Emission Abatement Outsourcing.

    Science.gov (United States)

    Wang, Qinpeng; He, Longfei

    2018-02-21

    Reducing carbon emissions, including emission abatement outsourcing at the supply-chain level, is becoming a significant but challenging problem in practice. Confronting this challenge, we therefore break down the practice to focus on a low-carbon supply chain consisting of one supplier, one manufacturer and one third-party emission-reducing contractor. The contractor offers a carbon reduction service to the manufacturer. In view of the increasing proportion of Greenhouse Gases (GHG) emissions and absence of carbon reduction policies in developing countries, we adopt the prospect of consumers' low-carbon preferences to capture the demand sensitivity on carbon emission. By exploiting the Mean-Variance (MV) model, we develop a supply chain game model considering risk aversion. Comparing the supply chain performances of the cases under risk neutrality and risk aversion, we investigate the impact of the risk aversion of the supplier and the manufacturer on the low-carbon supply chain performances, respectively. We show that the risk aversion of chain members will not influence the relationship underlain by the profit-sharing contract between the manufacturer and contractor, whereas they may extend the supplier's concerning range. Although the manufacturer's risk aversion has a positive impact on the wholesale price, interestingly, the supplier's impact on the wholesale price is negative. Furthermore, we propose a contract to coordinate the risk-averse low-carbon supply chain by tuning the aversion levels of the supplier and the manufacturer, respectively. Through numerical study, we draw on managerial insights for industrial practitioners to adopt a low carbon strategy potentially by managing the risk attitudes along the supply chain channel.

  4. Effects of loss aversion on neural responses to loss outcomes: An event-related potential study.

    Science.gov (United States)

    Kokmotou, Katerina; Cook, Stephanie; Xie, Yuxin; Wright, Hazel; Soto, Vicente; Fallon, Nicholas; Giesbrecht, Timo; Pantelous, Athanasios; Stancak, Andrej

    2017-05-01

    Loss aversion is the tendency to prefer avoiding losses over acquiring gains of the same amount. To shed light on the spatio-temporal processes underlying loss aversion, we analysed the associations between individual loss aversion and electrophysiological responses to loss and gain outcomes in a monetary gamble task. Electroencephalographic feedback-related negativity (FRN) was computed in 29 healthy participants as the difference in electrical potentials between losses and gains. Loss aversion was evaluated using non-linear parametric fitting of choices in a separate gamble task. Loss aversion correlated positively with FRN amplitude (233-263ms) at electrodes covering the lower face. Feedback related potentials were modelled by five equivalent source dipoles. From these dipoles, stronger activity in a source located in the orbitofrontal cortex was associated with loss aversion. The results suggest that loss aversion implemented during risky decision making is related to a valuation process in the orbitofrontal cortex, which manifests during learning choice outcomes. Copyright © 2017. Published by Elsevier B.V.

  5. Different components of conditioned food aversion memory.

    Science.gov (United States)

    Nikitin, Vladimir P; Solntseva, Svetlana V; Kozyrev, Sergey A; Nikitin, Pavel V; Shevelkin, Alexey V

    2016-07-01

    Memory reconsolidation processes and protein kinase Mzeta (PKMzeta) activity in memory maintenance and reorganization are poorly understood. Therefore, we examined memory reconsolidation and PKMzeta activity during the maintenance and reorganization of a conditioned food aversion memory among snails. These processes were specifically evaluated after administration of a serotonin receptor antagonist (methiothepin), NMDA glutamate receptor antagonist (MK-801), protein synthesis inhibitor (cycloheximide; CYH), or PKMzeta inhibitor (zeta inhibitory peptide; ZIP) either 2 or 10 days after aversion training. Two days post-training, injections of MK-801 or CYH, combined with a conditioned stimulus reminder, caused amnesia development, and a second training 11 days after this induction did not lead to long-term memory formation. Interestingly, MK-801 or CYH injections and the reminder 10 days after training did not affect memory retrieval. Methiothepin and the reminder, or ZIP without the reminder, at 2 and 10 days after training led to memory impairment, while a second training 11 days after amnesia induction resulted in memory formation. These results suggest that the maintenance of a conditioned food aversion involves two different components with variable dynamics. One component could be characterized by memory strengthening over time and involve N-methyl-D-aspartate receptors and protein synthesis reconsolidation at early, but not late, training stages. The other memory component could involve serotonin-dependent reconsolidation and Mzeta-like kinase activity at both early and late stages after learning. Deficiencies within these two components led to various forms of memory impairment, which differed in terms of the formation of a conditioned food aversion during the second training. Copyright © 2016 Elsevier B.V. All rights reserved.

  6. On Loss Aversion, Level-1 Reasoning, and Betting

    DEFF Research Database (Denmark)

    Erev, Ido; Gilat-Yihyie, Sharon; Marchiori, Davide

    2014-01-01

    Previous research suggests that human reaction to risky opportunities reflects two contradicting biases: “loss aversion”, and “limited level of reasoning” that leads to overconfidence. Rejection of attractive gambles is explained by loss aversion, while counterproductive risk seeking is attributed...... to limited level of reasoning. The current research highlights a shortcoming of this popular (but often implicit) “contradicting biases” assertion. Studies of “negative-sum betting games” reveal high rate of counterproductive betting even when limited level of reasoning and loss aversion imply no betting...

  7. Aversive reinforcement improves visual discrimination learning in free-flying honeybees.

    Directory of Open Access Journals (Sweden)

    Aurore Avarguès-Weber

    Full Text Available BACKGROUND: Learning and perception of visual stimuli by free-flying honeybees has been shown to vary dramatically depending on the way insects are trained. Fine color discrimination is achieved when both a target and a distractor are present during training (differential conditioning, whilst if the same target is learnt in isolation (absolute conditioning, discrimination is coarse and limited to perceptually dissimilar alternatives. Another way to potentially enhance discrimination is to increase the penalty associated with the distractor. Here we studied whether coupling the distractor with a highly concentrated quinine solution improves color discrimination of both similar and dissimilar colors by free-flying honeybees. As we assumed that quinine acts as an aversive stimulus, we analyzed whether aversion, if any, is based on an aversive sensory input at the gustatory level or on a post-ingestional malaise following quinine feeding. METHODOLOGY/PRINCIPAL FINDINGS: We show that the presence of a highly concentrated quinine solution (60 mM acts as an aversive reinforcer promoting rejection of the target associated with it, and improving discrimination of perceptually similar stimuli but not of dissimilar stimuli. Free-flying bees did not use remote cues to detect the presence of quinine solution; the aversive effect exerted by this substance was mediated via a gustatory input, i.e. via a distasteful sensory experience, rather than via a post-ingestional malaise. CONCLUSION: The present study supports the hypothesis that aversion conditioning is important for understanding how and what animals perceive and learn. By using this form of conditioning coupled with appetitive conditioning in the framework of a differential conditioning procedure, it is possible to uncover discrimination capabilities that may remain otherwise unsuspected. We show, therefore, that visual discrimination is not an absolute phenomenon but can be modulated by experience.

  8. Increased Loss Aversion in Unmedicated Patients with Obsessive–Compulsive Disorder

    Directory of Open Access Journals (Sweden)

    Kamila E. Sip

    2018-01-01

    Full Text Available IntroductionObsessive–compulsive disorder (OCD patients show abnormalities in decision-making and, clinically, appear to show heightened sensitivity to potential negative outcomes. Despite the importance of these cognitive processes in OCD, few studies have examined the disorder within an economic decision-making framework. Here, we investigated loss aversion, a key construct in the prospect theory that describes the tendency for individuals to be more sensitive to potential losses than gains when making decisions.MethodsAcross two study sites, groups of unmedicated OCD patients (n = 14, medicated OCD patients (n = 29, and healthy controls (n = 34 accepted or rejected a series of 50/50 gambles containing varying loss/gain values. Loss aversion was calculated as the ratio of the likelihood of rejecting a gamble with increasing potential losses to the likelihood of accepting a gamble with increasing potential gains. Decision times to accept or reject were also examined and correlated with loss aversion.ResultsUnmedicated OCD patients exhibited significantly more loss aversion compared to medicated OCD or controls, an effect that was replicated across both sites and remained significant even after controlling for OCD symptom severity, trait anxiety, and sex. Post hoc analyses further indicated that unmedicated patients’ increased likelihood to reject a gamble as its loss value increased could not be explained solely by greater risk aversion among patients. Unmedicated patients were also slower to accept than reject gambles, effects that were not found in the other two groups. Loss aversion was correlated with decision times in unmedicated patients but not in the other two groups.DiscussionThese data identify abnormalities of decision-making in a subgroup of OCD patients not taking psychotropic medication. The findings help elucidate the cognitive mechanisms of the disorder and suggest that future treatments could aim to target

  9. Increased Loss Aversion in Unmedicated Patients with Obsessive-Compulsive Disorder.

    Science.gov (United States)

    Sip, Kamila E; Gonzalez, Richard; Taylor, Stephan F; Stern, Emily R

    2017-01-01

    Obsessive-compulsive disorder (OCD) patients show abnormalities in decision-making and, clinically, appear to show heightened sensitivity to potential negative outcomes. Despite the importance of these cognitive processes in OCD, few studies have examined the disorder within an economic decision-making framework. Here, we investigated loss aversion, a key construct in the prospect theory that describes the tendency for individuals to be more sensitive to potential losses than gains when making decisions. Across two study sites, groups of unmedicated OCD patients ( n  = 14), medicated OCD patients ( n  = 29), and healthy controls ( n  = 34) accepted or rejected a series of 50/50 gambles containing varying loss/gain values. Loss aversion was calculated as the ratio of the likelihood of rejecting a gamble with increasing potential losses to the likelihood of accepting a gamble with increasing potential gains. Decision times to accept or reject were also examined and correlated with loss aversion. Unmedicated OCD patients exhibited significantly more loss aversion compared to medicated OCD or controls, an effect that was replicated across both sites and remained significant even after controlling for OCD symptom severity, trait anxiety, and sex. Post hoc analyses further indicated that unmedicated patients' increased likelihood to reject a gamble as its loss value increased could not be explained solely by greater risk aversion among patients. Unmedicated patients were also slower to accept than reject gambles, effects that were not found in the other two groups. Loss aversion was correlated with decision times in unmedicated patients but not in the other two groups. These data identify abnormalities of decision-making in a subgroup of OCD patients not taking psychotropic medication. The findings help elucidate the cognitive mechanisms of the disorder and suggest that future treatments could aim to target abnormalities of loss/gain processing during

  10. A highly selective CCR2 chemokine agonist encoded by human herpesvirus 6

    DEFF Research Database (Denmark)

    Lüttichau, Hans R; Clark-Lewis, Ian; Jensen, Peter Østrup

    2003-01-01

    The chemokine-like, secreted protein product of the U83 gene from human herpesvirus 6, here named vCCL4, was chemically synthesized to be characterized in a complete library of the 18 known human chemokine receptors expressed individually in stably transfected cell lines. vCCL4 was found to cause...... being equally or more efficacious in causing cell migration than CCL2 and CCL7 and considerably more efficacious than CCL8 and CCL13. It is concluded that human herpesvirus 6 encodes a highly selective and efficacious CCR2 agonist, which will attract CCR2 expressing cells, for example macrophages...

  11. Aversive Stimulation -- Criteria for Application.

    Science.gov (United States)

    O'Donnell, Patrick A.; Ohlson, Glenn A.

    Criteria for applying aversive stimulation with severely handicapped children are examined, and practical and ethical issues are considered. Factors seen to influence punishment outcomes include timing, intensity, and schedule of reinforcement. Suggested is the need for further research on the comparative effectiveness of positive and negative…

  12. Stimulus Similarity and Encoding Time Influence Incidental Recognition Memory in Adult Monkeys with Selective Hippocampal Lesions

    Science.gov (United States)

    Zeamer, Alyson; Meunier, Martine; Bachevalier, Jocelyne

    2011-01-01

    Recognition memory impairment after selective hippocampal lesions in monkeys is more profound when measured with visual paired-comparison (VPC) than with delayed nonmatching-to-sample (DNMS). To clarify this issue, we assessed the impact of stimuli similarity and encoding duration on the VPC performance in monkeys with hippocampal lesions and…

  13. Deciding for Others Reduces Loss Aversion

    DEFF Research Database (Denmark)

    Andersson, Ola; Holm, Håkan J.; Tyran, Jean-Robert Karl

    2016-01-01

    We study risk taking on behalf of others, both when choices involve losses and when they do not. A large-scale incentivized experiment with subjects randomly drawn from the Danish population is conducted. We find that deciding for others reduces loss aversion. When choosing between risky prospects...... when losses loom. This finding is consistent with an interpretation of loss aversion as a bias in decision making driven by emotions and that these emotions are reduced when making decisions for others....... for which losses are ruled out by design, subjects make the same choices for themselves as for others. In contrast, when losses are possible, we find that the two types of choices differ. In particular, we find that subjects who make choices for themselves take less risk than those who decide for others...

  14. Gender Differences in Risk Aversion Among Chinese University Students.

    Science.gov (United States)

    Lam, Desmond

    2015-12-01

    This paper examines gender differences in risk aversion among Chinese university students. Chinese females are proposed to be more risk averse and require a higher risk premium when faced with a gamble option in the gain-domain frame as compared to Chinese males. Two groups of 100 participants each (male = 100 and female = 100 in total) were recruited to fill up questionnaires that included items relating to objective probability lotteries. Within each group, it was found that Chinese males and females did not differ in their risk aversion. However, results show that Chinese males tend to react more readily to rising risk premium by taking up options with higher expected values when compared to Chinese females. Current findings will have useful implications to marketers (particularly, promoters of gambling products) and problem gambling counselors.

  15. Amygdala signals subjective appetitiveness and aversiveness of mixed gambles

    DEFF Research Database (Denmark)

    Gelskov, Sofie V.; Henningsson, Susanne; Madsen, Kristoffer Hougaard

    2015-01-01

    People are more sensitive to losses than to equivalent gains when making financial decisions. We used functional magnetic resonance imaging (fMRI) to illuminate how the amygdala contributes to loss aversion. The blood oxygen level dependent (BOLD) response of the amygdala was mapped while healthy...... individuals were responding to 50/50 gambles with varying potential gain and loss amounts. Overall, subjects demanded twice as high potential gain as loss to accept a gamble. The individual level of loss aversion was expressed by the decision boundary, i.e., the gain-loss ratio at which subjects accepted...... and rejected gambles with equal probability. Amygdala activity increased the more the gain-loss ratio deviated from the individual decision boundary showing that the amygdala codes action value. This response pattern was more strongly expressed in loss aversive individuals, linking amygdala activity...

  16. Appetitive but Not Aversive Olfactory Conditioning Modifies Antennal Movements in Honeybees

    Science.gov (United States)

    Cholé, Hanna; Junca, Pierre; Sandoz, Jean-Christophe

    2015-01-01

    In honeybees, two olfactory conditioning protocols allow the study of appetitive and aversive Pavlovian associations. Appetitive conditioning of the proboscis extension response (PER) involves associating an odor, the conditioned stimulus (CS) with a sucrose solution, the unconditioned stimulus (US). Conversely, aversive conditioning of the sting…

  17. Conditioned taste aversion, drugs of abuse and palatability.

    Science.gov (United States)

    Lin, Jian-You; Arthurs, Joe; Reilly, Steve

    2014-09-01

    We consider conditioned taste aversion to involve a learned reduction in the palatability of a taste (and hence in amount consumed) based on the association that develops when a taste experience is followed by gastrointestinal malaise. The present article evaluates the well-established finding that drugs of abuse, at doses that are otherwise considered rewarding and self-administered, cause intake suppression. Our recent work using lick pattern analysis shows that drugs of abuse also cause a palatability downshift and, therefore, support conditioned taste aversion learning. Copyright © 2014 Elsevier Ltd. All rights reserved.

  18. The neural basis of loss aversion in decision-making under risk.

    Science.gov (United States)

    Tom, Sabrina M; Fox, Craig R; Trepel, Christopher; Poldrack, Russell A

    2007-01-26

    People typically exhibit greater sensitivity to losses than to equivalent gains when making decisions. We investigated neural correlates of loss aversion while individuals decided whether to accept or reject gambles that offered a 50/50 chance of gaining or losing money. A broad set of areas (including midbrain dopaminergic regions and their targets) showed increasing activity as potential gains increased. Potential losses were represented by decreasing activity in several of these same gain-sensitive areas. Finally, individual differences in behavioral loss aversion were predicted by a measure of neural loss aversion in several regions, including the ventral striatum and prefrontal cortex.

  19. Are ambiguity aversion and ambiguity intolerance identical? A neuroeconomics investigation.

    Science.gov (United States)

    Tanaka, Yusuke; Fujino, Junya; Ideno, Takashi; Okubo, Shigetaka; Takemura, Kazuhisa; Miyata, Jun; Kawada, Ryosaku; Fujimoto, Shinsuke; Kubota, Manabu; Sasamoto, Akihiko; Hirose, Kimito; Takeuchi, Hideaki; Fukuyama, Hidenao; Murai, Toshiya; Takahashi, Hidehiko

    2014-01-01

    In recent years, there has been growing interest in understanding a person's reaction to ambiguous situations, and two similar constructs related to ambiguity, "ambiguity aversion" and "ambiguity intolerance," are defined in different disciplines. In the field of economic decision-making research, "ambiguity aversion" represents a preference for known risks relative to unknown risks. On the other hand, in clinical psychology, "ambiguity intolerance" describes the tendency to perceive ambiguous situations as undesirable. However, it remains unclear whether these two notions derived from different disciplines are identical or not. To clarify this issue, we combined an economic task, psychological questionnaires, and voxel-based morphometry (VBM) of structural brain magnetic resonance imaging (MRI) in a sample of healthy volunteers. The individual ambiguity aversion tendency parameter, as measured by our economic task, was negatively correlated with agreeableness scores on the self-reported version of the Revised NEO Personality Inventory. However, it was not correlated with scores of discomfort with ambiguity, one of the subscales of the Need for Closure Scale. Furthermore, the ambiguity aversion tendency parameter was negatively correlated with gray matter (GM) volume of areas in the lateral prefrontal cortex and parietal cortex, whereas ambiguity intolerance was not correlated with GM volume in any region. Our results suggest that ambiguity aversion, described in decision theory, may not necessarily be identical to ambiguity intolerance, referred to in clinical psychology. Cautious applications of decision theory to clinical neuropsychiatry are recommended.

  20. Managing Risk Aversion for Low-Carbon Supply Chains with Emission Abatement Outsourcing

    Science.gov (United States)

    Wang, Qinpeng; He, Longfei

    2018-01-01

    Reducing carbon emissions, including emission abatement outsourcing at the supply-chain level, is becoming a significant but challenging problem in practice. Confronting this challenge, we therefore break down the practice to focus on a low-carbon supply chain consisting of one supplier, one manufacturer and one third-party emission-reducing contractor. The contractor offers a carbon reduction service to the manufacturer. In view of the increasing proportion of Greenhouse Gases (GHG) emissions and absence of carbon reduction policies in developing countries, we adopt the prospect of consumers’ low-carbon preferences to capture the demand sensitivity on carbon emission. By exploiting the Mean-Variance (MV) model, we develop a supply chain game model considering risk aversion. Comparing the supply chain performances of the cases under risk neutrality and risk aversion, we investigate the impact of the risk aversion of the supplier and the manufacturer on the low-carbon supply chain performances, respectively. We show that the risk aversion of chain members will not influence the relationship underlain by the profit-sharing contract between the manufacturer and contractor, whereas they may extend the supplier’s concerning range. Although the manufacturer’s risk aversion has a positive impact on the wholesale price, interestingly, the supplier’s impact on the wholesale price is negative. Furthermore, we propose a contract to coordinate the risk-averse low-carbon supply chain by tuning the aversion levels of the supplier and the manufacturer, respectively. Through numerical study, we draw on managerial insights for industrial practitioners to adopt a low carbon strategy potentially by managing the risk attitudes along the supply chain channel. PMID:29466281

  1. Managing Risk Aversion for Low-Carbon Supply Chains with Emission Abatement Outsourcing

    Directory of Open Access Journals (Sweden)

    Qinpeng Wang

    2018-02-01

    Full Text Available Reducing carbon emissions, including emission abatement outsourcing at the supply-chain level, is becoming a significant but challenging problem in practice. Confronting this challenge, we therefore break down the practice to focus on a low-carbon supply chain consisting of one supplier, one manufacturer and one third-party emission-reducing contractor. The contractor offers a carbon reduction service to the manufacturer. In view of the increasing proportion of Greenhouse Gases (GHG emissions and absence of carbon reduction policies in developing countries, we adopt the prospect of consumers’ low-carbon preferences to capture the demand sensitivity on carbon emission. By exploiting the Mean-Variance (MV model, we develop a supply chain game model considering risk aversion. Comparing the supply chain performances of the cases under risk neutrality and risk aversion, we investigate the impact of the risk aversion of the supplier and the manufacturer on the low-carbon supply chain performances, respectively. We show that the risk aversion of chain members will not influence the relationship underlain by the profit-sharing contract between the manufacturer and contractor, whereas they may extend the supplier’s concerning range. Although the manufacturer’s risk aversion has a positive impact on the wholesale price, interestingly, the supplier’s impact on the wholesale price is negative. Furthermore, we propose a contract to coordinate the risk-averse low-carbon supply chain by tuning the aversion levels of the supplier and the manufacturer, respectively. Through numerical study, we draw on managerial insights for industrial practitioners to adopt a low carbon strategy potentially by managing the risk attitudes along the supply chain channel.

  2. A pilot study of loss aversion for drug and non-drug commodities in cocaine users.

    Science.gov (United States)

    Strickland, Justin C; Beckmann, Joshua S; Rush, Craig R; Stoops, William W

    2017-11-01

    Numerous studies in behavioral economics have demonstrated that individuals are more sensitive to the prospect of a loss than a gain (i.e., loss aversion). Although loss aversion has been well described in "healthy" populations, little research exists in individuals with substance use disorders. This gap is notable considering the prominent role that choice and decision-making play in drug use. The purpose of this pilot study was to evaluate loss aversion in active cocaine users. Current cocaine users (N=38; 42% female) participated in this within-subjects laboratory pilot study. Subjects completed a battery of tasks designed to assess loss aversion for drug and non-drug commodities under varying risk conditions. Standardized loss aversion coefficients (λ) were compared to theoretically and empirically relevant normative values (i.e., λ=2). Compared to normative loss aversion coefficient values, a precise and consistent decrease in loss aversion was observed in cocaine users (sample λ≈1). These values were observed across drug and non-drug commodities as well as under certain and risky conditions. These data represent the first systematic study of loss aversion in cocaine-using populations and provide evidence for equal sensitivity to losses and gains or loss equivalence. Futures studies should evaluate the specificity of these effects to a history of cocaine use as well as the impact of manipulations of loss aversion on drug use to determine how this phenomenon may contribute to intervention development efforts. Copyright © 2017 Elsevier B.V. All rights reserved.

  3. Aversive learning shapes neuronal orientation tuning in human visual cortex.

    Science.gov (United States)

    McTeague, Lisa M; Gruss, L Forest; Keil, Andreas

    2015-07-28

    The responses of sensory cortical neurons are shaped by experience. As a result perceptual biases evolve, selectively facilitating the detection and identification of sensory events that are relevant for adaptive behaviour. Here we examine the involvement of human visual cortex in the formation of learned perceptual biases. We use classical aversive conditioning to associate one out of a series of oriented gratings with a noxious sound stimulus. After as few as two grating-sound pairings, visual cortical responses to the sound-paired grating show selective amplification. Furthermore, as learning progresses, responses to the orientations with greatest similarity to the sound-paired grating are increasingly suppressed, suggesting inhibitory interactions between orientation-selective neuronal populations. Changes in cortical connectivity between occipital and fronto-temporal regions mirror the changes in visuo-cortical response amplitudes. These findings suggest that short-term behaviourally driven retuning of human visual cortical neurons involves distal top-down projections as well as local inhibitory interactions.

  4. Stress as a mnemonic filter: Interactions between medial temporal lobe encoding processes and post-encoding stress.

    Science.gov (United States)

    Ritchey, Maureen; McCullough, Andrew M; Ranganath, Charan; Yonelinas, Andrew P

    2017-01-01

    Acute stress has been shown to modulate memory for recently learned information, an effect attributed to the influence of stress hormones on medial temporal lobe (MTL) consolidation processes. However, little is known about which memories will be affected when stress follows encoding. One possibility is that stress interacts with encoding processes to selectively protect memories that had elicited responses in the hippocampus and amygdala, two MTL structures important for memory formation. There is limited evidence for interactions between encoding processes and consolidation effects in humans, but recent studies of consolidation in rodents have emphasized the importance of encoding "tags" for determining the impact of consolidation manipulations on memory. Here, we used functional magnetic resonance imaging in humans to test the hypothesis that the effects of post-encoding stress depend on MTL processes observed during encoding. We found that changes in stress hormone levels were associated with an increase in the contingency of memory outcomes on hippocampal and amygdala encoding responses. That is, for participants showing high cortisol reactivity, memories became more dependent on MTL activity observed during encoding, thereby shifting the distribution of recollected events toward those that had elicited relatively high activation. Surprisingly, this effect was generally larger for neutral, compared to emotionally negative, memories. The results suggest that stress does not uniformly enhance memory, but instead selectively preserves memories tagged during encoding, effectively acting as mnemonic filter. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

  5. Taste aversion learning produced by combined treatment with subthreshold radiation and lithium chloride

    International Nuclear Information System (INIS)

    Rabin, B.M.; Hunt, W.A.; Lee, J.

    1987-01-01

    These experiments were designed to determine whether treatment with two subthreshold doses of radiation or lithium chloride, either alone or in combination, could lead to taste aversion learning. The first experiment determined the thresholds for a radiation-induced taste aversion at 15-20 rad and for lithium chloride at 0.30-0.45 mEq/kg. In the second experiment it was shown that exposing rats to two doses of 15 rad separated by up to 3 hr produced a taste aversion. Treatment with two injections of lithium chloride (0.30 mEq/kg) did not produce a significant reduction in preference. Combined treatment with radiation and lithium chloride did produce a taste aversion when the two treatments were administered within 1 hr of each other. The results are discussed in terms of the implications of these findings for understanding the nature of the unconditioned stimuli leading to the acquisition of a conditioned taste aversion

  6. Uncertainty, loss aversion, and markets for energy efficiency

    International Nuclear Information System (INIS)

    Greene, David L.

    2011-01-01

    Increasing energy efficiency is critical to mitigating greenhouse gas emissions from fossil-fuel combustion, reducing oil dependence, and achieving a sustainable global energy system. The tendency of markets to neglect apparently cost-effective energy efficiency options has been called the 'efficiency gap' or 'energy paradox.' The market for energy efficiency in new, energy-using durable goods, however, appears to have a bias that leads to undervaluation of future energy savings relative to their expected value. This paper argues that the bias is chiefly produced by the combination of substantial uncertainty about the net value of future fuel savings and the loss aversion of typical consumers. This framework relies on the theory of context-dependent preferences. The uncertainty-loss aversion bias against energy efficiency is quantifiable, making it potentially correctible by policy measures. The welfare economics of such policies remains unresolved. Data on the costs of increased fuel economy of new passenger cars, taken from a National Research Council study, illustrate how an apparently cost-effective increase in energy efficiency would be uninteresting to loss-averse consumers.

  7. Onset and Offset of Aversive Events Establish Distinct Memories Requiring Fear and Reward Networks

    Science.gov (United States)

    Andreatta, Marta; Fendt, Markus; Muhlberger, Andreas; Wieser, Matthias J.; Imobersteg, Stefan; Yarali, Ayse; Gerber, Bertram; Pauli, Paul

    2012-01-01

    Two things are worth remembering about an aversive event: What made it happen? What made it cease? If a stimulus precedes an aversive event, it becomes a signal for threat and will later elicit behavior indicating conditioned fear. However, if the stimulus is presented upon cessation of the aversive event, it elicits behavior indicating…

  8. Experimental evidence against the paradigm of mortality risk aversion.

    Science.gov (United States)

    Rheinberger, Christoph M

    2010-04-01

    This article deals with the question of how societal impacts of fatal accidents can be integrated into the management of natural or man-made hazards. Today, many governmental agencies give additional weight to the number of potential fatalities in their risk assessments to reflect society's aversion to large accidents. Although mortality risk aversion has been proposed in numerous risk management guidelines, there has been no evidence that lay people want public decisionmakers to overweight infrequent accidents of large societal consequences against more frequent ones of smaller societal consequences. Furthermore, it is not known whether public decisionmakers actually do such overweighting when they decide upon the mitigation of natural or technical hazards. In this article, we report on two experimental tasks that required participants to evaluate negative prospects involving 1-100 potential fatalities. Our results show that neither lay people nor hazard experts exhibit risk-averse behavior in decisions on mortality risks.

  9. Taste aversion memory reconsolidation is independent of its retrieval.

    Science.gov (United States)

    Rodriguez-Ortiz, Carlos J; Balderas, Israela; Garcia-DeLaTorre, Paola; Bermudez-Rattoni, Federico

    2012-10-01

    Reconsolidation refers to the destabilization/re-stabilization memory process upon its activation. However, the conditions needed to undergo reconsolidation, as well as its functional significance is quite unclear and a matter of intense investigation. Even so, memory retrieval is held as requisite to initiate reconsolidation. Therefore, in the present work we examined whether transient pharmacological disruption of memory retrieval impedes reconsolidation of stored memory in the widely used associative conditioning task, taste aversion. We found that AMPA receptors inhibition in the amygdala impaired retrieval of taste aversion memory. Furthermore, AMPA receptors blockade impeded retrieval regardless of memory strength. However, inhibition of retrieval did not affect anisomycin-mediated disruption of reconsolidation. These results indicate that retrieval is a dispensable condition to undergo reconsolidation and provide evidence of molecular dissociation between retrieval and activation of memory in the non-declarative memory model taste aversion. Copyright © 2012 Elsevier Inc. All rights reserved.

  10. Neural systems underlying aversive conditioning in humans with primary and secondary reinforcers

    Directory of Open Access Journals (Sweden)

    Mauricio R Delgado

    2011-05-01

    Full Text Available Money is a secondary reinforcer commonly used across a range of disciplines in experimental paradigms investigating reward learning and decision-making. The effectiveness of monetary reinforcers during aversive learning and its neural basis, however, remains a topic of debate. Specifically, it is unclear if the initial acquisition of aversive representations of monetary losses depends on similar neural systems as more traditional aversive conditioning that involves primary reinforcers. This study contrasts the efficacy of a biologically defined primary reinforcer (shock and a socially defined secondary reinforcer (money during aversive learning and its associated neural circuitry. During a two-part experiment, participants first played a gambling game where wins and losses were based on performance to gain an experimental bank. Participants were then exposed to two separate aversive conditioning sessions. In one session, a primary reinforcer (mild shock served as an unconditioned stimulus (US and was paired with one of two colored squares, the conditioned stimuli (CS+ and CS-, respectively. In another session, a secondary reinforcer (loss of money served as the US and was paired with one of two different CS. Skin conductance responses were greater for CS+ compared to CS- trials irrespective of type of reinforcer. Neuroimaging results revealed that the striatum, a region typically linked with reward-related processing, was found to be involved in the acquisition of aversive conditioned response irrespective of reinforcer type. In contrast, the amygdala was involved during aversive conditioning with primary reinforcers, as suggested by both an exploratory fMRI analysis and a follow-up case study with a patient with bilateral amygdala damage. Taken together, these results suggest that learning about potential monetary losses may depend on reinforcement learning related systems, rather than on typical structures involved in more biologically based

  11. The Effect of Wealth Shocks on Loss Aversion: Behavior and Neural Correlates

    Directory of Open Access Journals (Sweden)

    V. S. Chandrasekhar Pammi

    2017-04-01

    Full Text Available Kahneman and Tversky (1979 first demonstrated that when individuals decide whether or not to accept a gamble, potential losses receive more weight than possible gains in the decision. This phenomenon is referred to as loss aversion. We investigated how loss aversion in risky financial decisions is influenced by sudden changes to wealth, employing both behavioral and neurobiological measures. We implemented an fMRI experimental paradigm, based on that employed by Tom et al. (2007. There are two treatments, called RANDOM and CONTINGENT. In RANDOM, the baseline setting, the changes to wealth, referred to as wealth shocks in economics, are independent of the actual choices participants make. Under CONTINGENT, we induce the belief that the changes in income are a consequence of subjects' own decisions. The magnitudes and sequence of the shocks to wealth are identical between the CONTINGENT and RANDOM treatments. We investigated whether more loss aversion existed in one treatment than another. The behavioral results showed significantly greater loss aversion in CONTINGENT compared to RANDOM after a negative wealth shock. No differences were observed in the response to positive shocks. The fMRI results revealed a neural loss aversion network, comprising the bilateral striatum, amygdala and dorsal anterior cingulate cortex that was common to the CONTINGENT and RANDOM tasks. However, the ventral prefrontal cortex, primary somatosensory cortex and superior occipital cortex, showed greater activation in response to a negative change in wealth due to individual's own decisions than when the change was exogenous. These results indicate that striatum activation correlates with loss aversion independently of the source of the shock, and that the ventral prefrontal cortex (vPFC codes the experimental manipulation of agency in one's actions influencing loss aversion.

  12. The Effect of Wealth Shocks on Loss Aversion: Behavior and Neural Correlates.

    Science.gov (United States)

    Pammi, V S Chandrasekhar; Ruiz, Sergio; Lee, Sangkyun; Noussair, Charles N; Sitaram, Ranganatha

    2017-01-01

    Kahneman and Tversky (1979) first demonstrated that when individuals decide whether or not to accept a gamble, potential losses receive more weight than possible gains in the decision. This phenomenon is referred to as loss aversion. We investigated how loss aversion in risky financial decisions is influenced by sudden changes to wealth, employing both behavioral and neurobiological measures. We implemented an fMRI experimental paradigm, based on that employed by Tom et al. (2007). There are two treatments, called RANDOM and CONTINGENT. In RANDOM, the baseline setting, the changes to wealth, referred to as wealth shocks in economics, are independent of the actual choices participants make. Under CONTINGENT, we induce the belief that the changes in income are a consequence of subjects' own decisions. The magnitudes and sequence of the shocks to wealth are identical between the CONTINGENT and RANDOM treatments. We investigated whether more loss aversion existed in one treatment than another. The behavioral results showed significantly greater loss aversion in CONTINGENT compared to RANDOM after a negative wealth shock. No differences were observed in the response to positive shocks. The fMRI results revealed a neural loss aversion network, comprising the bilateral striatum, amygdala and dorsal anterior cingulate cortex that was common to the CONTINGENT and RANDOM tasks. However, the ventral prefrontal cortex, primary somatosensory cortex and superior occipital cortex, showed greater activation in response to a negative change in wealth due to individual's own decisions than when the change was exogenous. These results indicate that striatum activation correlates with loss aversion independently of the source of the shock, and that the ventral prefrontal cortex (vPFC) codes the experimental manipulation of agency in one's actions influencing loss aversion.

  13. Risk-averse portfolio selection of renewable electricity generator investments in Brazil: An optimised multi-market commercialisation strategy

    International Nuclear Information System (INIS)

    Maier, Sebastian; Street, Alexandre; McKinnon, Ken

    2016-01-01

    Investment decisions in renewable energy sources such as small hydro, wind power, biomass and solar are frequently made in the context of enormous uncertainty surrounding both intermittent generation and the highly volatile electricity spot prices that are used for clearing of trades. This paper presents a new portfolio-based approach for selecting long-term investments in small-scale renewable energy projects and matching contracts for the sale of the resulting electricity. Using this approach, we have formulated a stochastic optimisation model that maximises a holding company's risk-averse measure of value. Using an illustrative example representative of investment decisions within the Brazilian electricity system, we investigate the sensitivity of the optimised portfolio composition and commercialisation strategy to contract prices in the free contracting environment and to the decision maker's attitude towards risk. The numerical results demonstrate it is possible to reduce significantly financial risks, such as the price-quantity risk, not only by exploiting the complementarity of the considered renewable sources generation profiles, but also by selecting the optimal mix of commercialisation contracts from different markets. We find that the multi-market strategy generally results in appreciably higher optimal value than single-market strategies and can be applied to a wide range of renewable generators and contracts. - Highlights: • Gives a portfolio-based multi-market, multi-asset approach to renewable investment. • Details how to model currently used contract types in each of the Brazilian markets. • Presents a test case using realistic contract and real renewable data from Brazil. • Shows that the approach controls financial risks and boosts optimal values. • Explains how relative contract prices and attitude to risk affect optimal decisions.

  14. Contrasting role of octopamine in appetitive and aversive learning in the crab Chasmagnathus.

    Directory of Open Access Journals (Sweden)

    Laura Kaczer

    Full Text Available BACKGROUND: Biogenic amines are implicated in reinforcing associative learning. Octopamine (OA is considered the invertebrate counterpart of noradrenaline and several studies in insects converge on the idea that OA mediates the reward in appetitive conditioning. However, it is possible to assume that OA could have a different role in an aversive conditioning. METHODOLOGY/PRINCIPAL FINDINGS: Here we pharmacologically studied the participation of OA in two learning processes in the crab Chasmagnathus granulatus, one appetitive and one aversive. It is shown that the aversive memory is impaired by an OA injection applied immediately or 30 minutes after the last training trial. By contrast, the appetitive memory is blocked by OA antagonists epinastine and mianserine, but enhanced by OA when injected together with the supply of a minimum amount of reinforcement. Finally, double-learning experiments in which crabs are given the aversive and the appetitive learning either successively or simultaneously allow us to study the interaction between both types of learning and analyze the presumed action of OA. We found that the appetitive training offered immediately, but not one hour, after an aversive training has an amnesic effect on the aversive memory, mimicking the effect and the kinetic of an OA injection. CONCLUSIONS/SIGNIFICANCE: Our results demonstrate that the role of OA is divergent in two memory processes of opposite signs: on the one hand it would mediate the reinforcement in appetitive learning, and on the other hand it has a deleterious effect over aversive memory consolidation.

  15. Comparing uncertainty aversion towards different sources

    NARCIS (Netherlands)

    Baillon, Aurélien; Liu, Ning; van Dolder, Dennie

    2017-01-01

    We propose simple behavioral definitions of comparative uncertainty aversion for a single agent towards different sources of uncertainty. Our definitions allow for the comparison of utility curvature for different sources if the agent’s choices satisfy subjective expected utility towards each

  16. Least-squares reverse time migration of marine data with frequency-selection encoding

    KAUST Repository

    Dai, Wei; Huang, Yunsong; Schuster, Gerard T.

    2013-01-01

    The phase-encoding technique can sometimes increase the efficiency of the least-squares reverse time migration (LSRTM) by more than one order of magnitude. However, traditional random encoding functions require all the encoded shots to share

  17. Re-engaging with the past: recapitulation of encoding operations during retrieval

    Directory of Open Access Journals (Sweden)

    Alexa eMorcom

    2014-05-01

    Full Text Available Recollection of events is accompanied by selective reactivation of cortical regions which responded to specific sensory and cognitive dimensions of the original events. This reactivation is thought to reflect the reinstatement of stored memory representations and therefore to reflect memory content, but it may also reveal processes which support both encoding and retrieval. The present study used event-related functional magnetic resonance imaging (fMRI to investigate whether regions selectively engaged in encoding face and scene context with studied words are also re-engaged when the context is later retrieved. As predicted, encoding face and scene context with visually presented words elicited activity in distinct, context-selective regions. Retrieval of face and scene context also re-engaged some of the regions which had shown successful encoding effects. However, this recapitulation of encoding activity did not show the same context selectivity observed at encoding. Successful retrieval of both face and scene context re-engaged regions which had been associated with encoding of the other type of context, as well as those associated with encoding the same type of context. This recapitulation may reflect retrieval attempts which are not context-selective, but use shared retrieval cues to re-engage encoding operations in service of recollection.

  18. On the descriptive value of loss aversion in decisions under risk: Six clarifications

    OpenAIRE

    Eyal Ert; Ido Erev

    2013-01-01

    Previous studies of loss aversion in decisions under risk have led to mixed results. Losses appear to loom larger than gains in some settings, but not in others. The current paper clarifies these results by highlighting six experimental manipulations that tend to increase the likelihood of the behavior predicted by loss aversion. These manipulations include: (1) framing of the safe alternative as the status quo; (2) ensuring that the choice pattern predicted by loss aversion maximizes the pro...

  19. "Incidental fear cues increase monetary loss aversion": Correction to Schulreich, Gerhardt, and Heekeren (2016).

    Science.gov (United States)

    2016-12-01

    Reports an error in "Incidental fear cues increase monetary loss aversion" by Stefan Schulreich, Holger Gerhardt and Hauke R. Heekeren ( Emotion , 2016[Apr], Vol 16[3], 402-412). In the current article, there was an error in the Study 2 portion of the article. The fourth paragraph of the Results section should read as follows: Performing the same analyses as in Study 1, we found an effect of incidental fear cues on decision behavior. Participants accepted fewer gambles in the fearful-face condition (32.77%) than in the neutral-face condition (33.96%), with Z = -2.187, p = .027, d = -0.998 in the Wilcoxon signed-ranks test and β = 0.012, SE = 0.0053, F(1, 21) = 4.434, p = .047, partial η² = .174 in the linear regression. This suggests increased risk aversion in the fearful-face condition. Concerning personality, however, there were no significant between-subjects effects or between-within interaction effects (all ps = .349). (The following abstract of the original article appeared in record 2015-52358-001.) In many everyday decisions, people exhibit loss aversion-a greater sensitivity to losses relative to gains of equal size. Loss aversion is thought to be (at least partly) mediated by emotional-in particular, fear-related-processes. Decision research has shown that even incidental emotions, which are unrelated to the decision at hand, can influence decision making. The effect of incidental fear on loss aversion, however, is thus far unclear. In two studies, we experimentally investigated how incidental fear cues, presented during (Study 1) or before (Study 2) choices to accept or reject mixed gambles over real monetary stakes, influence monetary loss aversion. We find that the presentation of fearful faces, relative to the presentation of neutral faces, increased risk aversion-an effect that could be attributed to increased loss aversion. The size of this effect was moderated by psychopathic personality: Fearless dominance, in particular its interpersonal facet

  20. Neural loss aversion differences between depression patients and healthy individuals: A functional MRI investigation.

    Science.gov (United States)

    Chandrasekhar Pammi, V S; Pillai Geethabhavan Rajesh, Purushothaman; Kesavadas, Chandrasekharan; Rappai Mary, Paramban; Seema, Satish; Radhakrishnan, Ashalatha; Sitaram, Ranganatha

    2015-04-01

    Neuroeconomics employs neuroscience techniques to explain decision-making behaviours. Prospect theory, a prominent model of decision-making, features a value function with parameters for risk and loss aversion. Recent work with normal participants identified activation related to loss aversion in brain regions including the amygdala, ventral striatum, and ventromedial prefrontal cortex. However, the brain network for loss aversion in pathologies such as depression has yet to be identified. The aim of the current study is to employ the value function from prospect theory to examine behavioural and neural manifestations of loss aversion in depressed and healthy individuals to identify the neurobiological markers of loss aversion in economic behaviour. We acquired behavioural data and fMRI scans while healthy controls and patients with depression performed an economic decision-making task. Behavioural loss aversion was higher in patients with depression than in healthy controls. fMRI results revealed that the two groups shared a brain network for value function including right ventral striatum, ventromedial prefrontal cortex, and right amygdala. However, the neural loss aversion results revealed greater activations in the right dorsal striatum and the right anterior insula for controls compared with patients with depression, and higher activations in the midbrain region ventral tegmental area for patients with depression compared with controls. These results suggest that while the brain network for loss aversion is shared between depressed and healthy individuals, some differences exist with respect to differential activation of additional areas. Our findings are relevant to identifying neurobiological markers for altered decision-making in the depressed. © The Author(s) 2015 Reprints and permissions: sagepub.co.uk/journalsPermissions.nav.

  1. Investigations on UCS-CS mediation in radiation-induced conditioned taste aversion

    International Nuclear Information System (INIS)

    Burns, T.C.

    1974-01-01

    Groups of 8 male Sprague-Dawley rats were used in an investigation of procaine and dimenhydrinate effects on radiation-induced taste aversion learning. Neither the local anesthetic procaine, administered intraperitoneally, nor the antinausea drug dimenhydrinate, administered intramuscularly, blocked acquisition of aversion to saccharin flavored water. Control animals confirmed that saccharin preferences appeared normally in non-irradiated animals, and that the drugs produced no aversion in the absence of radiation. Another investigation, using groups of 5 female Sprague-Dawley rats, showed a failure of dimenhydrinate in blocking the acquisition of a rotation-induced conditioned taste aversion. Two dose levels of the drug were used, 1 mg/kg and 2 mg/kg. At the dimenhydrinate dosage used in the study involving radiation (1.75 mg/kg) and at the higher dosage used in the study involving rotation, there appeared to be a potentiation of the effects of radiation and rotation, respectively. Results of these studies seem to favor a model for UCS-CS mediation as being diffuse and perhaps redundant. The possibility that nausea-producing stimuli may work synergistically was also discussed. (U.S.)

  2. Risk Aversion: As Perceived by U.S. and Swedish Officers

    Science.gov (United States)

    2011-06-10

    marginalized traditional morality . (Furedi 1997, 153f) The value of risk aversion means to not put people at risk and to regulate behavior. The main...difference compared to traditional morality lies in the individualistic orientation of risk aversion (Furedi 1997, 163) Ulrich Beck German Professor of...that distinguishes one group of people from another (Hofstede 2005, 3ff). Studying differences in culture demands a position of cultural relativism

  3. Effects of prior aversive experience upon retrograde amnesia induced by hypothermia.

    Science.gov (United States)

    Jensen, R A; Riccio, D C; Gehres, L

    1975-08-01

    Two experiments examined the extent to which retrograde amnesia (RA) is attenuated by prior learning experiences. In Experiment 1, rats initially received either passive avoidance training in a step-through apparatus, exposure to the apparatus, or noncontingent footshock. When training on a second but different passive avoidance task was followed by hypothermia treatment, RA was obtained only in the latter two groups. In Experiment 2, one-way active avoidance training, yoked noncontingent shocks, or apparatus exposure constituted the initial experience. Subsequent step-down passive avoidance training and amnestic treatment resulted in memory loss for the prior apparatus exposure group, but not for either of the preshocked conditions. These experiments demonstrate that certain types of prior aversive experience can substantially modify the magnitude of RA, and, in conjunction with other familiarization studies, emphasize a paradox for interpretations of RA based solely upon CNS disruption. The possibility that hypothermia treatment serves as an important contextual or encoding cue necessary for memory retrieval was considered. It was suggested that prior experience may block RA by enabling rats to differentiate training and treatment conditions.

  4. The functional and structural neural basis of individual differences in loss aversion.

    Science.gov (United States)

    Canessa, Nicola; Crespi, Chiara; Motterlini, Matteo; Baud-Bovy, Gabriel; Chierchia, Gabriele; Pantaleo, Giuseppe; Tettamanti, Marco; Cappa, Stefano F

    2013-09-04

    Decision making under risk entails the anticipation of prospective outcomes, typically leading to the greater sensitivity to losses than gains known as loss aversion. Previous studies on the neural bases of choice-outcome anticipation and loss aversion provided inconsistent results, showing either bidirectional mesolimbic responses of activation for gains and deactivation for losses, or a specific amygdala involvement in processing losses. Here we focused on loss aversion with the aim to address interindividual differences in the neural bases of choice-outcome anticipation. Fifty-six healthy human participants accepted or rejected 104 mixed gambles offering equal (50%) chances of gaining or losing different amounts of money while their brain activity was measured with functional magnetic resonance imaging (fMRI). We report both bidirectional and gain/loss-specific responses while evaluating risky gambles, with amygdala and posterior insula specifically tracking the magnitude of potential losses. At the individual level, loss aversion was reflected both in limbic fMRI responses and in gray matter volume in a structural amygdala-thalamus-striatum network, in which the volume of the "output" centromedial amygdala nuclei mediating avoidance behavior was negatively correlated with monetary performance. We conclude that outcome anticipation and ensuing loss aversion involve multiple neural systems, showing functional and structural individual variability directly related to the actual financial outcomes of choices. By supporting the simultaneous involvement of both appetitive and aversive processing in economic decision making, these results contribute to the interpretation of existing inconsistencies on the neural bases of anticipating choice outcomes.

  5. Heterogenous Intertemporal Elasticity of Substitution and Relative Risk Aversion

    DEFF Research Database (Denmark)

    Khorunzhina, Natalia; Gayle, Wayne-Roy

    This paper investigates the existence and degree of variation across house holds and over time in the intertemporal elasticity of substitution (IES) and the coefficient of relative risk aversion (RRA) that is generated by habit forming preferences. To do so, we develop a new nonlinear GMM estimator...... in food consumption. Using these estimates, we develop bounds for the expectation of the implied heterogenous intertemporal elasticity of substitution and relative risk aversion that account for measurement errors and compute asymptotically valid confidence intervals on these bounds. We find...

  6. Oxytocin attenuates aversive response to nicotine and anxiety-like behavior in adolescent rats.

    Science.gov (United States)

    Lee, Hyunchan; Jang, Minji; Noh, Jihyun

    2017-02-01

    Initial tobacco use is initiated with rewarding and aversive properties of nicotine and aversive response to nicotine plays a critical role in nicotine dependency. Decrease of nicotine aversion increases the nicotine use that causes behavioral and neuronal changes of animals. Oxytocin influences drug abuse and reciprocally affect vulnerability to drug use. To assess the effect of oxytocin on initial nicotine aversion and anxiety, we examined voluntary oral nicotine intake and anxiety-like behavior following oxytocin treatment in adolescent rats. Sprague-Dawley male rats (4 weeks old) were used. For oxytocin administration, rats were injected subcutaneously with saline or oxytocin (0.01, 0.1 and 1mg/kg) according to the assigned groups. Voluntary oral nicotine consumption test was performed by two bottle free-choice paradigm. To examine anxiety-like behavior in rats, we performed a light/dark box test. Oxytocin not only significantly increased the nicotine intake but also alleviated nicotine aversion after acclimation to nicotine solution in a concentration dependent manner. Meanwhile, oxytocin significantly reduced anxiety-like behavior. We suggest that oxytocin itself mitigates aversive response toward initial nicotine intake and anxiety-like behavior. These results widen the psychophysiological perspective on oxytocin for better understanding of nicotine addiction related behaviors influenced by diverse social factors. Copyright © 2016 Elsevier Ireland Ltd and Japan Neuroscience Society. All rights reserved.

  7. Loss aversion is associated with bilateral insula volume. A voxel based morphometry study.

    Science.gov (United States)

    Markett, S; Heeren, G; Montag, C; Weber, B; Reuter, M

    2016-04-21

    Loss aversion is a decision bias, reflecting a greater sensitivity to losses than to gains in a decision situation. Recent neuroscientific research has shown that mesocorticolimbic structures like ventromedial prefrontal cortex and the ventral striatum constitute a bidirectional neural system that processes gains and losses and exhibits a neural basis of loss aversion. On a functional and structural level, the amygdala and insula also seem to play an important role in the processing of loss averse behavior. By applying voxel-based morphometry to structural brain images in N=41 healthy participants, the current study provides further evidence for the relationship of brain structure and loss aversion. The results show a negative correlation of gray matter volume in bilateral posterior insula as well as left medial frontal gyrus with individual loss aversion. Hence, higher loss aversion is associated with lower gray matter volume in these brain areas. Both structures have been discussed to play important roles in the brain's salience network, where the posterior insula is involved in interoception and the detection of salience. The medial frontal gyrus might impact decision making through its dense connections with the anterior cingulate cortex. A possible explanation for the present finding is that structural differences in these regions alter the processing of losses and salience, possibly biasing decision making towards avoidance of negative outcomes. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  8. Hiring a Gay Man, Taking a Risk?: A Lab Experiment on Employment Discrimination and Risk Aversion.

    Science.gov (United States)

    Baert, Stijn

    2018-01-01

    We investigate risk aversion as a driver of labor market discrimination against homosexual men. We show that more hiring discrimination by more risk-averse employers is consistent with taste-based and statistical discrimination. To test this hypothesis we conduct a scenario experiment in which experimental employers take a fictitious hiring decision concerning a heterosexual or homosexual male job candidate. In addition, participants are surveyed on their risk aversion and other characteristics that might correlate with this risk aversion. Analysis of the (post-)experimental data confirms our hypothesis. The likelihood of a beneficial hiring decision for homosexual male candidates decreases by 31.7% when employers are a standard deviation more risk-averse.

  9. Loss Aversion in the Classroom: A Nudge towards a Better Grade?

    Science.gov (United States)

    Grijalva, Therese; Koford, Brandon C.; Parkhurst, Gregory

    2018-01-01

    Using data from 499 students over 12 sections, 2 courses, and 3 instructors, we estimate the effect of loss aversion on the probability of turning in extra credit assignments and the effect on the overall grade. Regression results indicate no effect of loss aversion on the probability of turning in extra credit assignments and no effect on a…

  10. Heuristics and Criterion Setting during Selective Encoding in Visual Decision-Making: Evidence from Eye Movements.

    Science.gov (United States)

    Schotter, Elizabeth R; Gerety, Cainen; Rayner, Keith

    2012-01-01

    When making a decision, people spend longer looking at the option they ultimately choose compared other options-termed the gaze bias effect-even during their first encounter with the options (Glaholt & Reingold, 2009a, 2009b; Schotter, Berry, McKenzie & Rayner, 2010). Schotter et al. (2010) suggested that this is because people selectively encode decision-relevant information about the options, on-line during the first encounter with them. To extend their findings and test this claim, we recorded subjects' eye movements as they made judgments about pairs of images (i.e., which one was taken more recently or which one was taken longer ago). We manipulated whether both images were presented in the same color content (e.g., both in color or both in black-and-white) or whether they differed in color content and the extent to which color content was a reliable cue to relative recentness of the images. We found that the magnitude of the gaze bias effect decreased when the color content cue was not reliable during the first encounter with the images, but no modulation of the gaze bias effect in remaining time on the trial. These data suggest people do selectively encode decision-relevant information on-line.

  11. Emotion-induced loss aversion and striatal-amygdala coupling in low-anxious individuals.

    Science.gov (United States)

    Charpentier, Caroline J; De Martino, Benedetto; Sim, Alena L; Sharot, Tali; Roiser, Jonathan P

    2016-04-01

    Adapting behavior to changes in the environment is a crucial ability for survival but such adaptation varies widely across individuals. Here, we asked how humans alter their economic decision-making in response to emotional cues, and whether this is related to trait anxiety. Developing an emotional decision-making task for functional magnetic resonance imaging, in which gambling decisions were preceded by emotional and non-emotional primes, we assessed emotional influences on loss aversion, the tendency to overweigh potential monetary losses relative to gains. Our behavioral results revealed that only low-anxious individuals exhibited increased loss aversion under emotional conditions. This emotional modulation of decision-making was accompanied by a corresponding emotion-elicited increase in amygdala-striatal functional connectivity, which correlated with the behavioral effect across participants. Consistent with prior reports of 'neural loss aversion', both amygdala and ventral striatum tracked losses more strongly than gains, and amygdala loss aversion signals were exaggerated by emotion, suggesting a potential role for this structure in integrating value and emotion cues. Increased loss aversion and striatal-amygdala coupling induced by emotional cues may reflect the engagement of adaptive harm-avoidance mechanisms in low-anxious individuals, possibly promoting resilience to psychopathology. © The Author (2015). Published by Oxford University Press.

  12. Increased dopaminergic signaling impairs aversive olfactory memory retention in Drosophila.

    Science.gov (United States)

    Zhang, Shixing; Yin, Yan; Lu, Huimin; Guo, Aike

    2008-05-23

    Dopamine is necessary for the aversive olfactory associative memory formation in Drosophila, but its effect on other stages of memory is not known. Herein, we studied the effect of enhanced dopaminergic signaling on aversive olfactory memory retention in flies. We used l-3,4-dihydroxyphenylalanine (l-DOPA) to elevate dopamine levels: l-DOPA-treated flies exhibited a normal learning performance, but a decrease in 1-h memory. Dopamine transporter (DAT) mutant flies or flies treated with the DAT inhibitor desipramine exhibited poor memory retention. Flies subjected to heat stress after training exhibited a decrease in memory. Memory was restored by blocking dopaminergic neuronal output during heat stress, suggesting that dopamine is involved in heat stress-induced memory impairment in flies. Taken together, our findings suggest that increased dopaminergic signaling impairs aversive olfactory memory retention in flies.

  13. Household portfolios and implicit risk aversion

    NARCIS (Netherlands)

    Bucciol, A.; Miniaci, R.

    2008-01-01

    We derive from a sample of US households the distribution of the risk aversion implicit in their portfolio choice. Our estimate minimizes the distance between the certainty equivalent return generated with observed portfolios and portfolios that are optimal in a mean-variance framework. Taking into

  14. Effects of subdiaphragmatic vagotomy on the acquisition of a radiation-induced conditioned taste aversion

    International Nuclear Information System (INIS)

    Hunt, W.A.; Rabin, B.M.; Lee, J.

    1987-01-01

    The effect of subdiaphragmatic vagotomy on the acquisition of a radiation-induced taste aversion was examined to assess the importance of the vagus nerve in transmitting information on the peripheral toxicity of radiation to the brain. Vagotomy had no effect on taste aversion learning, consistent with reports using other toxins. The data support the involvement of a blood-borne factor in the acquisition of taste aversion induced by ionizing radiation

  15. Modulation of the conflict monitoring intensity: the role of aversive reinforcement, cognitive demand, and trait-BIS.

    Science.gov (United States)

    Leue, Anja; Lange, Sebastian; Beauducel, André

    2012-06-01

    According to Botvinick's (2007) integrative account, conflict monitoring is aversive because individuals anticipate cognitive demand, whereas the revised reinforcement sensitivity theory (rRST) predicts that conflict processing is aversive because individuals anticipate aversive reinforcement of erroneous responses. Because these accounts give different reasons for the aversive aspects of conflict, we manipulated cognitive demand and the aversive reinforcement as a consequence of wrong choices in a go/no-go task. Thereby, we also aimed to investigate whether individual differences in conflict sensitivity (i.e., in trait anxiety, linked to high sensitivity of the behavioral inhibition system [trait-BIS]) represent the effects of aversive reinforcement and cognitive demand in conflict tasks. We expected that these manipulations would have effects on the frontal N2 component representing activity of the anterior cingulate cortex. Moreover, higher-trait-BIS individuals should be more sensitive than lower-trait-BIS individuals to aversive effects in conflict situations, resulting in a more negative frontal N2 for higher-trait-BIS individuals. In Study 1, with N = 104 students, and Study 2, with N = 47 students, aversive reinforcement was manipulated in three levels (within-subjects factor) and cognitive demand in two levels (between-subjects factor). The behavioral findings from the go/no-go task with noncounterbalanced reinforcement levels (Study 1) could be widely replicated in a task with counterbalanced reinforcement levels (Study 2). The frontal mean no-go N2 amplitude and the frontal no-go N2 dipole captured predicted reinforcement-related variations of conflict monitoring, indicating that the anticipation of aversive reinforcement induces variations in conflict monitoring intensity in frontal brain areas. The aversive nature of conflict was underlined by the more pronounced conflict monitoring in higher- than in lower-trait-BIS individuals.

  16. Mothers' depressive symptoms predict both increased and reduced negative reactivity: aversion sensitivity and the regulation of emotion.

    Science.gov (United States)

    Dix, Theodore; Moed, Anat; Anderson, Edward R

    2014-07-01

    This study examined whether, as mothers' depressive symptoms increase, their expressions of negative emotion to children increasingly reflect aversion sensitivity and motivation to minimize ongoing stress or discomfort. In multiple interactions over 2 years, negative affect expressed by 319 mothers and their children was observed across variations in mothers' depressive symptoms, the aversiveness of children's immediate behavior, and observed differences in children's general negative reactivity. As expected, depressive symptoms predicted reduced maternal negative reactivity when child behavior was low in aversiveness, particularly with children who were high in negative reactivity. Depressive symptoms predicted high negative reactivity and steep increases in negative reactivity as the aversiveness of child behavior increased, particularly when high and continued aversiveness from the child was expected (i.e., children were high in negative reactivity). The findings are consistent with the proposal that deficits in parenting competence as depressive symptoms increase reflect aversion sensitivity and motivation to avoid conflict and suppress children's aversive behavior. © The Author(s) 2014.

  17. Contrasting Effects of Histone Deacetylase Inhibitors on Reward and Aversive Olfactory Memories in the Honey Bee

    Directory of Open Access Journals (Sweden)

    Gabrielle A Lockett

    2014-06-01

    Full Text Available Much of what we have learnt from rodent models about the essential role of epigenetic processes in brain plasticity has made use of aversive learning, yet the role of histone acetylation in aversive memory in the honey bee, a popular invertebrate model for both memory and epigenetics, was previously unknown. We examined the effects of histone deacetylase (HDAC inhibition on both aversive and reward olfactory associative learning in a discrimination proboscis extension reflex (PER assay. We report that treatment with the HDAC inhibitors APHA compound 8 (C8, phenylbutyrate (PB or sodium butyrate (NaB impaired discrimination memory due to impairment of aversive memory in a dose-dependent manner, while simultaneously having no effect on reward memory. Treatment with C8 1 h before training, 1 h after training or 1 h before testing, impaired aversive but not reward memory at test. C8 treatment 1 h before training also improved aversive but not reward learning during training. PB treatment only impaired aversive memory at test when administered 1 h after training, suggesting an effect on memory consolidation specifically. Specific impairment of aversive memory (but not reward memory by HDAC inhibiting compounds was robust, reproducible, occurred following treatment with three drugs targeting the same mechanism, and is likely to be genuinely due to alterations to memory as sucrose sensitivity and locomotion were unaffected by HDAC inhibitor treatment. This pharmacological dissection of memory highlights the involvement of histone acetylation in aversive memory in the honey bee, and expands our knowledge of epigenetic control of neural plasticity in invertebrates.

  18. Analysis of Behavioral Economics in Crowdsensing: A Loss Aversion Cooperation Model

    Directory of Open Access Journals (Sweden)

    Deng Li

    2018-01-01

    Full Text Available The existing incentive mechanisms of crowdsourcing construct the expected utility function based on the assumption of rational people in traditional economics. A large number of studies in behavioral economics have demonstrated the defects of the traditional utility function and introduced a new parameter called loss aversion coefficient to calculate individual utility when it suffers a loss. In this paper, combination of behavioral economics and a payment algorithm based on the loss aversion is proposed. Compared with usual incentive mechanisms, the node utility function is redefined by the loss aversion characteristic of the node. Experimental results show that the proposed algorithm can get a higher rate of cooperation with a lower payment price and has good scalability compared with the traditional incentive mechanism.

  19. Lateral, Not Medial, Prefrontal Cortex Contributes to Punishment and Aversive Instrumental Learning

    Science.gov (United States)

    Jean-Richard-dit-Bressel , Philip; McNally, Gavan P.

    2016-01-01

    Aversive outcomes punish behaviors that cause their occurrence. The prefrontal cortex (PFC) has been implicated in punishment learning and behavior, although the exact roles for different PFC regions in instrumental aversive learning and decision-making remain poorly understood. Here, we assessed the role of the orbitofrontal (OFC), rostral…

  20. Differences between appetitive and aversive reinforcement on reorientation in a spatial working memory task.

    Science.gov (United States)

    Golob, Edward J; Taube, Jeffrey S

    2002-10-17

    Tasks using appetitive reinforcers show that following disorientation rats use the shape of an arena to reorient, and cannot distinguish two geometrically similar corners to obtain a reward, despite the presence of a prominent visual cue that provides information to differentiate the two corners. Other studies show that disorientation impairs performance on certain appetitive, but not aversive, tasks. This study evaluated whether rats would make similar geometric errors in a working memory task that used aversive reinforcement. We hypothesized that in a task that used aversive reinforcement rats that were initially disoriented would not reorient by arena shape and thus make similar geometric errors. Tests were performed in a rectangular arena having one polarizing cue. In the appetitive condition water consumption was the reward. The aversive condition was a water maze task with reinforcement provided by escape to a hidden platform. In the aversive condition rats returned to the reinforced corner significantly more often than in the dry condition, and did not favor the diagonally opposite corner. Results show that rats can use cues besides arena shape to reorient in an aversive reinforcement condition. These findings may also reflect different strategies, with an escape/homing strategy in the wet condition and a foraging strategy in the dry condition.

  1. Model dependencies of risk aversion and working interest estimates

    International Nuclear Information System (INIS)

    Lerche, I.

    1996-01-01

    Working interest, W, and risk adjusted value, RAV, are evaluated using both Cozzolino's formula for exponential dependence of risk aversion and also for a hyperbolic tangent dependence. In addition, the general method is given of constructing an RAV formula for any functional choice of risk aversion dependence. Two examples are given to illustrate how the model dependencies influence choices of working interest and risk adjusted value depending on whether the expected value of the project is positive or negative. In general the Cozzolino formula provides a more conservative position for risk than does the hyperbolic tangent formula, reflecting the difference in corporate attitudes to risk aversion. The commonly used Cozzolino formula is shown to have simple exact arithmetic expressions for maximum working interest and maximum RAV; the hyperbolic tangent formula has approximate analytic expressions. Both formulae also yield approximate analytical expressions for the working interest yielding a risk neutral RAV of zero. These arithmetic results are useful for making quick estimates of working interest ranges and risk adjusted values. (Author)

  2. Re-engaging with the past: recapitulation of encoding operations during episodic retrieval

    Science.gov (United States)

    Morcom, Alexa M.

    2014-01-01

    Recollection of events is accompanied by selective reactivation of cortical regions which responded to specific sensory and cognitive dimensions of the original events. This reactivation is thought to reflect the reinstatement of stored memory representations and therefore to reflect memory content, but it may also reveal processes which support both encoding and retrieval. The present study used event-related functional magnetic resonance imaging to investigate whether regions selectively engaged in encoding face and scene context with studied words are also re-engaged when the context is later retrieved. As predicted, encoding face and scene context with visually presented words elicited activity in distinct, context-selective regions. Retrieval of face and scene context also re-engaged some of the regions which had shown successful encoding effects. However, this recapitulation of encoding activity did not show the same context selectivity observed at encoding. Successful retrieval of both face and scene context re-engaged regions which had been associated with encoding of the other type of context, as well as those associated with encoding the same type of context. This recapitulation may reflect retrieval attempts which are not context-selective, but use shared retrieval cues to re-engage encoding operations in service of recollection. PMID:24904386

  3. Random queues and risk averse users

    DEFF Research Database (Denmark)

    de Palma, André; Fosgerau, Mogens

    2013-01-01

    We analyze Nash equilibrium in time of use of a congested facility. Users are risk averse with general concave utility. Queues are subject to varying degrees of random sorting, ranging from strict queue priority to a completely random queue. We define the key “no residual queue” property, which...

  4. Twins less frequent than expected among male births in risk averse populations.

    Science.gov (United States)

    Karasek, Deborah; Goodman, Julia; Gemmill, Alison; Falconi, April; Hartig, Terry; Magganas, Aristotle; Catalano, Ralph

    2015-06-01

    Male twin gestations exhibit higher incidence of fetal morbidity and mortality than singleton gestations. From an evolutionary perspective, the relatively high rates of infant and child mortality among male twins born into threatening environments reduce the fitness of these gestations, making them more vulnerable to fetal loss. Women do not perceive choosing to spontaneously abort gestations although the outcome may result from estimates, made without awareness, of the risks of continuing a pregnancy. Here, we examine whether the non-conscious decisional biology of gestation can be linked to conscious risk aversion. We test this speculation by measuring the association between household surveys in Sweden that gauge financial risk aversion in the population and the frequency of twins among live male births. We used time-series regression methods to estimate our suspected associations and Box-Jenkins modeling to ensure that autocorrelation did not confound the estimation or reduce its efficiency. We found, consistent with theory, that financial risk aversion in the population correlates inversely with the odds of a twin among Swedish males born two months later. The odds of a twin among males fell by approximately 3.5% two months after unexpectedly great risk aversion in the population. This work implies that shocks that affect population risk aversion carry implications for fetal loss in vulnerable twin pregnancies.

  5. Loss aversion and duration of residence

    Directory of Open Access Journals (Sweden)

    Philip S. Morrison

    2016-10-01

    Full Text Available Background: Studies of internal migration ask who moves, why they move, and what are the consequences - to themselves, their origin, and their destination. By contrast, studies of those who stay for very long durations are less common, despite the fact that most people move relatively infrequently. Objective: We argue that staying is the dominant, preferred state and that moving is simply an adjustment toward a desired state of stability (or equilibrium. The core of our argument, already recognized in the literature, is that migration is risky. However, we extend the argument to loss aversion as developed within prospect theory. Prospect theory posits that existing possessions, including the dwelling and existing commodities, are attributed a value well beyond their purchase price and that this extends the average period of staying among the loss-averse. Methods: Applying prospect theory has several challenges, including measurement of the reference point and potential degrees of gain and loss households face in deciding to change residence, as well as their own degree of loss aversion. The growing number of large panel sets should make it possible to estimate the degree to which endowment effects are likely to extend durations of residence as predicted by prospect theory. Conclusions: Rational expectations models of mobility focus on the changes in the level of consumption of residential services. By contrast, prospect theory focuses on potential gains and losses relative to the existing dwelling - the reference point. As we confront increasing durations of residence in contemporary society, an application of prospect theory is likely to yield important advantages over existing models of mobility and staying.

  6. Social interaction with non-averse group-mates modifies a learned food aversion in single- and mixed-species groups of tamarins (Saguinus fuscicollis and S. labiatus).

    Science.gov (United States)

    Prescott, M J; Buchanan-Smith, H M; Smith, A C

    2005-04-01

    For social species, being a member of a cohesive group and performing activities as a coordinated unit appear to provide a mechanism for the efficient transmission of information about food. Social learning about food palatability was investigated in two captive primates, Saguinus fuscicollis and S. labiatus, which form stable and cohesive mixed-species groups in the wild. We explored whether an induced food aversion toward a preferred food is modified during and after social interaction with non-averse conspecifics or congeners. Sets of intra- and interspecific pairs were presented with two foods, one of which was considered distasteful by one of the pairs (the other was palatable), and their behavior was compared pre-interaction, during interaction, and post-interaction. For the aversely-conditioned individuals of both species, the change in social context corresponded to a change in their preference for the food that they considered unpalatable, regardless of whether they had interacted with a conspecific or congeneric pair, and the change in food preference was maintained post-interaction. In a control condition, in which averse individuals did not have the opportunity to interact with non-averse animals, S. fuscicollis sampled the preferred food, but not as quickly as when given the opportunity to interact. We conclude that the social learning demonstrated here may allow individual tamarins to track environmental change, such as fruit ripening, more efficiently than asocial learning alone, because social learners can more quickly and safely focus on appropriate behavior by sharing up-to-date foraging information. Furthermore, since the behavior of congeners, as well as conspecifics, acts to influence food choice in a more adaptive direction, social learning about food palatability may be an advantage of mixed-species group formation to tamarins of both species. Copyright 2005 Wiley-Liss, Inc

  7. Measuring Risk Aversion for Nuclear Power Plant Accident: Results of Contingent Valuation Survey in Korea

    International Nuclear Information System (INIS)

    Lee, Sang Hun; Kang, Hyun Gook

    2015-01-01

    Within the evaluation of the external cost of nuclear energy, the estimation of the external cost of nuclear power plant (NPP) severe accident is one of the major topics to be addressed. For the evaluation of the external cost of NPP severe accident, the effect of public risk averse behavior against the group accidents, such as NPP accident, dam failure, must be addressed. Although the equivalent fatalities from a single group accident are not common and its risk is very small compared to other accidents, people perceive the group accident more seriously. In other words, people are more concerned about low probability/high consequence events than about high probability/low consequence events having the same mean damage. One of the representative method to integrate the risk aversion in the external costs of severe nuclear reactor accidents was developed by Eeckoudt et al., and he used the risk aversion coefficient, mainly based on the analysis of financial risks in the stock markets to evaluate the external cost of nuclear severe accident. However, the use of financial risk aversion coefficient to nuclear severe accidents is not appropriate, because financial risk and nuclear severe accident risk are entirely different. In this paper, the individual-level survey was conducted to measure the risk aversion coefficient and estimate the multiplication factor to integrate the risk aversion in the external costs of NPP severe accident. This study propose an integrated framework on estimation of the external cost associated with severe accidents of NPP considering public risk aversion behavior. The theoretical framework to estimate the risk aversion coefficient/multiplication factor and to assess economic damages from a hypothetical NPP accident was constructed. Based on the theoretical framework, the risk aversion coefficient can be analyzed by conducting public survey with a carefully designed lottery questions. Compared to the previous studies on estimation of the

  8. Measuring Risk Aversion for Nuclear Power Plant Accident: Results of Contingent Valuation Survey in Korea

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Sang Hun; Kang, Hyun Gook [KAIST, Daejeon (Korea, Republic of)

    2015-05-15

    Within the evaluation of the external cost of nuclear energy, the estimation of the external cost of nuclear power plant (NPP) severe accident is one of the major topics to be addressed. For the evaluation of the external cost of NPP severe accident, the effect of public risk averse behavior against the group accidents, such as NPP accident, dam failure, must be addressed. Although the equivalent fatalities from a single group accident are not common and its risk is very small compared to other accidents, people perceive the group accident more seriously. In other words, people are more concerned about low probability/high consequence events than about high probability/low consequence events having the same mean damage. One of the representative method to integrate the risk aversion in the external costs of severe nuclear reactor accidents was developed by Eeckoudt et al., and he used the risk aversion coefficient, mainly based on the analysis of financial risks in the stock markets to evaluate the external cost of nuclear severe accident. However, the use of financial risk aversion coefficient to nuclear severe accidents is not appropriate, because financial risk and nuclear severe accident risk are entirely different. In this paper, the individual-level survey was conducted to measure the risk aversion coefficient and estimate the multiplication factor to integrate the risk aversion in the external costs of NPP severe accident. This study propose an integrated framework on estimation of the external cost associated with severe accidents of NPP considering public risk aversion behavior. The theoretical framework to estimate the risk aversion coefficient/multiplication factor and to assess economic damages from a hypothetical NPP accident was constructed. Based on the theoretical framework, the risk aversion coefficient can be analyzed by conducting public survey with a carefully designed lottery questions. Compared to the previous studies on estimation of the

  9. Impact of Risk Aversion on Price and Quality Decisions under Demand Uncertainty via the CARA Utility Function

    Directory of Open Access Journals (Sweden)

    Qinqin Li

    2014-01-01

    Full Text Available This paper investigates optimal price and quality decisions of a manufacturer-retailer supply chain under demand uncertainty, in which players are both risk-averse decision makers. The manufacturer determines the wholesale price and quality of the product, and the retailer determines the retail price. By means of game theory, we employ the constant absolute risk aversion (CARA function to analyze two different supply chain structures, that is, manufacturer Stackelberg model (MS and retailer Stackelberg model (RS. We then analyze the results to explore the effects of risk aversion of the manufacturer and the retailer upon the equilibrium decisions. Our results imply that both the risk aversion of the manufacturer and the retailer play an important role in the price and quality decisions. We find that, in general, in MS and RS models, the optimal wholesale price and quality decrease with the risk aversion of the manufacturer but increase with the risk aversion of the retailer, while the retail price decreases with the risk aversion of the manufacturer as well as the retailer. We also examine the impact of quality cost coefficient on the optimal decisions. Finally, numerical examples are presented to illustrate the different degree of effects of players’ risk aversion on equilibrium results and to compare results in different models considered.

  10. Personality, risk aversion and speeding: an empirical investigation.

    Science.gov (United States)

    Greaves, Stephen P; Ellison, Adrian B

    2011-09-01

    Evidence suggests that in addition to demographics, there are strong relationships between facets of drivers' personality (e.g., aggression, thrill-seeking, altruism), aversion to risk and driving behaviour, particularly speeding. However, evidence is muted by the reliance on self-reported driving behaviour, which is thought to not accurately reflect actual driving behaviour. This paper reports on a study of 133 drivers in Sydney, who were asked to complete a short survey to develop their personality and risk aversion profiles and self-reported speeding behaviour. A Global Positioning System (GPS) device was then installed in their vehicle for several weeks as part of a major investigation of driving behaviour from which empirical measures of speeding are derived. Among the most pertinent findings are: (1) the tendency for drivers to both under and over-estimate their propensity to speed, (2) significant heterogeneity in speeding with a small, but notable number of drivers exceeding the limit for more than 20 percent of the distance driven, (3) weak relationships between the personality/risk-aversion measures and actual speeding, and (4) the suggestion that different personality traits appear to influence behaviour in different situations both from self-reported and actual speeding behaviour. Copyright © 2011 Elsevier Ltd. All rights reserved.

  11. Loss Aversion, Adaptive Beliefs, and Asset Pricing Dynamics

    Directory of Open Access Journals (Sweden)

    Kamal Samy Selim

    2015-01-01

    Full Text Available We study asset pricing dynamics in artificial financial markets model. The financial market is populated with agents following two heterogeneous trading beliefs, the technical and the fundamental prediction rules. Agents switch between trading rules with respect to their past performance. The agents are loss averse over asset price fluctuations. Loss aversion behaviour depends on the past performance of the trading strategies in terms of an evolutionary fitness measure. We propose a novel application of the prospect theory to agent-based modelling, and by simulation, the effect of evolutionary fitness measure on adaptive belief system is investigated. For comparison, we study pricing dynamics of a financial market populated with chartists perceive losses and gains symmetrically. One of our contributions is validating the agent-based models using real financial data of the Egyptian Stock Exchange. We find that our framework can explain important stylized facts in financial time series, such as random walk price behaviour, bubbles and crashes, fat-tailed return distributions, power-law tails in the distribution of returns, excess volatility, volatility clustering, the absence of autocorrelation in raw returns, and the power-law autocorrelations in absolute returns. In addition to this, we find that loss aversion improves market quality and market stability.

  12. Sensitivity of the brain to loss aversion during risky gambles.

    Science.gov (United States)

    Dreher, Jean-Claude

    2007-07-01

    Little is known about the neural systems that subserve human loss aversion. A recent neuroimaging study by Tom, Poldrack and colleagues reports that this pattern of behaviour is directly tied to the greater sensitivity of the brain to potential losses compared with potential gains and uncovers a brain network whose activity increases with potential gains and decreases with potential losses. These results challenge the common view that loss aversion engages a distinct emotion-related brain network (e.g. amygdala and insula).

  13. On Loss Aversion in Capuchin Monkeys

    Science.gov (United States)

    Silberberg, Alan; Roma, Peter G.; Huntsberry, Mary E.; Warren-Boulton, Frederick R.; Sakagami, Takayuki; Ruggiero, Angela M.; Suomi, Stephen J.

    2008-01-01

    Chen, Lakshminarayanan, and Santos (2006) claim to show in three choice experiments that monkeys react rationally to price and wealth shocks, but, when faced with gambles, display hallmark, human-like biases that include loss aversion. We present three experiments with monkeys and humans consistent with a reinterpretation of their data that…

  14. Optimal Ordering Policy of a Risk-Averse Retailer Subject to Inventory Inaccuracy

    Directory of Open Access Journals (Sweden)

    Lijing Zhu

    2013-01-01

    Full Text Available Inventory inaccuracy refers to the discrepancy between the actual inventory and the recorded inventory information. Inventory inaccuracy is prevalent in retail stores. It may result in a higher inventory level or poor customer service. Earlier studies of inventory inaccuracy have traditionally assumed risk-neutral retailers whose objective is to maximize expected profits. We investigate a risk-averse retailer within a newsvendor framework. The risk aversion attitude is measured by conditional-value-at-risk (CVaR. We consider inventory inaccuracy stemming both from permanent shrinkage and temporary shrinkage. Two scenarios of reducing inventory shrinkage are presented. In the first scenario, the retailer conducts physical inventory audits to identify the discrepancy. In the second scenario, the retailer deploys an automatic tracking technology, radiofrequency identification (RFID, to reduce inventory shrinkage. With the CVaR criterion, we propose optimal policies for the two scenarios. We show monotonicity between the retailer’s ordering policy and his risk aversion degree. A numerical analysis provides managerial insights for risk-averse retailers considering investing in RFID technology.

  15. Conditioned taste aversion to ethanol in a social context: impact of age and sex.

    Science.gov (United States)

    Morales, Melissa; Schatz, Kelcie C; Anderson, Rachel I; Spear, Linda P; Varlinskaya, Elena I

    2014-03-15

    Given that human adolescents place a high value on social interactions-particularly while consuming alcohol-the current study utilized a novel social drinking paradigm to examine rewarding and aversive properties of ethanol in non-water deprived rats that were housed and tested in groups of five same-sex littermates. On postnatal day P34 (adolescents) or P69 (adults), rats were habituated to the testing apparatus for 30 min. On the next day, animals were placed into the test apparatus and given 30 min access to a supersaccharin solution (3% sucrose; 0.125% saccharin), followed immediately by an intraperitoneal injection of ethanol (0, 0.25, 0.5, 1.0, 1.5 g/kg). Subsequent intake of the supersacharrin solution was assessed on three consecutive test days. Adolescent males were less sensitive to ethanol's aversive effects than adult males, with adolescent males maintaining an aversion on all three test days only at the 1.5 g/kg dose, whereas adults demonstrated aversions across test days to 1 and 1.5 g/kg. Adolescent females maintained aversions to 1 and 1.5 g/kg across days, whereas adult females continued to show an aversion to the 1.5 g/kg dose only. These opposite patterns of sensitivity that emerged among males and females at each age in the propensity to maintain an ethanol-induced taste aversion under social conditions may contribute to age- and sex-related differences in ethanol intake. Testing in social groups may be useful for future work when studying rodent models of adolescent alcohol use given the importance that human adolescents place on drinking in social settings. Copyright © 2014 Elsevier B.V. All rights reserved.

  16. Age-related deficits in selective attention during encoding increase demands on episodic reconstruction during context retrieval: An ERP study.

    Science.gov (United States)

    James, Taylor; Strunk, Jonathan; Arndt, Jason; Duarte, Audrey

    2016-06-01

    Previous event-related potential (ERP) and neuroimaging evidence suggests that directing attention toward single item-context associations compared to intra-item features at encoding improves context memory performance and reduces demands on strategic retrieval operations in young and older adults. In everyday situations, however, there are multiple event features competing for our attention. It is not currently known how selectively attending to one contextual feature while attempting to ignore another influences context memory performance and the processes that support successful retrieval in the young and old. We investigated this issue in the current ERP study. Young and older participants studied pictures of objects in the presence of two contextual features: a color and a scene, and their attention was directed to the object's relationship with one of those contexts. Participants made context memory decisions for both attended and unattended contexts and rated their confidence in those decisions. Behavioral results showed that while both groups were generally successful in applying selective attention during context encoding, older adults were less confident in their context memory decisions for attended features and showed greater dependence in context memory accuracy for attended and unattended contextual features (i.e., hyper-binding). ERP results were largely consistent between age groups but older adults showed a more pronounced late posterior negativity (LPN) implicated in episodic reconstruction processes. We conclude that age-related suppression deficits during encoding result in reduced selectivity in context memory, thereby increasing subsequent demands on episodic reconstruction processes when sought after details are not readily retrieved. Copyright © 2016 Elsevier Ltd. All rights reserved.

  17. Role of the area postrema in radiation-induced taste aversion learning and emesis in cats

    International Nuclear Information System (INIS)

    Rabin, B.M.; Hunt, W.A.; Chedester, A.L.; Lee, J.

    1986-01-01

    The role of the area postrema in radiation-induced emesis and taste aversion learning and the relationship between these behaviors were studied in cats. The potential involvement of neural factors which might be independent of the area postrema was minimized by using low levels of ionizing radiation (100 rads at a dose rate of 40 rads/min) to elicit a taste aversion, and by using body-only exposures (4500 and 6000 rads at 450 rads/min) to produce emesis. Lesions of the area postrema disrupted both taste aversion learning and emesis following irradiation. These results, which indicate that the area postrema is involved in the mediation of both radiation-induced emesis and taste aversion learning in cats under these experimental conditions, are interpreted as being consistent with the hypotheses that similar mechanisms mediate both responses to exposure to ionizing radiation, and that the taste aversion learning paradigm can therefore serve as a model system for studying radiation-induced emesis

  18. State-dependent interaction in the antihistamine-induced disruption of a radiation-induced conditioned taste aversion

    International Nuclear Information System (INIS)

    Rabin, B.M.; Hunt, W.A.; Lee, J.

    1982-01-01

    Two experiments were run to evaluate the possibility that injection of antihistamine can produce a state-dependent acquisition of a radiation-induced conditioned taste aversion. In the first experiment, pretreating rats with the antihistamine chlorpheniramine maleate prior to their initial exposure to sucrose and to low-level irradiation on the conditioning day did not prevent the acquisition of a taste aversion to sucrose when the antihistamine was also administered prior to a subsequent preference test. In the second experiment, rats were both conditioned and tested for a radiation-induced aversion in a drug-free state. Under these condtions, the rats continued to show an aversion to sucrose despite pretreating them with chlorpheniramine prior to irradiation. Since rats conditioned under the antihistamine do not show the radiation-induced conditioned taste aversion when tested for sucrose preference in a nondrug state, it would seem that pretreating rats with an antihistamine prior to conditioning affects only the retrieval of the previously learned response and not its acquisition

  19. Risk Aversion and the Value of Information.

    Science.gov (United States)

    Eeckhoudt, Louis; Godfroid, Phillippe

    2000-01-01

    Explains why risk aversion does not always induce a greater information value, but instead may induce a lower information value when increased. Presents a basic model defining the concept of perfect information value and providing a numerical illustration. Includes references. (CMK)

  20. Does Market Experience Attenuate Risk Aversion? Evidence from Landed Farm Households in Ethiopia

    NARCIS (Netherlands)

    Melesse, Mequanint Biset; Cecchi, Francesco

    2017-01-01

    Risk preferences are important drivers of many relevant economic decisions of farm households. High risk aversion is a well-known trigger of "poverty traps" for farm households in developing countries. This paper analyzes the effect of market experience on risk aversion for a relatively large sample

  1. Small- and large-stakes risk aversion: implications of concavity calabration for decision theory

    NARCIS (Netherlands)

    Cox, J.C.; Sadiraj, V.

    2006-01-01

    A growing literature reports the conclusions that: (a) expected utility theory does not provide a plausible theory of risk aversion for both small-stakes and large-stakes gambles; and (b) this decision theory should be replaced with an alternative theory characterized by loss aversion. This paper

  2. Does Market Experience Attenuate Risk Aversion? Evidence from Landed Farm Households in Ethiopia

    NARCIS (Netherlands)

    Melesse, Mequanint B.; Cecchi, Francesco

    2017-01-01

    Risk preferences are important drivers of many relevant economic decisions of farm households. High risk aversion is a well-known trigger of "poverty traps" for farm households in developing countries. This paper analyzes the effect of market experience on risk aversion for a relatively large

  3. Dietary GABA and food selection by rats.

    Science.gov (United States)

    Tews, J K; Repa, J J; Harper, A E

    1986-01-01

    To obtain further information pertaining to amino acid-induced alterations in feeding behavior, studies were performed to examine the food choices made by rats fed low protein diets made more or less aversive by the addition of various amino acids. When rats were allowed to choose between two diets, they preferred a low protein control, threonine-imbalanced or nonprotein diet to one containing 2.5% gamma-aminobutyric acid (GABA). Acceptance increased when GABA content was lowered to 1.5%; rats preferred this diet when the alternative diet was made sufficiently aversive. There were large individual differences among rats selecting from pairs of unacceptable diets. Avoidance of, or preference for, a given diet is clearly affected by the relative aversive qualities of the offered pair of diets.

  4. A psychological law of inertia and the illusion of loss aversion

    Directory of Open Access Journals (Sweden)

    David Gal

    2006-07-01

    Full Text Available The principle of loss aversion is thought to explain a wide range of anomalous phenomena involving tradeoffs between losses and gains. In this article, I show that the anomalies loss aversion was introduced to explain --- the risky bet premium, the endowment effect, and the status-quo bias --- are characterized not only by a loss/gain tradeoff, but by a tradeoff between the status-quo and change; and, that a propensity towards the status-quo in the latter tradeoff is sufficient to explain these phenomena. Moreover, I show that two basic psychological principles --- (1 that motives drive behavior; and (2 that preferences tend to be fuzzy and ill-defined --- imply the existence of a robust and fundamental propensity of this sort. Thus, a loss aversion principle is rendered superfluous to an account of the phenomena it was

  5. Neural markers of attention to aversive pictures predict response to cognitive behavioral therapy in anxiety and depression.

    Science.gov (United States)

    Stange, Jonathan P; MacNamara, Annmarie; Barnas, Olga; Kennedy, Amy E; Hajcak, Greg; Phan, K Luan; Klumpp, Heide

    2017-02-01

    Excessive attention toward aversive information may be a core mechanism underlying emotional disorders, but little is known about whether this is predictive of response to treatments. We evaluated whether enhanced attention toward aversive stimuli, as indexed by an event-related potential component, the late positive potential (LPP), would predict response to cognitive behavioral therapy (CBT) in patients with social anxiety disorder and/or major depressive disorder. Thirty-two patients receiving 12 weeks of CBT responded to briefly-presented pairs of aversive and neutral pictures that served as targets or distracters while electroencephaolography was recorded. Patients with larger pre-treatment LPPs to aversive relative to neutral distracters (when targets were aversive) were more likely to respond to CBT, and demonstrated larger reductions in symptoms of depression and anxiety following treatment. Increased attention toward irrelevant aversive stimuli may signal attenuated top-down control, so treatments like CBT that improve this control could be beneficial for these individuals. Copyright © 2016 Elsevier B.V. All rights reserved.

  6. Five-year-olds do not show ambiguity aversion in a risk and ambiguity task with physical objects.

    Science.gov (United States)

    Li, Rosa; Roberts, Rachel C; Huettel, Scott A; Brannon, Elizabeth M

    2017-07-01

    Ambiguity aversion arises when a decision maker prefers risky gambles with known probabilities over equivalent ambiguous gambles with unknown probabilities. This phenomenon has been consistently observed in adults across a large body of empirical work. Evaluating ambiguity aversion in young children, however, has posed methodological challenges because probabilistic representations appropriate for adults might not be understood by young children. Here, we established a novel method for representing risk and ambiguity with physical objects that overcomes previous methodological limitations and allows us to measure ambiguity aversion in young children. We found that individual 5-year-olds exhibited consistent choice preferences and, as a group, exhibited no ambiguity aversion in a task that evokes ambiguity aversion in adults. Across individuals, 5-year-olds exhibited greater variance in ambiguity preferences compared with adults tested under similar conditions. This suggests that ambiguity aversion is absent during early childhood and emerges over the course of development. Copyright © 2017 Elsevier Inc. All rights reserved.

  7. Individual Differences in Loss Aversion: Conscientiousness Predicts How Life Satisfaction Responds to Losses Versus Gains in Income.

    Science.gov (United States)

    Boyce, Christopher J; Wood, Alex M; Ferguson, Eamonn

    2016-04-01

    Loss aversion is considered a general pervasive bias occurring regardless of the context or the person making the decision. We hypothesized that conscientiousness would predict an aversion to losses in the financial domain. We index loss aversion by the relative impact of income losses and gains on life satisfaction. In a representative German sample (N = 105,558; replicated in a British sample, N = 33,848), with conscientiousness measured at baseline, those high on conscientiousness have the strongest reactions to income losses, suggesting a pronounced loss aversion effect, whereas for those moderately unconscientious, there is no loss aversion effect. Our research (a) provides the first evidence of personality moderation of any loss aversion phenomena, (b) supports contextual perspectives that both personality and situational factors need to be examined in combination, (c) shows that the small but robust relationship between income and life satisfaction is driven primarily by a subset of people experiencing highly impactful losses. © 2016 by the Society for Personality and Social Psychology, Inc.

  8. Averse to Initiative: Risk Management’s Effect on Mission Command

    Science.gov (United States)

    2017-05-25

    Master’s Thesis 3. DATES COVERED (From - To) JUN 2016 – MAY 2017 4. TITLE AND SUBTITLE Averse to Initiative: Risk Management’s Effect on Mission...decision weights and potential implications of educating leaders with Prospect Theory . Prospect Theory sheds light on how to look at loss and opportunity...the gain–causing risk aversion. Leaders educated in how to analyze a problem using Prospect Theory can rationally approach gains and losses. For the

  9. Fairness concerns and risk aversion on recycle pricing strategies: Implications for environmentally friendly supply chains

    OpenAIRE

    He, Jianhong; Zhang, Lei; Lu, Binbin; Li, Lin

    2018-01-01

    This paper studies the pricing strategy in the closed-loop supply chain with Nash bargaining when considering fairness concerns and risk aversion. Mainly, the authors argue that behavioral factors (i.e., fairness concern and risk aversion) should be introduced into pricing process. They consider three different pricing models: the first is that both manufacturer and retailer have fairness concern; the second is both manufacturer and retailer have risk aversion and the final is manufacturer ha...

  10. Strain-dependent sex differences in the effects of alcohol on cocaine-induced taste aversions.

    Science.gov (United States)

    Jones, Jermaine D; Busse, Gregory D; Riley, Anthony L

    2006-04-01

    Research using the conditioned taste aversion procedure has reported that a cocaine/alcohol combination induces a significantly stronger taste aversion than either cocaine or alcohol alone. These findings suggest that the co-administration of alcohol intensifies the aversive effects of cocaine. Although the behavioral interaction of cocaine and alcohol is well established, little is known about how the effects of this drug combination might be modulated by a variety of subject variables. The current investigation addressed this by assessing if the ability of alcohol to potentiate cocaine-induced taste aversions is dependent upon the strain and/or sex of the subject. In this series of studies, male and female rats of Long-Evans (Experiment 1) and Sprague-Dawley (Experiment 2) descent were given limited access to a novel saccharin solution to drink and were then injected with either vehicle, cocaine (20 mg/kg), alcohol (0.56 g/kg) or the alcohol/cocaine combination. This procedure was repeated every fourth day for a total of four conditioning trials. All subjects were then compared on an Aversion Test that followed the fourth conditioning cycle. In three of the groups tested (male Long-Evans; male and female Sprague-Dawley), cocaine induced a significant taste aversion that was unaffected by the co-administration of alcohol. However, in female Long-Evans subjects, the addition of alcohol significantly strengthened the avoidance of the saccharin solution. Although the effects of alcohol on cocaine-induced taste aversions are dependent upon an interaction of sex and strain, the basis for this SexxStrain interaction is not known. That such an interaction is evident suggests that attention to such factors in assessing the effects of drug combinations is important to understanding the likelihood of the use and abuse of such drugs.

  11. Radiation-induced taste aversion: effects of radiation exposure level and the exposure-taste interval

    International Nuclear Information System (INIS)

    Spector, A.C.; Smith, J.C.; Hollander, G.R.

    1986-01-01

    Radiation-induced taste aversion has been suggested to possibly play a role in the dietary difficulties observed in some radiotherapy patients. In rats, these aversions can still be formed even when the radiation exposure precedes the taste experience by several hours. This study was conducted to examine whether increasing the radiation exposure level could extend the range of the exposure-taste interval that would still support the formation of a taste aversion. Separate groups of rats received either a 100 or 300 R gamma-ray exposure followed 1, 3, 6, or 24 h later by a 10-min saccharin (0.1% w/v) presentation. A control group received a sham exposure followed 1 h later by a 10-min saccharin presentation. Twenty-four hours following the saccharin presentation all rats received a series of twelve 23-h two-bottle preference tests between saccharin and water. The results indicated that the duration of the exposure-taste interval plays an increasingly more important role in determining the initial extent of the aversion as the dose decreases. The course of recovery from taste aversion seems more affected by dose than by the temporal parameters of the conditioning trial

  12. Anticipation of electric shocks modulates low beta power and event-related fields during memory encoding.

    Science.gov (United States)

    Bauch, Eva M; Bunzeck, Nico

    2015-09-01

    In humans, the temporal and oscillatory dynamics of pain anticipation and its effects on long-term memory are largely unknown. Here, we investigated this open question by using a previously established behavioral paradigm in combination with magnetoencephalography (MEG). Healthy human subjects encoded a series of scene images, which was combined with cues predicting an aversive electric shock with different probabilities (0.2, 0.5 or 0.8). After encoding, memory for the studied images was tested using a remember/know recognition task. Behaviorally, pain anticipation did not modulate recollection-based recognition memory per se, but interacted with the perceived unpleasantness of the electric shock [visual analogue scale rating from 1 (not unpleasant) to 10 (highly unpleasant)]. More precisely, the relationship between pain anticipation and recollection followed an inverted u-shaped function the more unpleasant the shocks were rated by a subject. At the physiological level, this quadratic effect was mimicked in the event-related magnetic fields associated with successful memory formation ('DM-effect') ∼450ms after image onset at left frontal sensors. Importantly, across all subjects, shock anticipation modulated oscillatory power in the low beta frequency range (13-20Hz) in a linear fashion at left temporal sensors. Taken together, our findings indicate that beta oscillations provide a generic mechanism underlying pain anticipation; the effect on subsequent long-term memory, on the other hand, is much more variable and depends on the level of individual pain perception. As such, our findings give new and important insights into how aversive motivational states can drive memory formation. Copyright © 2015 Elsevier Inc. All rights reserved.

  13. The monetary value of the man-mSv for Korean NPP radiation workers assessed by the radiation aversion factor

    International Nuclear Information System (INIS)

    Lee, B. I.; Suh, D. H.; Kim, S. I.; Jeong, M. S.; Lim, Y. K.

    2008-01-01

    The monetary value of the man-mSv for operators of Korean nuclear power plants (NPPs) was calculated using a radiation aversion factor based on a survey of NPP workers. Initially, the life expectancy in the population is 79.4 y, the average age of cancer occurrence is 60 y, the average annual wage for an electric worker is 56 000 $ y -1 and the nominal risk coefficient induced by radiation is 4.2 E-5 mSv were used to evaluate the basic monetary value (α base) resulting in 45.6 $ mSv -1 . To investigate the degree of radiation aversion, the subject of the investigation was selected as the working radiation workers in 10 NPPs in Korea (Kori 1-2, Yeonggwang 1-3, Ulchin 1-3 and Wolseong 1-2). In August 2010, with the cooperation of KHNP and partner companies, a total of 2500 survey questionnaires to 10 NPPs (or 250 surveys to each NPP) were distributed to currently employed radiation workers. From these, 2157 responses were obtained between August and October 2010. The assessed radiation aversion factor and the monetary value of the man-mSv from the calculated radiation aversion factor were 1.26 and ∼50 $ in the 0-1 mSv range, 1.38 and ∼200 $ in the 1-5 mSv range, 1.52 and ∼1000 $ in the 5-10 mSv range, 1.65 and ∼4000 $ in the 10-20 mSv range and 1.74 and ∼8500 $ >20 mSv. (authors)

  14. Applying Four Different Risk Models in Local Ore Selection

    International Nuclear Information System (INIS)

    Richmond, Andrew

    2002-01-01

    Given the uncertainty in grade at a mine location, a financially risk-averse decision-maker may prefer to incorporate this uncertainty into the ore selection process. A FORTRAN program risksel is presented to calculate local risk-adjusted optimal ore selections using a negative exponential utility function and three dominance models: mean-variance, mean-downside risk, and stochastic dominance. All four methods are demonstrated in a grade control environment. In the case study, optimal selections range with the magnitude of financial risk that a decision-maker is prepared to accept. Except for the stochastic dominance method, the risk models reassign material from higher cost to lower cost processing options as the aversion to financial risk increases. The stochastic dominance model usually was unable to determine the optimal local selection

  15. Signal sequence and keyword trap in silico for selection of full-length human cDNAs encoding secretion or membrane proteins from oligo-capped cDNA libraries.

    Science.gov (United States)

    Otsuki, Tetsuji; Ota, Toshio; Nishikawa, Tetsuo; Hayashi, Koji; Suzuki, Yutaka; Yamamoto, Jun-ichi; Wakamatsu, Ai; Kimura, Kouichi; Sakamoto, Katsuhiko; Hatano, Naoto; Kawai, Yuri; Ishii, Shizuko; Saito, Kaoru; Kojima, Shin-ichi; Sugiyama, Tomoyasu; Ono, Tetsuyoshi; Okano, Kazunori; Yoshikawa, Yoko; Aotsuka, Satoshi; Sasaki, Naokazu; Hattori, Atsushi; Okumura, Koji; Nagai, Keiichi; Sugano, Sumio; Isogai, Takao

    2005-01-01

    We have developed an in silico method of selection of human full-length cDNAs encoding secretion or membrane proteins from oligo-capped cDNA libraries. Fullness rates were increased to about 80% by combination of the oligo-capping method and ATGpr, software for prediction of translation start point and the coding potential. Then, using 5'-end single-pass sequences, cDNAs having the signal sequence were selected by PSORT ('signal sequence trap'). We also applied 'secretion or membrane protein-related keyword trap' based on the result of BLAST search against the SWISS-PROT database for the cDNAs which could not be selected by PSORT. Using the above procedures, 789 cDNAs were primarily selected and subjected to full-length sequencing, and 334 of these cDNAs were finally selected as novel. Most of the cDNAs (295 cDNAs: 88.3%) were predicted to encode secretion or membrane proteins. In particular, 165(80.5%) of the 205 cDNAs selected by PSORT were predicted to have signal sequences, while 70 (54.2%) of the 129 cDNAs selected by 'keyword trap' preserved the secretion or membrane protein-related keywords. Many important cDNAs were obtained, including transporters, receptors, and ligands, involved in significant cellular functions. Thus, an efficient method of selecting secretion or membrane protein-encoding cDNAs was developed by combining the above four procedures.

  16. Aversive Life Events Enhance Human Freezing Responses

    NARCIS (Netherlands)

    Hagenaars, M.A.; Stins, J.F.; Roelofs, K.

    2012-01-01

    In the present study, we investigated the effect of prior aversive life events on freezing-like responses. Fifty healthy females were presented neutral, pleasant, and unpleasant images from the International Affective Picture System while standing on a stabilometric platform and wearing a polar band

  17. Aversive life events enhance human freezing responses

    NARCIS (Netherlands)

    Hagenaars, M.A.; Stins, J.F.; Roelofs, K.

    2012-01-01

    In the present study, we investigated the effect of prior aversive life events on freezing-like responses. Fifty healthy females were presented neutral, pleasant, and unpleasant images from the International Affective Picture System while standing on a stabilometric platform and wearing a polar band

  18. Risk Aversion and Skewness Preference: a comment

    NARCIS (Netherlands)

    G.T. Post (Thierry); P. van Vliet (Pim)

    2003-01-01

    textabstractEmpirically, co-skewness of asset returns seems to explain a substantial part of the cross-sectional variation of mean return not explained by beta. Thisfinding is typically interpreted in terms of a risk averse representativeinvestor with a cubic utility function. This comment questions

  19. Attenuation of radiation- and drug-induced conditioned taste aversions following area postrema lesions in the rat

    International Nuclear Information System (INIS)

    Rabin, B.M.; Hunt, W.A.; Lee, J.

    1983-01-01

    The effects of lesions of the area postrema on the acquisition of radiation- and drug-induced (histamine and lithium chloride) conditioned taste aversions were investigated. The results indicated that area postrema lesions caused a significant attenuation of the aversion produced by pairing a novel sucrose solution with radiation (100 rad) or drug injection. Further, the area postrema lesions produced a similar level of attenuation of the taste aversion in all three treatment conditions. The results are discussed in terms of the implications of this finding for defining the mechanisms by which exposure to ionizing radiation can lead to the acquisition of a conditioned taste aversion

  20. Conditioned taste aversion: modulation by 5-HT receptor activity and corticosterone

    DEFF Research Database (Denmark)

    Boris, Gorzalka; Hanson, Laura; Harrington, J

    2003-01-01

    Two experiments were designed to elucidate the involvement of the hypothalamic-pituitary-adrenal axis and the 5-hydroxytryptamine (5-HT) system in the acquisition of lithium chloride-conditioned taste aversion. In Experiment 1, rats were administered either vehicle or 50 mg/kg nefazodone daily fo......, corticosterone-treated animals required more trials to reach extinction. These results suggest the involvement of both the 5-HT system and the hypothalamic-pituitary-adrenal axis in lithium chloride-conditioned taste aversion....

  1. Leverage Aversion and Risk Parity

    DEFF Research Database (Denmark)

    Asness, Clifford; Frazzini, Andrea; Heje Pedersen, Lasse

    2012-01-01

    The authors show that leverage aversion changes the predictions of modern portfolio theory: Safer assets must offer higher risk-adjusted returns than riskier assets. Consuming the high risk-adjusted returns of safer assets requires leverage, creating an opportunity for investors with the ability...... to apply leverage. Risk parity portfolios exploit this opportunity by equalizing the risk allocation across asset classes, thus overweighting safer assets relative to their weight in the market portfolio....

  2. To answer or not to answer? A field test of loss aversion

    OpenAIRE

    Michał Krawczyk

    2011-01-01

    This study is a field experiment on loss aversion. The framing of scoring rules was differentiated in two exams at the University of Warsaw, with only half the students facing explicit penalty points in the case of giving an incorrect answer. Loss aversion predicts that less risk will be taken (less questions will be answered) when losses are possible but in fact, no treatment effect was observed.

  3. Attenuation and cross-attenuation in taste aversion learning in the rat: Studies with ionizing radiation, lithium chloride and ethanol

    International Nuclear Information System (INIS)

    Rabin, B.M.; Hunt, W.A.; Lee, J.

    1988-01-01

    The preexposure paradigm was utilized to evaluate the similarity of ionizing radiation, lithium chloride and ethanol as unconditioned stimuli for the acquisition of a conditioned taste aversion. Three unpaired preexposures to lithium chloride (3.0 mEq/kg, IP) blocked the acquisition of a taste aversion when a novel sucrose solution was paired with either the injection of the same dose of lithium chloride or exposure to ionizing radiation (100 rad). Similar pretreatment with radiation blocked the acquisition of a radiation-induced aversion, but had no effect on taste aversions produced by lithium chloride (3.0 or 1.5 mEq/kg). Preexposure to ethanol (4 g/kg, PO) disrupted the acquisition of an ethanol-induced taste aversion, but not radiation- or lithium chloride-induced aversions. In contrast, preexposure to either radiation or lithium chloride attenuated an ethanol-induced taste aversion in intact rats, but not in rats with lesions of the area postrema. The results are discussed in terms of relationships between these three unconditioned stimuli and in terms of implications of these results for understanding the nature of the proximal unconditioned stimulus in taste aversion learning

  4. Quantitative PCR is a Valuable Tool to Monitor the Performance of DNA-Encoded Chemical Library Selections.

    Science.gov (United States)

    Li, Yizhou; Zimmermann, Gunther; Scheuermann, Jörg; Neri, Dario

    2017-05-04

    Phage-display libraries and DNA-encoded chemical libraries (DECLs) represent useful tools for the isolation of specific binding molecules from large combinatorial sets of compounds. With both methods, specific binders are recovered at the end of affinity capture procedures by using target proteins of interest immobilized on a solid support. However, although the efficiency of phage-display selections is routinely quantified by counting the phage titer before and after the affinity capture step, no similar quantification procedures have been reported for the characterization of DECL selections. In this article, we describe the potential and limitations of quantitative PCR (qPCR) methods for the evaluation of selection efficiency by using a combinatorial chemical library with more than 35 million compounds. In the experimental conditions chosen for the selections, a quantification of DNA input/recovery over five orders of magnitude could be performed, revealing a successful enrichment of abundant binders, which could be confirmed by DNA sequencing. qPCR provided rapid information about the performance of selections, thus facilitating the optimization of experimental conditions. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  5. Aversion learning can reduce meal size without taste avoidance in rats.

    Science.gov (United States)

    Tracy, Andrea L; Schurdak, Jennifer D; Chambers, James B; Benoit, Stephen C

    2016-03-01

    Nausea and aversive food responses are commonly reported following bariatric surgery, along with post-surgical reduction in meal size. This study investigates whether a meal size limit can be conditioned by associating large meals with aversive outcomes. In rats, the intake of meals exceeding a pre-defined size threshold was paired with lithium chloride-induced gastric illness, and the effects on self-determined food intakes and body weight were measured. Rats given LiCl contingent on the intake of a large meal learned to reliably reduce intake below this meal size threshold, while post-meal saline or LiCl before meals did not change meal size. It was further demonstrated that this is not a conditioned taste aversion and that this effect transferred to foods not explicitly trained. Finally, when rats received LiCl following all large meals, the number of small meals increased, but total food intake and body weight decreased. While further work is needed, this is the first demonstration that meal size may be conditioned, using an aversion procedure, to remain under a target threshold and that this effect is distinct from taste avoidance. Corresponding reduction in food intake and body weight suggests that this phenomenon may have implications for developing weight loss strategies and understanding the efficacy of bariatric surgery. © 2016 The Obesity Society.

  6. Behavioral architecture of opioid reward and aversion in C57BL/6 substrains

    Directory of Open Access Journals (Sweden)

    Stacey L Kirkpatrick

    2015-01-01

    Full Text Available Drug liking versus drug disliking is a subjective motivational measure in humans that assesses the addiction liability of drugs. Variation in this trait is hypothesized to influence vulnerability versus resilience toward substance abuse disorders and likely contains a genetic component. In rodents and humans, conditioned place preference (CPP / aversion (CPA is a Pavlovian conditioning paradigm whereby a learned preference for the drug-paired environment is used to infer drug liking whereas a learned avoidance or aversion is used to infer drug disliking. C57BL/6 inbred mouse substrains are nearly genetically identical, yet demonstrate robust differences in addiction-relevant behaviors, including locomotor sensitization to cocaine and consumption of ethanol. Here, we tested the hypothesis that B6 substrains would demonstrate differences in the rewarding properties of the mu opioid receptor agonist oxycodone (5 mg/kg, i.p. and the aversive properties of the opioid receptor antagonist naloxone (4 mg/kg, i.p.. Both substrains showed similar degrees of oxycodone-induced CPP; however, there was a three-fold enhancement of naloxone-induced CPA in agonist-naïve C57BL/6J relative to C57Bl/6NJ mice. Exploratory factor analysis of CPP and CPA identified unique factors that explain variance in behavioral expression of reward versus aversion. Conditioned Opioid-Like Behavior was a reward-based factor whereby drug-free locomotor variables resembling opioid treatment co-varied with the degree of CPP. Avoidance and Freezing was an aversion-based factor, whereby the increase in the number of freezing bouts co-varied with the degree of aversion. These results provide new insight into the behavioral architecture of the motivational properties of opioids. Future studies will use quantitative trait locus mapping in B6 substrains to identify novel genetic factors that contribute to the marked strain difference in NAL-CPA.

  7. Nicotine aversion: Neurobiological mechanisms and relevance to tobacco dependence vulnerability

    Science.gov (United States)

    Fowler, Christie D.; Kenny, Paul J.

    2013-01-01

    Nicotine stimulates brain reward circuitries, most prominently the mesocorticolimbic dopamine system, and this action is considered critical in establishing and maintaining the tobacco smoking habit. Compounds that attenuate nicotine reward are considered promising therapeutic candidates for tobacco dependence, but many of these agents have other actions that limit their potential utility. Nicotine is also highly noxious, particularly at higher doses, and aversive reactions to nicotine after initial exposure can decrease the likelihood of developing a tobacco habit in many first time smokers. Nevertheless, relatively little is known about the mechanisms of nicotine aversion. The purpose of this review is to present recent new insights into the neurobiological mechanisms that regulate avoidance of nicotine. First, the role of the mesocorticolimbic system, so often associated with nicotine reward, in regulating nicotine aversion is highlighted. Second, genetic variation that modifies noxious responses to nicotine and thereby influences vulnerability to tobacco dependence, in particular variation in the CHRNA5-CHRNA3-CHRNB4 nicotinic acetylcholine receptor (nAChR) subunit gene cluster, will be discussed. Third, the role of the habenular complex in nicotine aversion, primarily medial habenular projections to the interpeduncular nucleus (IPN) but also lateral habenular projections to rostromedial tegmental nucleus (RMTg) and ventral tegmental area (VTA) are reviewed. Forth, brain circuits that are enriched in nAChRs, but whose role in nicotine avoidance has not yet been assessed, will be proposed. Finally, the feasibility of developing novel therapeutic agents for tobacco dependence that act not by blocking nicotine reward but by enhancing nicotine avoidance will be considered. PMID:24055497

  8. Investigating the Predictive Value of Functional MRI to Appetitive and Aversive Stimuli: A Pattern Classification Approach.

    Directory of Open Access Journals (Sweden)

    Ciara McCabe

    Full Text Available Dysfunctional neural responses to appetitive and aversive stimuli have been investigated as possible biomarkers for psychiatric disorders. However it is not clear to what degree these are separate processes across the brain or in fact overlapping systems. To help clarify this issue we used Gaussian process classifier (GPC analysis to examine appetitive and aversive processing in the brain.25 healthy controls underwent functional MRI whilst seeing pictures and receiving tastes of pleasant and unpleasant food. We applied GPCs to discriminate between the appetitive and aversive sights and tastes using functional activity patterns.The diagnostic accuracy of the GPC for the accuracy to discriminate appetitive taste from neutral condition was 86.5% (specificity = 81%, sensitivity = 92%, p = 0.001. If a participant experienced neutral taste stimuli the probability of correct classification was 92. The accuracy to discriminate aversive from neutral taste stimuli was 82.5% (specificity = 73%, sensitivity = 92%, p = 0.001 and appetitive from aversive taste stimuli was 73% (specificity = 77%, sensitivity = 69%, p = 0.001. In the sight modality, the accuracy to discriminate appetitive from neutral condition was 88.5% (specificity = 85%, sensitivity = 92%, p = 0.001, to discriminate aversive from neutral sight stimuli was 92% (specificity = 92%, sensitivity = 92%, p = 0.001, and to discriminate aversive from appetitive sight stimuli was 63.5% (specificity = 73%, sensitivity = 54%, p = 0.009.Our results demonstrate the predictive value of neurofunctional data in discriminating emotional and neutral networks of activity in the healthy human brain. It would be of interest to use pattern recognition techniques and fMRI to examine network dysfunction in the processing of appetitive, aversive and neutral stimuli in psychiatric disorders. Especially where problems with reward and punishment processing have been implicated in the pathophysiology of the disorder.

  9. How not to extend models of inequality aversion

    Czech Academy of Sciences Publication Activity Database

    Engelmann, Dirk

    2012-01-01

    Roč. 81, č. 2 (2012), s. 599-605 ISSN 0167-2681 Institutional research plan: CEZ:AV0Z70850503 Keywords : inequality aversion * efficiency * social preferences Subject RIV: AH - Economics Impact factor: 1.065, year: 2012

  10. Heightened aversion to risk and loss in depressed patients with a suicide attempt history.

    Science.gov (United States)

    Baek, Kwangyeol; Kwon, JaeHyung; Chae, Jeong-Ho; Chung, Yong An; Kralik, Jerald D; Min, Jung-Ah; Huh, HyuJung; Choi, Kyung Mook; Jang, Kuk-In; Lee, Na-Bin; Kim, Sunyoung; Peterson, Bradley S; Jeong, Jaeseung

    2017-09-11

    Suicide attempters have been found to be impaired in decision-making; however, their specific biases in evaluating uncertain outcomes remain unclear. Here we tested the hypothesis that suicidal behavior is associated with heightened aversion to risk and loss, which might produce negative predictions about uncertain future events. Forty-five depressed patients with a suicide attempt history, 47 nonsuicidal depressed patients, and 75 healthy controls participated in monetary decision-making tasks assessing risk and loss aversion. Suicide attempters compared with the other groups exhibited greater aversion to both risk and loss during gambles involving potential loss. Risk and loss aversion correlated with each other in the depressed patients, suggesting that a common pathophysiological mechanism underlies these biases. In addition, emotion regulation via suppression, a detrimental emotional control strategy, was positively correlated with loss aversion in the depressed patients, also implicating impairment in regulatory processes. A preliminary fMRI study also found disrupted neural responses to potential gains and losses in the subgenual anterior cingulate cortex, insula cortex, and left amygdala, brain regions involved in valuation, emotion reactivity, and emotion regulation. The findings thus implicate heightened negative valuation in decision-making under risk, and impaired emotion regulation in depressed patients with a history of suicide attempts.

  11. Two Independent Mushroom Body Output Circuits Retrieve the Six Discrete Components of Drosophila Aversive Memory

    Directory of Open Access Journals (Sweden)

    Emna Bouzaiane

    2015-05-01

    Full Text Available Understanding how the various memory components are encoded and how they interact to guide behavior requires knowledge of the underlying neural circuits. Currently, aversive olfactory memory in Drosophila is behaviorally subdivided into four discrete phases. Among these, short- and long-term memories rely, respectively, on the γ and α/β Kenyon cells (KCs, two distinct subsets of the ∼2,000 neurons in the mushroom body (MB. Whereas V2 efferent neurons retrieve memory from α/β KCs, the neurons that retrieve short-term memory are unknown. We identified a specific pair of MB efferent neurons, named M6, that retrieve memory from γ KCs. Moreover, our network analysis revealed that six discrete memory phases actually exist, three of which have been conflated in the past. At each time point, two distinct memory components separately recruit either V2 or M6 output pathways. Memory retrieval thus features a dramatic convergence from KCs to MB efferent neurons.

  12. Effects of antiemetics on the acquisition and recall of radiation- and lithium chloride-induced conditioned taste aversions

    International Nuclear Information System (INIS)

    Rabin, B.M.; Hunt, W.A.

    1983-01-01

    A series of experiments were run to evaluate the effect of antiemetics on the acquisition and recall of a conditioned taste aversion induced by exposure to ionizing radiation or by injection of lithium chloride. Groups of male rats were exposed to 100 rad gamma radiation or 3 mEq/kg lithium chloride following consumption of a 10% sucrose solution. They were then injected with saline or with one of three antiemetics (prochlorperazine, trimethobenzamide, or cyclizine) at dose levels that have been reported to be effective in attenuating a previously acquired lithium chloride-induced taste aversion. The pretreatments with antiemetics had no effect on the acquisition or recall of either the lithium chloride- or radiation-induced taste aversion. The data suggest that antiemetics do not disrupt lithium chloride-induced taste aversions as previously reported, nor do they effect radiation-induced taste aversion learning

  13. Low- and high-testosterone individuals exhibit decreased aversion to economic risk.

    Science.gov (United States)

    Stanton, Steven J; Mullette-Gillman, O'Dhaniel A; McLaurin, R Edward; Kuhn, Cynthia M; LaBar, Kevin S; Platt, Michael L; Huettel, Scott A

    2011-04-01

    Testosterone is positively associated with risk-taking behavior in social domains (e.g., crime, physical aggression). However, the scant research linking testosterone to economic risk preferences presents inconsistent findings. We examined the relationship between endogenous testosterone and individuals' economic preferences (i.e., risk preference, ambiguity preference, and loss aversion) in a large sample (N = 298) of men and women. We found that endogenous testosterone levels have a significant U-shaped association with individuals' risk and ambiguity preferences, but not loss aversion. Specifically, individuals with low or high levels of testosterone (more than 1.5 SD from the mean for their gender) were risk and ambiguity neutral, whereas individuals with intermediate levels of testosterone were risk and ambiguity averse. This relationship was highly similar in men and women. In contrast to received wisdom regarding testosterone and risk, the present data provide the first robust evidence for a nonlinear association between economic preferences and levels of endogenous testosterone.

  14. Long-term aversive taste memory requires insular and amygdala protein degradation.

    Science.gov (United States)

    Rodriguez-Ortiz, Carlos J; Balderas, Israela; Saucedo-Alquicira, Fernando; Cruz-Castañeda, Paulina; Bermudez-Rattoni, Federico

    2011-03-01

    Some reports have shown that the ubiquitin-proteasome system (UPS) is necessary to degrade repressor factors to produce new proteins essential to memory consolidation. Furthermore, recent evidence suggests that memory updating also relies on protein degradation through the UPS. To evaluate whether degradation of proteins is part of the cellular events needed for long-term storage of taste aversion, we injected lactacystin--an UPS inhibitor--into the amygdala and/or insular cortex 30 min before the first or second training trials. The results revealed that degradation of proteins in either the amygdala or insular cortex suffices for long-term stabilization of first-time encounter taste aversion. On the other hand, lactacystin applied in the insula, but not in the amygdala, before the second training prevented long-term storage of updated information. Our results support that degradation of proteins by means of the UPS is required every time taste aversion is to be stored in long-term memory. Copyright © 2010 Elsevier Inc. All rights reserved.

  15. Public Sector Employees: Risk Averse and Altruistic?

    NARCIS (Netherlands)

    M.W.J.M. Buurman (Margaretha); A.J. Dur (Robert); S. Bossche, van den (Seth)

    2009-01-01

    textabstractWe assess whether public sector employees have a stronger inclination to serve others and are more risk averse than employees in the private sector. A unique feature of our study is that we use revealed rather than stated preferences data. Respondents of a large-scale survey were offered

  16. Public sector employees: risk averse and altruistic?

    NARCIS (Netherlands)

    Buurman, M.; Delfgaauw, J.; Dur, R.; Bossche, S.N.J. van den

    2012-01-01

    We assess whether public sector employees have a stronger inclination to serve others and are more risk averse than employees in the private sector. A unique feature of our study is that we use revealed rather than stated preferences data. Respondents of a large-scale survey were offered a

  17. Public sector employees: risk averse and altruistic?

    NARCIS (Netherlands)

    Buurman, M.; Dur, R.; Bossche, S.N.J. van den

    2009-01-01

    We assess whether public sector employees have a stronger inclination to serve others and are more risk averse than employees in the private sector. A unique feature of our study is that we use revealed rather than stated preferences data. Respondents of a large-scale survey were offered a

  18. Long-term changes in amphetamine-induced reinforcement and aversion in rats following exposure to 56Fe particle

    Science.gov (United States)

    Rabin, B. M.; Joseph, J. A.; Shukitt-Hale, B.

    Exposing rats to heavy particles produces alterations in the functioning of dopaminergic neurons and in the behaviors that depend upon the integrity of the dopaminergic system. Two of these dopamine-dependent behaviors include amphetamine-induced reinforcement, measure using the conditioned place preference procedure, and amphetamine-induced reinforcement, measured using the conditioned place preference procedure, and amphetamine-induced aversion, measured using the conditioned taste aversion. Previous research has shown that exposing rats to 1.0 Gy of 1GeV/n 56Fe particles produced a disruption of an amphetamine-induced taste aversion 3 days following exposure, but produced an apparent enhancement of the aversion 112 days following exposure. The present experiments were designed to provide a further evaluation of these results by examining taste aversion learning 154 days following exposure to 1.0Gy 56Fe particles and to establish the convergent validity of the taste aversion results by looking at the effects of exposure on the establishment of an amphetamine-induced conditioned place preference 3, 7, and 16 weeks following irradiation. The taste aversion results failed to confirm the apparent enhancement of the amphetamine-induced CTA observed in the prior experiment. However, exposure to 56Fe particles prevented the acquisition of amphetamine-induced place preference at all three-time intervals. The results are interpreted as indicating that exposure to heavy particles can produce long-term changes in behavioral functioning.

  19. PERFORMANCE EVALUATION AND RISK AVERSION RATE FOR SEVERAL STOCK INDICES IN INDONESIA STOCK EXCHANGE

    Directory of Open Access Journals (Sweden)

    Robiyanto Robiyanto

    2017-03-01

    Full Text Available There are numerous stock indices in Indonesia Stock Exchange. Several of them are LQ-45, MBX, DBX, JII, SRI-KEHATI, PEFINDO-25, BISNIS-27, IDX-30 and KOMPAS-100. Unfortunately there are limi­ted researches which have been done to measure those indices performance specifically. The same condition also occurs on risk aversion level usage in Indonesia Stock Exchange, only few numbers of researches use this me­a­surement in the portfolio valuation. Based on that, this research measured the performance and risk aversion rate of those indices in Indonesia Stock Exchange. The results of this study were SRI-KEHATI becomes the best performer with the highest risk aversion rate, while Jakarta Islamic Index (JII produces the lowest positive per­formance with the lowest risk aversion rate. This finding shows that sharia stocks’ characters (i.e. usury free could give relieveness and convenience regardless its per­formance.

  20. A Marketing Strategy in a Closed-Loop Supply Chain with Loss-Averse Consumers

    Directory of Open Access Journals (Sweden)

    Bi-feng Liao

    2018-01-01

    Full Text Available The importance of remanufacturing system has been extensively investigated in recent years. Taking into account the consumer valuation uncertainty and the demand uncertainty, this paper addresses the issue of closed-loop supply chain with remanufacturing by game theory. We consider two types of consumers in the market: loss-neutral consumers and loss-averse consumers. The loss-neutral consumers are completely rational. The loss-averse consumers, on the other hand, are with losses being more painful than equal-sized gains being pleasant. When multichannel structure can be chosen, the manufacturer has three pricing strategies in direct market: (1 keeping the price high with a small discount, no customers choose the online store; (2 keeping the price high with a moderate discount, only the loss-neutral customers choose the online store; (3 keeping the price low with a big discount, all customers choose the online store. Consumers make up their decisive selections through comparing the price and channel attributes. We introduce utility function for analyzing the market demand and then identify the optimal pricing and channel strategy to maximize the manufacturer’s profit. Finally, the rationality and validities of the proposed model are illustrated by numerical examples, and sensitivity analyses of the parameters are also presented.

  1. Cross-sectional survey: risk-averse French general practitioners are more favorable toward influenza vaccination.

    Science.gov (United States)

    Massin, Sophie; Ventelou, Bruno; Nebout, Antoine; Verger, Pierre; Pulcini, Céline

    2015-01-29

    We tested the following hypotheses: (i) risk-averse general practitioners (GPs) are more likely to be vaccinated against influenza; (ii) and risk-averse GPs recommend influenza vaccination more often to their patients. In risk-averse GPs, the perceived benefits of the vaccine and/or the perceived risks of the infectious disease might indeed outweigh the perceived risks of the vaccine. In 2010-2012, we conducted a cross-sectional survey of a nationwide French representative sample of 1136 GPs. Multivariate analyses adjusted for four stratification variables (age, gender, urban/suburban/rural practice location and annual patient consultations) and for GPs' characteristics (group/solo practice, and occasional practice of alternative medicine, e.g., homeopathy) looked for associations between their risk attitudes and self-reported vaccination behavior. Individual risk attitudes were expressed as a continuous variable, from 0 (risk-tolerant) to 10 (risk-averse). Overall, 69% of GPs reported that they were very favorable toward vaccination in general. Self-reported vaccination coverage was 78% for 2009/2010 seasonal influenza and 62% for A/H1N1 pandemic influenza. Most GPs (72%) reported recommending the pandemic influenza vaccination to at-risk young adults in 2009, but few than half (42%) to young adults not at risk. In multivariate analyses, risk-averse GPs were more often vaccinated against seasonal (marginal effect=1.3%, P=0.02) and pandemic influenza (marginal effect=1.5%, P=0.02). Risk-averse GPs recommended the pandemic influenza vaccination more often than their more risk-tolerant colleagues to patients without risk factors (marginal effect=1.7%, P=0.01), but not to their at-risk patients and were more favorable toward vaccination in general (marginal effect=1.5%, P=0.04). Individual risk attitudes may influence GPs' practices regarding influenza vaccination, both for themselves and their patients. Our results suggest that risk-averse GPs may perceive the risks

  2. Aversive learning of odor-heat associations in ants.

    Science.gov (United States)

    Desmedt, Lucie; Baracchi, David; Devaud, Jean-Marc; Giurfa, Martin; d'Ettorre, Patrizia

    2017-12-15

    Ants have recently emerged as useful models for the study of olfactory learning. In this framework, the development of a protocol for the appetitive conditioning of the maxilla-labium extension response (MaLER) provided the possibility of studying Pavlovian odor-food learning in a controlled environment. Here we extend these studies by introducing the first Pavlovian aversive learning protocol for harnessed ants in the laboratory. We worked with carpenter ants Camponotus aethiops and first determined the capacity of different temperatures applied to the body surface to elicit the typical aversive mandible opening response (MOR). We determined that 75°C is the optimal temperature to induce MOR and chose the hind legs as the stimulated body region because of their high sensitivity. We then studied the ability of ants to learn and remember odor-heat associations using 75°C as the unconditioned stimulus. We studied learning and short-term retention after absolute (one odor paired with heat) and differential conditioning (a punished odor versus an unpunished odor). Our results show that ants successfully learn the odor-heat association under a differential-conditioning regime and thus exhibit a conditioned MOR to the punished odor. Yet, their performance under an absolute-conditioning regime is poor. These results demonstrate that ants are capable of aversive learning and confirm previous findings about the different attentional resources solicited by differential and absolute conditioning in general. © 2017. Published by The Company of Biologists Ltd.

  3. Mushroom body output neurons encode valence and guide memory-based action selection in Drosophila

    Science.gov (United States)

    Aso, Yoshinori; Sitaraman, Divya; Ichinose, Toshiharu; Kaun, Karla R; Vogt, Katrin; Belliart-Guérin, Ghislain; Plaçais, Pierre-Yves; Robie, Alice A; Yamagata, Nobuhiro; Schnaitmann, Christopher; Rowell, William J; Johnston, Rebecca M; Ngo, Teri-T B; Chen, Nan; Korff, Wyatt; Nitabach, Michael N; Heberlein, Ulrike; Preat, Thomas; Branson, Kristin M; Tanimoto, Hiromu; Rubin, Gerald M

    2014-01-01

    Animals discriminate stimuli, learn their predictive value and use this knowledge to modify their behavior. In Drosophila, the mushroom body (MB) plays a key role in these processes. Sensory stimuli are sparsely represented by ∼2000 Kenyon cells, which converge onto 34 output neurons (MBONs) of 21 types. We studied the role of MBONs in several associative learning tasks and in sleep regulation, revealing the extent to which information flow is segregated into distinct channels and suggesting possible roles for the multi-layered MBON network. We also show that optogenetic activation of MBONs can, depending on cell type, induce repulsion or attraction in flies. The behavioral effects of MBON perturbation are combinatorial, suggesting that the MBON ensemble collectively represents valence. We propose that local, stimulus-specific dopaminergic modulation selectively alters the balance within the MBON network for those stimuli. Our results suggest that valence encoded by the MBON ensemble biases memory-based action selection. DOI: http://dx.doi.org/10.7554/eLife.04580.001 PMID:25535794

  4. Mushroom body output neurons encode valence and guide memory-based action selection in Drosophila.

    Science.gov (United States)

    Aso, Yoshinori; Sitaraman, Divya; Ichinose, Toshiharu; Kaun, Karla R; Vogt, Katrin; Belliart-Guérin, Ghislain; Plaçais, Pierre-Yves; Robie, Alice A; Yamagata, Nobuhiro; Schnaitmann, Christopher; Rowell, William J; Johnston, Rebecca M; Ngo, Teri-T B; Chen, Nan; Korff, Wyatt; Nitabach, Michael N; Heberlein, Ulrike; Preat, Thomas; Branson, Kristin M; Tanimoto, Hiromu; Rubin, Gerald M

    2014-12-23

    Animals discriminate stimuli, learn their predictive value and use this knowledge to modify their behavior. In Drosophila, the mushroom body (MB) plays a key role in these processes. Sensory stimuli are sparsely represented by ∼2000 Kenyon cells, which converge onto 34 output neurons (MBONs) of 21 types. We studied the role of MBONs in several associative learning tasks and in sleep regulation, revealing the extent to which information flow is segregated into distinct channels and suggesting possible roles for the multi-layered MBON network. We also show that optogenetic activation of MBONs can, depending on cell type, induce repulsion or attraction in flies. The behavioral effects of MBON perturbation are combinatorial, suggesting that the MBON ensemble collectively represents valence. We propose that local, stimulus-specific dopaminergic modulation selectively alters the balance within the MBON network for those stimuli. Our results suggest that valence encoded by the MBON ensemble biases memory-based action selection.

  5. Determining the Neural Substrate for Encoding a Memory of Human Pain and the Influence of Anxiety.

    Science.gov (United States)

    Tseng, Ming-Tsung; Kong, Yazhuo; Eippert, Falk; Tracey, Irene

    2017-12-06

    To convert a painful stimulus into a briefly maintainable construct when the painful stimulus is no longer accessible is essential to guide human behavior and avoid dangerous situations. Because of the aversive nature of pain, this encoding process might be influenced by emotional aspects and could thus vary across individuals, but we have yet to understand both the basic underlying neural mechanisms as well as potential interindividual differences. Using fMRI in combination with a delayed-discrimination task in healthy volunteers of both sexes, we discovered that brain regions involved in this working memory encoding process were dissociable according to whether the to-be-remembered stimulus was painful or not, with the medial thalamus and the rostral anterior cingulate cortex encoding painful and the primary somatosensory cortex encoding nonpainful stimuli. Encoding of painful stimuli furthermore significantly enhanced functional connectivity between the thalamus and medial prefrontal cortex (mPFC). With regards to emotional aspects influencing encoding processes, we observed that more anxious participants showed significant performance advantages when encoding painful stimuli. Importantly, only during the encoding of pain, the interindividual differences in anxiety were associated with the strength of coupling between medial thalamus and mPFC, which was furthermore related to activity in the amygdala. These results indicate not only that there is a distinct signature for the encoding of a painful experience in humans, but also that this encoding process involves a strong affective component. SIGNIFICANCE STATEMENT To convert the sensation of pain into a briefly maintainable construct is essential to guide human behavior and avoid dangerous situations. Although this working memory encoding process is implicitly contained in the majority of studies, the underlying neural mechanisms remain unclear. Using fMRI in a delayed-discrimination task, we found that the

  6. Event-related potential components as measures of aversive conditioning in humans.

    Science.gov (United States)

    Bacigalupo, Felix; Luck, Steven J

    2018-04-01

    For more than 60 years, the gold standard for assessing aversive conditioning in humans has been the skin conductance response (SCR), which arises from the activation of the peripheral nervous system. Although the SCR has been proven useful, it has some properties that impact the kinds of questions it can be used to answer. In particular, the SCR is slow, reaching a peak 4-5 s after stimulus onset, and it decreases in amplitude after a few trials (habituation). The present study asked whether the late positive potential (LPP) of the ERP waveform could be a useful complementary method for assessing aversive conditioning in humans. The SCR and LPP were measured in an aversive conditioning paradigm consisting of three blocks in which one color was paired with a loud noise (CS+) and other colors were not paired with the noise (CS-). Participants also reported the perceived likelihood of being exposed to the noise for each color. Both SCR and LPP were significantly larger on CS+ trials than on CS- trials. However, SCR decreased steeply after the first conditioning block, whereas LPP and self-reports were stable over blocks. These results indicate that the LPP can be used to assess aversive conditioning and has several useful properties: (a) it is a direct response of the central nervous system, (b) it is fast, with an onset latency of 300 ms, (c) it does not habituate over time. © 2017 Society for Psychophysiological Research.

  7. Effects of Swim Stress on Neophobia and Reconditioning Using a Conditioned Taste Aversion Procedure

    Science.gov (United States)

    Walker, Jennifer M.; Ramsey, Ashley K.; Fowler, Stephanie W.; Schachtman, Todd R.

    2012-01-01

    Previous research has found that swim stress during a classical conditioning trial attenuates conditioned taste aversion (CTA). In the current study, rats were used to examine the effects of inescapable swim stress on the habituation of neophobia to a flavored solution and reacquisition of an extinguished conditioned taste aversion. In Experiment…

  8. Extinction of Aversive Classically Conditioned Human Sexual Response

    NARCIS (Netherlands)

    Brom, M.; Laan, E.; Everaerd, W.; Spinhoven, P.; Both, S.

    INTRODUCTION: Research has shown that acquired subjective likes and dislikes are quite resistant to extinction. Moreover, studies on female sexual response demonstrated that diminished genital arousal and positive affect toward erotic stimuli due to aversive classical conditioning did not extinguish

  9. Extinction of aversive classically conditioned human sexual response

    NARCIS (Netherlands)

    Brom, Mirte; Laan, Ellen; Everaerd, Walter; Spinhoven, Philip; Both, Stephanie

    2015-01-01

    Research has shown that acquired subjective likes and dislikes are quite resistant to extinction. Moreover, studies on female sexual response demonstrated that diminished genital arousal and positive affect toward erotic stimuli due to aversive classical conditioning did not extinguish during an

  10. Rethinking a Negative Event: The Affective Impact of Ruminative versus Imagery-Based Processing of Aversive Autobiographical Memories.

    Science.gov (United States)

    Slofstra, Christien; Eisma, Maarten C; Holmes, Emily A; Bockting, Claudi L H; Nauta, Maaike H

    2017-01-01

    Ruminative (abstract verbal) processing during recall of aversive autobiographical memories may serve to dampen their short-term affective impact. Experimental studies indeed demonstrate that verbal processing of non-autobiographical material and positive autobiographical memories evokes weaker affective responses than imagery-based processing. In the current study, we hypothesized that abstract verbal or concrete verbal processing of an aversive autobiographical memory would result in weaker affective responses than imagery-based processing. The affective impact of abstract verbal versus concrete verbal versus imagery-based processing during recall of an aversive autobiographical memory was investigated in a non-clinical sample ( n  = 99) using both an observational and an experimental design. Observationally, it was examined whether spontaneous use of processing modes (both state and trait measures) was associated with impact of aversive autobiographical memory recall on negative and positive affect. Experimentally, the causal relation between processing modes and affective impact was investigated by manipulating the processing mode during retrieval of the same aversive autobiographical memory. Main findings were that higher levels of trait (but not state) measures of both ruminative and imagery-based processing and depressive symptomatology were positively correlated with higher levels of negative affective impact in the observational part of the study. In the experimental part, no main effect of processing modes on affective impact of autobiographical memories was found. However, a significant moderating effect of depressive symptomatology was found. Only for individuals with low levels of depressive symptomatology, concrete verbal (but not abstract verbal) processing of the aversive autobiographical memory did result in weaker affective responses, compared to imagery-based processing. These results cast doubt on the hypothesis that ruminative processing of

  11. My loss is your loss ... Sometimes: loss aversion and the effect of motivational biases.

    Science.gov (United States)

    Wilson, Robyn S; Arvai, Joseph L; Arkes, Hal R

    2008-08-01

    Findings from previous studies of individual decision-making behavior predict that losses will loom larger than gains. It is less clear, however, if this loss aversion applies to the way in which individuals attribute value to the gains and losses of others, or if it is robust across a broad spectrum of policy and management decision contexts. Consistent with previous work, the results from a series of experiments reported here revealed that subjects exhibited loss aversion when evaluating their own financial gains and losses. The presence of loss aversion was also confirmed for the way in which individuals attribute value to the financial gains and losses of others. However, similar evaluations within social and environmental contexts did not exhibit loss aversion. In addition, research subjects expected that individuals who were unknown to them would significantly undervalue the subjects' own losses across all contexts. The implications of these findings for risk-based policy and management are many. Specifically, they warrant caution when relying upon loss aversion to explain or predict the reaction of affected individuals to risk-based decisions that involve moral or protected values. The findings also suggest that motivational biases may lead decisionmakers to assume that their attitudes and beliefs are common among those affected by a decision, while those affected may expect unfamiliar others to be unable to identify and act in accordance with shared values.

  12. Molecular signals into the insular cortex and amygdala during aversive gustatory memory formation.

    Science.gov (United States)

    Bermúdez-Rattoni, Federico; Ramírez-Lugo, Leticia; Gutiérrez, Ranier; Miranda, María Isabel

    2004-02-01

    In this paper, we will provide evidence of the putative molecular signals and biochemical events that mediate the formation of long-lasting gustatory memory trace. When an animal drinks a novel taste (the conditioned stimulus; CS) and it is later associated with malaise (unconditioned stimulus; US), the animal will reject it in the next presentation, developing a long-lasting taste aversion, i.e., the taste cue becomes an aversive signal, and this is referred to as conditioning taste aversion. Different evidence indicates that the novel stimulus (taste) induces a rapid and strong cortical acetylcholine activity that decreases when the stimulus becomes familiar after several presentations. Cholinergic activation via muscarinic receptors initiates a series of intracellular events leading to plastic changes that could be related to short- and/or long-term memory gustatory trace. Such plastic changes facilitate the incoming US signals carried out by, in part, the glutamate release induced by the US. Altogether, these events could produce the cellular changes related to the switch from safe to aversive taste memory trace. A proposed working model to explain the biochemical sequence of signals during taste memory formation will be discussed.

  13. Exploring disadvantageous inequality aversion in children: How cost and discrepancy influence decision-making

    Directory of Open Access Journals (Sweden)

    Amanda eWilliams

    2014-09-01

    Full Text Available This research examined disadvantageous inequality aversion in 4- and 6-year-old children. Using the resource allocation paradigm, we explored how inequality aversion was influenced by whether a cost was associated with the equitable choice. We also investigated whether preferences for equality differed depending on whether the inequitable choice presented a small or large discrepancy between the payoff of the participant and their partner. The results demonstrated that cost plays a large role in decision-making, as children preferred equality more when there was no cost associated with it compared to when there was a cost. Interestingly, the effect of cost also affected discrepancy, with children more likely to choose equality when the discrepancy was large as opposed to small, in cost trials but not in no cost trials. Finally, the effect of discrepancy also interacted with age, with older children being more sensitive to the discrepancy between themselves and their partner Together, these results suggest that children’s behaviour is not indiscriminately guided by a generalized aversion to inequality or established fairness norms. Alternate motives for inequality aversion are discussed.

  14. Effects of phenobarbital on taste aversion induced by x-radiation

    International Nuclear Information System (INIS)

    Jolicoeur, F.B.; Wayner, M.J.; Rondeau, D.B.; Merkel, A.D.; Bassano, D.A.

    1979-01-01

    The effects of phenobarbital on taste aversion induced by x-radiation were examined. Rats were adapted to a 23 hr 50 min water deprivation schedule. On the Treatment Day animals were given a novel 0.125% Na saccharin solution during the 10 min drinking session and were then exposed to 100 rads of x-radiation. The saccharin solution was presented again on six subsequent Test Days. Phenobarbital in doses of 20, 40, 60 and 80 mg/kg was adminstered 15 min prior to drinking on the first Test Day. Results demonstrate the phenobarbital in all doses tested has a significant attenuating effect on radiation induced taste aversion

  15. The Use of Aversives in Special Education: Legal and Practice Considerations for School Principals

    Science.gov (United States)

    Katsiyannis, Antonis; Losinski, Mickey; Whitford, Denise K.; Counts, Jennifer

    2017-01-01

    The use of aversives as a method for behavioral intervention in U.S. public schools has been a persistent concern and often subject to litigation, particularly among students with disabilities. The use of aversives (restraint, seclusion, and corporal punishment) have been supported in some cases due to their perceived necessity to keep children…

  16. Aversive effects of ethanol in adolescent versus adult rats: potential causes and implication for future drinking.

    Science.gov (United States)

    Schramm-Sapyta, Nicole L; DiFeliceantonio, Alexandra G; Foscue, Ethan; Glowacz, Susan; Haseeb, Naadeyah; Wang, Nancy; Zhou, Cathy; Kuhn, Cynthia M

    2010-12-01

    Many people experiment with alcohol and other drugs of abuse during their teenage years. Epidemiological evidence suggests that younger initiates into drug taking are more likely to develop problematic drug seeking behavior, including binge and other high-intake behaviors. The level of drug intake for any individual depends on the balance of rewarding and aversive effects of the drug in that individual. Multiple rodent studies have demonstrated that aversive effects of drugs of abuse are reduced in adolescent compared to adult animals. In this study, we addressed 2 key questions: First, do reduced aversive effects of ethanol in younger rats correlate with increased ethanol consumption? Second, are the reduced aversive effects in adolescents attributable to reduced sensitivity to ethanol's physiologic effects? Adolescent and adult rats were tested for ethanol conditioned taste aversion (CTA) followed by a voluntary drinking period, including postdeprivation consumption. Multivariate regression was used to assess correlations. In separate experiments, adolescent and adult rats were tested for their sensitivity to the hypothermic and sedative effects of ethanol, and for blood ethanol concentrations (BECs). We observed that in adolescent rats but not adults, taste aversion was inversely correlated with postdeprivation consumption. Adolescents also exhibited a greater increase in consumption after deprivation than adults. Furthermore, the age difference in ethanol CTA was not attributable to differences in hypothermia, sedation, or BECs. These results suggest that during adolescence, individuals that are insensitive to aversive effects are most likely to develop problem drinking behaviors. These results underscore the importance of the interaction between developmental stage and individual variation in sensitivity to alcohol. Copyright © 2010 by the Research Society on Alcoholism.

  17. Genotypic Influence on Aversive Conditioning in Honeybees, Using a Novel Thermal Reinforcement Procedure

    Science.gov (United States)

    Junca, Pierre; Carcaud, Julie; Moulin, Sibyle; Garnery, Lionel; Sandoz, Jean-Christophe

    2014-01-01

    In Pavlovian conditioning, animals learn to associate initially neutral stimuli with positive or negative outcomes, leading to appetitive and aversive learning respectively. The honeybee (Apis mellifera) is a prominent invertebrate model for studying both versions of olfactory learning and for unraveling the influence of genotype. As a queen bee mates with about 15 males, her worker offspring belong to as many, genetically-different patrilines. While the genetic dependency of appetitive learning is well established in bees, it is not the case for aversive learning, as a robust protocol was only developed recently. In the original conditioning of the sting extension response (SER), bees learn to associate an odor (conditioned stimulus - CS) with an electric shock (unconditioned stimulus - US). This US is however not a natural stimulus for bees, which may represent a potential caveat for dissecting the genetics underlying aversive learning. We thus first tested heat as a potential new US for SER conditioning. We show that thermal stimulation of several sensory structures on the bee’s body triggers the SER, in a temperature-dependent manner. Moreover, heat applied to the antennae, mouthparts or legs is an efficient US for SER conditioning. Then, using microsatellite analysis, we analyzed heat sensitivity and aversive learning performances in ten worker patrilines issued from a naturally inseminated queen. We demonstrate a strong influence of genotype on aversive learning, possibly indicating the existence of a genetic determinism of this capacity. Such determinism could be instrumental for efficient task partitioning within the hive. PMID:24828422

  18. Rationality on the rise: Why relative risk aversion increases with stake size

    OpenAIRE

    Fehr-Duda, Helga; Bruhin, Adrian; Epper, Thomas F.; Schubert, Renate

    2008-01-01

    How does risk tolerance vary with stake size? This important question cannot be adequately answered if framing effects, nonlinear probability weighting, and heterogeneity of preference types are neglected. We show that, contrary to gains, no coherent change in relative risk aversion is observed for losses. The increase in relative risk aversion over gains cannot be captured by the curvature of the utility function. It is driven predominantly by a change in probability weighting of a majority ...

  19. The Neural Bases of Interoceptive Encoding and Recall in Healthy Adults and Adults With Depression.

    Science.gov (United States)

    DeVille, Danielle C; Kerr, Kara L; Avery, Jason A; Burrows, Kaiping; Bodurka, Jerzy; Feinstein, Justin S; Khalsa, Sahib S; Paulus, Martin P; Simmons, W Kyle

    2018-06-01

    Theoretical models assert that the brain's interoceptive network links external stimuli with their interoceptive consequences, thereby supporting later recall of these associations to guide the selection of healthy behaviors. If these accounts are correct, previously reported interoceptive abnormalities in major depressive disorder (MDD) should lead to altered recall of associations between external stimuli and their interoceptive (somatic) consequences. To date, the processes underlying interoceptive recall have never been experimentally investigated. We designed and implemented the Interoceptive Encoding and Recall task to compare interoceptive and exteroceptive recall among subjects with MDD (n = 24) and healthy comparison subjects (n = 21). During the encoding phase, subjects learned to pair neutral visual cues (geometric shapes) with aversive interoceptive and exteroceptive stimuli. Later, while undergoing functional magnetic resonance imaging, subjects were prompted to recall the stimulus associated with each shape. Interoceptive recall, relative to exteroceptive recall, was associated with bilateral mid-to-posterior insula activation. Relative to the healthy control participants, participants with depression exhibited marked hypoactivation of the right dorsal mid-insula during interoceptive recall. In healthy control subjects, simply recalling a stimulus associated with a previous interoceptive challenge activated a key region in the brain's interoceptive network. Although previous research has linked MDD with aberrant processing of interoceptive stimuli, the current study is the first to demonstrate that individuals with MDD exhibit decreased insula activity while recalling interoceptive memories. It is possible that insula hypoactivation during interoceptive recall may affect the representation of prior interoceptive experiences in ways that contribute to depressive symptomology and the relationship between depression and systemic health. Copyright

  20. Optimal combined purchasing strategies for a risk-averse manufacturer under price uncertainty

    Directory of Open Access Journals (Sweden)

    Qiao Wu

    2015-09-01

    Full Text Available Purpose: The purpose of our paper is to analyze optimal purchasing strategies when a manufacturer can buy raw materials from a long-term contract supplier and a spot market under spot price uncertainty. Design/methodology/approach: This procurement model can be solved by using dynamic programming. First, we maximize the DM’s utility of the second period, obtaining the optimal contract quantity and spot quantity for the second period. Then, maximize the DM’s utility of both periods, obtaining the optimal purchasing strategy for the first period. We use a numerical method to compare the performance level of a pure spot sourcing strategy with that of a mixed strategy. Findings: Our results show that optimal purchasing strategies vary with the trend of contract prices. If the contract price falls, the total quantity purchased in period 1 will decrease in the degree of risk aversion. If the contract price increases, the total quantity purchased in period 1 will increase in the degree of risk aversion. The relationship between the optimal contract quantity and the degree of risk aversion depends on whether the expected spot price or the contract price is larger in period 2. Finally, we compare the performance levels between a combined strategy and a spot sourcing strategy. It shows that a combined strategy is optimal for a risk-averse buyer. Originality/value: It’s challenging to deal with a two-period procurement problem with risk consideration. We have obtained results of a two-period procurement problem with two sourcing options, namely contract procurement and spot purchases. Our model incorporates the buyer’s risk aversion factor and the change of contract prices, which are not addressed in early studies.

  1. Subjective expected utility with non-increasing risk aversion

    NARCIS (Netherlands)

    Wakker, P.P.

    1989-01-01

    It is shown that assumptions about risk aversion, usually studied under the presupposition of expected utility maximization, have a surprising extra merit at an earlier stage of the measurement work: together with the sure-thing principle, these assumptions imply subjective expected utility

  2. The effect of post-conditioning exposure to morphine on the retention of a morphine-induced conditioned taste aversion.

    Science.gov (United States)

    Jacobs, W J; Zellner, D A; LoLordo, V M; Riley, A L

    1981-06-01

    In the following experiment, multiple injections of morphine sulfate following the acquisition of a morphine-induced taste aversion had no effect on the retention of the previously acquired aversion. Post-conditioning injections of morphine resulted in the development of physical dependence to morphine and led to a decrement in the ability of morphine to induce a subsequent aversion to a second novel taste. This failure of post-conditioning exposures to morphine to affect a previously acquired morphine-induced taste aversion even though tolerance to morphine had occurred was discussed in the context of Rescorla's event-memory model of conditioning.

  3. Reward-centricity and attenuated aversions: An adolescent phenotype emerging from studies in laboratory animals.

    Science.gov (United States)

    Doremus-Fitzwater, Tamara L; Spear, Linda P

    2016-11-01

    Adolescence is an evolutionarily conserved developmental period, with neural circuits and behaviors contributing to the detection, procurement, and receipt of rewards bearing similarity across species. Studies with laboratory animals suggest that adolescence is typified by a "reward-centric" phenotype-an increased sensitivity to rewards relative to adults. In contrast, adolescent rodents are reportedly less sensitive to the aversive properties of many drugs and naturally aversive stimuli. Alterations within the mesocorticolimbic dopamine and endocannabinoid systems likely contribute to an adolescent reward-sensitive, yet aversion-resistant, phenotype. Although early hypotheses postulated that developmental changes in dopaminergic circuitry would result in a "reward deficiency" syndrome, evidence now suggests the opposite: that adolescents are uniquely poised to seek out hedonic stimuli, experience greater "pleasure" from rewards, and consume rewarding stimuli in excess. Future studies that more clearly define the role of specific brain regions and neurotransmitter systems in the expression of behaviors toward reward- and aversive-related cues and stimuli are necessary to more fully understand an adolescent-proclivity for and vulnerability to rewards and drugs of potential abuse. Copyright © 2016 Elsevier Ltd. All rights reserved.

  4. Developmental differences in aversive conditioning, extinction, and reinstatement: A study with children, adolescents, and adults.

    Science.gov (United States)

    Waters, Allison M; Theresiana, Cindy; Neumann, David L; Craske, Michelle G

    2017-07-01

    This study investigated developmental differences in aversive conditioning, extinction, and reinstatement (i.e., the recovery of conditioned aversive associations following reexposure to the unconditioned stimulus [US] post-extinction). This study examined these mechanisms in children (M age =8.8years), adolescents (M age =16.1years), and adults (M age =32.3years) using differential aversive conditioning with a geometric shape conditional stimulus (CS+) paired with an aversive sound US and another shape (CS-) presented alone. Following an extinction phase in which both CSs were presented alone, half of the participants in each age group received three US exposures (reinstatement condition) and the other half did not (control condition), followed by all participants completing an extinction retest phase on the same day. Findings indicated (a) significant differences in generalizing aversive expectancies to safe stimuli during conditioning and extinction that persisted during retest in children relative to adults and adolescents, (b) significantly less positive CS reevaluations during extinction that persisted during retest in adolescents relative to adults and children, and (c) reinstatement of US expectancies to the CS+ relative to the CS- in all age groups. Results suggest important differences in stimulus safety learning in children and stimulus valence reevaluation in adolescents relative to adults. Copyright © 2017 Elsevier Inc. All rights reserved.

  5. Dexamethasone: a potent blocker for radiation-induced taste aversion in rats

    International Nuclear Information System (INIS)

    Cairnie, A.B.; Leach, K.E.

    1982-01-01

    Rats, trained to drink water during a single 30-min period each day, were then given 0.1% saccharin twice a week and water on other days for 30 min. If 20 rad of radiation (0.2 Gy) were given each time 30 to 40 min after the saccharin the rats developed a profound aversion to saccharin during the course of three weeks, whereas control groups failed to do so. This paradigm was then used to test the ability of drugs, given twice weekly immediately after the saccharin, to prevent the development during three weeks of an aversion when 20 rad was given, 30 to 40 min later. Insulin, domperidone, haloperidol, acetylsalicylic acid, naloxone, chlorpheniramine, cimetidine, and dimethyl sulphoxide were tested without notable success. However dexamethasone, at doses ranging from 0.013 mg/kg to 1.3 mg/kg, significantly attenuated the conditioned taste aversion by up to 60 percent. The results are discussed in terms of a search for an antinauseant and antiemetic drug effective against radiation in man

  6. [Diagnostic value of selective anorexia in pathological weight loss].

    Science.gov (United States)

    Braquet, P; Mercier, G; Reynes, J; Jeandel, C; Pinzani, V; Guilpain, P; Rivière, S; Le Quellec, A

    2016-02-01

    The diagnostic value of selective anorexia is debated. Some authors have suggested an association between meat aversion and cancer, but most do not use it as a diagnostic tool. We aimed to characterize anorexia of different diseases to search for an association between selective aversions and diagnostic groups. All the patients admitted to three departments of a teaching hospital were included consecutively for 22months if they had more than 10 % weight loss in less than one year. Patients were excluded if history taking was not reliable, or if they suffered from anorexia nervosa. We compiled diagnoses at discharge and validated them six months later. We used logistic regression to identify independent factors associated with selective anorexia. Inclusion criteria were met in 106patients (female 44 %, median age 65years). Most frequent diagnoses were: cancer (36 %), infection (35 %), digestive diseases (19 %), non organic diseases (21 %). Recent selective anorexia was found in 46 % of the cases. It was significantly associated with female gender (P=0.002), marginally with young age (P=0.069) and long duration of weight loss (P=0.079). Opioid use at admission was negatively associated with selective anorexia (P=0.001). No specific diagnostic category was found to be associated. Selective anorexia does not appear to be a useful symptom to investigate pathological weight loss. It behaves more like a non-specific reactivation by current disease of earlier latent personal food aversions. Copyright © 2015 Société nationale française de médecine interne (SNFMI). Published by Elsevier SAS. All rights reserved.

  7. Variation in the Williams syndrome GTF2I gene and anxiety proneness interactively affect prefrontal cortical response to aversive stimuli.

    Science.gov (United States)

    Jabbi, M; Chen, Q; Turner, N; Kohn, P; White, M; Kippenhan, J S; Dickinson, D; Kolachana, B; Mattay, V; Weinberger, D R; Berman, K F

    2015-08-18

    Characterizing the molecular mechanisms underlying the heritability of complex behavioral traits such as human anxiety remains a challenging endeavor for behavioral neuroscience. Copy-number variation (CNV) in the general transcription factor gene, GTF2I, located in the 7q11.23 chromosomal region that is hemideleted in Williams syndrome and duplicated in the 7q11.23 duplication syndrome (Dup7), is associated with gene-dose-dependent anxiety in mouse models and in both Williams syndrome and Dup7. Because of this recent preclinical and clinical identification of a genetic influence on anxiety, we examined whether sequence variation in GTF2I, specifically the single-nucleotide polymorphism rs2527367, interacts with trait and state anxiety to collectively impact neural response to anxiety-laden social stimuli. Two hundred and sixty healthy adults completed the Tridimensional Personality Questionnaire Harm Avoidance (HA) subscale, a trait measure of anxiety proneness, and underwent functional magnetic resonance imaging (fMRI) while matching aversive (fearful or angry) facial identity. We found an interaction between GTF2I allelic variations and HA that affects brain response: in individuals homozygous for the major allele, there was no correlation between HA and whole-brain response to aversive cues, whereas in heterozygotes and individuals homozygous for the minor allele, there was a positive correlation between HA sub-scores and a selective dorsolateral prefrontal cortex (DLPFC) responsivity during the processing of aversive stimuli. These results demonstrate that sequence variation in the GTF2I gene influences the relationship between trait anxiety and brain response to aversive social cues in healthy individuals, supporting a role for this neurogenetic mechanism in anxiety.

  8. Static vs Dynamic Auctions with Ambiguity Averse Bidders

    NARCIS (Netherlands)

    Carvalho, M.

    2012-01-01

    Abstract: This paper presents the outcome of a dynamic price-descending auction when the distribution of the private values is uncertain and bidders exhibit ambiguity aversion. In contrast to sealed-bid auctions, in open auctions the bidders get information about the other bidders' private values

  9. Joint measurement of risk aversion, prudence, and temperance

    NARCIS (Netherlands)

    Ebert, S.; Wiesen, D.

    Risk aversion—but also the higher-order risk preferences of prudence and temperance—are fundamental concepts in the study of economic decision making. We propose a method to jointly measure the intensity of risk aversion, prudence, and temperance. Our theoretical approach is to define risk

  10. Myopic Loss Aversion : Information Feedback vs. Investment Flexibility

    NARCIS (Netherlands)

    Bellemare, C.; Krause, M.; Kroger, S.; Zhang, C.

    2004-01-01

    We experimentally disentangle the effect of information feedback from the effect of investment flexibility on the investment behavior of a myopically loss averse investor.Our findings show that varying the information condition alone suffices to induce behavior that is in line with the hypothesis of

  11. Aversive Techniques and the Doctrine of Least Restrictive Alternative.

    Science.gov (United States)

    Barton, Lyle E.; And Others

    1983-01-01

    Litigation and the issues surrounding the use of behavioral procedures to handicapped persons are reviewed. Attention is directed to the use of aversive techniques, e.g., corporal punishment, electric shock, timeout, and restraint. (SEW)

  12. Differentiating aversive conditioning in bistable perception: Avoidance of a percept vs. salience of a stimulus.

    Science.gov (United States)

    Wilbertz, Gregor; Sterzer, Philipp

    2018-05-01

    Alternating conscious visual perception of bistable stimuli is influenced by several factors. In order to understand the effect of negative valence, we tested the effect of two types of aversive conditioning on dominance durations in binocular rivalry. Participants received either aversive classical conditioning of the stimuli shown alone between rivalry blocks, or aversive percept conditioning of one of the two possible perceptual choices during rivalry. Both groups showed successful aversive conditioning according to skin conductance responses and affective valence ratings. However, while classical conditioning led to an immediate but short-lived increase in dominance durations of the conditioned stimulus, percept conditioning yielded no significant immediate effect but tended to decrease durations of the conditioned percept during extinction. These results show dissociable effects of value learning on perceptual inference in situations of perceptual conflict, depending on whether learning relates to the decision between conflicting perceptual choices or the sensory stimuli per se. Copyright © 2018 Elsevier Inc. All rights reserved.

  13. Lateral Habenula determines long-term storage of aversive memories.

    Directory of Open Access Journals (Sweden)

    Micol eTomaiuolo

    2014-05-01

    Full Text Available The Lateral Habenula (LHb is a small brain structure that codifies negative motivational value and has been related to major depression. It has been shown recently that LHb activation is sufficient to induce aversive associative learning; however the key question about whether LHb activation is required for an aversive memory to be formed has not been addressed. In this article we studied the function of the LHb in memory formation using the Inhibitory Avoidance task (IA. We found that LHb inactivation during IA training does not disrupt memory when assessed 24 hours after, but abolishes it 7 days later, indicating that LHb activity during memory acquisition is not necessary for memory formation, but regulates its temporal stability. These effects suggest that LHb inactivation modifies subjective perception of the training experience.

  14. Eliciting and Measuring Betrayal Aversion using the BDM Mechanism*

    Science.gov (United States)

    Quercia, Simone

    2016-01-01

    Betrayal aversion has been operationalized as the evidence that subjects demand a higher risk premium to take social risks compared to natural risks. This evidence has been first shown by Bohnet and Zeckhauser (2004) using an adaptation of the Becker – DeGroot – Marschak mechanism (BDM, Becker et al. (1964)). We compare their implementation of the BDM mechanism with a new version designed to facilitate subjects’ comprehension. We find that, although the two versions produce different distributions of values, the size of betrayal aversion, measured as an average treatment difference between social and natural risk settings, is not different across the two versions. We further show that our implementation is preferable to use in practice as it reduces substantially subjects’ mistakes and the likelihood of noisy valuations. PMID:27366658

  15. Left-right functional asymmetry of ventral hippocampus depends on aversiveness of situations.

    Science.gov (United States)

    Sakaguchi, Yukitoshi; Sakurai, Yoshio

    2017-05-15

    Many studies suggest that animals exhibit lateralized behaviors during aversive situations, and almost all animals exhibit right hemisphere-dominant behaviors associated with fear or anxiety. However, which brain structure in each hemisphere underlies such lateralized function is unclear. In this study, we focused on the hippocampus and investigated the effects of bilateral and unilateral lesions of the ventral hippocampus (VH) on anxiety-like behavior using the successive alleys test. We also examined the expression of c-fos in the VH, which was induced by an aversive situation. Results revealed that consistent right VH dominance trended with the anxiety level. Weaker anxiety induced both right and left VH functions, whereas stronger anxiety induced right VH function. From these results, we conclude that animals are able to adaptively regulate their behaviors to avoid aversive stimuli by changing the functional dominance of their left and right VH. Copyright © 2017 Elsevier B.V. All rights reserved.

  16. Female babies and risk-aversion: Causal evidence from hospital wards.

    Science.gov (United States)

    Pogrebna, Ganna; Oswald, Andrew J; Haig, David

    2018-03-01

    Using ultrasound scan data from paediatric hospitals, and the exogenous 'shock' of learning the gender of an unborn baby, the paper documents the first causal evidence that offspring gender affects adult risk-aversion. On a standard Holt-Laury criterion, parents of daughters, whether unborn or recently born, become almost twice as risk-averse as parents of sons. The study demonstrates this in longitudinal and cross-sectional data, for fathers and mothers, for babies in the womb and new-born children, and in a West European nation and East European nation. These findings may eventually aid our understanding of risky health behaviors and gender inequalities. Copyright © 2018 The Authors. Published by Elsevier B.V. All rights reserved.

  17. Rethinking a Negative Event: The Affective Impact of Ruminative versus Imagery-Based Processing of Aversive Autobiographical Memories

    Directory of Open Access Journals (Sweden)

    Christien Slofstra

    2017-05-01

    Full Text Available IntroductionRuminative (abstract verbal processing during recall of aversive autobiographical memories may serve to dampen their short-term affective impact. Experimental studies indeed demonstrate that verbal processing of non-autobiographical material and positive autobiographical memories evokes weaker affective responses than imagery-based processing. In the current study, we hypothesized that abstract verbal or concrete verbal processing of an aversive autobiographical memory would result in weaker affective responses than imagery-based processing.MethodsThe affective impact of abstract verbal versus concrete verbal versus imagery-based processing during recall of an aversive autobiographical memory was investigated in a non-clinical sample (n = 99 using both an observational and an experimental design. Observationally, it was examined whether spontaneous use of processing modes (both state and trait measures was associated with impact of aversive autobiographical memory recall on negative and positive affect. Experimentally, the causal relation between processing modes and affective impact was investigated by manipulating the processing mode during retrieval of the same aversive autobiographical memory.ResultsMain findings were that higher levels of trait (but not state measures of both ruminative and imagery-based processing and depressive symptomatology were positively correlated with higher levels of negative affective impact in the observational part of the study. In the experimental part, no main effect of processing modes on affective impact of autobiographical memories was found. However, a significant moderating effect of depressive symptomatology was found. Only for individuals with low levels of depressive symptomatology, concrete verbal (but not abstract verbal processing of the aversive autobiographical memory did result in weaker affective responses, compared to imagery-based processing.DiscussionThese results cast doubt

  18. A conditioned aversion study of sucrose and SC45647 taste in TRPM5 knockout mice.

    Science.gov (United States)

    Eddy, Meghan C; Eschle, Benjamin K; Peterson, Darlene; Lauras, Nathan; Margolskee, Robert F; Delay, Eugene R

    2012-06-01

    Previously, published studies have reported mixed results regarding the role of the TRPM5 cation channel in signaling sweet taste by taste sensory cells. Some studies have reported a complete loss of sweet taste preference in TRPM5 knockout (KO) mice, whereas others have reported only a partial loss of sweet taste preference. This study reports the results of conditioned aversion studies designed to motivate wild-type (WT) and KO mice to respond to sweet substances. In conditioned taste aversion experiments, WT mice showed nearly complete LiCl-induced response suppression to sucrose and SC45647. In contrast, TRPM5 KO mice showed a much smaller conditioned aversion to either sweet substance, suggesting a compromised, but not absent, ability to detect sweet taste. A subsequent conditioned flavor aversion experiment was conducted to determine if TRPM5 KO mice were impaired in their ability to learn a conditioned aversion. In this experiment, KO and WT mice were conditioned to a mixture of SC45647 and amyl acetate (an odor cue). Although WT mice avoided both components of the stimulus mixture, they avoided SC45647 more than the odor cue. The KO mice also avoided both stimuli, but they avoided the odor component more than SC45647, suggesting that while the KO mice are capable of learning an aversion, to them the odor cue was more salient than the taste cue. Collectively, these findings suggest the TRPM5 KO mice have some residual ability to detect SC45647 and sucrose, and, like bitter, there may be a TRPM5-independent transduction pathway for detecting these substances.

  19. Risk aversion and religious behaviour

    DEFF Research Database (Denmark)

    Nielsen, Jytte Seested; Bech, Mickael; Christensen, Kaare

    2017-01-01

    would expect that risk averse individuals would demand a more generous protection plan which they may do by devoting more effort and resources into religious activities such as church attendance and prayer, which seems to be in accordance with previous empirical results. However, a general concern...... and prayer frequency on the other controlling for unobservable variables using survey data of Danish same-sex twin pairs. We verify the correlation between risk preferences and religion found previously by carrying out cross-sectional analyses. We also show that the association between risk attitudes...

  20. Pupillometry reveals the physiological underpinnings of the aversion to holes.

    Science.gov (United States)

    Ayzenberg, Vladislav; Hickey, Meghan R; Lourenco, Stella F

    2018-01-01

    An unusual, but common, aversion to images with clusters of holes is known as trypophobia. Recent research suggests that trypophobic reactions are caused by visual spectral properties also present in aversive images of evolutionary threatening animals (e.g., snakes and spiders). However, despite similar spectral properties, it remains unknown whether there is a shared emotional response to holes and threatening animals. Whereas snakes and spiders are known to elicit a fear reaction, associated with the sympathetic nervous system, anecdotal reports from self-described trypophobes suggest reactions more consistent with disgust, which is associated with activation of the parasympathetic nervous system. Here we used pupillometry in a novel attempt to uncover the distinct emotional response associated with a trypophobic response to holes. Across two experiments, images of holes elicited greater constriction compared to images of threatening animals and neutral images. Moreover, this effect held when controlling for level of arousal and accounting for the pupil grating response. This pattern of pupillary response is consistent with involvement of the parasympathetic nervous system and suggests a disgust, not a fear, response to images of holes. Although general aversion may be rooted in shared visual-spectral properties, we propose that the specific emotion is determined by cognitive appraisal of the distinct image content.

  1. Negative learning bias is associated with risk aversion in a genetic animal model of depression.

    Science.gov (United States)

    Shabel, Steven J; Murphy, Ryan T; Malinow, Roberto

    2014-01-01

    The lateral habenula (LHb) is activated by aversive stimuli and the omission of reward, inhibited by rewarding stimuli and is hyperactive in helpless rats-an animal model of depression. Here we test the hypothesis that congenital learned helpless (cLH) rats are more sensitive to decreases in reward size and/or less sensitive to increases in reward than wild-type (WT) control rats. Consistent with the hypothesis, we found that cLH rats were slower to switch preference between two responses after a small upshift in reward size on one of the responses but faster to switch their preference after a small downshift in reward size. cLH rats were also more risk-averse than WT rats-they chose a response delivering a constant amount of reward ("safe" response) more often than a response delivering a variable amount of reward ("risky" response) compared to WT rats. Interestingly, the level of bias toward negative events was associated with the rat's level of risk aversion when compared across individual rats. cLH rats also showed impaired appetitive Pavlovian conditioning but more accurate responding in a two-choice sensory discrimination task. These results are consistent with a negative learning bias and risk aversion in cLH rats, suggesting abnormal processing of rewarding and aversive events in the LHb of cLH rats.

  2. Mangifera indica L. extract (Vimang improves the aversive memory in spinocerebellar ataxia type 2 transgenic mice.

    Directory of Open Access Journals (Sweden)

    Natasha Maurmann

    2014-06-01

    Full Text Available Context: The spinocerebellar ataxia type 2 (SCA-2 is a progressive neurodegenerative disorder without specific therapy identified, and it is related to the loss of function in the cerebellum, mitochondrial dysfunction, oxidative stress and neurotoxic processes. Scientific evidence indicates that Mangifera indica L. aqueous extract (MiE and its major constituent (mangiferin display antioxidant, anti-inflammatory and neuroprotective actions. Aims: To investigate the MiE and mangiferin effects on behavioral outcomes of neurological function in SCA-2 transgenic mice. Methods: The SCA-2 transgenic mice were daily and orally administered during 12 months with MiE (10, 50, and 100 mg/kg, mangiferin (10 mg/kg or vehicle. It was evaluated locomotion (open-field, aversive memory (inhibitory avoidance and declarative memory (object recognition. To explore possible cellular mechanisms underlying the in vivo effects was also evaluated their effects on nerve grow factor (NGF and tumor necrosis factor-α (TNF-α levels in the human glioblastoma cell line U138-MG supernatant. Results: MiE administration did not affect the object recognition memory, but mangiferin did. The natural extract improved selectively the aversive memory in SCA-2 mice, indicating that MiE can affect behavioral parameters regarding fear-related memory. MiE also induced a significant increase in supernatant levels of NGF and TNF-α in vitro in human U138-MG glioblastoma cells. Conclusions: The results suggest that MiE enhances the aversive memory through a mechanism that might involve an increase in neurotrophin and cytokine levels. These findings constitute the basis for the use of the natural extract in the prevention/treatment of memory deficits in SCA-2.

  3. Internet Filtering Technology and Aversive Online Experiences in Adolescents.

    Science.gov (United States)

    Przybylski, Andrew K; Nash, Victoria

    2017-05-01

    To evaluate the effectiveness of Internet filtering tools designed to shield adolescents from aversive experiences online. A total of 1030 in-home interviews were conducted with early adolescents aged from 12 to 15 years (M = 13.50, SD = 1.18) and their caregivers. Caregivers were asked about their use of Internet filtering and adolescent participants were interviewed about their recent online experiences. Contrary to our hypotheses, policy, and industry advice regarding the assumed benefits of filtering we found convincing evidence that Internet filters were not effective at shielding early adolescents from aversive online experiences. Preregistered prospective and randomised controlled trials are needed to determine the extent to which Internet filtering technology supports vs thwarts young people online and if their widespread use justifies their financial and informational costs. Copyright © 2017 Elsevier Inc. All rights reserved.

  4. Conflict and disfluency as aversive signals: context-specific processing adjustments are modulated by affective location associations.

    Science.gov (United States)

    Dreisbach, Gesine; Reindl, Anna-Lena; Fischer, Rico

    2018-03-01

    Context-specific processing adjustments are one signature feature of flexible human action control. However, up to now the precise mechanisms underlying these adjustments are not fully understood. Here it is argued that aversive signals produced by conflict- or disfluency-experience originally motivate such context-specific processing adjustments. We tested whether the efficiency of the aversive conflict signal for control adaptation depends on the affective nature of the context it is presented in. In two experiments, high vs. low proportions of aversive signals (Experiment 1: conflict trials; Experiment 2: disfluent trials) were presented either above or below the screen center. This location manipulation was motivated by existing evidence that verticality is generally associated with affective valence with up being positive and down being negative. From there it was hypothesized that the aversive signals would lose their trigger function for processing adjustments when presented at the lower (i.e., more negative) location. This should then result in a reduced context-specific proportion effect when the high proportion of aversive signals was presented at the lower location. Results fully confirmed the predictions. In both experiments, the location-specific proportion effects were only present when the high proportion of aversive signals occurred at the more positive location above but were reduced (Experiment 1) or even eliminated (Experiment 2) when the high proportion occurred at the more negative location below. This interaction of processing adjustments with affective background contexts can thus be taken as further hint for an affective origin of control adaptations.

  5. Motivational state controls the prediction error in Pavlovian appetitive-aversive interactions.

    Science.gov (United States)

    Laurent, Vincent; Balleine, Bernard W; Westbrook, R Frederick

    2018-01-01

    Contemporary theories of learning emphasize the role of a prediction error signal in driving learning, but the nature of this signal remains hotly debated. Here, we used Pavlovian conditioning in rats to investigate whether primary motivational and emotional states interact to control prediction error. We initially generated cues that positively or negatively predicted an appetitive food outcome. We then assessed how these cues modulated aversive conditioning when a novel cue was paired with a foot shock. We found that a positive predictor of food enhances, whereas a negative predictor of that same food impairs, aversive conditioning. Critically, we also showed that the enhancement produced by the positive predictor is removed by reducing the value of its associated food. In contrast, the impairment triggered by the negative predictor remains insensitive to devaluation of its associated food. These findings provide compelling evidence that the motivational value attributed to a predicted food outcome can directly control appetitive-aversive interactions and, therefore, that motivational processes can modulate emotional processes to generate the final error term on which subsequent learning is based. Copyright © 2017 Elsevier Inc. All rights reserved.

  6. Emotion regulation reduces loss aversion and decreases amygdala responses to losses.

    Science.gov (United States)

    Sokol-Hessner, Peter; Camerer, Colin F; Phelps, Elizabeth A

    2013-03-01

    Emotion regulation strategies can alter behavioral and physiological responses to emotional stimuli and the neural correlates of those responses in regions such as the amygdala or striatum. The current study investigates the brain systems engaged when using an emotion regulation technique during financial decisions. In decision making, regulating emotion with reappraisal-focused strategies that encourage taking a different perspective has been shown to reduce loss aversion as observed both in choices and in the relative arousal responses to actual loss and gain outcomes. In the current study, we find using fMRI that behavioral loss aversion correlates with amygdala activity in response to losses relative to gains. Success in regulating loss aversion also correlates with the reduction in amygdala responses to losses but not to gains. Furthermore, across both decisions and outcomes, we find the reappraisal strategy increases baseline activity in dorsolateral and ventromedial prefrontal cortex and the striatum. The similarity of the neural circuitry observed to that seen in emotion regulation, despite divergent tasks, serves as further evidence for a role of emotion in decision making, and for the power of reappraisal to change assessments of value and thereby choices.

  7. A Representation Theorem for Guilt Aversion

    OpenAIRE

    Jensen, Martin Kaae; Kozlovskaya, Maria

    2016-01-01

    Guilt aversion has been shown to play an important role in economic decision-making. In this paper, we take an axiomatic approach to guilt by deducing a utility representation from a list of easily interpretable assumptions on an agent's preferences. It turns out that our logarithmic representation can mitigate the problem of multiplicity of equilibria to which psychological games are prone. We apply the model in three well-known games and show that its predictions are consistent with experim...

  8. Memory trace in feeding neural circuitry underlying conditioned taste aversion in Lymnaea.

    Directory of Open Access Journals (Sweden)

    Etsuro Ito

    Full Text Available BACKGROUND: The pond snail Lymnaea stagnalis can maintain a conditioned taste aversion (CTA as a long-term memory. Previous studies have shown that the inhibitory postsynaptic potential (IPSP evoked in the neuron 1 medial (N1M cell by activation of the cerebral giant cell (CGC in taste aversion-trained snails was larger and lasted longer than that in control snails. The N1M cell is one of the interneurons in the feeding central pattern generator (CPG, and the CGC is a key regulatory neuron for the feeding CPG. METHODOLOGY/PRINCIPLE FINDINGS: Previous studies have suggested that the neural circuit between the CGC and the N1M cell consists of two synaptic connections: (1 the excitatory connection from the CGC to the neuron 3 tonic (N3t cell and (2 the inhibitory connection from the N3t cell to the N1M cell. However, because the N3t cell is too small to access consistently by electrophysiological methods, in the present study the synaptic inputs from the CGC to the N3t cell and those from the N3t cell to the N1M cell were monitored as the monosynaptic excitatory postsynaptic potential (EPSP recorded in the large B1 and B3 motor neurons, respectively. The evoked monosynaptic EPSPs of the B1 motor neurons in the brains isolated from the taste aversion-trained snails were identical to those in the control snails, whereas the spontaneous monosynaptic EPSPs of the B3 motor neurons were significantly enlarged. CONCLUSION/SIGNIFICANCE: These results suggest that, after taste aversion training, the monosynaptic inputs from the N3t cell to the following neurons including the N1M cell are specifically facilitated. That is, one of the memory traces for taste aversion remains as an increase in neurotransmitter released from the N3t cell. We thus conclude that the N3t cell suppresses the N1M cell in the feeding CPG, in response to the conditioned stimulus in Lymnaea CTA.

  9. Memory trace in feeding neural circuitry underlying conditioned taste aversion in Lymnaea.

    Science.gov (United States)

    Ito, Etsuro; Otsuka, Emi; Hama, Noriyuki; Aonuma, Hitoshi; Okada, Ryuichi; Hatakeyama, Dai; Fujito, Yutaka; Kobayashi, Suguru

    2012-01-01

    The pond snail Lymnaea stagnalis can maintain a conditioned taste aversion (CTA) as a long-term memory. Previous studies have shown that the inhibitory postsynaptic potential (IPSP) evoked in the neuron 1 medial (N1M) cell by activation of the cerebral giant cell (CGC) in taste aversion-trained snails was larger and lasted longer than that in control snails. The N1M cell is one of the interneurons in the feeding central pattern generator (CPG), and the CGC is a key regulatory neuron for the feeding CPG. Previous studies have suggested that the neural circuit between the CGC and the N1M cell consists of two synaptic connections: (1) the excitatory connection from the CGC to the neuron 3 tonic (N3t) cell and (2) the inhibitory connection from the N3t cell to the N1M cell. However, because the N3t cell is too small to access consistently by electrophysiological methods, in the present study the synaptic inputs from the CGC to the N3t cell and those from the N3t cell to the N1M cell were monitored as the monosynaptic excitatory postsynaptic potential (EPSP) recorded in the large B1 and B3 motor neurons, respectively. The evoked monosynaptic EPSPs of the B1 motor neurons in the brains isolated from the taste aversion-trained snails were identical to those in the control snails, whereas the spontaneous monosynaptic EPSPs of the B3 motor neurons were significantly enlarged. These results suggest that, after taste aversion training, the monosynaptic inputs from the N3t cell to the following neurons including the N1M cell are specifically facilitated. That is, one of the memory traces for taste aversion remains as an increase in neurotransmitter released from the N3t cell. We thus conclude that the N3t cell suppresses the N1M cell in the feeding CPG, in response to the conditioned stimulus in Lymnaea CTA.

  10. Imagery Rescripting: The Impact of Conceptual and Perceptual Changes on Aversive Autobiographical Memories.

    Directory of Open Access Journals (Sweden)

    Christien Slofstra

    Full Text Available Imagery rescripting (ImRs is a process by which aversive autobiographical memories are rendered less unpleasant or emotional. ImRs is thought only to be effective if a change in the meaning-relevant (semantic content of the mental image is produced, according to a cognitive hypothesis of ImRs. We propose an additional hypothesis: that ImRs can also be effective by the manipulation of perceptual features of the memory, without explicitly targeting meaning-relevant content.In two experiments using a within-subjects design (both N = 48, community samples, both Conceptual-ImRs-focusing on changing meaning-relevant content-and Perceptual-ImRs-focusing on changing perceptual features-were compared to Recall-only of aversive autobiographical image-based memories. An active control condition, Recall + Attentional Breathing (Recall+AB was added in the first experiment. In the second experiment, a Positive-ImRs condition was added-changing the aversive image into a positive image that was unrelated to the aversive autobiographical memory. Effects on the aversive memory's unpleasantness, vividness and emotionality were investigated.In Experiment 1, compared to Recall-only, both Conceptual-ImRs and Perceptual-ImRs led to greater decreases in unpleasantness, and Perceptual-ImRs led to greater decreases in emotionality of memories. In Experiment 2, the effects on unpleasantness were not replicated, and both Conceptual-ImRs and Perceptual-ImRs led to greater decreases in emotionality, compared to Recall-only, as did Positive-ImRs. There were no effects on vividness, and the ImRs conditions did not differ significantly from Recall+AB.Results suggest that, in addition to traditional forms of ImRs, targeting the meaning-relevant content of an image during ImRs, relatively simple techniques focusing on perceptual aspects or positive imagery might also yield benefits. Findings require replication and extension to clinical samples.

  11. Imagery Rescripting: The Impact of Conceptual and Perceptual Changes on Aversive Autobiographical Memories.

    Science.gov (United States)

    Slofstra, Christien; Nauta, Maaike H; Holmes, Emily A; Bockting, Claudi L H

    2016-01-01

    Imagery rescripting (ImRs) is a process by which aversive autobiographical memories are rendered less unpleasant or emotional. ImRs is thought only to be effective if a change in the meaning-relevant (semantic) content of the mental image is produced, according to a cognitive hypothesis of ImRs. We propose an additional hypothesis: that ImRs can also be effective by the manipulation of perceptual features of the memory, without explicitly targeting meaning-relevant content. In two experiments using a within-subjects design (both N = 48, community samples), both Conceptual-ImRs-focusing on changing meaning-relevant content-and Perceptual-ImRs-focusing on changing perceptual features-were compared to Recall-only of aversive autobiographical image-based memories. An active control condition, Recall + Attentional Breathing (Recall+AB) was added in the first experiment. In the second experiment, a Positive-ImRs condition was added-changing the aversive image into a positive image that was unrelated to the aversive autobiographical memory. Effects on the aversive memory's unpleasantness, vividness and emotionality were investigated. In Experiment 1, compared to Recall-only, both Conceptual-ImRs and Perceptual-ImRs led to greater decreases in unpleasantness, and Perceptual-ImRs led to greater decreases in emotionality of memories. In Experiment 2, the effects on unpleasantness were not replicated, and both Conceptual-ImRs and Perceptual-ImRs led to greater decreases in emotionality, compared to Recall-only, as did Positive-ImRs. There were no effects on vividness, and the ImRs conditions did not differ significantly from Recall+AB. Results suggest that, in addition to traditional forms of ImRs, targeting the meaning-relevant content of an image during ImRs, relatively simple techniques focusing on perceptual aspects or positive imagery might also yield benefits. Findings require replication and extension to clinical samples.

  12. Some aversive characteristics of centrifugally generated gravity.

    Science.gov (United States)

    Altman, F.

    1973-01-01

    The effective weight of rats was manipulated by centrifugation. Two effective weight levels were obtained. In three escape avoidance conditions a lever press produced a change from a base level of 2.1 g to a response level of 1.1 g. In a punishment condition a response produced a change from a 1.1 g level to a 2.1 g level and in an extinction condition responses had no effect on the 2.1 g effective weight level present. All changes took 30 sec and were maintained for an additional 10 sec before a return to base level was initiated. When responses occurred closer together than the 40 sec, they delayed the return to base level by 40 sec. This 40 sec interval is referred to as response-contingent-time. The response rate and amount of response-contingent-time served as the data. The results confirmed previous data that centrifugation is aversive. The results are interpreted as indicating that the aversiveness is attributable to the increase in effective weight, and that rats can discriminate the different angular velocity-radius of rotation combinations used.

  13. Loss Aversion and the Asymmetric Transmission of Monetary Policy

    DEFF Research Database (Denmark)

    Santoro, Emiliano; Petrella, Ivan; Pfajfar, Damjan

    2014-01-01

    depends on consumption deviations from a reference level below which loss aversion is displayed. State-dependent degrees of real rigidity and elasticity of intertemporal substitution in consumption generate competing effects on output and inflation. Contractions face the Central Bank with higher...

  14. Risk Aversion and Public Reporting. Part 1: Observations From Cardiac Surgery and Interventional Cardiology.

    Science.gov (United States)

    Shahian, David M; Jacobs, Jeffrey P; Badhwar, Vinay; D'Agostino, Richard S; Bavaria, Joseph E; Prager, Richard L

    2017-12-01

    Risk aversion is a potential unintended consequence of health care public reporting. In Part 1 of this review, four possible consequences of this phenomenon are discussed, including the denial of interventions to some high-risk patients, stifling of innovation, appropriate avoidance of futile interventions, and better matching of high-risk patients to more capable providers. We also summarize relevant observational clinical reports and survey results from cardiovascular medicine and surgery, the two specialties from which almost all risk aversion observations have been derived. Although these demonstrate that risk aversion does occur, the empirical data are much more consistent and compelling for interventional cardiology than for cardiac surgery. Copyright © 2017 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.

  15. Failure of Serial Taste-Taste Compound Presentations to Produce Overshadowing of Extinction of Conditioned Taste Aversion

    Science.gov (United States)

    Pineno, Oskar

    2010-01-01

    Two experiments were conducted to study overshadowing of extinction in a conditioned taste aversion preparation. In both experiments, aversive conditioning with sucrose was followed by extinction treatment with either sucrose alone or in compound with another taste, citric acid. Experiment 1 employed a simultaneous compound extinction treatment…

  16. The Neurobiological Mechanism of Chemical Aversion (Emetic Therapy for Alcohol Use Disorder: An fMRI Study

    Directory of Open Access Journals (Sweden)

    Ralph L. Elkins

    2017-09-01

    Full Text Available A recent NIH epidemiology study found the lifetime prevalence of alcohol use disorder in the United States to be 29%. Alcohol drinking behavior is strongly “learned” via pleasure center activation/reinforcement. Alcohol craving is a powerful desire to drink alcoholic beverages. Craving was added as one of the defining criteria for alcohol use disorder in DSM5, and craving reduction is becoming an increasingly important treatment goal. In the current study, patients with alcohol use disorder received 10 days of inpatient multi-modal treatments at Schick Shadel Hospital (SSH of Seattle. The treatments included five chemical aversion conditioning sessions that associated alcohol cues (and alcohol with nausea and emesis. All patients met DSM4 criteria for alcohol use disorder, were heavy drinkers, and reported craving alcohol pre-treatment. Craving reduction was one of the primary treatment goals. This is the first fMRI study to measure the effects of chemical aversion therapy on alcohol craving-related brain activity. Patients were recruited as subjects for the University of Washington (UW brain scan study following SSH admission but before treatment onset. Prior to treatment, patients reported craving/desire for alcohol. After treatment (after four SSH chemical aversion treatments, again after five SSH chemical treatments, 30 and 90-days post-discharge, these same patients reported avoidance/aversion to alcohol. Most of the participants (69% reported being still sober 12 months post-treatment. Consistent with a craving reduction mechanism of how chemical aversion therapy facilitates sobriety, results of the UW fMRI brain scans showed significant pre- to post-treatment reductions in craving-related brain activity in the occipital cortex. Additional fMRI brain scan studies are needed to further explore the neurobiological mechanism of chemical aversion therapy treatment for alcohol use disorder, and other substance use disorders for which

  17. Egr-1 induction provides a genetic response to food aversion in zebrafish

    Directory of Open Access Journals (Sweden)

    Brigitte eBoyer

    2013-05-01

    Full Text Available As soon as zebrafish larvae start eating, they exhibit a marked aversion for bitter and acidic substances, as revealed by a consumption assay, in which fluorescent Tetrahymena serve as a feeding basis, to which various stimuli can be added. Bitter and acidic substances elicited an increase in mRNA accumulation of the immediate-early response gene egr-1, as revealed by in situ hybridization. Conversely, chemostimulants that did not induce aversion did not induce egr-1 response. Maximum labelling was observed in cells located in the oropharyngeal cavity and on the gill rakers. Gustatory areas of the brain were also labelled. Interestingly, when bitter tastants were repeatedly associated with food reward, zebrafish juveniles learned to ingest food in the presence of the bitter compound. After habituation, the acquisition of acceptance for bitterness was accompanied by a loss of egr-1 labelling. Altogether, our data indicate that egr-1 participates specifically in food aversion. The existence of reward-coupled changes in taste sensitivity in humans suggests that our results are relevant to situations in humans.

  18. Egr-1 induction provides a genetic response to food aversion in zebrafish.

    Science.gov (United States)

    Boyer, Brigitte; Ernest, Sylvain; Rosa, Frédéric

    2013-01-01

    As soon as zebrafish larvae start eating, they exhibit a marked aversion for bitter and acidic substances, as revealed by a consumption assay, in which fluorescent Tetrahymena serve as a feeding basis, to which various stimuli can be added. Bitter and acidic substances elicited an increase in mRNA accumulation of the immediate-early response gene egr-1, as revealed by in situ hybridization. Conversely, chemostimulants that did not induce aversion did not induce egr-1 response. Maximum labeling was observed in cells located in the oropharyngeal cavity and on the gill rakers. Gustatory areas of the brain were also labeled. Interestingly, when bitter tastants were repeatedly associated with food reward, zebrafish juveniles learned to ingest food in the presence of the bitter compound. After habituation, the acquisition of acceptance for bitterness was accompanied by a loss of egr-1 labeling. Altogether, our data indicate that egr-1 participates specifically in food aversion. The existence of reward-coupled changes in taste sensitivity in humans suggests that our results are relevant to situations in humans.

  19. On the robustness and possible accounts of ambiguity aversion

    NARCIS (Netherlands)

    Keren, G.; Gerritsen, L.E.M.

    1999-01-01

    Ambiguity aversion is one of the most robust phenomena documented in the decision making literature, though there are still disagreements concerning what constitutes an adequate account for its occurrence. We describe six experiments that shed additional light on the enigmatic phenomenon of

  20. Differential effects of beta-adrenergic receptor blockade in the medial prefrontal cortex during aversive and incidental taste memory formation.

    Science.gov (United States)

    Reyes-López, J; Nuñez-Jaramillo, L; Morán-Guel, E; Miranda, M I

    2010-08-11

    The medial prefrontal cortex (mPFC) is a brain area crucial for memory, attention, and decision making. Specifically, the noradrenergic system in this cortex is involved in aversive learning, as well as in the retrieval of these memories. Some evidence suggests that this area has an important role during taste memory, particularly during conditioned taste aversion (CTA), a model of aversive memory. Despite some previous evidence, there is scarce information about the role of adrenergic receptors in the mPFC during formation of aversive taste memory and appetitive/incidental taste memory. The goal of this research was to evaluate the role of mPFC beta-adrenergic receptors during CTA acquisition/consolidation or CTA retrieval, as well as during incidental taste memory formation using the model of latent inhibition of CTA. The results showed that infusions in the mPFC of the beta-adrenergic antagonist propranolol before CTA acquisition impaired both short- and long-term aversive taste memory formation, and also that propranolol infusions before the memory test impaired CTA retrieval. However, propranolol infusions before pre-exposure to the taste during the latent inhibition procedure had no effect on incidental taste memory acquisition or consolidation. These data indicate that beta-adrenergic receptors in the mPFC have different functions during taste memory formation: they have an important role during aversive taste association as well as during aversive retrieval but not during incidental taste memory formation. Copyright (c) 2010 IBRO. Published by Elsevier Ltd. All rights reserved.

  1. Modeling Inequity Aversion in a Dictator Game with Production

    Directory of Open Access Journals (Sweden)

    Ismael Rodriguez-Lara

    2012-10-01

    Full Text Available We expand upon the previous models of inequity aversion of Fehr and Schmidt [1], and Frohlich et al. [2], which assume that dictators get disutility if the final allocation of surplus deviates from the equal split (egalitarian principle or from the subjects' production (libertarian principle. In our model, dictators may also account for the way in which the surplus was generated. More precisely, our model incorporates the idea of liberal egalitarian ethics into the analysis, making it possible for dictators to divide the surplus according to the accountability principle, which states that subjects should only be rewarded for factors under their control. This fairness ideal does not hold subjects responsible for factors beyond their control in the production of the surplus, an idea that is absent in the models of inequity aversion cited above (JEL Codes: D3, D6, D63.

  2. Fos and Egr1 Expression in the Rat Brain in Response to Olfactory Cue after Taste-Potentiated Odor Aversion Retrieval

    Science.gov (United States)

    Cattarelli, Martine; Dardou, David; Datiche, Frederique

    2006-01-01

    When an odor is paired with a delayed illness, rats acquire a relatively weak odor aversion. In contrast, rats develop a strong aversion to an olfactory cue paired with delayed illness if it is presented simultaneously with a gustatory cue. Such a conditioning effect has been referred to as taste-potentiated odor aversion learning (TPOA). TPOA is…

  3. Coordinating a Supply Chain with a Loss-Averse Retailer and Effort Dependent Demand

    Science.gov (United States)

    Li, Liying

    2014-01-01

    This study investigates the channel coordination issue of a supply chain with a risk-neutral manufacturer and a loss-averse retailer facing stochastic demand that is sensitive to sales effort. Under the loss-averse newsvendor setting, a distribution-free gain/loss-sharing-and-buyback (GLB) contract has been shown to be able to coordinate the supply chain. However, we find that a GLB contract remains ineffective in managing the supply chain when retailer sales efforts influence the demand. To effectively coordinate the channel, we propose to combine a GLB contract with sales rebate and penalty (SRP) contract. In addition, we discover a special class of gain/loss contracts that can coordinate the supply chain and arbitrarily allocate the expected supply chain profit between the manufacturer and the retailer. We then analyze the effect of loss aversion on the retailer's decision-making behavior and supply chain performance. Finally, we perform a numerical study to illustrate the findings and gain additional insights. PMID:25197696

  4. Coordinating a supply chain with a loss-averse retailer and effort dependent demand.

    Science.gov (United States)

    Li, Liying; Wang, Yong

    2014-01-01

    This study investigates the channel coordination issue of a supply chain with a risk-neutral manufacturer and a loss-averse retailer facing stochastic demand that is sensitive to sales effort. Under the loss-averse newsvendor setting, a distribution-free gain/loss-sharing-and-buyback (GLB) contract has been shown to be able to coordinate the supply chain. However, we find that a GLB contract remains ineffective in managing the supply chain when retailer sales efforts influence the demand. To effectively coordinate the channel, we propose to combine a GLB contract with sales rebate and penalty (SRP) contract. In addition, we discover a special class of gain/loss contracts that can coordinate the supply chain and arbitrarily allocate the expected supply chain profit between the manufacturer and the retailer. We then analyze the effect of loss aversion on the retailer's decision-making behavior and supply chain performance. Finally, we perform a numerical study to illustrate the findings and gain additional insights.

  5. Loss-Averse Inventory and Borrowing Decisions with Constraints on Working Capital in Fashion and Textiles Industry

    Directory of Open Access Journals (Sweden)

    Lijun Ma

    2013-01-01

    Full Text Available Traditional inventory models focus on operational decisions and inventory control. Quite few models consider the financial constraint and decision bias such as loss aversion, which are the reality in today's business environment, especially for the fashion and textiles industry. In this paper we study the inventory control problem for a loss-averse retailer with financial constraint for operations in a periodic review setting in a finite horizon. We characterize the optimal inventory control policies with self-financing or with borrowing as capital-dependent base-stock policies. We demonstrate with numerical examples that the optimal base-stock level is nonincreasing in the accumulated wealth and the loss-aversion indicator.

  6. Identification of risk aversion factor for radiation workers in Korea

    International Nuclear Information System (INIS)

    Fadul, Abdulbagi; Na, Seong H.

    2016-01-01

    Radiation aversion factor reflects the degree of avoidance of radiation exposure which is considered a fundamental element in the optimization of radiation protection and a key factor in determining the real monetary value of the man-Sievert (Sv). This study provides an adjusted risk aversion factor, which was prescribed by the Korea Institute for Nuclear Safety (KINS), a regulatory body in Korea. Specifically, the Korea Hydro and Nuclear Power Co., Ltd. (KHNP) evaluated the monetary value of the man-Sv for Korean Nuclear Power Plants (NPPs) workers. This monetary value was assessed by the radiation aversion factor. Consequently, identifying the monetary value of the man-Sv in this study will enhance not only the effectiveness of optimization of radiation protection in Korea but also contribute to reduce doses to As Low As Reasonably Achievable (ALARA) when accounting for economic and societal aspects. The primary purpose of this study is to obtain the risk aversion factor for radiation workers in medical and industrial facilities in Korea. The secondary purpose is to evaluate the real monetary value of the man-Sv.These objectives will be accomplished by collecting data from surveys that consider a variety of socio-economic conditions. The value of 1.45 represents considerable avoidance of radiation risk for the majority of NDT radiographers due to familiarity and work experience with radiation hazards. On the other hand, the value 1.57 indicates that most of radiation medical practitioners, in particular, interventional radiologists have a strong will to avoid radiation risk. However, they will accept more risk with incremental salary increases. For international comparison, the concept of Purchasing Power Parity (PPP) should be adopted to obtain the alpha values in real term. Certainly, this monetary value of the man-Sv is expected to contribute effectively in optimization of radiation protection in both medical and industrial fields. The findings of this study

  7. Dismissing Attachment Characteristics Dynamically Modulate Brain Networks Subserving Social Aversion.

    Science.gov (United States)

    Krause, Anna Linda; Borchardt, Viola; Li, Meng; van Tol, Marie-José; Demenescu, Liliana Ramona; Strauss, Bernhard; Kirchmann, Helmut; Buchheim, Anna; Metzger, Coraline D; Nolte, Tobias; Walter, Martin

    2016-01-01

    Attachment patterns influence actions, thoughts and feeling through a person's "inner working model". Speech charged with attachment-dependent content was proposed to modulate the activation of cognitive-emotional schemata in listeners. We performed a 7 Tesla rest-task-rest functional magnetic resonance imaging (fMRI)-experiment, presenting auditory narratives prototypical of dismissing attachment representations to investigate their effect on 23 healthy males. We then examined effects of participants' attachment style and childhood trauma on brain state changes using seed-based functional connectivity (FC) analyses, and finally tested whether subjective differences in responsivity to narratives could be predicted by baseline network states. In comparison to a baseline state, we observed increased FC in a previously described "social aversion network" including dorsal anterior cingulated cortex (dACC) and left anterior middle temporal gyrus (aMTG) specifically after exposure to insecure-dismissing attachment narratives. Increased dACC-seeded FC within the social aversion network was positively related to the participants' avoidant attachment style and presence of a history of childhood trauma. Anxious attachment style on the other hand was positively correlated with FC between the dACC and a region outside of the "social aversion network", namely the dorsolateral prefrontal cortex, which suggests decreased network segregation as a function of anxious attachment. Finally, the extent of subjective experience of friendliness towards the dismissing narrative was predicted by low baseline FC-values between hippocampus and inferior parietal lobule (IPL). Taken together, our study demonstrates an activation of networks related to social aversion in terms of increased connectivity after listening to insecure-dismissing attachment narratives. A causal interrelation of brain state changes and subsequent changes in social reactivity was further supported by our observation of

  8. Identification of risk aversion factor for radiation workers in Korea

    Energy Technology Data Exchange (ETDEWEB)

    Fadul, Abdulbagi [KAIST, Daejeon (Korea, Republic of); Na, Seong H. [Korea Institute of Nuclear Safety, Daejeon (Korea, Republic of)

    2016-10-15

    Radiation aversion factor reflects the degree of avoidance of radiation exposure which is considered a fundamental element in the optimization of radiation protection and a key factor in determining the real monetary value of the man-Sievert (Sv). This study provides an adjusted risk aversion factor, which was prescribed by the Korea Institute for Nuclear Safety (KINS), a regulatory body in Korea. Specifically, the Korea Hydro and Nuclear Power Co., Ltd. (KHNP) evaluated the monetary value of the man-Sv for Korean Nuclear Power Plants (NPPs) workers. This monetary value was assessed by the radiation aversion factor. Consequently, identifying the monetary value of the man-Sv in this study will enhance not only the effectiveness of optimization of radiation protection in Korea but also contribute to reduce doses to As Low As Reasonably Achievable (ALARA) when accounting for economic and societal aspects. The primary purpose of this study is to obtain the risk aversion factor for radiation workers in medical and industrial facilities in Korea. The secondary purpose is to evaluate the real monetary value of the man-Sv.These objectives will be accomplished by collecting data from surveys that consider a variety of socio-economic conditions. The value of 1.45 represents considerable avoidance of radiation risk for the majority of NDT radiographers due to familiarity and work experience with radiation hazards. On the other hand, the value 1.57 indicates that most of radiation medical practitioners, in particular, interventional radiologists have a strong will to avoid radiation risk. However, they will accept more risk with incremental salary increases. For international comparison, the concept of Purchasing Power Parity (PPP) should be adopted to obtain the alpha values in real term. Certainly, this monetary value of the man-Sv is expected to contribute effectively in optimization of radiation protection in both medical and industrial fields. The findings of this study

  9. Dismissing attachment characteristics dynamically modulate brain networks subserving social aversion.

    Directory of Open Access Journals (Sweden)

    Anna Linda eKrause

    2016-03-01

    Full Text Available Attachment patterns influence actions, thoughts and feeling through a person’s ‘Inner Working Model’. Speech charged with attachment-dependent content was proposed to modulate the activation of cognitive-emotional schemata in listeners. We performed a 7 Tesla rest-task-rest fMRI-experiment, presenting auditory narratives prototypical of dismissing attachment representations to investigate their effect on 23 healthy males. We then examined effects of participants’ attachment style and childhood trauma on brain state changes using seed-based functional connectivity (FC analyses, and finally tested whether subjective differences in responsivity to narratives could be predicted by baseline network states. In comparison to a baseline state, we observed increased FC in a previously described ‘social aversion network’ including dorsal anterior cingulated cortex (dACC and left anterior middle temporal gyrus (aMTG specifically after exposure to insecure-dismissing attachment narratives. Increased dACC-seeded FC within the social aversion network was positively related to the participants’ avoidant attachment style and presence of a history of childhood trauma. Anxious attachment style on the other hand was positively correlated with FC between the dACC and a region outside of the ‘social aversion network’, namely the dorsolateral prefrontal cortex, which suggests decreased network segregation as a function of anxious attachment. Finally, the extent of subjective experience of friendliness towards the dismissing narrative was predicted by low baseline FC-values between hippocampus and inferior parietal lobule. Taken together, our study demonstrates an activation of networks related to social aversion in terms of increased connectivity after listening to insecure-dismissing attachment narratives. A causal interrelation of brain state changes and subsequent changes in social reactivity was further supported by our observation of direct

  10. An encoding device and a method of encoding

    DEFF Research Database (Denmark)

    2012-01-01

    The present invention relates to an encoding device, such as an optical position encoder, for encoding input from an object, and a method for encoding input from an object, for determining a position of an object that interferes with light of the device. The encoding device comprises a light source...... in the area in the space and may interfere with the light, which interference may be encoded into a position or activation....

  11. Review of Random Phase Encoding in Volume Holographic Storage

    Directory of Open Access Journals (Sweden)

    Wei-Chia Su

    2012-09-01

    Full Text Available Random phase encoding is a unique technique for volume hologram which can be applied to various applications such as holographic multiplexing storage, image encryption, and optical sensing. In this review article, we first review and discuss diffraction selectivity of random phase encoding in volume holograms, which is the most important parameter related to multiplexing capacity of volume holographic storage. We then review an image encryption system based on random phase encoding. The alignment of phase key for decryption of the encoded image stored in holographic memory is analyzed and discussed. In the latter part of the review, an all-optical sensing system implemented by random phase encoding and holographic interconnection is presented.

  12. What a relief! A role for dopamine in positive (but not negative) valence.

    Science.gov (United States)

    Sharpe, Melissa J

    2018-02-27

    We have long known that dopamine encodes the predictive relationship between cues and rewards. But what about relief learning? In this issue of Neuropsychopharmacology, Meyer et al. show that the same circuits encoding rewarding events also encode relief from aversive events. And this appears to be in a manner distinct from encoding of the aversive event itself. So does dopamine only contribute to learning about positive events? And are these events encoded in the same way regardless of how that positive experience came about? Not quite. Turns out, the devil is in the details.

  13. Electricity capacity investment under risk aversion: A case study of coal, gas, and concentrated solar power

    International Nuclear Information System (INIS)

    Fan Lin; Norman, Catherine S.; Patt, Anthony G.

    2012-01-01

    The policy instrument many economists favor to reduce greenhouse gas emissions and to shift new investment towards low carbon technologies is the tradable allowance system. Experience with this instrument has been mixed, with a crucial design issue being the choice of whether to auction allowances to firms, or to grandfather them based on historical emissions. In this paper, we examine the changing incentives of investment in different technologies, when investors are risk averse and are expecting an allowance system with a certain allocation rule but do not know if the policy is going to take place in the near future. Investors also cannot fully predict future investment costs for the low-carbon technology. We apply a game theoretic model to examine the combined effects of uncertainty and risk aversion on the actions of potential investors into high and low carbon generating capacity, under both allocation rules and uncertain costs. We find that uncertainty and risk aversion do have implications towards investment incentives. We discuss policy implications of these findings. - Highlights: ► We examined capacity investments under alternative carbon permit allocation schemes. ► Uncertainty in future permit markets’ existence reduces investments into renewables. ► If permits are grandfathered, risk averse companies decrease renewable investment. ► Risk aversion minimizes the effects of uncertainty if carbon permits are auctioned.

  14. Selecting for memory? The influence of selective attention on the mnemonic binding of contextual information.

    Science.gov (United States)

    Uncapher, Melina R; Rugg, Michael D

    2009-06-24

    Not all of what is experienced is remembered later. Behavioral evidence suggests that the manner in which an event is processed influences which aspects of the event will later be remembered. The present experiment investigated the neural correlates of "selective encoding," or the mechanisms that support the encoding of some elements of an event in preference to others. Event-related MRI data were acquired while volunteers selectively attended to one of two different contextual features of study items (color or location). A surprise memory test for the items and both contextual features was subsequently administered to determine the influence of selective attention on the neural correlates of contextual encoding. Activity in several cortical regions indexed later memory success selectively for color or location information, and this encoding-related activity was enhanced by selective attention to the relevant feature. Critically, a region in the hippocampus responded selectively to attended source information (whether color or location), demonstrating encoding-related activity for attended but not for nonattended source features. Together, the findings suggest that selective attention modulates the magnitude of activity in cortical regions engaged by different aspects of an event, and hippocampal encoding mechanisms seem to be sensitive to this modulation. Thus, the information that is encoded into a memory representation is biased by selective attention, and this bias is mediated by cortical-hippocampal interactions.

  15. Absolute Risk Aversion and the Returns to Education.

    Science.gov (United States)

    Brunello, Giorgio

    2002-01-01

    Uses 1995 Italian household income and wealth survey to measure individual absolute risk aversion of 1,583 married Italian male household heads. Uses this measure as an instrument for attained education in a standard-log earnings equation. Finds that the IV estimate of the marginal return to schooling is much higher than the ordinary least squares…

  16. Mice do not develop conditioned taste aversion because of immunity loss.

    Science.gov (United States)

    Vidal, Jose

    2011-01-01

    This study intends to test the generation of conditioned taste aversion and conditioned immunodepression by daily paired administration of saccharin solution with cyclophosphamide, 15 mg/kg, for 4 days. One group of male mice of the outbred CD1 strain drank 0.15% saccharin and received 1 injection of cyclophosphamide, 15 mg/kg, for 4 days (paired group), another group (unpaired group) received the same doses of saccharin and cyclophosphamide noncontingently, the third group (cy60) received saccharin paired with cyclophosphamide, 60 mg/kg, and the fourth group (placebo) received saccharin in the absence of cyclophosphamide. All mice were immunized with keyhole limpet hemocyanin (KLH), 0.2 mg, 1 day before the treatments. Mice of the paired, unpaired and cy60 groups displayed a similarly decreased antibody response to KLH, but mice of the paired group did not develop an aversion to saccharin while mice of the cy60 group did. Besides, repeat presentation of saccharin to mice of the paired group did not alter their antibody response to ovalbumin compared with mice of the unpaired or placebo group. Taste aversion was not elicited in response to impaired immunity and the conditioned stimulus (saccharin) did not impair the antibody response. 2011 S. Karger AG, Basel.

  17. A behavioural approach to financial portfolio selection problem: an empirical study using heuristics

    OpenAIRE

    Grishina, Nina

    2014-01-01

    This thesis was submitted for the degree of Doctor of Philosophy and awarded by Brunel University The behaviourally based portfolio selection problem with investor's loss aversion and risk aversion biases in portfolio choice under uncertainty are studied. The main results of this work are developed heuristic approaches for the prospect theory and cumulative prospect theory models proposed by Kahneman and Tversky in 1979 and 1992 as well as an empirical comparative analysis of these models ...

  18. A note on testing guilt aversion

    DEFF Research Database (Denmark)

    Bellemare, Charles; Sebald, Alexander Christopher; Suetens, Sigrid

    2017-01-01

    We compare three approaches to test for guilt aversion in two economic experiments. The first approach elicits second-order beliefs using self-reports. The second approach discloses first-order beliefs of matched players to decision makers, which are taken as exogenous second-order beliefs...... of decision makers. The third approach lets decision makers make choices conditional on a sequence of possible first-order beliefs of matched players. We find that the first and third approach generate similar results, both qualitatively and quantitatively. The second approach, however, generates...

  19. Effect of sex on ethanol consumption and conditioned taste aversion in adolescent and adult rats.

    Science.gov (United States)

    Schramm-Sapyta, Nicole L; Francis, Reynold; MacDonald, Andrea; Keistler, Colby; O'Neill, Lauren; Kuhn, Cynthia M

    2014-04-01

    Vulnerability to alcoholism is determined by many factors, including the balance of pleasurable vs. aversive alcohol-induced sensations: pleasurable sensations increase intake, while aversive sensations decrease it. Female sex and adolescent age are associated with lower sensitivity to intake-reducing effects and more rapid development of alcohol abuse. This study assessed voluntary drinking and the aversive effects of alcohol to determine whether these measures are inversely related across the sexes and development. Voluntary drinking of 20 % ethanol in an every-other-day (EOD) availability pattern and the dose-response relationship of ethanol conditioned taste aversion (CTA) were assessed in male and female adolescent and adult rats. CTA was sex specific in adult but not adolescent rats, with adult females exhibiting less aversion. Voluntary ethanol consumption varied according to age and individual differences but was not sex specific. Adolescents initially drank more than adults, exhibited greater day-to-day variation in consumption, were more susceptible to the alcohol deprivation effect, and took longer to establish individual differences in consumption patterns. These results show that the emergence of intake patterns differs between adolescents and adults. Adolescents as a group initiate drinking at high levels but decrease intake as they mature. A subset of adolescents maintained high drinking levels into adulthood. In contrast, most adults consumed at steady, low levels, but a small subset quickly established and maintained high-consumption patterns. Adolescents also showed marked deprivation-induced increases. Sex differences were not observed in EOD drinking during either adolescence or adulthood.

  20. Reward and aversion in a heterogeneous midbrain dopamine system.

    Science.gov (United States)

    Lammel, Stephan; Lim, Byung Kook; Malenka, Robert C

    2014-01-01

    The ventral tegmental area (VTA) is a heterogeneous brain structure that serves a central role in motivation and reward processing. Abnormalities in the function of VTA dopamine (DA) neurons and the targets they influence are implicated in several prominent neuropsychiatric disorders including addiction and depression. Recent studies suggest that the midbrain DA system is composed of anatomically and functionally heterogeneous DA subpopulations with different axonal projections. These findings may explain a number of previously confusing observations that suggested a role for DA in processing both rewarding as well as aversive events. Here we will focus on recent advances in understanding the neural circuits mediating reward and aversion in the VTA and how stress as well as drugs of abuse, in particular cocaine, alter circuit function within a heterogeneous midbrain DA system. This article is part of a Special Issue entitled 'NIDA 40th Anniversary Issue'. Copyright © 2013 Elsevier Ltd. All rights reserved.

  1. Drug-induced conditioned place preference and aversion in mice.

    Science.gov (United States)

    Cunningham, Christopher L; Gremel, Christina M; Groblewski, Peter A

    2006-01-01

    This protocol describes the equipment and methods used to establish conditioned place preference (CPP) or aversion (CPA). Place conditioning is a form of Pavlovian conditioning routinely used to measure the rewarding or aversive motivational effects of objects or experiences (e.g., abused drugs). Here, we present a place conditioning procedure that has been used extensively to study the motivational effects of ethanol and other abused drugs in mice. This protocol involves three phases: (i) habituation (or a pretest), (ii) conditioning of an association between the drug and a tactile or visual stimulus and (iii) a test that offers a choice between the drug-associated cue and a neutral cue. If the drug has motivational significance, mice will spend significantly more time (CPP) or less time (CPA) in proximity to the drug-associated cue. Potential problems in the design and interpretation of place conditioning studies are discussed. A typical experiment lasts 2 weeks.

  2. Cognitive decline is associated with risk aversion and temporal discounting in older adults without dementia.

    Directory of Open Access Journals (Sweden)

    Bryan D James

    Full Text Available Risk aversion and temporal discounting are preferences that are strongly linked to sub-optimal financial and health decision making ability. Prior studies have shown they differ by age and cognitive ability, but it remains unclear whether differences are due to age-related cognitive decline or lower cognitive abilities over the life span. We tested the hypothesis that cognitive decline is associated with higher risk aversion and temporal discounting in 455 older persons without dementia from the Memory and Aging Project, a longitudinal cohort study of aging in Chicago. All underwent repeated annual cognitive evaluations using a detailed battery including 19 tests. Risk aversion was measured using standard behavioral economics questions: participants were asked to choose between a certain monetary payment versus a gamble in which they could gain more or nothing; potential gamble gains varied across questions. Temporal discounting: participants were asked to choose between an immediate, smaller payment and a delayed, larger one; two sets of questions addressed small and large stakes based on payment amount. Regression analyses were used to examine whether prior rate of cognitive decline predicted level of risk aversion and temporal discounting, controlling for age, sex, and education. Over an average of 5.5 (SD=2.9 years, cognition declined at an average of 0.016 units per year (SD=0.03. More rapid cognitive decline predicted higher levels of risk aversion (p=0.002 and temporal discounting (small stakes: p=0.01, high stakes: p=0.006. Further, associations between cognitive decline and risk aversion (p=0.015 and large stakes temporal discounting (p=0.026 persisted in analyses restricted to persons without any cognitive impairment (i.e., no dementia or mild cognitive impairment; the association of cognitive decline and small stakes temporal discounting was no longer statistically significant (p=0.078. These findings are consistent with the

  3. Cognitive decline is associated with risk aversion and temporal discounting in older adults without dementia.

    Science.gov (United States)

    James, Bryan D; Boyle, Patricia A; Yu, Lei; Han, S Duke; Bennett, David A

    2015-01-01

    Risk aversion and temporal discounting are preferences that are strongly linked to sub-optimal financial and health decision making ability. Prior studies have shown they differ by age and cognitive ability, but it remains unclear whether differences are due to age-related cognitive decline or lower cognitive abilities over the life span. We tested the hypothesis that cognitive decline is associated with higher risk aversion and temporal discounting in 455 older persons without dementia from the Memory and Aging Project, a longitudinal cohort study of aging in Chicago. All underwent repeated annual cognitive evaluations using a detailed battery including 19 tests. Risk aversion was measured using standard behavioral economics questions: participants were asked to choose between a certain monetary payment versus a gamble in which they could gain more or nothing; potential gamble gains varied across questions. Temporal discounting: participants were asked to choose between an immediate, smaller payment and a delayed, larger one; two sets of questions addressed small and large stakes based on payment amount. Regression analyses were used to examine whether prior rate of cognitive decline predicted level of risk aversion and temporal discounting, controlling for age, sex, and education. Over an average of 5.5 (SD=2.9) years, cognition declined at an average of 0.016 units per year (SD=0.03). More rapid cognitive decline predicted higher levels of risk aversion (p=0.002) and temporal discounting (small stakes: p=0.01, high stakes: p=0.006). Further, associations between cognitive decline and risk aversion (p=0.015) and large stakes temporal discounting (p=0.026) persisted in analyses restricted to persons without any cognitive impairment (i.e., no dementia or mild cognitive impairment); the association of cognitive decline and small stakes temporal discounting was no longer statistically significant (p=0.078). These findings are consistent with the hypothesis that

  4. Lossed in translation: an off-the-shelf method to recover probabilistic beliefs from loss-averse agents.

    Science.gov (United States)

    Offerman, Theo; Palley, Asa B

    2016-01-01

    Strictly proper scoring rules are designed to truthfully elicit subjective probabilistic beliefs from risk neutral agents. Previous experimental studies have identified two problems with this method: (i) risk aversion causes agents to bias their reports toward the probability of [Formula: see text], and (ii) for moderate beliefs agents simply report [Formula: see text]. Applying a prospect theory model of risk preferences, we show that loss aversion can explain both of these behavioral phenomena. Using the insights of this model, we develop a simple off-the-shelf probability assessment mechanism that encourages loss-averse agents to report true beliefs. In an experiment, we demonstrate the effectiveness of this modification in both eliminating uninformative reports and eliciting true probabilistic beliefs.

  5. Relationship between vomiting and taste aversion learning in the ferret: studies with ionizing radiation, lithium chloride, and amphetamine.

    Science.gov (United States)

    Rabin, B M; Hunt, W A

    1992-09-01

    The relationship between emesis and taste aversion learning was studied in ferrets (Mustela putorius furo) following exposure to ionizing radiation (50-200 cGy) or injection of lithium chloride (1.5-3.0 mEq/kg, ip). When 10% sucrose or 0.1% saccharin was used as the conditioned stimulus, neither unconditioned stimulus produced a taste aversion, even when vomiting was produced by the stimulus (Experiments 1 and 2). When a canned cat food was used as the conditioned stimulus, lithium chloride, but not ionizing radiation, produced a taste aversion (Experiment 3). Lithium chloride was effective in producing a conditioned taste aversion when administration of the toxin was delayed by up to 90 min following the ingestion of the canned cat food, indicating that the ferrets are capable of showing long-delay learning (Experiment 4). Experiment 5 examined the capacity of amphetamine, which is a qualitatively different stimulus than lithium chloride or ionizing radiation, to produce taste aversion learning in rats and cats as well as in ferrets. Injection of amphetamine (3 mg/kg, ip) produced a taste aversion in rats and cats but not in ferrets which required a higher dose (> 5 mg/kg). The results of these experiments are interpreted as indicating that, at least for the ferret, there is no necessary relationship between toxin-induced illness and the acquisition of a CTA and that gastrointestinal distress is not a sufficient condition for CTA learning.

  6. Understanding the Uncanny: Both Atypical Features and Category Ambiguity Provoke Aversion toward Humanlike Robots

    Directory of Open Access Journals (Sweden)

    Megan K. Strait

    2017-08-01

    Full Text Available Robots intended for social contexts are often designed with explicit humanlike attributes in order to facilitate their reception by (and communication with people. However, observation of an “uncanny valley”—a phenomenon in which highly humanlike entities provoke aversion in human observers—has lead some to caution against this practice. Both of these contrasting perspectives on the anthropomorphic design of social robots find some support in empirical investigations to date. Yet, owing to outstanding empirical limitations and theoretical disputes, the uncanny valley and its implications for human-robot interaction remains poorly understood. We thus explored the relationship between human similarity and people's aversion toward humanlike robots via manipulation of the agents' appearances. To that end, we employed a picture-viewing task (Nagents = 60 to conduct an experimental test (Nparticipants = 72 of the uncanny valley's existence and the visual features that cause certain humanlike robots to be unnerving. Across the levels of human similarity, we further manipulated agent appearance on two dimensions, typicality (prototypic, atypical, and ambiguous and agent identity (robot, person, and measured participants' aversion using both subjective and behavioral indices. Our findings were as follows: (1 Further substantiating its existence, the data show a clear and consistent uncanny valley in the current design space of humanoid robots. (2 Both category ambiguity, and more so, atypicalities provoke aversive responding, thus shedding light on the visual factors that drive people's discomfort. (3 Use of the Negative Attitudes toward Robots Scale did not reveal any significant relationships between people's pre-existing attitudes toward humanlike robots and their aversive responding—suggesting positive exposure and/or additional experience with robots is unlikely to affect the occurrence of an uncanny valley effect in humanoid robotics

  7. Understanding the Uncanny: Both Atypical Features and Category Ambiguity Provoke Aversion toward Humanlike Robots.

    Science.gov (United States)

    Strait, Megan K; Floerke, Victoria A; Ju, Wendy; Maddox, Keith; Remedios, Jessica D; Jung, Malte F; Urry, Heather L

    2017-01-01

    Robots intended for social contexts are often designed with explicit humanlike attributes in order to facilitate their reception by (and communication with) people. However, observation of an "uncanny valley"-a phenomenon in which highly humanlike entities provoke aversion in human observers-has lead some to caution against this practice. Both of these contrasting perspectives on the anthropomorphic design of social robots find some support in empirical investigations to date. Yet, owing to outstanding empirical limitations and theoretical disputes, the uncanny valley and its implications for human-robot interaction remains poorly understood. We thus explored the relationship between human similarity and people's aversion toward humanlike robots via manipulation of the agents' appearances. To that end, we employed a picture-viewing task ( N agents = 60) to conduct an experimental test ( N participants = 72) of the uncanny valley's existence and the visual features that cause certain humanlike robots to be unnerving. Across the levels of human similarity, we further manipulated agent appearance on two dimensions, typicality (prototypic, atypical, and ambiguous) and agent identity (robot, person), and measured participants' aversion using both subjective and behavioral indices. Our findings were as follows: (1) Further substantiating its existence, the data show a clear and consistent uncanny valley in the current design space of humanoid robots. (2) Both category ambiguity, and more so, atypicalities provoke aversive responding, thus shedding light on the visual factors that drive people's discomfort. (3) Use of the Negative Attitudes toward Robots Scale did not reveal any significant relationships between people's pre-existing attitudes toward humanlike robots and their aversive responding-suggesting positive exposure and/or additional experience with robots is unlikely to affect the occurrence of an uncanny valley effect in humanoid robotics. This work furthers

  8. Economic assessment of flood forecasts for a risk-averse decision-maker

    Science.gov (United States)

    Matte, Simon; Boucher, Marie-Amélie; Boucher, Vincent; Fortier-Filion, Thomas-Charles

    2017-04-01

    A large effort has been made over the past 10 years to promote the operational use of probabilistic or ensemble streamflow forecasts. It has also been suggested in past studies that ensemble forecasts might possess a greater economic value than deterministic forecasts. However, the vast majority of recent hydro-economic literature is based on the cost-loss ratio framework, which might be appealing for its simplicity and intuitiveness. One important drawback of the cost-loss ratio is that it implicitly assumes a risk-neutral decision maker. By definition, a risk-neutral individual is indifferent to forecasts' sharpness: as long as forecasts agree with observations on average, the risk-neutral individual is satisfied. A risk-averse individual, however, is sensitive to the level of precision (sharpness) of forecasts. This person is willing to pay to increase his or her certainty about future events. In fact, this is how insurance companies operate: the probability of seeing one's house burn down is relatively low, so the expected cost related to such event is also low. However, people are willing to buy insurance to avoid the risk, however small, of loosing everything. Similarly, in a context where people's safety and property is at stake, the typical decision maker is more risk-averse than risk-neutral. Consequently, the cost-loss ratio is not the most appropriate tool to assess the economic value of flood forecasts. This presentation describes a more realistic framework for assessing the economic value of such forecasts for flood mitigation purposes. Borrowing from economics, the Constant Absolute Risk Aversion utility function (CARA) is the central tool of this new framework. Utility functions allow explicitly accounting for the level of risk aversion of the decision maker and fully exploiting the information related to ensemble forecasts' uncertainty. Three concurrent ensemble streamflow forecasting systems are compared in terms of quality (comparison with

  9. Brain-derived neurotrophic factor into adult neocortex strengthens a taste aversion memory.

    Science.gov (United States)

    Martínez-Moreno, Araceli; Rodríguez-Durán, Luis F; Escobar, Martha L

    2016-01-15

    Nowadays, it is known that brain derived neurotrophic-factor (BDNF) is a protein critically involved in regulating long-term memory related mechanisms. Previous studies from our group in the insular cortex (IC), a brain structure of the temporal lobe implicated in acquisition, consolidation and retention of conditioned taste aversion (CTA), demonstrated that BDNF is essential for CTA consolidation. Recent studies show that BDNF-TrkB signaling is able to mediate the enhancement of memory. However, whether BDNF into neocortex is able to enhance aversive memories remains unexplored. In the present work, we administrated BDNF in a concentration capable of inducing in vivo neocortical LTP, into the IC immediately after CTA acquisition in two different conditions: a "strong-CTA" induced by 0.2M lithium chloride i.p. as unconditioned stimulus, and a "weak-CTA" induced by 0.1M lithium chloride i.p. Our results show that infusion of BDNF into the IC converts a weak CTA into a strong one, in a TrkB receptor-dependent manner. The present data suggest that BDNF into the adult insular cortex is sufficient to increase an aversive memory-trace. Copyright © 2015 Elsevier B.V. All rights reserved.

  10. Response to palatability after area postrema lesions: a result of learned aversions.

    Science.gov (United States)

    Tomoyasu, N; Kenney, N J

    1989-11-01

    The role of palatability, novelty, and food aversion in determining changes of food choice after ablation of the area postrema and caudal-medial aspect of the nucleus of the solitary tract (AP/cmNTS) is examined through a series of studies utilizing 24-h, two-food choice tests. On test days, the food that the animal has ingested since the time of lesioning or sham surgery is presented along with a novel food that varies in palatability. The results indicate that postlesion diet history is the major determinant of food choice by lesioned rats. Lesioned rats consistently take less of their familiar postlesion food than diet-matched controls, suggesting that the lesioned rats have developed an aversion to that food. Over-ingestion of the novel food may occur, but this outcome is not reliable. No indication that the animals' response to food palatability is affected by AP/cmNTS ablation was found. Learned aversion to a food ingested after AP/cmNTS ablation may account not only for changes of food preference after the lesion but also may be involved in the hypophagia and weight loss resulting from the ablation.

  11. Risk-Averse Suppliers’ Optimal Pricing Strategies in a Two-Stage Supply Chain

    Directory of Open Access Journals (Sweden)

    Rui Shen

    2013-01-01

    Full Text Available Risk-averse suppliers’ optimal pricing strategies in two-stage supply chains under competitive environment are discussed. The suppliers in this paper focus more on losses as compared to profits, and they care their long-term relationship with their customers. We introduce for the suppliers a loss function, which covers both current loss and future loss. The optimal wholesale price is solved under situations of risk neutral, risk averse, and a combination of minimizing loss and controlling risk, respectively. Besides, some properties of and relations among these optimal wholesale prices are given as well. A numerical example is given to illustrate the performance of the proposed method.

  12. Boundary Conditions for the Maintenance of Memory by PKM[zeta] in Neocortex

    Science.gov (United States)

    Shema, Reul; Hazvi, Shoshi; Sacktor, Todd C.; Dudai, Yadin

    2009-01-01

    We report here that ZIP, a selective inhibitor of the atypical protein kinase C isoform PKM[zeta], abolishes very long-term conditioned taste aversion (CTA) associations in the insular cortex of the behaving rat, at least 3 mo after encoding. The effect of ZIP is not replicated by a general serine/threonine protein kinase inhibitor that is…

  13. Modeling OPEC behavior: theories of risk aversion for oil producer decisions

    International Nuclear Information System (INIS)

    Reynolds, D.B.

    1999-01-01

    Theories of OPEC such as price leadership, cartel, or game theoretic models suggest an incentive for OPEC members to expand their production capacity well above current levels in order to maximize revenues. Yet individual OPEC members consistently explore for and develop oil fields at a level well below their potential. The cause of low oil exploration and development efforts among OPEC members, and even some non-OPEC members, may have to do with risk aversion. This paper describes an alternative theory for OPEC behavior based on risk aversion using a two piece non-Neumann-Morgenstern utility function similar to Fishburn and Koehenberger (1979, Decision Science 10, 503-518), and Friedman and Savage (1948, Journal of political Economy 56). The model shows possible low oil production behavior. (author)

  14. Intrahousehold Allocation of Nutrients in Rural India: Are Boys Favored? Do Parents Exhibit Inequality Aversion?

    OpenAIRE

    Behrman, Jere R

    1988-01-01

    This paper develops a multinutrient input, multihealth related outcome model of intrahousehold nutrient allocation that permits identification of gender preferences and equity-productivity tradeoffs. Estimates for rural South India suggest that parents display male preference during the lean season, particularly in lower-caste households. Parents also exhibit inequality aversion so pure investment models may be misleading, though such inequality aversion is less in the lean season than estima...

  15. Optimal fuel-mix in CHP plants under a stochastic permit price. Risk-neutrality versus risk-aversion

    International Nuclear Information System (INIS)

    Lappi, Pauli; Ollikka, Kimmo; Ollikainen, Markku

    2010-01-01

    This paper studies the optimal fuel-mix of a CHP producer under emission permit price risk. The producer's multi-fuel plant uses two CO 2 -intensive fuels and one clean fuel. Using a mean-variance framework we develop three models. The models are divided into spot-models (risk neutral and risk averse cases) and a forward-model (risk averse case). We derive the effects of price risk on optimal fuel use. An increase in price risk can in fact increase the use of CO 2 -intensive fuel in the spot-model. In the forward-model, the production and financial decisions are separate. We also evaluate the risk-bearing behavior of seven Finnish CHP producers. We found that risk-neutrality describes behavior better than risk-aversion. (author)

  16. Predicting Cancer-Prevention Behavior: Disentangling the Effects of Risk Aversion and Risk Perceptions.

    Science.gov (United States)

    Riddel, Mary; Hales, David

    2018-05-16

    Experimental and survey research spanning the last two decades concludes that people who are more risk tolerant are more likely to engage in risky health activities such as smoking and heavy alcohol consumption, and are more likely to be obese. Subjective perceptions of the risk associated with different activities have also been found to be associated with health behaviors. While there are numerous studies that link risk perceptions with risky behavior, it is notable that none of these controls for risk aversion. Similarly, studies that control for risk aversion fail to control for risk misperceptions. We use a survey of 474 men and women to investigate the influence of risk aversion, risk misperceptions, and cognitive ability on the choice to engage in behaviors that either increase or mitigate cancer risk. We measure optimism in two dimensions: baseline optimists are those who inaccurately believe their cancer risk to be below its expert-assessed level, while control optimists are those who believe they can reduce their risk of cancer (by changing their lifestyle choices) to a greater extent than is actually the case. Our results indicate that baseline optimism is significantly and negatively correlated with subjects' tendencies to engage in cancer-risk-reducing behaviors, and positively correlated with risky behaviors. Subjects' control misperceptions also appear to play a role in their tendency to engage in risky and prevention behaviors. When controlling for both of these types of risk misperception, risk aversion plays a much smaller role in determining health behaviors than found in past studies. © 2018 Society for Risk Analysis.

  17. Selecting for memory? The influence of selective attention on the mnemonic binding of contextual information

    Science.gov (United States)

    Uncapher, Melina R.; Rugg, Michael D.

    2009-01-01

    Not all of what is experienced is remembered later. Behavioral evidence suggests that the manner in which an event is processed influences which aspects of the event will later be remembered. The present experiment investigated the neural correlates of ‘selective encoding’, or the mechanisms that support the encoding of some elements of an event in preference to others. Event-related functional magnetic resonance imaging (fMRI) data were acquired while volunteers selectively attended to one of two different contextual features of study items (color or location). A surprise memory test for the items and both contextual features was subsequently administered to determine the influence of selective attention on the neural correlates of contextual encoding. Activity in several cortical regions indexed later memory success selectively for color or location information, and this encoding-related activity was enhanced by selective attention to the relevant feature. Critically, a region in the hippocampus responded selectively to attended source information (whether color or location), demonstrating encoding-related activity for attended but not for nonattended source features. Together, the findings suggest that selective attention modulates the magnitude of activity in cortical regions engaged by different aspects of an event, and hippocampal encoding mechanisms seem to be sensitive to this modulation. Thus, the information that is encoded into a memory representation is biased by selective attention, and this bias is mediated by cortico-hippocampal interactions. PMID:19553466

  18. Mechanisms of attention for appetitive and aversive outcomes in Pavlovian conditioning.

    Science.gov (United States)

    Austin, A J; Duka, T

    2010-11-12

    Different mechanisms of attention controlling learning have been proposed in appetitive and aversive conditioning. The aim of the present study was to compare attention and learning in a Pavlovian conditioning paradigm using visual stimuli of varying predictive value of either monetary reward (appetitive conditioning; 10p or 50p) or blast of white noise (aversive conditioning; 97 dB or 102 dB). Outcome values were matched across the two conditions with regard to their emotional significance. Sixty-four participants were allocated to one of the four conditions matched for age and gender. All participants underwent a discriminative learning task using pairs of visual stimuli that signalled a 100%, 50%, or 0% probability of receiving an outcome. Learning was measured using a 9-point Likert scale of expectancy of the outcome, while attention using an eyetracker device. Arousal and emotional conditioning were also evaluated. Dwell time was greatest for the full predictor in the noise groups, while in the money groups attention was greatest for the partial predictor over the other two predictors. The progression of learning was the same for both groups. These findings suggest that in aversive conditioning attention is driven by the predictive salience of the stimulus while in appetitive conditioning attention is error-driven, when emotional value of the outcome is comparable. (c) 2010 Elsevier B.V. All rights reserved.

  19. Role of PKA signaling in D2 receptor-expressing neurons in the core of the nucleus accumbens in aversive learning.

    Science.gov (United States)

    Yamaguchi, Takashi; Goto, Akihiro; Nakahara, Ichiro; Yawata, Satoshi; Hikida, Takatoshi; Matsuda, Michiyuki; Funabiki, Kazuo; Nakanishi, Shigetada

    2015-09-08

    The nucleus accumbens (NAc) serves as a key neural substrate for aversive learning and consists of two distinct subpopulations of medium-sized spiny neurons (MSNs). The MSNs of the direct pathway (dMSNs) and the indirect pathway (iMSNs) predominantly express dopamine (DA) D1 and D2 receptors, respectively, and are positively and negatively modulated by DA transmitters via Gs- and Gi-coupled cAMP-dependent protein kinase A (PKA) signaling cascades, respectively. In this investigation, we addressed how intracellular PKA signaling is involved in aversive learning in a cell type-specific manner. When the transmission of either dMSNs or iMSNs was unilaterally blocked by pathway-specific expression of transmission-blocking tetanus toxin, infusion of PKA inhibitors into the intact side of the NAc core abolished passive avoidance learning toward an electric shock in the indirect pathway-blocked mice, but not in the direct pathway-blocked mice. We then examined temporal changes in PKA activity in dMSNs and iMSNs in behaving mice by monitoring Förster resonance energy transfer responses of the PKA biosensor with the aid of microendoscopy. PKA activity was increased in iMSNs and decreased in dMSNs in both aversive memory formation and retrieval. Importantly, the increased PKA activity in iMSNs disappeared when aversive memory was prevented by keeping mice in the conditioning apparatus. Furthermore, the increase in PKA activity in iMSNs by aversive stimuli reflected facilitation of aversive memory retention. These results indicate that PKA signaling in iMSNs plays a critical role in both aversive memory formation and retention.

  20. Identification of flap structure-specific endonuclease 1 as a factor involved in long-term memory formation of aversive learning.

    Science.gov (United States)

    Saavedra-Rodríguez, Lorena; Vázquez, Adrinel; Ortiz-Zuazaga, Humberto G; Chorna, Nataliya E; González, Fernando A; Andrés, Lissette; Rodríguez, Karen; Ramírez, Fernando; Rodríguez, Alan; Peña de Ortiz, Sandra

    2009-05-06

    We previously proposed that DNA recombination/repair processes play a role in memory formation. Here, we examined the possible role of the fen-1 gene, encoding a flap structure-specific endonuclease, in memory consolidation of conditioned taste aversion (CTA). Quantitative real-time PCR showed that amygdalar fen-1 mRNA induction was associated to the central processing of the illness experience related to CTA and to CTA itself, but not to the central processing resulting from the presentation of a novel flavor. CTA also increased expression of the Fen-1 protein in the amygdala, but not the insular cortex. In addition, double immunofluorescence analyses showed that amygdalar Fen-1 expression is mostly localized within neurons. Importantly, functional studies demonstrated that amygdalar antisense knockdown of fen-1 expression impaired consolidation, but not short-term memory, of CTA. Overall, these studies define the fen-1 endonuclease as a new DNA recombination/repair factor involved in the formation of long-term memories.

  1. Good luck, bad luck, and ambiguity aversion

    OpenAIRE

    Briony D. Pulford; Poonam Gill

    2014-01-01

    We report a series of experiments investigating the influence of feeling lucky or unlucky on people's choice of known-risk or ambiguous options using the traditional Ellsberg Urns decision-making task. We induced a state of feeling lucky or unlucky in subjects by using a rigged wheel-of-fortune game, which just missed either the bankrupt or the jackpot outcome. In the first experiment a large reversal of the usual ambiguity aversion effect was shown, indicating that feeling ...

  2. Inflation Aversion and the Optimal Inflation Tax

    OpenAIRE

    Gaowang Wang; Heng-fu Zou

    2011-01-01

    The optimal inflation tax is reexamined in the framework of dynamic second best economy populated by individuals with inflation aversion. A simple formula for the optimal inflation rate is derived. Different from the literature, it is shown that if the marginal excess burden of other distorting taxes approaches zero, Friedman's rule for optimum quantity of money is not optimal, and the optimal inflation tax is negative; if the marginal excess burden of other taxes is nonzero, the optimal infl...

  3. Effects of dose and of partial body ionizing radiation on taste aversion learning in rats with lesions of the area postrema

    International Nuclear Information System (INIS)

    Rabin, B.M.; Hunt, W.A.; Lee, J.

    1984-01-01

    The effect of area postrema lesions on the acquisition of a conditioned taste aversion following partial body exposure to ionizing radiation was investigated in rats exposed to head-only irradiation at 100, 200 and 300 rad or to body-only irradiation at 100 and 200 rad. Following head-only irradiation area postrema lesions produced a significant attenuation of the radiation-induced taste aversion at all dose levels, although the rats still showed a significant reduction in sucrose preference. Following body-only exposure, area postrema lesions completely disrupted the acquisition of the conditioned taste aversion. The results are interpreted as indicating that: (a) the acquisition of a conditioned taste aversion following body-only exposure is mediated by the area postrema; and (b) taste aversion learning following radiation exposure to the head-only is mediated by both the area postrema and a mechanism which is independent of the area postrema

  4. Cisplatin-Induced Conditioned Taste Aversion: Attenuation by Dexamethasone but not Zacopride or GR38032F

    Science.gov (United States)

    1992-01-01

    SR2-1 Cisplatin-induced conditioned taste aversion: ateuto by dexamethasone but not zacopride or GR38032F Nm I- Paul C Mele, John R. McDonough, David...to 5-H1’, receptor blockade. 5-HT., receptor antagonists; Zacopridc: GR38032F; Desamethasone: Cisplatin: Taste aversion (conditioned) I. Introductlon...intake) was used as the area known as the chemoreceptor trigger zone (Borri- index of the CTA. son, 1974). Moreover. the findings that rats, ferrets

  5. Effects of dividing attention during encoding on perceptual priming of unfamiliar visual objects

    Science.gov (United States)

    Soldan, Anja; Mangels, Jennifer A.; Cooper, Lynn A.

    2008-01-01

    According to the distractor-selection hypothesis (Mulligan, 2003), dividing attention during encoding reduces perceptual priming when responses to non-critical (i.e., distractor) stimuli are selected frequently and simultaneously with critical stimulus encoding. Because direct support for this hypothesis comes exclusively from studies using familiar word stimuli, the present study tested whether the predictions of the distractor-selection hypothesis extend to perceptual priming of unfamiliar visual objects using the possible/impossible object-decision test. Consistent with the distractor-selection hypothesis, Experiments 1 and 2 found no reduction in priming when the non-critical stimuli were presented infrequently and non-synchronously with the critical target stimuli, even though explicit recognition memory was reduced. In Experiment 3, non-critical stimuli were presented frequently and simultaneously during encoding of critical stimuli; however, no decrement in priming was detected, even when encoding time was reduced. These results suggest that priming in the possible/impossible object-decision test is relatively immune to reductions in central attention and that not all aspects of the distractor-selection hypothesis generalize to priming of unfamiliar visual objects. Implications for theoretical models of object-decision priming are discussed. PMID:18821167

  6. Individual differences in aversion to ambiguity regarding medical tests and treatments: association with cancer screening cognitions.

    Science.gov (United States)

    Han, Paul K J; Williams, Andrew E; Haskins, Amy; Gutheil, Caitlin; Lucas, F Lee; Klein, William M P; Mazor, Kathleen M

    2014-12-01

    Aversion to "ambiguity"-uncertainty about the reliability, credibility, or adequacy of information-about medical tests and treatments is an important psychological response that varies among individuals, but little is known about its nature and extent. The purpose of this study was to examine how individual-level ambiguity aversion relates to important health cognitions related to different cancer screening tests. A survey of 1,074 adults, ages 40 to 70 years, was conducted in four integrated U.S. healthcare systems. The Ambiguity Aversion in Medicine (AA-Med) scale, a measure of individual differences in aversion to ambiguity (AA) about medical tests and treatments, was administered along with measures of several cancer screening-related cognitions: perceived benefits and harms of colonoscopy, mammography, and PSA screening, and ambivalence and future intentions regarding these tests. Multivariable analyses were conducted to assess the associations between AA-Med scores and cancer screening cognitions. Individual-level AA as assessed by the AA-Med scale was significantly associated (P ambiguity. Individual-level AA constitutes a measurable, wide-ranging cognitive bias against medical intervention, and more research is needed to elucidate its mechanisms and effects. ©2014 American Association for Cancer Research.

  7. Risk-averse formulations and methods for a virtual power plant

    KAUST Repository

    Lima, Ricardo M.; Conejo, Antonio J.; Langodan, Sabique; Hoteit, Ibrahim; Knio, Omar M.

    2017-01-01

    In this paper we address the optimal operation of a virtual power plant using stochastic programming. We consider one risk-neutral and two risk-averse formulations that rely on the conditional value at risk. To handle large-scale problems, we implement two decomposition methods with variants using single- and multiple-cuts. We propose the utilization of wind ensembles obtained from the European Centre for Medium Range Weather Forecasts (ECMWF) to quantify the uncertainty of the wind forecast. We present detailed results relative to the computational performance of the risk-averse formulations, the decomposition methods, and risk management and sensitivities analysis as a function of the number of scenarios and risk parameters. The implementation of the two decomposition methods relies on the parallel solution of subproblems, which turns out to be paramount for computational efficiency. The results show that one of the two decomposition methods is the most efficient.

  8. Risk-averse formulations and methods for a virtual power plant

    KAUST Repository

    Lima, Ricardo M.

    2017-12-15

    In this paper we address the optimal operation of a virtual power plant using stochastic programming. We consider one risk-neutral and two risk-averse formulations that rely on the conditional value at risk. To handle large-scale problems, we implement two decomposition methods with variants using single- and multiple-cuts. We propose the utilization of wind ensembles obtained from the European Centre for Medium Range Weather Forecasts (ECMWF) to quantify the uncertainty of the wind forecast. We present detailed results relative to the computational performance of the risk-averse formulations, the decomposition methods, and risk management and sensitivities analysis as a function of the number of scenarios and risk parameters. The implementation of the two decomposition methods relies on the parallel solution of subproblems, which turns out to be paramount for computational efficiency. The results show that one of the two decomposition methods is the most efficient.

  9. Effect of risk aversion on prioritizing conservation projects.

    Science.gov (United States)

    Tulloch, Ayesha I T; Maloney, Richard F; Joseph, Liana N; Bennett, Joseph R; Di Fonzo, Martina M I; Probert, William J M; O'Connor, Shaun M; Densem, Jodie P; Possingham, Hugh P

    2015-04-01

    Conservation outcomes are uncertain. Agencies making decisions about what threat mitigation actions to take to save which species frequently face the dilemma of whether to invest in actions with high probability of success and guaranteed benefits or to choose projects with a greater risk of failure that might provide higher benefits if they succeed. The answer to this dilemma lies in the decision maker's aversion to risk--their unwillingness to accept uncertain outcomes. Little guidance exists on how risk preferences affect conservation investment priorities. Using a prioritization approach based on cost effectiveness, we compared 2 approaches: a conservative probability threshold approach that excludes investment in projects with a risk of management failure greater than a fixed level, and a variance-discounting heuristic used in economics that explicitly accounts for risk tolerance and the probabilities of management success and failure. We applied both approaches to prioritizing projects for 700 of New Zealand's threatened species across 8303 management actions. Both decision makers' risk tolerance and our choice of approach to dealing with risk preferences drove the prioritization solution (i.e., the species selected for management). Use of a probability threshold minimized uncertainty, but more expensive projects were selected than with variance discounting, which maximized expected benefits by selecting the management of species with higher extinction risk and higher conservation value. Explicitly incorporating risk preferences within the decision making process reduced the number of species expected to be safe from extinction because lower risk tolerance resulted in more species being excluded from management, but the approach allowed decision makers to choose a level of acceptable risk that fit with their ability to accommodate failure. We argue for transparency in risk tolerance and recommend that decision makers accept risk in an adaptive management

  10. The Aversive Agent Lithium Chloride Suppresses Phasic Dopamine Release Through Central GLP-1 Receptors.

    Science.gov (United States)

    Fortin, Samantha M; Chartoff, Elena H; Roitman, Mitchell F

    2016-02-01

    Unconditioned rewarding stimuli evoke phasic increases in dopamine concentration in the nucleus accumbens (NAc) while discrete aversive stimuli elicit pauses in dopamine neuron firing and reductions in NAc dopamine concentration. The unconditioned effects of more prolonged aversive states on dopamine release dynamics are not well understood and are investigated here using the malaise-inducing agent lithium chloride (LiCl). We used fast-scan cyclic voltammetry to measure phasic increases in NAc dopamine resulting from electrical stimulation of dopamine cell bodies in the ventral tegmental area (VTA). Systemic LiCl injection reduced electrically evoked dopamine release in the NAc of both anesthetized and awake rats. As some behavioral effects of LiCl appear to be mediated through glucagon-like peptide-1 receptor (GLP-1R) activation, we hypothesized that the suppression of phasic dopamine by LiCl is GLP-1R dependent. Indeed, peripheral pretreatment with the GLP-1R antagonist exendin-9 (Ex-9) potently attenuated the LiCl-induced suppression of dopamine. Pretreatment with Ex-9 did not, however, affect the suppression of phasic dopamine release by the kappa-opioid receptor agonist, salvinorin A, supporting a selective effect of GLP-1R stimulation in LiCl-induced dopamine suppression. By delivering Ex-9 to either the lateral or fourth ventricle, we highlight a population of central GLP-1 receptors rostral to the hindbrain that are involved in the LiCl-mediated suppression of NAc dopamine release.

  11. The Effect of Swimming Experience on Acquisition and Retention of Swimming-Based Taste Aversion Learning in Rats

    Science.gov (United States)

    Masaki, Takahisa; Nakajima, Sadahiko

    2010-01-01

    Swimming endows rats with an aversion to a taste solution consumed before swimming. The present study explored whether the experience of swimming before or after the taste-swimming trials interferes with swimming-based taste aversion learning. Experiment 1 demonstrated that a single preexposure to 20 min of swimming was as effective as four or…

  12. Voting over Selective Immigration Policies with Immigration Aversion

    OpenAIRE

    Giuseppe Russo

    2011-01-01

    The claim that "skilled immigration is welcome" is often associated to the increasing adoption of selective immigration policies. I study the voting over differentiated immigration policies in a two-country, three-factor general equilibrium model where there exist skilled and unskilled workers, migration decisions are endogenous, enforcing immigration restriction is costly, and natives dislike unskilled immigration. According to my findings, decisions over border closure are made to protect t...

  13. Differential involvement of cortical muscarinic and NMDA receptors in short- and long-term taste aversion memory.

    Science.gov (United States)

    Ferreira, G; Gutiérrez, R; De La Cruz, V; Bermúdez-Rattoni, F

    2002-09-01

    In conditioned taste aversion, an animal avoids a taste previously associated with toxic effects, and this aversive memory formation requires an intact insular cortex. In this paper, we investigated the possible differential involvement of cholinergic and glutamatergic receptors in the insular cortex in short-term memory (STM) and long-term memory (LTM) of taste aversion in rats. Taste aversion was induced by intraperitoneal administration of lithium chloride (a malaise-inducing drug) 15 min after experience with an unfamiliar taste. In order to test STM and LTM of taste aversion, taste stimulus was again presented 4 h and 72 h after lithium injection, respectively. During the acquisition, microinjection of the muscarinic antagonist, scopolamine, in the insular cortex before, but not after, the presentation of the new taste, abolished STM as well as LTM. Blockade of the NMDA receptor, in the insular cortex, by AP5 before, but not after, the presentation of the taste stimulus, impaired LTM but left STM intact. Moreover, when injected 1 h after malaise induction (i.e., during taste-illness association), AP5 disrupted both STM and LTM. These results suggest that activation of muscarinic receptors in the insular cortex is involved in the acquisition of taste memory, whereas NMDA receptors participate in taste memory consolidation. These data demonstrate that different neurochemical mechanisms subserve different memory phases. NMDA receptors are also probably involved in processing the visceral input, thus allowing subsequent taste-illness association. This indicates that in the same cortical area the same neurotransmitter system can be involved in distinct processes: taste memory consolidation vs. taste-illness association.

  14. Studies on the role of central histamine in the acquisition of a radiation-induced conditioned taste aversion

    International Nuclear Information System (INIS)

    Rabin, B.M.; Hunt, W.A.; Lee, J.

    1982-01-01

    The experiments described in this report were designed to test two hypotheses about how exposure to low-level radiation can affect the behavior of an organism: first, tht radiation effects on behavior are mediated by a radiation-induced release of histamine; and second, that this radiation-induced histamine release can exert relatively direct effects on the central nervous system. The results of the first experiment showed that microinjection of histamine directly into the fourth ventricle of rats produced a taste aversion to a novel sucrose solution. Pretreating rats with intraventricular H 1 or H 2 blockers was not effective in preventing the acquisition of the radiation-induced aversion, although the H 1 blocker did prevent the acquisition of a histamine-induced taste aversion. It also was not possible to establish a cross-tolerance between centrally administered histamine and radiation. The results are interpreted as not supporting the hypothesis that a radiation-induced release of central histamine mediates the acquisition of a conditioned taste aversion following exposure to low-level radiation

  15. Quantifying uncertainty in pest risk maps and assessments: adopting a risk-averse decision maker’s perspective

    Directory of Open Access Journals (Sweden)

    Denys Yemshanov

    2013-09-01

    Full Text Available Pest risk maps are important decision support tools when devising strategies to minimize introductions of invasive organisms and mitigate their impacts. When possible management responses to an invader include costly or socially sensitive activities, decision-makers tend to follow a more certain (i.e., risk-averse course of action. We presented a new mapping technique that assesses pest invasion risk from the perspective of a risk-averse decision maker.We demonstrated the method by evaluating the likelihood that an invasive forest pest will be transported to one of the U.S. states or Canadian provinces in infested firewood by visitors to U.S. federal campgrounds. We tested the impact of the risk aversion assumption using distributions of plausible pest arrival scenarios generated with a geographically explicit model developed from data documenting camper travel across the study area. Next, we prioritized regions of high and low pest arrival risk via application of two stochastic ordering techniques that employed, respectively, first- and second-degree stochastic dominance rules, the latter of which incorporated the notion of risk aversion. We then identified regions in the study area where the pest risk value changed considerably after incorporating risk aversion.While both methods identified similar areas of highest and lowest risk, they differed in how they demarcated moderate-risk areas. In general, the second-order stochastic dominance method assigned lower risk rankings to moderate-risk areas. Overall, this new method offers a better strategy to deal with the uncertainty typically associated with risk assessments and provides a tractable way to incorporate decision-making preferences into final risk estimates, and thus helps to better align these estimates with particular decision-making scenarios about a pest organism of concern. Incorporation of risk aversion also helps prioritize the set of locations to target for inspections and

  16. Learning context modulates aversive taste strength in honey bees.

    Science.gov (United States)

    de Brito Sanchez, Maria Gabriela; Serre, Marion; Avarguès-Weber, Aurore; Dyer, Adrian G; Giurfa, Martin

    2015-03-01

    The capacity of honey bees (Apis mellifera) to detect bitter substances is controversial because they ingest without reluctance different kinds of bitter solutions in the laboratory, whereas free-flying bees avoid them in visual discrimination tasks. Here, we asked whether the gustatory perception of bees changes with the behavioral context so that tastes that are less effective as negative reinforcements in a given context become more effective in a different context. We trained bees to discriminate an odorant paired with 1 mol l(-1) sucrose solution from another odorant paired with either distilled water, 3 mol l(-1) NaCl or 60 mmol l(-1) quinine. Training was either Pavlovian [olfactory conditioning of the proboscis extension reflex (PER) in harnessed bees], or mainly operant (olfactory conditioning of free-walking bees in a Y-maze). PER-trained and maze-trained bees were subsequently tested both in their original context and in the alternative context. Whereas PER-trained bees transferred their choice to the Y-maze situation, Y-maze-trained bees did not respond with a PER to odors when subsequently harnessed. In both conditioning protocols, NaCl and distilled water were the strongest and the weakest aversive reinforcement, respectively. A significant variation was found for quinine, which had an intermediate aversive effect in PER conditioning but a more powerful effect in the Y-maze, similar to that of NaCl. These results thus show that the aversive strength of quinine varies with the learning context, and reveal the plasticity of the bee's gustatory system. We discuss the experimental constraints of both learning contexts and focus on stress as a key modulator of taste in the honey bee. Further explorations of bee taste are proposed to understand the physiology of taste modulation in bees. © 2015. Published by The Company of Biologists Ltd.

  17. Correlations of self-esteem and intolerance of ambiguity with risk aversion.

    Science.gov (United States)

    Johanson, J C

    2000-10-01

    The current paper reports for 80 undergraduates that risk aversion is greater among those with lower self-esteem scores on Rosenberg's Self-esteem Scale and those with higher scores on Budner's Intolerance of Ambiguity Scale.

  18. Optimal fuel-mix in CHP plants under a stochastic permit price. Risk-neutrality versus risk-aversion

    Energy Technology Data Exchange (ETDEWEB)

    Lappi, Pauli; Ollikka, Kimmo; Ollikainen, Markku [Department of Economics and Management, P.O. Box 27, University of Helsinki, FIN-00014 Helsinki (Finland)

    2010-02-15

    This paper studies the optimal fuel-mix of a CHP producer under emission permit price risk. The producer's multi-fuel plant uses two CO{sub 2}-intensive fuels and one clean fuel. Using a mean-variance framework we develop three models. The models are divided into spot-models (risk neutral and risk averse cases) and a forward-model (risk averse case). We derive the effects of price risk on optimal fuel use. An increase in price risk can in fact increase the use of CO{sub 2}-intensive fuel in the spot-model. In the forward-model, the production and financial decisions are separate. We also evaluate the risk-bearing behavior of seven Finnish CHP producers. We found that risk-neutrality describes behavior better than risk-aversion. (author)

  19. Optimal fuel-mix in CHP plants under a stochastic permit price: Risk-neutrality versus risk-aversion

    Energy Technology Data Exchange (ETDEWEB)

    Lappi, Pauli, E-mail: pauli.lappi@helsinki.f [Department of Economics and Management, P.O. Box 27, University of Helsinki, FIN-00014 Helsinki (Finland); Ollikka, Kimmo, E-mail: kimmo.ollikka@helsinki.f [Department of Economics and Management, P.O. Box 27, University of Helsinki, FIN-00014 Helsinki (Finland); Ollikainen, Markku, E-mail: markku.ollikainen@helsinki.f [Department of Economics and Management, P.O. Box 27, University of Helsinki, FIN-00014 Helsinki (Finland)

    2010-02-15

    This paper studies the optimal fuel-mix of a CHP producer under emission permit price risk. The producer's multi-fuel plant uses two CO{sub 2}-intensive fuels and one clean fuel. Using a mean-variance framework we develop three models. The models are divided into spot-models (risk neutral and risk averse cases) and a forward-model (risk averse case). We derive the effects of price risk on optimal fuel use. An increase in price risk can in fact increase the use of CO{sub 2}-intensive fuel in the spot-model. In the forward-model, the production and financial decisions are separate. We also evaluate the risk-bearing behavior of seven Finnish CHP producers. We found that risk-neutrality describes behavior better than risk-aversion.

  20. On the genetics of loss aversion: An interaction effect of BDNF Val66Met and DRD2/ANKK1 Taq1a.

    Science.gov (United States)

    Voigt, Gesine; Montag, Christian; Markett, Sebastian; Reuter, Martin

    2015-12-01

    Loss aversion is the tendency to overweight losses compared with gains in decision situations. Several studies have investigated the neurobiological background of this phenomenon and it was found that activation in the mesolimbic-mesocortical dopamine system during a gambling decision correlates with loss aversion. In a behavioral experiment with N = 143 subjects, the present study investigates the influence of 2 functional single-nucleotide polymorphisms on the BDNF gene (BDNF Val66Met polymorphism) and ANKK1 gene (DRD2 Taq1a/ANKK1 polymorphism), that are known to affect the dopamine system, on loss aversion. Additionally, associations of alexithymia, a personality construct describing the disability to consciously experience emotions in the self, with loss aversion and with the mentioned polymorphisms were assessed using the TAS-20 questionnaire, to replicate associations that have been reported before. Results revealed a significant interaction effect of the 2 polymorphisms on loss aversion. Carriers of the genetic constellation 66Met+/A1+ had the lowest loss aversion scores, compared with all other allelic groups. According to the literature this allelic configuration is characterized by a relatively low D2/3 receptor binding in the striatum and an impaired activity-dependent secretion of BDNF. This is the first study showing that loss aversion is related to naturally occurring differences in dopamine function. (c) 2015 APA, all rights reserved).

  1. Aversion to ambiguity and willingness to take risks affect therapeutic decisions in managing atrial fibrillation for stroke prevention: results of a pilot study in family physicians.

    Science.gov (United States)

    Raptis, Stavroula; Chen, Jia Ning; Saposnik, Florencia; Pelyavskyy, Roman; Liuni, Andrew; Saposnik, Gustavo

    2017-01-01

    Anticoagulation is the therapeutic paradigm for stroke prevention in patients with atrial fibrillation (AF). It is unknown how physicians make treatment decisions in primary stroke prevention for patients with AF. To evaluate the association between family physicians' risk preferences (aversion risk and ambiguity) and therapeutic recommendations (anticoagulation) in the management of AF for primary stroke prevention by applying concepts from behavioral economics. Overall, 73 family physicians participated and completed the study. Our study comprised seven simulated case vignettes, three behavioral experiments, and two validated surveys. Behavioral experiments and surveys incorporated an economic framework to determine risk preferences and biases (e.g., ambiguity aversion, willingness to take risks). The primary outcome was making the correct decision of anticoagulation therapy. Secondary outcomes included medical errors in the management of AF for stroke prevention. Overall, 23.3% (17/73) of the family physicians elected not to escalate the therapy from antiplatelets to anticoagulation when recommended by best practice guidelines. A total of 67.1% of physicians selected the correct therapeutic options in two or more of the three simulated case vignettes. Multivariate analysis showed that aversion to ambiguity was associated with appropriate change to anticoagulation therapy in the management of AF (OR 5.48, 95% CI 1.08-27.85). Physicians' willingness to take individual risk in multiple domains was associated with lower errors (OR 0.16, 95% CI 0.03-0.86). Physicians' aversion to ambiguity and willingness to take risks are associated with appropriate therapeutic decisions in the management of AF for primary stroke prevention. Further large scale studies are needed.

  2. Dorsal hippocampal NMDA receptor blockade impairs extinction of naloxone-precipitated conditioned place aversion in acute morphine-treated rats by suppressing ERK and CREB phosphorylation in the basolateral amygdala.

    Science.gov (United States)

    Wang, Wei-Sheng; Chen, Zhong-Guo; Liu, Wen-Tao; Chi, Zhi-Qiang; He, Ling; Liu, Jing-Gen

    2015-01-01

    Substantial evidence shows that negative reinforcement resulting from the aversive affective consequences of opiate withdrawal may play a crucial role in drug relapse. Understanding the mechanisms underlying the loss (extinction) of conditioned aversion of drug withdrawal could facilitate the treatment of drug addiction. Naloxone-induced conditioned place aversion (CPA) of Sprague-Dawley rats was used to measure conditioned aversion. An NMDA receptor antagonist and MAPK kinase inhibitor were applied through intracranial injections. The phosphorylation of ERK and cAMP response element-binding protein (CREB) was detected using Western blot. The extinction of CPA behaviour increased the phosphorylation of ERK and CREB in the dorsal hippocampus (DH) and basolateral amygdala (BLA), but not in the central amygdala (CeA). Intra-DH injection of AP5 or intra-BLA injection of AP-5 or U0126 before extinction training significantly attenuated ERK and CREB phosphorylation in the BLA and impaired the extinction of CPA behaviour. Although intra-DH injections of AP-5 attenuated extinction training-induced activation of the ERK-CREB pathway in the BLA, intra-BLA injection of AP5 had no effect on extinction training-induced activation of the ERK-CREB pathway in the DH. These results suggest that activation of ERK and CREB in the BLA and DH is involved in the extinction of CPA behaviour and that the DH, via a direct or indirect pathway, modulates the activity of ERK and CREB in the BLA through activation of NMDA receptors after extinction training. Understanding the mechanisms underlying the extinction of conditioned aversion could facilitate the treatment of drug addiction. This article is part of a themed section on Opioids: New Pathways to Functional Selectivity. To view the other articles in this section visit http://dx.doi.org/10.1111/bph.2015.172.issue-2. © 2014 The British Pharmacological Society.

  3. Extraordinarily Adaptive Properties of the Genetically Encoded Amino Acids

    Science.gov (United States)

    Ilardo, Melissa; Meringer, Markus; Freeland, Stephen; Rasulev, Bakhtiyor; Cleaves II, H. James

    2015-01-01

    Using novel advances in computational chemistry, we demonstrate that the set of 20 genetically encoded amino acids, used nearly universally to construct all coded terrestrial proteins, has been highly influenced by natural selection. We defined an adaptive set of amino acids as one whose members thoroughly cover relevant physico-chemical properties, or “chemistry space.” Using this metric, we compared the encoded amino acid alphabet to random sets of amino acids. These random sets were drawn from a computationally generated compound library containing 1913 alternative amino acids that lie within the molecular weight range of the encoded amino acids. Sets that cover chemistry space better than the genetically encoded alphabet are extremely rare and energetically costly. Further analysis of more adaptive sets reveals common features and anomalies, and we explore their implications for synthetic biology. We present these computations as evidence that the set of 20 amino acids found within the standard genetic code is the result of considerable natural selection. The amino acids used for constructing coded proteins may represent a largely global optimum, such that any aqueous biochemistry would use a very similar set. PMID:25802223

  4. Extraordinarily adaptive properties of the genetically encoded amino acids.

    Science.gov (United States)

    Ilardo, Melissa; Meringer, Markus; Freeland, Stephen; Rasulev, Bakhtiyor; Cleaves, H James

    2015-03-24

    Using novel advances in computational chemistry, we demonstrate that the set of 20 genetically encoded amino acids, used nearly universally to construct all coded terrestrial proteins, has been highly influenced by natural selection. We defined an adaptive set of amino acids as one whose members thoroughly cover relevant physico-chemical properties, or "chemistry space." Using this metric, we compared the encoded amino acid alphabet to random sets of amino acids. These random sets were drawn from a computationally generated compound library containing 1913 alternative amino acids that lie within the molecular weight range of the encoded amino acids. Sets that cover chemistry space better than the genetically encoded alphabet are extremely rare and energetically costly. Further analysis of more adaptive sets reveals common features and anomalies, and we explore their implications for synthetic biology. We present these computations as evidence that the set of 20 amino acids found within the standard genetic code is the result of considerable natural selection. The amino acids used for constructing coded proteins may represent a largely global optimum, such that any aqueous biochemistry would use a very similar set.

  5. Multimethod Behavioral Treatment of Long-Term Selective Mutism.

    Science.gov (United States)

    Watson, T. Steuart; Kramer, Jack J.

    1992-01-01

    Conducted single-subject, experimental research to examine efficacy of treating severe, long-term selective mutism in nine-year-old male using shaping, multiple reinforcers, natural consequences, stimulus fading, and mild aversives. Implemented different treatment regimens in home and school environments. Home intervention resulted in increase in…

  6. Algorithm aversion: people erroneously avoid algorithms after seeing them err.

    Science.gov (United States)

    Dietvorst, Berkeley J; Simmons, Joseph P; Massey, Cade

    2015-02-01

    Research shows that evidence-based algorithms more accurately predict the future than do human forecasters. Yet when forecasters are deciding whether to use a human forecaster or a statistical algorithm, they often choose the human forecaster. This phenomenon, which we call algorithm aversion, is costly, and it is important to understand its causes. We show that people are especially averse to algorithmic forecasters after seeing them perform, even when they see them outperform a human forecaster. This is because people more quickly lose confidence in algorithmic than human forecasters after seeing them make the same mistake. In 5 studies, participants either saw an algorithm make forecasts, a human make forecasts, both, or neither. They then decided whether to tie their incentives to the future predictions of the algorithm or the human. Participants who saw the algorithm perform were less confident in it, and less likely to choose it over an inferior human forecaster. This was true even among those who saw the algorithm outperform the human.

  7. Forward conditioning with wheel running causes place aversion in rats.

    Science.gov (United States)

    Masaki, Takahisa; Nakajima, Sadahiko

    2008-09-01

    Backward pairings of a distinctive chamber as a conditioned stimulus and wheel running as an unconditioned stimulus (i.e., running-then-chamber) can produce a conditioned place preference in rats. The present study explored whether a forward conditioning procedure with these stimuli (i.e., chamber-then-running) would yield place preference or aversion. Confinement of a rat in one of two distinctive chambers was followed by a 20- or 60-min running opportunity, but confinement in the other was not. After four repetitions of this treatment (i.e., differential conditioning), a choice preference test was given in which the rat had free access to both chambers. This choice test showed that the rats given 60-min running opportunities spent less time in the running-paired chamber than in the unpaired chamber. Namely, a 60-min running opportunity after confinement in a distinctive chamber caused conditioned aversion to that chamber after four paired trials. This result was discussed with regard to the opponent-process theory of motivation.

  8. Does ambiguity aversion influence the framing effect during decision making?

    Science.gov (United States)

    Osmont, Anaïs; Cassotti, Mathieu; Agogué, Marine; Houdé, Olivier; Moutier, Sylvain

    2015-04-01

    Decision-makers present a systematic tendency to avoid ambiguous options for which the level of risk is unknown. This ambiguity aversion is one of the most striking decision-making biases. Given that human choices strongly depend on the options' presentation, the purpose of the present study was to examine whether ambiguity aversion influences the framing effect during decision making. We designed a new financial decision-making task involving the manipulation of both frame and uncertainty levels. Thirty-seven participants had to choose between a sure option and a gamble depicting either clear or ambiguous probabilities. The results revealed a clear preference for the sure option in the ambiguity condition regardless of frame. However, participants presented a framing effect in both the risk and ambiguity conditions. Indeed, the framing effect was bidirectional in the risk condition and unidirectional in the ambiguity condition given that it did not involve preference reversal but only a more extreme choice tendency.

  9. Effects of kappa opioid receptors on conditioned place aversion and social interaction in males and females

    Science.gov (United States)

    Robles, Cindee F.; McMackin, Marissa Z.; Campi, Katharine L.; Doig, Ian E.; Takahashi, Elizabeth Y.; Pride, Michael; Trainor, Brian C.

    2014-01-01

    The effects of kappa opioid receptors (KOR) on motivated behavior are well established based on studies in male rodents, but relatively little is known about the effects of KOR in females. We examined the effects of KOR activation on conditioned place aversion and social interaction in the California mouse (Peromyscus californicus). Important differences were observed in long-term (place aversion) and short-term (social interaction) effects. Females but not males treated with a 2.5mg/kg dose of U50,488 formed a place aversion, whereas males but not females formed a place aversion at the 10 mg/kg dose. In contrast the short term effects of different doses of U50,488 on social interaction behavior were similar in males and females. Acute injection with 10 mg/kg of U50,488 (but not lower doses) reduced social interaction behavior in both males and females. The effects of U50,488 on phosphorylated extracellular signal regulated kinase (pERK) and p38 MAP kinase were cell type and region specific. Higher doses of U50,488 increased the number of pERK neurons in the ventrolateral bed nucleus of the stria terminals in males but not females, a nucleus implicated in male aggressive behavior. In contrast, both males and females treated with U50,488 had more activated p38 cells in the nucleus accumbens shell. Unexpectedly, cells expressing activated p38 co-expressed Iba-1, a widely used microglia marker. In summary we found strong sex differences in the effects of U50,488 on place aversion whereas the acute effects on U50,488 induced similar behavioral effects in males and females. PMID:24445073

  10. Aversive Learning and Appetitive Motivation Toggle Feed-Forward Inhibition in the Drosophila Mushroom Body.

    Science.gov (United States)

    Perisse, Emmanuel; Owald, David; Barnstedt, Oliver; Talbot, Clifford B; Huetteroth, Wolf; Waddell, Scott

    2016-06-01

    In Drosophila, negatively reinforcing dopaminergic neurons also provide the inhibitory control of satiety over appetitive memory expression. Here we show that aversive learning causes a persistent depression of the conditioned odor drive to two downstream feed-forward inhibitory GABAergic interneurons of the mushroom body, called MVP2, or mushroom body output neuron (MBON)-γ1pedc>α/β. However, MVP2 neuron output is only essential for expression of short-term aversive memory. Stimulating MVP2 neurons preferentially inhibits the odor-evoked activity of avoidance-directing MBONs and odor-driven avoidance behavior, whereas their inhibition enhances odor avoidance. In contrast, odor-evoked activity of MVP2 neurons is elevated in hungry flies, and their feed-forward inhibition is required for expression of appetitive memory at all times. Moreover, imposing MVP2 activity promotes inappropriate appetitive memory expression in food-satiated flies. Aversive learning and appetitive motivation therefore toggle alternate modes of a common feed-forward inhibitory MVP2 pathway to promote conditioned odor avoidance or approach. Copyright © 2016 The Author(s). Published by Elsevier Inc. All rights reserved.

  11. Temporal limits of selection and memory encoding: A comparison of whole versus partial report in rapid serial visual presentation.

    Science.gov (United States)

    Nieuwenstein, Mark R; Potter, Mary C

    2006-06-01

    People often fail to recall the second of two visual targets presented within 500 ms in rapid serial visual presentation (RSVP). This effect is called the attentional blink. One explanation of the attentional blink is that processes involved in encoding the first target into memory are slow and capacity limited. Here, however, we show that the attentional blink should be ascribed to attentional selection, not consolidation of the first target. Rapid sequences of six letters were presented, and observers had to report either all the letters (whole-report condition) or a subset of the letters (partial-report condition). Selection in partial report was based on color (e.g., report the two red letters) or identity (i.e., report all letters from a particular letter onward). In both cases, recall of letters presented shortly after the first selected letter was impaired, whereas recall of the corresponding letters was relatively accurate with whole report.

  12. Acute infusion of brain-derived neurotrophic factor in the insular cortex promotes conditioned taste aversion extinction.

    Science.gov (United States)

    Rodríguez-Serrano, Luis M; Ramírez-León, Betsabee; Rodríguez-Durán, Luis F; Escobar, Martha L

    2014-12-01

    Brain-derived neurotrophic factor (BDNF) has emerged as one of the most potent molecular mediators not only for synaptic plasticity, but also for the behavioral organism-environment interactions. Our previous studies in the insular cortex (IC), a neocortical region that has been related with acquisition and retention of conditioned taste aversion (CTA), have demonstrated that intracortical microinfusion of BDNF induces a lasting potentiation of synaptic efficacy in the basolateral amygdaloid nucleus (Bla)-IC projection and enhances the retention of CTA memory of adult rats in vivo. The aim of the present study was to analyze whether acute BDNF-infusion in the IC modifies the extinction of CTA. Accordingly, animals were trained in the CTA task and received bilateral IC microinfusions of BDNF before extinction training. Our results showed that taste aversion was significantly reduced in BDNF rats from the first extinction trial. Additionally, we found that the effect of BDNF on taste aversion did not require extinction training. Finally we showed that the BDNF effect does not degrade the original taste aversion memory trace. These results emphasize that BDNF activity underlies memory extinction in neocortical areas and support the idea that BDNF is a key regulator and mediator of long-term synaptic modifications. Copyright © 2014 Elsevier Inc. All rights reserved.

  13. Dopamine Regulates Aversive Contextual Learning and Associated In Vivo Synaptic Plasticity in the Hippocampus

    Directory of Open Access Journals (Sweden)

    John I. Broussard

    2016-03-01

    Full Text Available Dopamine release during reward-driven behaviors influences synaptic plasticity. However, dopamine innervation and release in the hippocampus and its role during aversive behaviors are controversial. Here, we show that in vivo hippocampal synaptic plasticity in the CA3-CA1 circuit underlies contextual learning during inhibitory avoidance (IA training. Immunohistochemistry and molecular techniques verified sparse dopaminergic innervation of the hippocampus from the midbrain. The long-term synaptic potentiation (LTP underlying the learning of IA was assessed with a D1-like dopamine receptor agonist or antagonist in ex vivo hippocampal slices and in vivo in freely moving mice. Inhibition of D1-like dopamine receptors impaired memory of the IA task and prevented the training-induced enhancement of both ex vivo and in vivo LTP induction. The results indicate that dopamine-receptor signaling during an aversive contextual task regulates aversive memory retention and regulates associated synaptic mechanisms in the hippocampus that likely underlie learning.

  14. Artificial theta stimulation impairs encoding of contextual fear memory.

    Directory of Open Access Journals (Sweden)

    Arto Lipponen

    Full Text Available Several experiments have demonstrated an intimate relationship between hippocampal theta rhythm (4-12 Hz and memory. Lesioning the medial septum or fimbria-fornix, a fiber track connecting the hippocampus and the medial septum, abolishes the theta rhythm and results in a severe impairment in declarative memory. To assess whether there is a causal relationship between hippocampal theta and memory formation we investigated whether restoration of hippocampal theta by electrical stimulation during the encoding phase also restores fimbria-fornix lesion induced memory deficit in rats in the fear conditioning paradigm. Male Wistar rats underwent sham or fimbria-fornix lesion operation. Stimulation electrodes were implanted in the ventral hippocampal commissure and recording electrodes in the septal hippocampus. Artificial theta stimulation of 8 Hz was delivered during 3-min free exploration of the test cage in half of the rats before aversive conditioning with three foot shocks during 2 min. Memory was assessed by total freezing time in the same environment 24 h and 28 h after fear conditioning, and in an intervening test session in a different context. As expected, fimbria-fornix lesion impaired fear memory and dramatically attenuated hippocampal theta power. Artificial theta stimulation produced continuous theta oscillations that were almost similar to endogenous theta rhythm in amplitude and frequency. However, contrary to our predictions, artificial theta stimulation impaired conditioned fear response in both sham and fimbria-fornix lesioned animals. These data suggest that restoration of theta oscillation per se is not sufficient to support memory encoding after fimbria-fornix lesion and that universal theta oscillation in the hippocampus with a fixed frequency may actually impair memory.

  15. Sudden-Death Aversion: Avoiding Superior Options Because They Feel Riskier.

    Science.gov (United States)

    Walker, Jesse; Risen, Jane L; Gilovich, Thomas; Thaler, Richard

    2018-01-15

    We present evidence of sudden-death aversion (SDA)-the tendency to avoid "fast" strategies that provide a greater chance of success, but include the possibility of immediate defeat, in favor of "slow" strategies that reduce the possibility of losing quickly, but have lower odds of ultimate success. Using a combination of archival analyses and controlled experiments, we explore the psychology behind SDA. First, we provide evidence for SDA and its cost to decision makers by tabulating how often NFL teams send games into overtime by kicking an extra point rather than going for the 2-point conversion (Study 1) and how often NBA teams attempt potentially game-tying 2-point shots rather than potentially game-winning 3-pointers (Study 2). To confirm that SDA is not limited to sports, we demonstrate SDA in a military scenario (Study 3). We then explore two mechanisms that contribute to SDA: myopic loss aversion and concerns about "tempting fate." Studies 4 and 5 show that SDA is due, in part, to myopic loss aversion, such that decision makers narrow the decision frame, paying attention to the prospect of immediate loss with the "fast" strategy, but not the downstream consequences of the "slow" strategy. Study 6 finds that people are more pessimistic about a risky strategy that needn't be pursued (opting for sudden death) than the same strategy that must be pursued. We end by discussing how these twin mechanisms lead to differential expectations of blame from the self and others, and how SDA influences decisions in several different walks of life. (PsycINFO Database Record (c) 2018 APA, all rights reserved).

  16. Discrete Serotonin Systems Mediate Memory Enhancement and Escape Latencies after Unpredicted Aversive Experience in Drosophila Place Memory

    Directory of Open Access Journals (Sweden)

    Divya Sitaraman

    2017-12-01

    Full Text Available Feedback mechanisms in operant learning are critical for animals to increase reward or reduce punishment. However, not all conditions have a behavior that can readily resolve an event. Animals must then try out different behaviors to better their situation through outcome learning. This form of learning allows for novel solutions and with positive experience can lead to unexpected behavioral routines. Learned helplessness, as a type of outcome learning, manifests in part as increases in escape latency in the face of repeated unpredicted shocks. Little is known about the mechanisms of outcome learning. When fruit fly Drosophilamelanogaster are exposed to unpredicted high temperatures in a place learning paradigm, flies both increase escape latencies and have a higher memory when given control of a place/temperature contingency. Here we describe discrete serotonin neuronal circuits that mediate aversive reinforcement, escape latencies, and memory levels after place learning in the presence and absence of unexpected aversive events. The results show that two features of learned helplessness depend on the same modulatory system as aversive reinforcement. Moreover, changes in aversive reinforcement and escape latency depend on local neural circuit modulation, while memory enhancement requires larger modulation of multiple behavioral control circuits.

  17. Sensory-specific associations stored in the lateral amygdala allow for selective alteration of fear memories.

    Science.gov (United States)

    Díaz-Mataix, Lorenzo; Debiec, Jacek; LeDoux, Joseph E; Doyère, Valérie

    2011-06-29

    Consolidated long-term fear memories become labile and can be disrupted after being reactivated by the presentation of the unconditioned stimulus (US). Whether this is due to an alteration of the conditioned stimulus (CS) representation in the lateral amygdala (LA) is not known. Here, we show in rats that fear memory reactivation through presentation of the aversive US, like CS presentation, triggers a process which, when disrupted, results in a selective depotentiation of CS-evoked neural responses in the LA in correlation with a selective suppression of CS-elicited fear memory. Thus, an aversive US triggers the reconsolidation of its associated predictor representation in LA. This new finding suggests that sensory-specific associations are stored in the lateral amygdala, allowing for their selective alteration by either element of the association.

  18. Induction of latent memory for conditioned food aversion and its transformation into "active" state depend on translation and transcription processes.

    Science.gov (United States)

    Solntseva, S V; Nikitin, V P

    2014-05-01

    Mechanisms of induction and retrieval of latent (hidden) memory for conditioned food aversion were investigated in snails. After initial training (single combination of a food stimulus with electric shock), aversive reactions to presentation of the conditioned food stimulus were not revealed. Repeated presentation of the stimuli in 12 days after the first combination was followed by the appearance of aversive food reactions that persisted for at least 14 days. Injections of inhibitors of protein (cycloheximide) or RNA (α-amanitin) synthesis immediately after the first or second combined presentation of the stimuli disturbed skill performance. We hypothesized that single combination of food and reinforcing stimuli led to translation- and transcription-dependent induction of latent conditioned food aversion memory. Transformation of this memory into an active state after repeated presentation of the stimulus combination also depends on the synthesis of new proteins and RNA.

  19. Reward salience and risk aversion underlie differential ACC activity in substance dependence.

    Science.gov (United States)

    Alexander, William H; Fukunaga, Rena; Finn, Peter; Brown, Joshua W

    2015-01-01

    The medial prefrontal cortex, especially the dorsal anterior cingulate cortex (ACC), has long been implicated in cognitive control and error processing. Although the association between ACC and behavior has been established, it is less clear how ACC contributes to dysfunctional behavior such as substance dependence. Evidence from neuroimaging studies investigating ACC function in substance users is mixed, with some studies showing disengagement of ACC in substance dependent individuals (SDs), while others show increased ACC activity related to substance use. In this study, we investigate ACC function in SDs and healthy individuals performing a change signal task for monetary rewards. Using a priori predictions derived from a recent computational model of ACC, we find that ACC activity differs between SDs and controls in factors related to reward salience and risk aversion between SDs and healthy individuals. Quantitative fits of a computational model to fMRI data reveal significant differences in best fit parameters for reward salience and risk preferences. Specifically, the ACC in SDs shows greater risk aversion, defined as concavity in the utility function, and greater attention to rewards relative to reward omission. Furthermore, across participants risk aversion and reward salience are positively correlated. The results clarify the role that ACC plays in both the reduced sensitivity to omitted rewards and greater reward valuation in SDs. Clinical implications of applying computational modeling in psychiatry are also discussed.

  20. LINKING GABAA RECEPTOR SUBUNITS TO ALCOHOL-INDUCED CONDITIONED TASTE AVERSION AND RECOVERY FROM ACUTE ALCOHOL INTOXICATION

    Science.gov (United States)

    Blednov, Y.A.; Benavidez, J.M.; Black, M.; Chandra, D.; Homanics, G.E.; Rudolph, U.; Harris, R.A.

    2012-01-01

    GABA type A receptors (GABAA-R) are important for ethanol actions and it is of interest to link individual subunits with specific ethanol behaviors. We studied null mutant mice for six different GABAA-R subunits (α1, α2, α3, α4, α5 and δ). Only mice lacking the α2 subunit showed reduction of conditioned taste aversion (CTA) to ethanol. These results are in agreement with data from knock-in mice with mutation of the ethanol-sensitive site in the α2-subunit (Blednov et al., 2011) and indicate this aversive property of ethanol is dependent on ethanol action on α2-containing GABAA-R. Deletion of the α2-subunit led to faster recovery whereas absence of the α3-subunit slowed recovery from ethanol-induced incoordination (rotarod). Deletion of the other four subunits did not affect this behavior. Similar changes in this behavior for the α2 and α3 null mutants were found for flurazepam motor-incoordination. However, no differences in recovery were found in motor-incoordinating effects of an α1-selective modulator (zolpidem) or an α4-selective agonist (gaboxadol). Therefore, recovery of rotarod incoordination is under control of two GABAA-R subunits: α2 and α3. For motor activity, α3 null mice demonstrated higher activation by ethanol (1 g/kg) whereas both α2 and α3 (-/-) knockout mice were less sensitive to ethanol-induced reduction of motor activity (1.5 g/kg). These studies demonstrate that the effects of ethanol at GABAergic synapses containing α2 subunit are important for specific behavioral effects of ethanol which may be relevant to the genetic linkage of the α2 subunit with human alcoholism. PMID:23147414

  1. Playing it safe but losing anyway--serotonergic signaling of negative outcomes in dorsomedial prefrontal cortex in the context of risk-aversion.

    Science.gov (United States)

    Macoveanu, Julian; Rowe, James B; Hornboll, Bettina; Elliott, Rebecca; Paulson, Olaf B; Knudsen, Gitte M; Siebner, Hartwig R

    2013-08-01

    Risk avoidance is an important determinant of human behavior. The neurotransmitter serotonin has been implicated in processing negative outcomes caused by risky decisions. However, it is unclear whether serotonin provides a neurobiological link between making a risk aversive decision and the response to a negative outcome. Using pharmacological fMRI, we manipulated the availability of serotonin in healthy volunteers while performing a gambling task. The same group of participants was studied in three fMRI sessions: (i) during intravenous administration of the SSRI citalopram to increase the serotonergic tone, (ii) after acute tryptophan depletion (ATD) to reduce central serotonin levels, or (iii) without interventions. ATD and citalopram had opposite effects on outcome related activity in dorsomedial prefrontal cortex (dmPFC) and amygdala. Relative to the control condition, ATD increased and citalopram decreased the neural response to negative outcomes in dmPFC. Conversely, ATD decreased and citalopram increased the neural response to negative outcomes in left amygdala. Critically, these pharmacological effects were restricted to negative outcomes that were caused by low-risk decisions and led to a high missed reward. ATD and citalopram did not alter the neural response to positive outcomes in dmPFC, but relative to ATD, citalopram produced a bilateral increase in the amygdala response to large wins caused by high-risk choices. The results show a selective involvement of the serotonergic system in neocortical processing of negative outcomes resulting from risk-averse decisions, thereby linking risk aversion and processing of negative outcomes in goal-directed behaviors. Copyright © 2012 Elsevier B.V. and ECNP. All rights reserved.

  2. Extreme expansion of NBS-encoding genes in Rosaceae.

    Science.gov (United States)

    Jia, YanXiao; Yuan, Yang; Zhang, Yanchun; Yang, Sihai; Zhang, Xiaohui

    2015-05-03

    Nucleotide binding site leucine-rich repeats (NBS-LRR) genes encode a large class of disease resistance (R) proteins in plants. Extensive studies have been carried out to identify and investigate NBS-encoding gene families in many important plant species. However, no comprehensive research into NBS-encoding genes in the Rosaceae has been performed. In this study, five whole-genome sequenced Rosaceae species, including apple, pear, peach, mei, and strawberry, were analyzed to investigate the evolutionary pattern of NBS-encoding genes and to compare them to those of three Cucurbitaceae species, cucumber, melon, and watermelon. Considerable differences in the copy number of NBS-encoding genes were observed between Cucurbitaceae and Rosaceae species. In Rosaceae species, a large number and a high proportion of NBS-encoding genes were observed in peach (437, 1.52%), mei (475, 1.51%), strawberry (346, 1.05%) and pear (617, 1.44%), and apple contained a whopping 1303 (2.05%) NBS-encoding genes, which might be the highest number of R-genes in all of these reported diploid plant. However, no more than 100 NBS-encoding genes were identified in Cucurbitaceae. Many more species-specific gene families were classified and detected with the signature of positive selection in Rosaceae species, especially in the apple genome. Taken together, our findings indicate that NBS-encoding genes in Rosaceae, especially in apple, have undergone extreme expansion and rapid adaptive evolution. Useful information was provided for further research on the evolutionary mode of disease resistance genes in Rosaceae crops.

  3. Dorsal medial prefrontal cortex contributes to conditioned taste aversion memory consolidation and retrieval.

    Science.gov (United States)

    Gonzalez, Maria Carolina; Villar, Maria Eugenia; Igaz, Lionel M; Viola, Haydée; Medina, Jorge H

    2015-12-01

    The medial prefrontal cortex (mPFC) is known for its role in decision making and memory processing, including the participation in the formation of extinction memories. However, little is known regarding its contribution to aversive memory consolidation. Here we demonstrate that neural activity and protein synthesis are required in the dorsal mPFC for memory formation of a conditioned taste aversion (CTA) task and that this region is involved in the retrieval of recent and remote long-term CTA memory. In addition, both NMDA receptor and CaMKII activity in dorsal mPFC are needed for CTA memory consolidation, highlighting the complexity of mPFC functions. Copyright © 2015 Elsevier Inc. All rights reserved.

  4. The Commonality of Loss Aversion across Procedures and Stimuli.

    Science.gov (United States)

    Lee, Sang; Lee, Myung J; Kim, Byoung W; Gilman, Jodi M; Kuster, John K; Blood, Anne J; Kuhnen, Camelia M; Breiter, Hans C

    2015-01-01

    Individuals tend to give losses approximately 2-fold the weight that they give gains. Such approximations of loss aversion (LA) are almost always measured in the stimulus domain of money, rather than objects or pictures. Recent work on preference-based decision-making with a schedule-less keypress task (relative preference theory, RPT) has provided a mathematical formulation for LA similar to that in prospect theory (PT), but makes no parametric assumptions in the computation of LA, uses a variable tied to communication theory (i.e., the Shannon entropy or information), and works readily with non-monetary stimuli. We evaluated if these distinct frameworks described similar LA in healthy subjects, and found that LA during the anticipation phase of the PT-based task correlated significantly with LA related to the RPT-based task. Given the ease with which non-monetary stimuli can be used on the Internet, or in animal studies, these findings open an extensive range of applications for the study of loss aversion. Furthermore, the emergence of methodology that can be used to measure preference for both social stimuli and money brings a common framework to the evaluation of preference in both social psychology and behavioral economics.

  5. SnoVault and encodeD: A novel object-based storage system and applications to ENCODE metadata.

    Directory of Open Access Journals (Sweden)

    Benjamin C Hitz

    Full Text Available The Encyclopedia of DNA elements (ENCODE project is an ongoing collaborative effort to create a comprehensive catalog of functional elements initiated shortly after the completion of the Human Genome Project. The current database exceeds 6500 experiments across more than 450 cell lines and tissues using a wide array of experimental techniques to study the chromatin structure, regulatory and transcriptional landscape of the H. sapiens and M. musculus genomes. All ENCODE experimental data, metadata, and associated computational analyses are submitted to the ENCODE Data Coordination Center (DCC for validation, tracking, storage, unified processing, and distribution to community resources and the scientific community. As the volume of data increases, the identification and organization of experimental details becomes increasingly intricate and demands careful curation. The ENCODE DCC has created a general purpose software system, known as SnoVault, that supports metadata and file submission, a database used for metadata storage, web pages for displaying the metadata and a robust API for querying the metadata. The software is fully open-source, code and installation instructions can be found at: http://github.com/ENCODE-DCC/snovault/ (for the generic database and http://github.com/ENCODE-DCC/encoded/ to store genomic data in the manner of ENCODE. The core database engine, SnoVault (which is completely independent of ENCODE, genomic data, or bioinformatic data has been released as a separate Python package.

  6. Impact of appetitive and aversive outcomes on brain responses: Linking the animal and human literatures

    Directory of Open Access Journals (Sweden)

    Gregory B Bissonette

    2014-03-01

    Full Text Available Decision-making is motivated by the possibility of obtaining reward and/or avoiding punishment. Though many have investigated behavior associated with appetitive or aversive outcomes, few have examined behaviors that rely on both. Fewer still have addressed questions related to how anticipated appetitive and aversive outcomes interact to alter neural signals related to expected value, motivation, and salience. Here we review recent rodent, monkey, and human research that address these issues. Further development of this area will be fundamental to understanding the etiology behind human psychiatric diseases and cultivating more effective treatments.

  7. The involvement of CRF1 receptor within the basolateral amygdala and dentate gyrus in the naloxone-induced conditioned place aversion in morphine-dependent mice.

    Science.gov (United States)

    Valero, E; Gómez-Milanés, I; Almela, P; Ribeiro Do Couto, B; Laorden, M L; Milanés, M V; Núñez, C

    2018-06-08

    Drug withdrawal-associated aversive memories trigger relapse to drug-seeking behavior. Corticotrophin-releasing factor (CRF) is an important mediator of the reinforcing properties of drugs of abuse. However, the involvement of CRF1 receptor (CRF1R) in aversive memory induced by opiate withdrawal has yet to be elucidated. We used the conditioned-place aversion (CPA) paradigm to evaluate the role of CRF1R on opiate withdrawal memory acquisition, along with plasticity-related processes that occur after CPA within the basolateral amygdala (BLA) and dentate gyrus (DG). Male mice were rendered dependent on morphine and injected acutely with naloxone before paired to confinement in a naloxone-associated compartment. The CPA scores as well as the number of TH-positive neurons (in the NTS-A2 noradrenergic cell group), and the expression of the transcription factors Arc and pCREB (in the BLA and DG) were measured with and without CRF1R blockade. Mice subjected to conditioned naloxone-induced morphine withdrawal robustly expressed CPA. Pre-treatment with the selective CRF1R antagonist CP-154,526 before naloxone conditioning session impaired morphine withdrawal-induced aversive memory acquisition. CP-154,526 also antagonized the enhanced number of TH-positive neurons in the NTS-A2 that was seen after CPA. Increased Arc expression and Arc-pCREB co-localization were seen in the BLA after CPA, which was not modified by CP-154,526. In the DG, CPA was accompanied by a decrease of Arc expression and no changes in Arc-pCREB co-localization, whereas pre-treatment with CP-154,526 induced an increase in both parameters. These results indicate that CRF-CRF1R pathway could be a critical factor governing opiate withdrawal memory storage and retrieval and might suggest a role for TH-NA pathway in the effects of withdrawal on memory. Our results might indicate that the blockade of CRF1R could represent a promising pharmacological treatment strategy approach for the attenuation of the relapse

  8. Ethanol-induced conditioned taste avoidance: reward or aversion?

    Science.gov (United States)

    Liu, Chuang; Showalter, John; Grigson, Patricia Sue

    2009-03-01

    Rats avoid intake of a palatable taste cue when paired with all drugs of abuse tested. Evidence suggests that, at least for morphine and cocaine, rats avoid the taste cue because they are anticipating the rewarding properties of the drug. Thus, the suppressive effects of a rewarding sucrose solution and cocaine, but not those of the putatively aversive agent, lithium chloride (LiCl), are exaggerated in drug-sensitive Lewis rats. Likewise, the suppressive effects of sucrose and morphine, but not those of LiCl, are eliminated by bilateral lesions of the gustatory thalamus. Unlike morphine and cocaine, it is less clear whether rewarding or aversive drug properties are responsible for ethanol-induced suppression of intake of a taste cue. The present set of studies tests whether, like cocaine, ethanol-induced suppression of intake of a taste cue also is greater in the drug-sensitive Lewis rats and whether the suppressive effects of the drug are prevented by bilateral lesions of the taste thalamus. In Experiment 1, fluid-deprived Lewis and Fischer rats were given 5-minute access to 0.15% saccharin and then injected with saline or a range of doses of ethanol (0.5, 0.75, 1.0, or 1.5 g/kg). There was a total of 6 such pairings. In Experiments 2 and 3, Sprague-Dawley rats received bilateral electrophysiologically guided lesions of the gustatory thalamus. After recovery, suppression of intake of the saccharin cue was evaluated following repeated daily pairings with either a high (1.5 g/kg) or a low (0.75 g/kg) dose of ethanol. Ethanol-induced suppression of intake of the saccharin conditioned stimulus (CS) did not differ between the drug-sensitive Lewis rats relative to the less-sensitive Fischer rats. Lesions of the taste thalamus, however, prevented the suppressive effect of the 0.75 g/kg dose of the drug, but had no impact on the suppressive effect of the 1.5 g/kg dose of ethanol. The results suggest that the suppressive effects of ethanol on CS intake are mediated by both

  9. Risk aversion and willingness to pay for energy efficient systems in rental apartments

    Energy Technology Data Exchange (ETDEWEB)

    Farsi, Mehdi [Centre for Energy Policy and Economics, ETH Zurich, Zuerichbergstr. 18, Zurich 8032 (Switzerland)

    2010-06-15

    This paper uses a random utility model to estimate consumers' valuation of energy efficient insulation and ventilation systems in rental apartments. Given consumers' limited experience in residential buildings and the perceived uncertainty about their comfort benefits and resulting energy savings, these relatively new technologies might be undervalued by risk-averse consumers. Using the concept of certainty-equivalence, this paper proposes a model to assess the consumers' risk-aversion for adopting energy-efficient systems. These systems are treated as risky assets while conventional commodities are assumed to be risk-free. The curvature of the utility function is interpreted as a measure of aversion to perceived risks as opposed to explicit risks measured by observed variances. The proposed formulation is applicable in stated preference data with qualitative variables. The model is applied to data from a choice experiment conducted among 264 apartment tenants in Switzerland. The estimated curvatures reject the risk-neutrality hypothesis. The range of the estimated risk premiums suggests that risk considerations remain a central issue in dealing with energy efficiency in residential buildings. The analysis also indicates that assuming same risk attitudes toward new and conventional systems could bias the estimates of the willingness to pay, especially when the system is comprised of several components. (author)

  10. Risk aversion and willingness to pay for energy efficient systems in rental apartments

    International Nuclear Information System (INIS)

    Farsi, Mehdi

    2010-01-01

    This paper uses a random utility model to estimate consumers' valuation of energy efficient insulation and ventilation systems in rental apartments. Given consumers' limited experience in residential buildings and the perceived uncertainty about their comfort benefits and resulting energy savings, these relatively new technologies might be undervalued by risk-averse consumers. Using the concept of certainty-equivalence, this paper proposes a model to assess the consumers' risk-aversion for adopting energy-efficient systems. These systems are treated as risky assets while conventional commodities are assumed to be risk-free. The curvature of the utility function is interpreted as a measure of aversion to perceived risks as opposed to explicit risks measured by observed variances. The proposed formulation is applicable in stated preference data with qualitative variables. The model is applied to data from a choice experiment conducted among 264 apartment tenants in Switzerland. The estimated curvatures reject the risk-neutrality hypothesis. The range of the estimated risk premiums suggests that risk considerations remain a central issue in dealing with energy efficiency in residential buildings. The analysis also indicates that assuming same risk attitudes toward new and conventional systems could bias the estimates of the willingness to pay, especially when the system is comprised of several components.

  11. Roles of octopaminergic and dopaminergic neurons in appetitive and aversive memory recall in an insect.

    Science.gov (United States)

    Mizunami, Makoto; Unoki, Sae; Mori, Yasuhiro; Hirashima, Daisuke; Hatano, Ai; Matsumoto, Yukihisa

    2009-08-04

    In insect classical conditioning, octopamine (the invertebrate counterpart of noradrenaline) or dopamine has been suggested to mediate reinforcing properties of appetitive or aversive unconditioned stimulus, respectively. However, the roles of octopaminergic and dopaminergic neurons in memory recall have remained unclear. We studied the roles of octopaminergic and dopaminergic neurons in appetitive and aversive memory recall in olfactory and visual conditioning in crickets. We found that pharmacological blockade of octopamine and dopamine receptors impaired aversive memory recall and appetitive memory recall, respectively, thereby suggesting that activation of octopaminergic and dopaminergic neurons and the resulting release of octopamine and dopamine are needed for appetitive and aversive memory recall, respectively. On the basis of this finding, we propose a new model in which it is assumed that two types of synaptic connections are formed by conditioning and are activated during memory recall, one type being connections from neurons representing conditioned stimulus to neurons inducing conditioned response and the other being connections from neurons representing conditioned stimulus to octopaminergic or dopaminergic neurons representing appetitive or aversive unconditioned stimulus, respectively. The former is called 'stimulus-response connection' and the latter is called 'stimulus-stimulus connection' by theorists studying classical conditioning in higher vertebrates. Our model predicts that pharmacological blockade of octopamine or dopamine receptors during the first stage of second-order conditioning does not impair second-order conditioning, because it impairs the formation of the stimulus-response connection but not the stimulus-stimulus connection. The results of our study with a cross-modal second-order conditioning were in full accordance with this prediction. We suggest that insect classical conditioning involves the formation of two kinds of memory

  12. Mean-Preserving-Spread Risk Aversion and The CAPM

    OpenAIRE

    Phelim P. Boyle; Chenghu Ma

    2013-01-01

    This paper establishes conditions under which the classical CAPM holds in equilibrium. Our derivation uses simple arguments to clarify and extend results available in the literature. We show that if agents are risk averse in the sense of mean-preserving-spread (MPS) the CAPM will necessarily hold, along with two-fund separation. We derive this result without imposing any distributional assumptions on asset returns. The CAPM holds even when the market contains an infinite number of securities ...

  13. A hybrid bit-encoding for SAT planning based on clique-partitioning

    Science.gov (United States)

    Tapia, Cristóbal; San Segundo, Pablo; Galán, Ramón

    2017-09-01

    Planning as satisfiability is one of the most efficient ways to solve classic automated planning problems. In SAT planning, the encoding used to convert the problem to a SAT formula is critical for the performance of the SAT solver. This paper presents a novel bit-encoding that reduces the number of bits required to represent actions in a SAT-based automated planning problem. To obtain such encoding we first build a conflict graph, which represents incompatibilities of pairs of actions, and bitwise encode the subsets of actions determined by a clique partition. This reduces the number of Boolean variables and clauses of the SAT encoding, while preserving the possibility of parallel execution of compatible (non-neighbor) actions. The article also describes an appropriate algorithm for selecting the clique partition for this application and compares the new encodings obtained over some standard planning problems.

  14. Myopic Loss Aversion: Demystifying the Key Factors Influencing Decision Problem Framing

    Science.gov (United States)

    Hardin, Andrew M.; Looney, Clayton Arlen

    2012-01-01

    Advancement of myopic loss aversion theory has been hamstrung by conflicting results, methodological inconsistencies, and a piecemeal approach toward understanding the key factors influencing decision problem framing. A series of controlled experiments provides a more holistic view of the variables promoting myopia. Extending the information…

  15. Differential participation of temporal structures in the consolidation and reconsolidation of taste aversion extinction.

    Science.gov (United States)

    Garcia-Delatorre, Paola; Rodríguez-Ortiz, Carlos J; Balderas, Israela; Bermúdez-Rattoni, Federico

    2010-09-01

    The extinction process has been described as the decline in the frequency or intensity of the conditioned response following the withdrawal of reinforcement. Hence, experimental extinction does not reflect loss of the original memory, but rather reflects new learning, which in turn requires consolidation in order to be maintained in the long term. During extinction of conditioned taste aversion (CTA), a taste previously associated with aversive consequences acquires a safe status through continuous presentations of the flavor with no aversive consequence. In addition, reconsolidation has been defined as the labile state of a consolidated memory after its reactivation by the presentation of relevant information. In this study, we analyzed structures from the temporal lobe that could be involved in consolidation and reconsolidation of extinction of CTA by means of new protein synthesis. Our results showed that protein synthesis in the hippocampus (HC), the perirhinal cortex (PR) and the insular cortex (IC) of rats participate in extinction consolidation, whereas the basolateral amygdala plays no part in this phenomenon. Furthermore, we found that inhibition of protein synthesis in the IC in a third extinction trial had an effect on reconsolidation of extinction. The participation of the HC in taste memory has been described as a downmodulator for CTA consolidation, and has been related to a context-taste association. Altogether, these data suggest that extinction of aversive taste memories are subserved by the IC, HC and PR, and that extinction can undergo reconsolidation, a process depending only on the IC. © 2010 The Authors. European Journal of Neuroscience © 2010 Federation of European Neuroscience Societies and Blackwell Publishing Ltd.

  16. Roles of dopamine neurons in mediating the prediction error in aversive learning in insects.

    Science.gov (United States)

    Terao, Kanta; Mizunami, Makoto

    2017-10-31

    In associative learning in mammals, it is widely accepted that the discrepancy, or error, between actual and predicted reward determines whether learning occurs. The prediction error theory has been proposed to account for the finding of a blocking phenomenon, in which pairing of a stimulus X with an unconditioned stimulus (US) could block subsequent association of a second stimulus Y to the US when the two stimuli were paired in compound with the same US. Evidence for this theory, however, has been imperfect since blocking can also be accounted for by competitive theories. We recently reported blocking in classical conditioning of an odor with water reward in crickets. We also reported an "auto-blocking" phenomenon in appetitive learning, which supported the prediction error theory and rejected alternative theories. The presence of auto-blocking also suggested that octopamine neurons mediate reward prediction error signals. Here we show that blocking and auto-blocking occur in aversive learning to associate an odor with salt water (US) in crickets, and our results suggest that dopamine neurons mediate aversive prediction error signals. We conclude that the prediction error theory is applicable to both appetitive learning and aversive learning in insects.

  17. Memory of conditioned taste aversion is erased by inhibition of PI3K in the insular cortex.

    Science.gov (United States)

    Slouzkey, Ilana; Rosenblum, Kobi; Maroun, Mouna

    2013-06-01

    The conditioned taste aversion (CTA) paradigm, in which association between a novel taste and visceral malaise is formed, gives a unique experimental setting to examine the mechanisms underlying memory acquisition and extinction processes. AKT is a main kinase of the phosphoinositide 3-kinase cascade (PI3K) and has been implicated in long-term memory. We have recently reported that blockade of PI3K in the basolateral amygdala (BLA) before retrieval of fear memory was associated with long-term reduction in fear responses, suggesting a possible role of PI3K inhibition in fear erasure. In this study, we aimed to elucidate whether PI3K has a similar role in the insular cortex (IC), which has a crucial role in CTA acquisition, consolidation, maintenance, and extinction. To that end, we (1) monitored AKT phosphorylation in the IC following CTA acquisition and extinction and (2) inhibited PI3K by local microinjection of the PI3K inhibitor LY294002 at different stages of CTA acquisition and extinction. Our results show that while AKT phosphorylation is increased following CTA learning, it is decreased following CTA extinction. Inhibition of AKT phosphorylation in the IC before or after the first CTA retrieval test resulted in reduction in the aversion index. This reduction in aversion is due to the erasure of the original CTA trace memory, as re-application of the unconditioned stimulus (lithium chloride) did not induce the recovery of aversion in LY294002-treated animals. Our present data add new evidence to suggest that PI3K is engaged in consolidation of aversive memories, as its inhibition is associated with erasure of CTA memory.

  18. Loss Aversion and Inhibition in Dynamical Models of Multialternative Choice

    Science.gov (United States)

    Usher, Marius; McClelland, James L.

    2004-01-01

    The roles of loss aversion and inhibition among alternatives are examined in models of the similarity, compromise, and attraction effects that arise in choices among 3 alternatives differing on 2 attributes. R. M. Roe, J. R. Busemeyer, and J. T. Townsend (2001) have proposed a linear model in which effects previously attributed to loss aversion…

  19. False memory and importance: can we prioritize encoding without consequence?

    Science.gov (United States)

    Bui, Dung C; Friedman, Michael C; McDonough, Ian M; Castel, Alan D

    2013-10-01

    Given the large amount of information that we encounter, we often must prioritize what information we attempt to remember. Although critical for everyday functioning, relatively little research has focused on how people prioritize the encoding of information. Recent research has shown that people can and do selectively remember information assigned with higher, relative to lower, importance. However, the mechanisms underlying this prioritization process and the consequences of these processes are still not well understood. In the present study, we sought to better understand these prioritization processes and whether implementing these processes comes at the cost of memory accuracy, by increasing false memories. We used a modified form of the Deese/Roediger-McDermott (DRM) paradigm, in which participants studied DRM lists, with each list paired with low, medium, or high point values. In Experiment 1, encoding higher values led to more false memories than did encoding lower values, possibly because prioritizing information enhanced relational processing among high-value words. In Experiment 2, disrupting relational processing selectively reduced false memories for high-value words. Finally, in Experiment 3, facilitating relational processing selectively increased false memories for low-value words. These findings suggest that while prioritizing information can enhance true memory, this process concomitantly increases false memories. Furthermore, the mechanism underlying these prioritization processes depends on the ability to successfully engage in relational processing. Thus, how we prioritize the encoding of incoming information can come at a cost in terms of accurate memory.

  20. Worry-inducing stimuli in an aversive Go/NoGo task enhance reactive control in individuals with lower trait-anxiety.

    Science.gov (United States)

    Leue, Anja; Rodilla, Carmen Cano; Beauducel, André

    2017-04-01

    This study relates predictions on reactive and proactive cognitive control to findings on anxious apprehension/worry and ERN/Ne. We investigated whether worry-inducing stimuli in an aversive performance setting lead to a more pronounced increase of the ERN/Ne in individuals with lower anxious apprehension/worry. We also explored the N2 amplitude in the context of worry-inducing stimuli. Fifty-eight participants performed an extended Go/NoGo task. A neutral or fearful face was presented at the beginning of each trial, with the fearful face as a worry-inducing, distracting stimulus. In an aversive feedback condition, aversive feedback was provided for false or too slow responses. We found a more pronounced decrease of the ERN/Ne after worry-inducing stimuli compared to neutral stimuli in participants with lower anxious apprehension/worry. Moreover, less pronounced N2 amplitudes were associated with shorter reaction times in the aversive feedback condition. Implications for future research on error monitoring and trait-anxiety are discussed. Copyright © 2017 Elsevier B.V. All rights reserved.