Long-term phase reorganization of conditioned food aversion memory in edible snail.

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Kozyrev, S A; Solntseva, S V; Nikitin, V P

2014-08-01

The specific features of memory reconsolidation in edible snails were studied over 30 days after learning of conditioned food aversion. Injections of a NMDA glutamate receptor antagonist MK-801 or protein synthesis inhibitor cycloheximide in combination with the conditioned food stimulus (reminder) on day 2 after learning were followed by the development of amnesia. Repeated training on day 10 after the induction of amnesia did not result in skill formation. Injections of MK-801 or cycloheximide and reminder by the 10th day after training had no effect on memory retention. Injections of MK-801 or cycloheximide and reminder by the 30th day after training were followed by the development of amnesia. In these experiments, memory was recovered after repeated training. Our results indicate that a complex phase reorganization of memory occurs over 30 days after learning. This process includes memory consolidation over the first days after training, stabilization and resistance to adverse factors after 10 days, and newly acquired ability for reconsolidation by the 30th day after training.

Relationship between the grades of a learned aversive-feeding response and the dopamine contents in Lymnaea

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Hitoshi Aonuma

2016-12-01

Full Text Available The pond snail Lymnaea learns conditioned taste aversion (CTA and remembers not to respond to food substances that initially cause a feeding response. The possible relationship between how well snails learn to follow taste-aversion training and brain dopamine contents is not known. We examined this relationship and found the following: first, snails in the act of eating just before the commencement of CTA training were poor learners and had the highest dopamine contents in the brain; second, snails which had an ad libitum access to food, but were not eating just before training, were average learners and had lower dopamine contents; third, snails food-deprived for one day before training were the best learners and had significantly lower contents of dopamine compared to the previous two cohorts. There was a negative correlation between the CTA grades and the brain dopamine contents in these three cohorts. Fourth, snails food-deprived for five days before training were poor learners and had higher dopamine contents. Thus, severe hunger increased the dopamine content in the brain. Because dopamine functions as a reward transmitter, CTA in the severely deprived snails (i.e. the fourth cohort was thought to be mitigated by a high dopamine content.

What are the elements of motivation for acquisition of conditioned taste aversion?

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Mita, Koichi; Okuta, Akiko; Okada, Ryuichi; Hatakeyama, Dai; Otsuka, Emi; Yamagishi, Miki; Morikawa, Mika; Naganuma, Yuki; Fujito, Yutaka; Dyakonova, Varvara; Lukowiak, Ken; Ito, Etsuro

2014-01-01

The pond snail Lymnaea stagnalis is capable of being classically conditioned to avoid food and to consolidate this aversion into a long-term memory (LTM). Previous studies have shown that the length of food deprivation is important for both the acquisition of taste aversion and its consolidation into LTM, which is referred to as conditioned taste aversion (CTA). Here we tested the hypothesis that the hemolymph glucose concentration is an important factor in the learning and memory of CTA. One-day food deprivation resulted in the best learning and memory, whereas more prolonged food deprivation had diminishing effects. Five-day food deprivation resulted in snails incapable of learning or remembering. During this food deprivation period, the hemolymph glucose concentration decreased. If snails were fed for 2days following the 5-day food deprivation, their glucose levels increased significantly and they exhibited both learning and memory, but neither learning nor memory was as good as with the 1-day food-deprived snails. Injection of the snails with insulin to reduce glucose levels resulted in better learning and memory. Insulin is also known to cause a long-term enhancement of synaptic transmission between the feeding-related neurons. On the other hand, injection of glucose into 5-day food-deprived snails did not alter their inability to learn and remember. However, if these snails were fed on sucrose for 3min, they then exhibited learning and memory formation. Our data suggest that hemolymph glucose concentration is an important factor in motivating acquisition of CTA in Lymnaea and that the action of insulin in the brain and the feeding behavior are also important factors. Copyright © 2013 Elsevier Inc. All rights reserved.

Reappraising social insect behavior through aversive responsiveness and learning.

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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

Reappraising social insect behavior through aversive responsiveness and learning.

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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

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

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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.

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

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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…

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

Drosophila learn efficient paths to a food source

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Stewart, James; Lim, Terrence; Claridge-Chang, Adam; Wang, Zhiping; Toh, Alicia; Rahman, Mashiur; Navawongse, Rapeechai; Raczkowska, Marlena; Choudhury, Deepak

2016-01-01

Elucidating the genetic, and neuronal bases for learned behavior is a central problem in neuroscience. A leading system for neurogenetic discovery is the vinegar fly Drosophila melanogaster; fly memory research has identified genes and circuits that mediate aversive and appetitive learning. However, methods to study adaptive food-seeking behavior in this animal have lagged decades behind rodent feeding analysis, largely due to the challenges presented by their small scale. There is currently ...

Induction of latent memory for conditioned food aversion and its transformation into "active" state depend on translation and transcription processes.

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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.

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

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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.

The strength of aversive and appetitive associations and maladaptive behaviors.

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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.

Drosophila learn efficient paths to a food source.

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Navawongse, Rapeechai; Choudhury, Deepak; Raczkowska, Marlena; Stewart, James Charles; Lim, Terrence; Rahman, Mashiur; Toh, Alicia Guek Geok; Wang, Zhiping; Claridge-Chang, Adam

2016-05-01

Elucidating the genetic, and neuronal bases for learned behavior is a central problem in neuroscience. A leading system for neurogenetic discovery is the vinegar fly Drosophila melanogaster; fly memory research has identified genes and circuits that mediate aversive and appetitive learning. However, methods to study adaptive food-seeking behavior in this animal have lagged decades behind rodent feeding analysis, largely due to the challenges presented by their small scale. There is currently no method to dynamically control flies' access to food. In rodents, protocols that use dynamic food delivery are a central element of experimental paradigms that date back to the influential work of Skinner. This method is still commonly used in the analysis of learning, memory, addiction, feeding, and many other subjects in experimental psychology. The difficulty of microscale food delivery means this is not a technique used in fly behavior. In the present manuscript we describe a microfluidic chip integrated with machine vision and automation to dynamically control defined liquid food presentations and sensory stimuli. Strikingly, repeated presentations of food at a fixed location produced improvements in path efficiency during food approach. This shows that improved path choice is a learned behavior. Active control of food availability using this microfluidic system is a valuable addition to the methods currently available for the analysis of learned feeding behavior in flies. Copyright © 2016 The Authors. Published by Elsevier Inc. All rights reserved.

Roles of dopamine neurons in mediating the prediction error in aversive learning in insects.

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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.

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

Brain mechanisms of flavor learning

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Takashi eYamamoto

2011-09-01

Full Text Available Once the flavor of the ingested food (conditioned stimulus, CS is associated with a preferable (e.g., good taste or nutritive satisfaction or aversive (e.g., malaise with displeasure signal (unconditioned stimulus, US, animals react to its subsequent exposure by increasing or decreasing ingestion to the food. These two types of association learning (preference learning vs. aversion learning are known as classical conditioned reactions which are basic learning and memory phenomena, leading selection of food and proper food intake. Since the perception of flavor is generated by interaction of taste and odor during food intake, taste and/or odor are mainly associated with bodily signals in the flavor learning. After briefly reviewing flavor learning in general, brain mechanisms of conditioned taste aversion is described in more detail. The CS-US association leading to long-term potentiation in the amygdala, especially in its basolateral nucleus, is the basis of establishment of conditioned taste aversion. The novelty of the CS detected by the cortical gustatory area may be supportive in CS-US association. After the association, CS input is conveyed through the amygdala to different brain regions including the hippocampus for contextual fear formation, to the supramammilary and thalamic paraventricular nuclei for stressful anxiety or memory dependent fearful or stressful emotion, to the reward system to induce aversive expression to the CS, or hedonic shift from positive to negative, and to the CS-responsive neurons in the gustatory system to enhance the responsiveness to facilitate to detect the harmful stimulus.

Brain mechanisms of flavor learning.

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Yamamoto, Takashi; Ueji, Kayoko

2011-01-01

Once the flavor of the ingested food (conditioned stimulus, CS) is associated with a preferable (e.g., good taste or nutritive satisfaction) or aversive (e.g., malaise with displeasure) signal (unconditioned stimulus, US), animals react to its subsequent exposure by increasing or decreasing ingestion to the food. These two types of association learning (preference learning vs. aversion learning) are known as classical conditioned reactions which are basic learning and memory phenomena, leading selection of food and proper food intake. Since the perception of flavor is generated by interaction of taste and odor during food intake, taste and/or odor are mainly associated with bodily signals in the flavor learning. After briefly reviewing flavor learning in general, brain mechanisms of conditioned taste aversion is described in more detail. The CS-US association leading to long-term potentiation in the amygdala, especially in its basolateral nucleus, is the basis of establishment of conditioned taste aversion. The novelty of the CS detected by the cortical gustatory area may be supportive in CS-US association. After the association, CS input is conveyed through the amygdala to different brain regions including the hippocampus for contextual fear formation, to the supramammillary and thalamic paraventricular nuclei for stressful anxiety or memory dependent fearful or stressful emotion, to the reward system to induce aversive expression to the CS, or hedonic shift from positive to negative, and to the CS-responsive neurons in the gustatory system to enhance the responsiveness to facilitate to detect the harmful stimulus.

Dopamine Regulates Aversive Contextual Learning and Associated In Vivo Synaptic Plasticity in the Hippocampus

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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.

Drosophila Learn Opposing Components of a Compound Food Stimulus

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Das, Gaurav; Klappenbach, Martín; Vrontou, Eleftheria; Perisse, Emmanuel; Clark, Christopher M.; Burke, Christopher J.; Waddell, Scott

2014-01-01

Summary Dopaminergic neurons provide value signals in mammals and insects [1–3]. During Drosophila olfactory learning, distinct subsets of dopaminergic neurons appear to assign either positive or negative value to odor representations in mushroom body neurons [4–9]. However, it is not known how flies evaluate substances that have mixed valence. Here we show that flies form short-lived aversive olfactory memories when trained with odors and sugars that are contaminated with the common insect repellent DEET. This DEET-aversive learning required the MB-MP1 dopaminergic neurons that are also required for shock learning [7]. Moreover, differential conditioning with DEET versus shock suggests that formation of these distinct aversive olfactory memories relies on a common negatively reinforcing dopaminergic mechanism. Surprisingly, as time passed after training, the behavior of DEET-sugar-trained flies reversed from conditioned odor avoidance into odor approach. In addition, flies that were compromised for reward learning exhibited a more robust and longer-lived aversive-DEET memory. These data demonstrate that flies independently process the DEET and sugar components to form parallel aversive and appetitive olfactory memories, with distinct kinetics, that compete to guide learned behavior. PMID:25042590

Conditioned food aversion to control poisoning by Ipomoea carnea subsp. fistulosa in goats

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Ipomoea carnea is a toxic plant often ingested by livestock in Brazil. Three experiments were conducted to determine if conditioned food aversion was effective in reducing goats’ consumption of I. carnea. In the fi rst experiment, 10 mildly intoxicated goats that had been eating I. carnea were avert...

Negative learning bias is associated with risk aversion in a genetic animal model of depression.

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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.

The combination of appetitive and aversive reinforcers and the nature of their interaction during auditory learning.

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Ilango, A; Wetzel, W; Scheich, H; Ohl, F W

2010-03-31

Learned changes in behavior can be elicited by either appetitive or aversive reinforcers. It is, however, not clear whether the two types of motivation, (approaching appetitive stimuli and avoiding aversive stimuli) drive learning in the same or different ways, nor is their interaction understood in situations where the two types are combined in a single experiment. To investigate this question we have developed a novel learning paradigm for Mongolian gerbils, which not only allows rewards and punishments to be presented in isolation or in combination with each other, but also can use these opposite reinforcers to drive the same learned behavior. Specifically, we studied learning of tone-conditioned hurdle crossing in a shuttle box driven by either an appetitive reinforcer (brain stimulation reward) or an aversive reinforcer (electrical footshock), or by a combination of both. Combination of the two reinforcers potentiated speed of acquisition, led to maximum possible performance, and delayed extinction as compared to either reinforcer alone. Additional experiments, using partial reinforcement protocols and experiments in which one of the reinforcers was omitted after the animals had been previously trained with the combination of both reinforcers, indicated that appetitive and aversive reinforcers operated together but acted in different ways: in this particular experimental context, punishment appeared to be more effective for initial acquisition and reward more effective to maintain a high level of conditioned responses (CRs). The results imply that learning mechanisms in problem solving were maximally effective when the initial punishment of mistakes was combined with the subsequent rewarding of correct performance. Copyright 2010 IBRO. Published by Elsevier Ltd. All rights reserved.

Phenotypic transformation affects associative learning in the desert locust.

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Simões, Patrício M V; Niven, Jeremy E; Ott, Swidbert R

2013-12-02

In desert locusts, increased population densities drive phenotypic transformation from the solitarious to the gregarious phase within a generation [1-4]. Here we show that when presented with odor-food associations, the two extreme phases differ in aversive but not appetitive associative learning, with solitarious locusts showing a conditioned aversion more quickly than gregarious locusts. The acquisition of new learned aversions was blocked entirely in acutely crowded solitarious (transiens) locusts, whereas appetitive learning and prior learned associations were unaffected. These differences in aversive learning support phase-specific feeding strategies. Associative training with hyoscyamine, a plant alkaloid found in the locusts' habitat [5, 6], elicits a phase-dependent odor preference: solitarious locusts avoid an odor associated with hyoscyamine, whereas gregarious locusts do not. Remarkably, when solitarious locusts are crowded and then reconditioned with the odor-hyoscyamine pairing as transiens, the specific blockade of aversive acquisition enables them to override their prior aversive memory with an appetitive one. Under fierce food competition, as occurs during crowding in the field, this provides a neuroecological mechanism enabling locusts to reassign an appetitive value to an odor that they learned previously to avoid. Copyright © 2013 Elsevier Ltd. All rights reserved.

Learning context modulates aversive taste strength in honey bees.

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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.

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.

Induction of aversive learning through thermogenetic activation of Kenyon cell ensembles in Drosophila

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David eVasmer

2014-05-01

Full Text Available Drosophila represents a model organism to analyze neuronal mechanisms underlying learning and memory. Kenyon cells of the Drosophila mushroom body are required for associative odor learning and memory retrieval. But is the mushroom body sufficient to acquire and retrieve an associative memory? To answer this question we have conceived an experimental approach to bypass olfactory sensory input and to thermogenetically activate sparse and random ensembles of Kenyon cells directly. We found that if the artifical activation of Kenyon cell ensembles coincides with a salient, aversive stimulus learning was induced The animals adjusted their behavior in a subsequent test situation and actively avoided reactivation of these Kenyon cells. Our results show that Kenyon cell activity in coincidence with a salient aversive stimulus can suffice to form an associative memory. Memory retrieval is characterized by a closed feedback loop between a behavioral action and the reactivation of sparse ensembles of Kenyon cells.

The Effect of Swimming Experience on Acquisition and Retention of Swimming-Based Taste Aversion Learning in Rats

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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…

Drugs and taste aversion

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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

Role of PKA signaling in D2 receptor-expressing neurons in the core of the nucleus accumbens in aversive learning.

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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.

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

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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.

Effects of 5-HT and insulin on learning and memory formation in food-deprived snails.

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Aonuma, Hitoshi; Totani, Yuki; Kaneda, Mugiho; Nakamura, Ryota; Watanabe, Takayuki; Hatakeyama, Dai; Dyakonova, Varvara E; Lukowiak, Ken; Ito, Etsuro

2018-02-01

The pond snail Lymnaea stagnalis learns conditioned taste aversion (CTA) and consolidates it into long-term memory (LTM). How well they learn and form memory depends on the degree of food deprivation. Serotonin (5-HT) plays an important role in mediating feeding, and insulin enhances the memory consolidation process following CTA training. However, the relationship between these two signaling pathways has not been addressed. We measured the 5-HT content in the central nervous system (CNS) of snails subjected to different durations of food deprivation. One-day food-deprived snails, which exhibit the best learning and memory, had the lowest 5-HT content in the CNS, whereas 5-day food-deprived snails, which do not learn, had a high 5-HT content. Immersing 1-day food-deprived snails in 5-HT impaired learning and memory by causing an increase in 5-HT content, and that the injection of insulin into these snails reversed this impairment. We conclude that insulin rescues the CTA deficit and this may be due to a decrease in the 5-HT content in the CNS of Lymnaea. Copyright © 2018 Elsevier Inc. All rights reserved.

Integration of Neurobiological and Computational Analyses of the Neural Network Essentials for Conditioned Taste Aversion

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1991-04-29

cortex. Physiology a Behavior, IQ, 203-206, 1983. Garcia, J., Hankins, W. G., Coil, S. D. Koalas , men and other conditional gastronomes. In Food...Conditioned taste aversion and the pituitary-adrenal system. Behavioral Biology , 16, 413-424, 1976. Kalat, J. W., Rozin, P. "Learned safety" as a

Complexity and competition in appetitive and aversive neural circuits

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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.

The Neural Foundations of Reaction and Action in Aversive Motivation.

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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.

Steroid Hormone (20-Hydroxyecdysone) Modulates the Acquisition of Aversive Olfactory Memories in Pollen Forager Honeybees

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Geddes, Lisa H.; McQuillan, H. James; Aiken, Alastair; Vergoz, Vanina; Mercer, Alison R.

2013-01-01

Here, we examine effects of the steroid hormone, 20-hydroxyecdysone (20-E), on associative olfactory learning in the honeybee, "Apis mellifera." 20-E impaired the bees' ability to associate odors with punishment during aversive conditioning, but did not interfere with their ability to associate odors with a food reward (appetitive…

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

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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

Conditioned food aversion to control outbreaks of intoxication by Ipomoea carnea and Turbina cordata in goats

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Conditioned food aversion is used to train livestock to avoid the ingestion of toxic plants. This technique was used to control Turbina cordata poisoning in goats in one farm, and to control Ipomoea carnea subsp. istulosa poisoning in another farm. The goats were penned at night and the next mornin...

Gene Network Analysis in Amygdala following Taste Aversion Learning in Rats

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Siva K. Panguluri

2013-01-01

Full Text Available Conditioned taste aversion (CTA is an adaptive behavior that benefits survival of animals including humans and also serves as a powerful model to study the neural mechanisms of learning. Memory formation is a necessary component of CTA learning and involves neural processing and regulation of gene expression in the amygdala. Many studies have been focused on the identification of intracellular signaling cascades involved in CTA, but not late responsive genes underlying the long-lasting behavioral plasticity. In this study, we explored in silico experiments to identify persistent changes in gene expression associated with CTA in rats. We used oligonucleotide microarrays to identify 248 genes in the amygdala regulated by CTA. Pathway Studio and IPA software analyses showed that the differentially expressed genes in the amygdala fall in diverse functional categories such as behavior, psychological disorders, nervous system development and function, and cell-to-cell signaling. Conditioned taste aversion is a complex behavioral trait which involves association of visceral and taste inputs, consolidation of taste and visceral information, memory formation, retrieval of stored information, and extinction phase. In silico analysis of differentially expressed genes is therefore necessary to manipulate specific phase/stage of CTA to understand the molecular insight.

[Inhibitor influence on conditional food aversion long-term memory retention and reconsolidation in snail].

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Nikitin, V P; Solntseva, S V; Kozyrev, S A

2014-08-01

In snails trained for conditional food aversion, the effect of ZIP-protein kinase Mzeta (PKMzeta) inhibitor on mechanisms of memory retention and reconsolidation was studied. It was shown that two days after ZIP injections the dose of 1.25 mg/kg, which were not combined with a reminding procedure, there was no effects, but in dose of 2.5 mg/kg a transient memory impairment after 1 day after the injection with its spontaneous recovery on day 10 was disclosed. ZIP injection in a dose of 5 mg/kg without reminding procedure caused memory impairment and the development of persistent amnesia. During animal repeating training after 11 days after amnesia induction caused by ZIP in dose 5 mg/kg, the number of combined food and reinforcing stimulus needed for memory formation was similar to that seen in the initial training. ZIP in doses of 5 or 10 mg/kg combined with a reminding procedure caused the development of amnesia, however, repeating training after 11 days resulted in a dose-dependent and more rapid formation of memory than in the initial training. It was proposed that in snails trained to conditional food aversion without reminding procedure, inhibition of PKMzeta-like enzyme might cause "erase the memory trace" and in repeating training a new memory was formed. PKMzeta apparently not directly involved in the processes of memory reconsolidation, however, a reminding decreased amnesic effect of ZIP.

Opponent appetitive-aversive neural processes underlie predictive learning of pain relief.

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Seymour, Ben; O'Doherty, John P; Koltzenburg, Martin; Wiech, Katja; Frackowiak, Richard; Friston, Karl; Dolan, Raymond

2005-09-01

Termination of a painful or unpleasant event can be rewarding. However, whether the brain treats relief in a similar way as it treats natural reward is unclear, and the neural processes that underlie its representation as a motivational goal remain poorly understood. We used fMRI (functional magnetic resonance imaging) to investigate how humans learn to generate expectations of pain relief. Using a pavlovian conditioning procedure, we show that subjects experiencing prolonged experimentally induced pain can be conditioned to predict pain relief. This proceeds in a manner consistent with contemporary reward-learning theory (average reward/loss reinforcement learning), reflected by neural activity in the amygdala and midbrain. Furthermore, these reward-like learning signals are mirrored by opposite aversion-like signals in lateral orbitofrontal cortex and anterior cingulate cortex. This dual coding has parallels to 'opponent process' theories in psychology and promotes a formal account of prediction and expectation during pain.

Aversive aftertaste changes visual food cue reactivity: An fMRI study on cross-modal perception.

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Wabnegger, Albert; Schwab, Daniela; Schienle, Anne

2018-04-23

In western cultures, we are surrounded by appealing visual food cues that stimulate our desire to eat, overeating and subsequent weight gain. Cognitive control of appetite (reappraisal) requires substantial attentional resources and effort in order to work. Therefore, we tested an alternative approach for appetite regulation via functional magnetic resonance imaging. Healthy, normal-weight women were presented with images depicting food (high-/low-caloric), once in combination with a bitter aftertaste (a gustatory stop signal) and once with a neutral taste (water), in a retest design. The aversive aftertaste elicited increased activation in the orbitofrontal/dorsolateral prefrontal cortex (OFC, DLPFC), striatum and frontal operculum during the viewing of high-caloric food (vs. low-caloric food). In addition, the increase in DLPFC activity to high-caloric food in the bitter condition was correlated with reported appetite reduction. The findings indicate that this aftertaste procedure was able to reduce the appetitive value of visual food cues. Copyright © 2018 Elsevier B.V. All rights reserved.

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

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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.

Further evidence for conditioned taste aversion induced by forced swimming.

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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.

Integration of Neurobiological and Computational Analyses of the Neural Network Essentials for Conditioned Taste Aversions

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1990-06-30

gastronomes . In Food Aversion Learning, ed. N. W. Milgram, L. Krames, T. Alloway. New York: Plenum Press, 1977. Grill, H. J., Berridge, K. C. Taste...Jun 25 10:4,6:21 1990 ZLS: syr GRP: Po JOB: aug 0V: 12 Pb ok, &,vpr. VoL 4&, 000-=. 0 Pervnoe Press pl. 1990. Prited a tft USA . 0031-938"S90 53.00 + .00

5-HT1A receptor antagonists reduce food intake and body weight by reducing total meals with no conditioned taste aversion.

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Dill, M Joelle; Shaw, Janice; Cramer, Jeff; Sindelar, Dana K

2013-11-01

Serotonin acts through receptors controlling several physiological functions, including energy homeostasis regulation and food intake. Recent experiments demonstrated that 5-HT1A receptor antagonists reduce food intake. We sought to examine the microstructure of feeding with 5-HT1A receptor antagonists using a food intake monitoring system. We also examined the relationship between food intake, inhibition of binding and pharmacokinetic (PK) profiles of the antagonists. Ex vivo binding revealed that, at doses used in this study to reduce food intake, inhibition of binding of a 5-HT1A agonist by ~40% was reached in diet-induced obese (DIO) mice with a trend for higher binding in DIO vs. lean animals. Additionally, PK analysis detected levels from 2 to 24h post-compound administration. Male DIO mice were administered 5-HT1A receptor antagonists LY439934 (10 or 30 mg/kg, p.o.), WAY100635 (3 or 10mg/kg, s.c.), SRA-333 (10 or 30 mg/kg, p.o.), or NAD-299 (3 or 10mg/kg, s.c.) for 3 days and meal patterns were measured. Analyses revealed that for each antagonist, 24-h food intake was reduced through a specific decrease in the total number of meals. Compared to controls, meal number was decreased 14-35% in the high dose. Average meal size was not changed by any of the compounds. The reduction in food intake reduced body weight 1-4% compared to Vehicle controls. Subsequently, a conditioned taste aversion (CTA) assay was used to determine whether the feeding decrease might be an indicator of aversion, nausea, or visceral illness caused by the antagonists. Using a two bottle preference test, it was found that none of the compounds produced a CTA. The decrease in food intake does not appear to be a response to nausea or malaise. These results indicate that 5-HT1A receptor antagonist suppresses feeding, specifically by decreasing the number of meals, and induce weight loss without an aversive side effect. © 2013 Elsevier Inc. All rights reserved.

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

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

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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).

[Food intake regulation - 2nd part].

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Brunerová, Ludmila; Anděl, Michal

2014-01-01

The review article summarizes the principles of hedonic regulation of food intake which represents the food intake independent on the maintenance of homeostasis. The theory describing hedonic regulation, so called Incentive Salience Theory, comprises three major processes: liking (positive attribution to food stimulus), wanting (motivation to gain it) and learning (identification of these stimuli and distinguishing them from those connected with aversive reaction). Neuronal reward circuits are the anatomical and functional substrates of hedonic regulation. They react to gustatory and olfactory (or visual) stimuli associated with food intake. A food item is preferred in case its consumption is connected with a pleasant feeling thus promoting the behavioural reaction. The probability of this reaction after repetitive exposure to such a stimulus is increased (learned preference). On the contrary, learned aversion after repetitive exposure is connected with avoidance of a food item associated with a negative feeling. Main mediators of hedonic regulation are endocannabinoids, opioids and monoamines (dopamine, serotonin). Dopamine in dorsal striatum via D2 receptors generates food motivation as a key means of survival, however in ventral striatum (nucleus accumbens) is responsible for motivation to food bringing pleasure. Serotonin via its receptors 5-HT1A a T-HT2C decreases intake of palatable food. It plays a significant role in the pathogenesis of eating disorders, particularly mental anorexia. There, a food restriction represents a kind of automedication to constitutionally pathologically increased serotonin levels. Detailed understanding of processes regulating food intake is a key to new pharmacological interventions in eating disorders.

Hypnobehavioral approaches for school-age children with dysphagia and food aversion: a case series.

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Culbert, T P; Kajander, R L; Kohen, D P; Reaney, J B

1996-10-01

The purpose of this article is to describe hypnobehavioral treatment of five school-age children with maladaptive eating behaviors, including functional dysphagia, food aversion, globus hystericus, and conditioned fear of eating (phagophobia). The unique treatment approach described emphasizes the successful use of self-management techniques, particularly hypnosis, by all five children. Common etiological factors, treatment strategies, and proposed mechanisms of change are discussed. To the authors' knowledge, this is the first such case series in the mainstream pediatric literature describing the use of a hypnobehavioral approach for children with these maladaptive eating problems.

Conditioned taste aversion, drugs of abuse and palatability.

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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.

Delayed effect of chronic administration of corticoids on the taste aversion learning.

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Zach, Petr; Mrzilkova, Jana; Stuchlik, Ales; Vales, Karel; Rezacova, Lenka

2011-01-01

Long term permanent changes of eating behavior and concomitant structural changes in the CNS are matter of debade in literature. Often there is not enough distinction beween acute and chronic exposure to corticoids in evaluating its effect on behavior and/or brain structural changes. For behavioral evaluation we used well established conditioned taste aversion (CTA) paradigm and coronal Nissl-stained brain sections for evaluation of neuroanatomical changes. The CTA is part of complex adaptive behavioral processes controling food intake. It is well established methodological tool for study of biological substrates of learning and memory. Our hypothesis was that long term changes in laboratory rat behavior induced by exogenous corticosterone are not accompanyied by neurohistological changes in the rat brain, previously described in literature. Firstly, our results support CTA paradigm as promising tool for testing chronic influence of stress hormones on eating behavior and memory. The results support fact that previous long term elevated corticosterone levels disrupt normal eating behavior and it could also lead to structural changes, which could be biological substrates of behavioral changes. The fact we have not found significant morphological changes in brain strengthen the notion of possible subcellular impairment taking place instead of simple neuronal loss.

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

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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

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

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

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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

Searching for learning-dependent changes in the antennal lobe: simultaneous recording of neural activity and aversive olfactory learning in honeybees

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Edith Roussel

2010-09-01

Full Text Available Plasticity in the honeybee brain has been studied using the appetitive olfactory conditioning of the proboscis extension reflex, in which a bee learns the association between an odor and a sucrose reward. In this framework, coupling behavioral measurements of proboscis extension and invasive recordings of neural activity has been difficult because proboscis movements usually introduce brain movements that affect physiological preparations. Here we took advantage of a new conditioning protocol, the aversive olfactory conditioning of the sting extension reflex, which does not generate this problem. We achieved the first simultaneous recordings of conditioned sting extension responses and calcium imaging of antennal lobe activity, thus revealing on-line processing of olfactory information during conditioning trials. Based on behavioral output we distinguished learners and non-learners and analyzed possible learning-dependent changes in antennal lobe activity. We did not find differences between glomerular responses to the CS+ and the CS- in learners. Unexpectedly, we found that during conditioning trials non-learners exhibited a progressive decrease in physiological responses to odors, irrespective of their valence. This effect could neither be attributed to a fitness problem nor to abnormal dye bleaching. We discuss the absence of learning-induced changes in the antennal lobe of learners and the decrease in calcium responses found in non-learners. Further studies will have to extend the search for functional plasticity related to aversive learning to other brain areas and to look on a broader range of temporal scales

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.

Appetitive and aversive visual learning in freely moving Drosophila

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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.

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...

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.

Ambiguity aversion in rhesus macaques

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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.

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.

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.

Discrete Serotonin Systems Mediate Memory Enhancement and Escape Latencies after Unpredicted Aversive Experience in Drosophila Place Memory

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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.

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.

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

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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.

5-Bromo-2'-deoxyuridine impairs long-term food aversion memory in edible snail.

Science.gov (United States)

Efimova, O I; Anokhin, K V

2012-09-01

We studied the involvement of DNA synthesis into molecular mechanisms of long-term memory. Nucleoside analogue 5-bromo-2'-deoxyuridine (BrdU) is known to incorporate into synthesizing DNA and prevent subsequent DNA replication from this region. To investigate the effect of BrdU administration on long-term memory, terrestrial gastropods edible snails Helix lucorum were trained in the food aversion paradigm. Single-session training (carrot presentation combined with application of 10% quinine solution, three carrot presentations with 10-min intervals) resulted in the formation of long-term memory that persisted for at least 45° days. BrdU administration (250 mg/kg) 30 min before training impaired long-term memory tested 24 h later. Immunohistochemical study revealed BrdU incorporation in the nuclei of identified neurons of defensive behavior.

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

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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.

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...

Involvement of Glycogen Synthase Kinase-3 in the Mechanisms of Conditioned Food Aversion Memory Reconsolidation.

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Nikitin, V P; Solntseva, S V; Kozyrev, S A

2017-02-01

Experiments were performed on the snails trained in conditioned food aversion for 3 days. Injection of TDZD-8 (glycogen synthase kinase-3 inhibitor, 2 mg/kg) in combination with reminder (presentation of a conditioned food stimulus) led to memory impairment developing 3 days after inhibitor/reminder exposure and followed by spontaneous recovery in 10 days. Injections of TDZD-8 in a dose of 4 or 20 mg/kg before reminder were shown to cause amnesia that persisted for more than 10 days. Memory recovery during repeated training was observed at the earlier period than after initial training. The impairment of memory reconsolidation by TDZD-8 after training of snails for 1 day was less pronounced than under standard training conditions (3 days). The effect of a glycogen synthase kinase-3 inhibitor during memory reconsolidation is probably followed by impairment of memory retrieval and/or partial loss, which can be compensated spontaneously or after repeated training.

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)

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

Eliciting conditioned taste aversion in lizards: Live toxic prey are more effective than scent and taste cues alone.

Science.gov (United States)

Ward-Fear, Georgia; Thomas, Jai; Webb, Jonathan K; Pearson, David J; Shine, Richard

2017-03-01

Conditioned taste aversion (CTA) is an adaptive learning mechanism whereby a consumer associates the taste of a certain food with symptoms caused by a toxic substance, and thereafter avoids eating that type of food. Recently, wildlife researchers have employed CTA to discourage native fauna from ingesting toxic cane toads (Rhinella marina), a species that is invading tropical Australia. In this paper, we compare the results of 2 sets of CTA trials on large varanid lizards ("goannas," Varanus panoptes). One set of trials (described in this paper) exposed recently-captured lizards to sausages made from cane toad flesh, laced with a nausea-inducing chemical (lithium chloride) to reinforce the aversion response. The other trials (in a recently-published paper, reviewed herein) exposed free-ranging lizards to live juvenile cane toads. The effectiveness of the training was judged by how long a lizard survived in the wild before it was killed (fatally poisoned) by a cane toad. Both stimuli elicited rapid aversion to live toads, but the CTA response did not enhance survival rates of the sausage-trained goannas after they were released into the wild. In contrast, the goannas exposed to live juvenile toads exhibited higher long-term survival rates than did untrained conspecifics. Our results suggest that although it is relatively easy to elicit short-term aversion to toad cues in goannas, a biologically realistic stimulus (live toads, encountered by free-ranging predators) is most effective at buffering these reptiles from the impact of invasive toxic prey. © 2016 International Society of Zoological Sciences, Institute of Zoology/Chinese Academy of Sciences and John Wiley & Sons Australia, Ltd.

Social signals and aversive learning in honey bee drones and workers

Science.gov (United States)

Pérez, Eddie; Vallejo, Lianna; Pérez, María E.; Abramson, Charles I.; Giray, Tugrul

2017-01-01

ABSTRACT The dissemination of information is a basic element of group cohesion. In honey bees (Apis mellifera Linnaeus 1758), like in other social insects, the principal method for colony-wide information exchange is communication via pheromones. This medium of communication allows multiple individuals to conduct tasks critical to colony survival. Social signaling also establishes conflict at the level of the individual who must trade-off between attending to the immediate environment or the social demand. In this study we examined this conflict by challenging highly social worker honey bees, and less social male drone honey bees undergoing aversive training by presenting them with a social stress signal (isopentyl acetate, IPA). We utilized IPA exposure methods that caused lower learning performance in appetitive learning in workers. Exposure to isopentyl acetate (IPA) did not affect performance of drones and had a dose-specific effect on worker response, with positive effects diminishing at higher IPA doses. The IPA effects are specific because non-social cues, such as the odor cineole, improve learning performance in drones, and social homing signals (geraniol) did not have a discernible effect on drone or worker performance. We conclude that social signals do generate conflict and that response to them is dependent on signal relevance to the individual as well as the context. We discuss the effect of social signal on learning both related to its social role and potential evolutionary history. PMID:27895050

Social signals and aversive learning in honey bee drones and workers

Directory of Open Access Journals (Sweden)

Arian Avalos

2017-01-01

Full Text Available The dissemination of information is a basic element of group cohesion. In honey bees (Apis mellifera Linnaeus 1758, like in other social insects, the principal method for colony-wide information exchange is communication via pheromones. This medium of communication allows multiple individuals to conduct tasks critical to colony survival. Social signaling also establishes conflict at the level of the individual who must trade-off between attending to the immediate environment or the social demand. In this study we examined this conflict by challenging highly social worker honey bees, and less social male drone honey bees undergoing aversive training by presenting them with a social stress signal (isopentyl acetate, IPA. We utilized IPA exposure methods that caused lower learning performance in appetitive learning in workers. Exposure to isopentyl acetate (IPA did not affect performance of drones and had a dose-specific effect on worker response, with positive effects diminishing at higher IPA doses. The IPA effects are specific because non-social cues, such as the odor cineole, improve learning performance in drones, and social homing signals (geraniol did not have a discernible effect on drone or worker performance. We conclude that social signals do generate conflict and that response to them is dependent on signal relevance to the individual as well as the context. We discuss the effect of social signal on learning both related to its social role and potential evolutionary history.

Social signals and aversive learning in honey bee drones and workers.

Science.gov (United States)

Avalos, Arian; Pérez, Eddie; Vallejo, Lianna; Pérez, María E; Abramson, Charles I; Giray, Tugrul

2017-01-15

The dissemination of information is a basic element of group cohesion. In honey bees (Apis mellifera Linnaeus 1758), like in other social insects, the principal method for colony-wide information exchange is communication via pheromones. This medium of communication allows multiple individuals to conduct tasks critical to colony survival. Social signaling also establishes conflict at the level of the individual who must trade-off between attending to the immediate environment or the social demand. In this study we examined this conflict by challenging highly social worker honey bees, and less social male drone honey bees undergoing aversive training by presenting them with a social stress signal (isopentyl acetate, IPA). We utilized IPA exposure methods that caused lower learning performance in appetitive learning in workers. Exposure to isopentyl acetate (IPA) did not affect performance of drones and had a dose-specific effect on worker response, with positive effects diminishing at higher IPA doses. The IPA effects are specific because non-social cues, such as the odor cineole, improve learning performance in drones, and social homing signals (geraniol) did not have a discernible effect on drone or worker performance. We conclude that social signals do generate conflict and that response to them is dependent on signal relevance to the individual as well as the context. We discuss the effect of social signal on learning both related to its social role and potential evolutionary history. © 2017. Published by The Company of Biologists Ltd.

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

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.

Intra-Amygdala ZIP Injections Impair the Memory of Learned Active Avoidance Responses and Attenuate Conditioned Taste-Aversion Acquisition in Rats

Science.gov (United States)

Gamiz, Fernando; Gallo, Milagros

2011-01-01

We have investigated the effect of protein kinase Mzeta (PKM[zeta]) inhibition in the basolateral amygdala (BLA) upon the retention of a nonspatial learned active avoidance response and conditioned taste-aversion (CTA) acquisition in rats. ZIP (10 nmol/[mu]L) injected into the BLA 24 h after training impaired retention of a learned…

An increase in insulin is important for the acquisition conditioned taste aversion in Lymnaea.

Science.gov (United States)

Mita, Koichi; Yamagishi, Miki; Fujito, Yutaka; Lukowiak, Ken; Ito, Etsuro

2014-12-01

Conditioned taste aversion (CTA) in Lymnaea is brought about by pairing a sucrose solution (the conditioned stimulus, CS) with an electric shock (the unconditioned stimulus, US). Following repeated CS-US pairings, CTA occurs and it is consolidated into long-term memory (LTM). The best CTA is achieved, if snails are food-deprived for 1 day before training commences. With a longer period of food deprivation (5 days), learning and memory formation does not occur. It has been hypothesized that the levels of insulin in the central nervous system (CNS) are very important for CTA to occur. To test his hypothesis, we injected insulin directly into 5-day food-deprived snails. The injection of insulin, as expected, resulted in a decrease in hemolymph glucose concentration. Consistent with our hypothesis with insulin injection, learning and memory formation of CTA occurred. That is, the 'insulin spike' is more important than an increase in hemolymph glucose concentration for CTA-LTM. If we injected an insulin receptor antibody into the snails before the insulin injection, learning was formed but memory formation was not, which is consistent with our previous study. Therefore, a rise in the insulin concentration (i.e., insulin spike) in the CNS is considered to be a key determining factor in the process of CTA-LTM. Copyright © 2014 Elsevier Inc. All rights reserved.

Differences in risk aversion between young and older adults

Directory of Open Access Journals (Sweden)

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

One-trial conditioned taste aversion in Lymnaea: good and poor performers in long-term memory acquisition.

Science.gov (United States)

Sugai, Rio; Azami, Sachiyo; Shiga, Hatsuki; Watanabe, Takayuki; Sadamoto, Hisayo; Kobayashi, Suguru; Hatakeyama, Dai; Fujito, Yutaka; Lukowiak, Ken; Ito, Etsuro

2007-04-01

In the majority of studies designed to elucidate the causal mechanisms of memory formation, certain members of the experimental cohort, even though subjected to exactly the same conditioning procedures, remember significantly better than others, whereas others show little or no long-term memory (LTM) formation. To begin to address the question of why this phenomenon occurs and thereby help clarify the causal mechanism of LTM formation, we used a conditioned taste aversion (CTA) procedure on individuals of the pond snail Lymnaea stagnalis and analyzed their subsequent behavior. Using sucrose as an appetitive stimulus and KCl as an aversive stimulus, we obtained a constant ratio of ;poor' to ;good' performers for CTA-LTM. We found that approximately 40% of trained snails possessed LTM following a one-trial conditioning procedure. When we examined the time-window necessary for the memory consolidation, we found that if we cooled snails to 4 degrees C for 30 min within 10 min after the one-trial conditioning, LTM was blocked. However, with delayed cooling (i.e. longer than 10 min), LTM was present. We could further interfere with LTM formation by inducing inhibitory learning (i.e. backward conditioning) after the one-trial conditioning. Finally, we examined whether we could motivate snails to acquire LTM by depriving them of food for 5 days before the one-trial conditioning. Food-deprived snails, however, failed to exhibit LTM following the one-trial conditioning. These results will help us begin to clarify why some individuals are better at learning and forming memory for specific tasks at the neuronal level.

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.

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.

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....

Neurobiological mechanisms underlying the blocking effect in aversive learning.

Science.gov (United States)

Eippert, Falk; Gamer, Matthias; Büchel, Christian

2012-09-19

Current theories of classical conditioning assume that learning depends on the predictive relationship between events, not just on their temporal contiguity. Here we employ the classic experiment substantiating this reasoning-the blocking paradigm-in combination with functional magnetic resonance imaging (fMRI) to investigate whether human amygdala responses in aversive learning conform to these assumptions. In accordance with blocking, we demonstrate that significantly stronger behavioral and amygdala responses are evoked by conditioned stimuli that are predictive of the unconditioned stimulus than by conditioned stimuli that have received the same pairing with the unconditioned stimulus, yet have no predictive value. When studying the development of this effect, we not only observed that it was related to the strength of previous conditioned responses, but also that predictive compared with nonpredictive conditioned stimuli received more overt attention, as measured by fMRI-concurrent eye tracking, and that this went along with enhanced amygdala responses. We furthermore observed that prefrontal regions play a role in the development of the blocking effect: ventromedial prefrontal cortex (subgenual anterior cingulate) only exhibited responses when conditioned stimuli had to be established as nonpredictive for an outcome, whereas dorsolateral prefrontal cortex also showed responses when conditioned stimuli had to be established as predictive. Most importantly, dorsolateral prefrontal cortex connectivity to amygdala flexibly switched between positive and negative coupling, depending on the requirements posed by predictive relationships. Together, our findings highlight the role of predictive value in explaining amygdala responses and identify mechanisms that shape these responses in human fear conditioning.

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.

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.

How Does Food Taste in Anorexia and Bulimia Nervosa? A Protocol for a Quasi-Experimental, Cross-Sectional Design to Investigate Taste Aversion or Increased Hedonic Valence of Food in Eating Disorders

Directory of Open Access Journals (Sweden)

David Garcia-Burgos

2018-03-01

Full Text Available Background: Despite on-going efforts to better understand dysregulated eating, the olfactory-gustatory deficits and food preferences in eating disorders (ED, and the mechanisms underlying the perception of and responses to food properties in anorexia nervosa (AN and bulimia nervosa (BN remain largely unknown; both during the course of the illness and compared to healthy populations. It is, therefore, necessary to systematically investigate the gustatory perception and hedonics of taste in patients with AN and BN. To this end, we will examine whether aversions to the taste of high-calorie food is related to the suppression of energy intake in restricting-type AN, and whether an increased hedonic valence of sweet, caloric-dense foods may be part of the mechanisms triggering binge-eating episodes in BN. In addition, the role of cognitions influencing these mechanisms will be examined.Method: In study 1, four mixtures of sweet-fat stimuli will be presented in a sensory two-alternative forced-choice test involving signal detection analysis. In study 2, a full-scale taste reactivity test will be carried out, including psychophysiological and behavioral measures to assess subtle and covert hedonic changes. We will compare the responses of currently-ill AN and BN patients to those who have recovered from AN and BN, and also to those of healthy normal-weight and underweight individuals without any eating disorder pathology.Discussion: If taste response profiles are differentially linked to ED types, then future studies should investigate whether taste responsiveness represents a useful diagnostic measure in the prevention, assessment and treatment of EDs. The expected results on cognitive mechanisms in the top-down processes of food hedonics will complement current models and contribute to the refinement of interventions to change cognitive aspects of taste aversions, to establish functional food preferences and to better manage food cravings associated

How Does Food Taste in Anorexia and Bulimia Nervosa? A Protocol for a Quasi-Experimental, Cross-Sectional Design to Investigate Taste Aversion or Increased Hedonic Valence of Food in Eating Disorders

Science.gov (United States)

Garcia-Burgos, David; Maglieri, Sabine; Vögele, Claus; Munsch, Simone

2018-01-01

Background: Despite on-going efforts to better understand dysregulated eating, the olfactory-gustatory deficits and food preferences in eating disorders (ED), and the mechanisms underlying the perception of and responses to food properties in anorexia nervosa (AN) and bulimia nervosa (BN) remain largely unknown; both during the course of the illness and compared to healthy populations. It is, therefore, necessary to systematically investigate the gustatory perception and hedonics of taste in patients with AN and BN. To this end, we will examine whether aversions to the taste of high-calorie food is related to the suppression of energy intake in restricting-type AN, and whether an increased hedonic valence of sweet, caloric-dense foods may be part of the mechanisms triggering binge-eating episodes in BN. In addition, the role of cognitions influencing these mechanisms will be examined. Method: In study 1, four mixtures of sweet-fat stimuli will be presented in a sensory two-alternative forced-choice test involving signal detection analysis. In study 2, a full-scale taste reactivity test will be carried out, including psychophysiological and behavioral measures to assess subtle and covert hedonic changes. We will compare the responses of currently-ill AN and BN patients to those who have recovered from AN and BN, and also to those of healthy normal-weight and underweight individuals without any eating disorder pathology. Discussion: If taste response profiles are differentially linked to ED types, then future studies should investigate whether taste responsiveness represents a useful diagnostic measure in the prevention, assessment and treatment of EDs. The expected results on cognitive mechanisms in the top-down processes of food hedonics will complement current models and contribute to the refinement of interventions to change cognitive aspects of taste aversions, to establish functional food preferences and to better manage food cravings associated with binge

How Does Food Taste in Anorexia and Bulimia Nervosa? A Protocol for a Quasi-Experimental, Cross-Sectional Design to Investigate Taste Aversion or Increased Hedonic Valence of Food in Eating Disorders.

Science.gov (United States)

Garcia-Burgos, David; Maglieri, Sabine; Vögele, Claus; Munsch, Simone

2018-01-01

Background: Despite on-going efforts to better understand dysregulated eating, the olfactory-gustatory deficits and food preferences in eating disorders (ED), and the mechanisms underlying the perception of and responses to food properties in anorexia nervosa (AN) and bulimia nervosa (BN) remain largely unknown; both during the course of the illness and compared to healthy populations. It is, therefore, necessary to systematically investigate the gustatory perception and hedonics of taste in patients with AN and BN. To this end, we will examine whether aversions to the taste of high-calorie food is related to the suppression of energy intake in restricting-type AN, and whether an increased hedonic valence of sweet, caloric-dense foods may be part of the mechanisms triggering binge-eating episodes in BN. In addition, the role of cognitions influencing these mechanisms will be examined. Method: In study 1, four mixtures of sweet-fat stimuli will be presented in a sensory two-alternative forced-choice test involving signal detection analysis. In study 2, a full-scale taste reactivity test will be carried out, including psychophysiological and behavioral measures to assess subtle and covert hedonic changes. We will compare the responses of currently-ill AN and BN patients to those who have recovered from AN and BN, and also to those of healthy normal-weight and underweight individuals without any eating disorder pathology. Discussion: If taste response profiles are differentially linked to ED types, then future studies should investigate whether taste responsiveness represents a useful diagnostic measure in the prevention, assessment and treatment of EDs. The expected results on cognitive mechanisms in the top-down processes of food hedonics will complement current models and contribute to the refinement of interventions to change cognitive aspects of taste aversions, to establish functional food preferences and to better manage food cravings associated with binge

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.

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…

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.

Glucocorticoids interact with the noradrenergic arousal system in the nucleus accumbens shell to enhance memory consolidation of both appetitive and aversive taste learning.

Science.gov (United States)

Wichmann, Romy; Fornari, Raquel V; Roozendaal, Benno

2012-09-01

It is well established that glucocorticoid hormones strengthen the consolidation of long-term memory of emotionally arousing experiences but have little effect on memory of low-arousing experiences. Although both positive and negative emotionally arousing events tend to be well remembered, studies investigating the neural mechanism underlying glucocorticoid-induced memory enhancement focused primarily on negatively motivated training experiences. In the present study we show an involvement of glucocorticoids within the nucleus accumbens (NAc) in enhancing memory consolidation of both an appetitive and aversive form of taste learning. The specific glucocorticoid receptor (GR) agonist RU 28362 (1 or 3ng) administered bilaterally into the NAc shell, but not core, of male Sprague-Dawley rats immediately after an appetitive saccharin drinking experience dose-dependently enhanced 24-h retention of the safe taste, resulting in a facilitated attenuation of neophobia. Similarly, GR agonist infusions given into the NAc shell immediately after pairing of the saccharin taste with a malaise-inducing agent enhanced memory of this negative experience, resulting in an intensified conditioned aversion. Importantly, a suppression of noradrenergic activity within the NAc shell with the β-adrenoceptor antagonist propranolol blocked the facilitating effect of a concurrently administered GR agonist on memory consolidation in both the appetitive and aversive learning task. Thus, these findings indicate that GR activation interacts with the noradrenergic arousal system within the NAc to enhance memory consolidation of emotionally arousing training experiences regardless of valence. Copyright © 2012 Elsevier Inc. All rights reserved.

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.)

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.

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.

Loss aversion in schizophrenia.

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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.

A high-protein diet enhances satiety without conditioned taste aversion in the rat.

Science.gov (United States)

Bensaïd, Ahmed; Tomé, Daniel; L'Heureux-Bourdon, Diane; Even, Patrick; Gietzen, Dorothy; Morens, Céline; Gaudichon, Claire; Larue-Achagiotis, Christiane; Fromentin, Gilles

2003-02-01

In order to determine the respective roles of conditioned food aversion, satiety and palatability, we studied behavioral responses to a 50% total milk protein diet, compared with those to a normal protein diet containing 14% total milk protein. Different paradigms were employed, including meal pattern analysis, two-choice testing, flavor testing, a behavioral satiety sequence (BSS) and taste reactivity. Our experiments showed that only behavioral and food intake parameters were disturbed during the first day when an animal ate the high-protein (P50) diet, and that most parameters returned to baseline values as soon as the second day of P50. Rats adapted to P50 did not acquire a conditioned taste aversion (CTA) but exhibited satiety, and a normal BSS. The initial reduction in high-protein diet intake appeared to result from the lower palatability of the food combined with the satiety effect of the high-protein diet and the delay required for metabolic adaptation to the higher protein level.

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,

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

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.

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

Variant BDNF Val66Met polymorphism affects extinction of conditioned aversive memory.

Science.gov (United States)

Yu, Hui; Wang, Yue; Pattwell, Siobhan; Jing, Deqiang; Liu, Ting; Zhang, Yun; Bath, Kevin G; Lee, Francis S; Chen, Zhe-Yu

2009-04-01

Brain-derived neurotrophic factor (BDNF) plays important roles in activity-dependent plasticity processes, such as long-term potentiation, learning, and memory. The recently reported human BDNF Val66Met (BDNF(Met)) polymorphism has been shown to lead to altered hippocampal volume and impaired hippocampal-dependent memory and is associated with a variety of neuropsychiatric disorders. There are few studies, however, that investigate the effect of the BDNF(Met) polymorphism on hippocampal-independent memory processes. A conditioned taste aversion (CTA) task was used for studying the mechanisms of long-term, hippocampal-independent, nondeclarative memory in the mammalian brain. Using the CTA paradigm, we found a novel impairment in extinction learning, but not acquisition or retention, of aversive memories resulting from the variant BDNF(Met). BDNF(Met) mice were slower to extinguish an aversive CTA memory compared with wild-type counterparts. Moreover, the BDNF(Met) was associated with smaller volume and decreased neuronal dendritic complexity in the ventromedial prefrontal cortex (vmPFC), which plays a significant role in extinction of CTA. Finally, this delay in extinction learning could be rescued pharmacologically with a cognitive enhancer, d-cycloserine (DCS). To our knowledge, this is the first evidence that the BDNF(Met) polymorphism contributes to abnormalities in memory extinction. This abnormality in extinction learning may be explained by alterations in neuronal morphology, as well as decreased neural activity in the vmPFC. Importantly, DCS was effective in rescuing this delay in extinction, suggesting that when coupled with behavior therapy, DCS may be an effective treatment option for anxiety disorders in humans with this genetic variant BDNF.

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.

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.

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

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.

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.

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

Lateral Habenula determines long-term storage of aversive memories.

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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.

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

Aversive olfactory associative memory loses odor specificity over time.

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König, Christian; Antwi-Adjei, Emmanuel; Ganesan, Mathangi; Kilonzo, Kasyoka; Viswanathan, Vignesh; Durairaja, Archana; Voigt, Anne; Yarali, Ayse

2017-05-01

Avoiding associatively learned predictors of danger is crucial for survival. Aversive memories can, however, become counter-adaptive when they are overly generalized to harmless cues and contexts. In a fruit fly odor-electric shock associative memory paradigm, we found that learned avoidance lost its specificity for the trained odor and became general to novel odors within a day of training. We discuss the possible neural circuit mechanisms of this effect and highlight the parallelism to over-generalization of learned fear behavior after an incubation period in rodents and humans, with due relevance for post-traumatic stress disorder. © 2017. Published by The Company of Biologists Ltd.

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

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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.

Colour Separation and Aversion

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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.

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

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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.

The effect of accountability on loss aversion.

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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.

Peer effects in risk aversion.

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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.

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 ...

Incidental fear cues increase monetary loss aversion.

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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).

Unpleasant odors increase aversion to monetary losses.

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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.

Impaired associative learning with food rewards in obese women.

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Zhang, Zhihao; Manson, Kirk F; Schiller, Daniela; Levy, Ifat

2014-08-04

Obesity is a major epidemic in many parts of the world. One of the main factors contributing to obesity is overconsumption of high-fat and high-calorie food, which is driven by the rewarding properties of these types of food. Previous studies have suggested that dysfunction in reward circuits may be associated with overeating and obesity. The nature of this dysfunction, however, is still unknown. Here, we demonstrate impairment in reward-based associative learning specific to food in obese women. Normal-weight and obese participants performed an appetitive reversal learning task in which they had to learn and modify cue-reward associations. To test whether any learning deficits were specific to food reward or were more general, we used a between-subject design in which half of the participants received food reward and the other half received money reward. Our results reveal a marked difference in associative learning between normal-weight and obese women when food was used as reward. Importantly, no learning deficits were observed with money reward. Multiple regression analyses also established a robust negative association between body mass index and learning performance in the food domain in female participants. Interestingly, such impairment was not observed in obese men. These findings suggest that obesity may be linked to impaired reward-based associative learning and that this impairment may be specific to the food domain. Copyright © 2014 Elsevier Ltd. All rights reserved.

The influence of serotonin on fear learning.

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Catherine Hindi Attar

Full Text Available Learning of associations between aversive stimuli and predictive cues is the basis of Pavlovian fear conditioning and is driven by a mismatch between expectation and outcome. To investigate whether serotonin modulates the formation of such aversive cue-outcome associations, we used functional magnetic resonance imaging (fMRI and dietary tryptophan depletion to reduce brain serotonin (5-HT levels in healthy human subjects. In a Pavlovian fear conditioning paradigm, 5-HT depleted subjects compared to a non-depleted control group exhibited attenuated autonomic responses to cues indicating the upcoming of an aversive event. These results were closely paralleled by reduced aversive learning signals in the amygdala and the orbitofrontal cortex, two prominent structures of the neural fear circuit. In agreement with current theories of serotonin as a motivational opponent system to dopamine in fear learning, our data provide first empirical evidence for a role of serotonin in representing formally derived learning signals for aversive events.

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

AFRRI Reports, Third Quarter 1994

Science.gov (United States)

1994-10-01

COLE, S. 0.: Combined effects of chlordiazepoxide treatment and food deprivation on concurrent measures of feeding and activity. Pharmacol... WHITTINGTON , R.: Clinical implications of learned food aversions in patients with cancer treated with chemotherapy or radiation therapy. Cancer 70: 192-200...1992. MATTES, R. D., CURRAN, W. J., POWLIS, W. AND WHITTINGTON R.: A descriptive study of learned food aversions in radiotherapy patients. Physiol

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

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.

Alcohol reduces aversion to ambiguity

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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.

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.

A physiological increase of insulin in the olfactory bulb decreases detection of a learned aversive odor and abolishes food odor-induced sniffing behavior in rats.

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Pascaline Aimé

Full Text Available Insulin is involved in multiple regulatory mechanisms, including body weight and food intake, and plays a critical role in metabolic disorders such as obesity and diabetes. An increasing body of evidence indicates that insulin is also involved in the modulation of olfactory function. The olfactory bulb (OB contains the highest level of insulin and insulin receptors (IRs in the brain. However, a role for insulin in odor detection and sniffing behavior remains to be elucidated. Using a behavioral paradigm based on conditioned olfactory aversion (COA to isoamyl-acetate odor, we demonstrated that an intracerebroventricular (ICV injection of 14 mU insulin acutely decreased olfactory detection of fasted rats to the level observed in satiated animals. In addition, whereas fasted animals demonstrated an increase in respiratory frequency upon food odor detection, this effect was absent in fasted animals receiving a 14 mU insulin ICV injection as well as in satiated animals. In parallel, we showed that the OB and plasma insulin levels were increased in satiated rats compared to fasted rats, and that a 14 mU insulin ICV injection elevated the OB insulin level of fasted rats to that of satiated rats. We further quantified insulin receptors (IRs distribution and showed that IRs are preferentially expressed in the caudal and lateral parts of the main OB, with the highest labeling found in the mitral cells, the main OB projection neurons. Together, these data suggest that insulin acts on the OB network to modulate olfactory processing and demonstrate that olfactory function is under the control of signals involved in energy homeostasis regulation and feeding behaviors.

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

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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

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...

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.

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

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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.

The role of food experiences during early childhood in food pleasure learning.

Science.gov (United States)

Nicklaus, Sophie

2016-09-01

Infants are born equipped to ingest nutrients, but have to learn what to eat. This must occur early, because the mode of feeding evolves dramatically, from "tube" feeding in utero to eating family foods. Eating habits established during early years contribute to the development of subsequent eating habits. Therefore, it is fundamental to understand the most important early periods (between birth and 2 years, i.e. onset of food neophobia) for the development of eating habits and the drivers of this development. The role of pleasure in eating is central, especially during childhood when cognitive drivers of food choices may be less prominent than later in life. It is not easy to define and measure pleasure of eating in early childhood. However, it is possible to identify the characteristics of the eating experience which contribute to drive infant's eating and to shape preferences (food sensory properties; food rewarding properties; social context of eating). The learning processes involve repeated exposure (including to a variety of flavours), association with post-absorptive consequences and with contextual signals (including family members). The important early periods for learning food pleasure start being well identified. Beyond the first flavour discoveries during the prenatal and lactation periods (through the infant's exposure to flavours from foods of the mother's diet), the most important phase may be the beginning of complementary feeding. Infants discover the sensory (texture, taste and flavour) and nutritional properties (energy density) of the foods that will ultimately compose their adult diet; parents are still in charge of providing appropriate foods, timing, context for eating. Inter-individual differences in food pleasure learning, related to temperamental dimensions, or to sensory sensitivity also have to be taken into account. Copyright © 2015 Elsevier Ltd. All rights reserved.

Rho-associated kinase in the gustatory cortex is involved in conditioned taste aversion memory formation but not in memory retrieval or relearning.

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Sweetat, Sahar; Rosenblum, Kobi; Lamprecht, Raphael

2012-01-01

Rho-associated kinase (ROCK) is intimately involved in cortical neuronal morphogenesis. The present study explores the roles of ROCK in conditioned taste aversion (CTA) memory formation in gustatory cortex (GC) in adult rat. Microinjection of the ROCK inhibitor Y-27632 into the GC 30 min before CTA training or 10 min after the conditioned stimulus (CS) impaired long-term CTA memory (LTM) formation. ROCK inhibitor had no effect on taste aversion when injected before the first LTM test day and did not alter taste aversion on subsequent test days. Microinjection of ROCK inhibitor into GC 30 min before preexposure to the taste CS had no effect on latent inhibition of CTA learning suggesting that ROCK is involved in CS-US association rather than taste learning per se. Cumulatively, these results show that ROCK is needed for normal CTA memory formation but not retrieval, relearning or incidental taste learning. Copyright © 2011 Elsevier Inc. All rights reserved.

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

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.

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.

Living and learning food processing

Science.gov (United States)

This year’s annual event promises to be both exciting and educational for those who wish to learn more about food processing. This column will provide a brief overview of the multitude of scientific sessions that reveal new research related to food processing. In addition to the symposia previewed h...

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.

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

Testing the disgust conditioning theory of food-avoidance in adolescents with recent onset anorexia nervosa.

Science.gov (United States)

Hildebrandt, Tom; Grotzinger, Andrew; Reddan, Marianne; Greif, Rebecca; Levy, Ifat; Goodman, Wayne; Schiller, Daniela

2015-08-01

Anorexia nervosa is characterized by chronic food avoidance that is resistant to change. Disgust conditioning offers one potential unexplored mechanism for explaining this behavioral disturbance because of its specific role in facilitating food avoidance in adaptive situations. A food based reversal learning paradigm was used to study response flexibility in 14 adolescent females with restricting subtype anorexia nervosa (AN-R) and 15 healthy control (HC) participants. Expectancy ratings were coded as a behavioral measure of flexibility and electromyography recordings from the levator labii (disgust), zygomaticus major (pleasure), and corrugator (general negative affect) provided psychophysiological measures of emotion. Response inflexibility was higher for participants with AN-R, as evidenced by lower extinction and updated expectancy ratings during reversal. EMG responses to food stimuli were predictive of both extinction and new learning. Among AN-R patients, disgust specific responses to food were associated with impaired extinction, as were elevated pleasure responses to the cued absence of food. Disgust conditioning appears to influence food learning in acutely ill patients with AN-R and may be maintained by counter-regulatory acquisition of a pleasure response to food avoidance and an aversive response to food presence. Developing strategies to target disgust may improve existing interventions for patients with AN. Copyright © 2015 Elsevier Ltd. All rights reserved.

How Infants and Young Children Learn About Food: A Systematic Review

Directory of Open Access Journals (Sweden)

Manon Mura Paroche

2017-07-01

Full Text Available Early childhood is a critical time for establishing food preferences and dietary habits. In order for appropriate advice to be available to parents and healthcare professionals it is essential for researchers to understand the ways in which children learn about foods. This review summarizes the literature relating to the role played by known developmental learning processes in the establishment of early eating behavior, food preferences and general knowledge about food, and identifies gaps in our knowledge that remain to be explored. A systematic literature search identified 48 papers exploring how young children learn about food from the start of complementary feeding to 36 months of age. The majority of the papers focus on evaluative components of children's learning about food, such as their food preferences, liking and acceptance. A smaller number of papers focus on other aspects of what and how children learn about food, such as a food's origins or appropriate eating contexts. The review identified papers relating to four developmental learning processes: (1 Familiarization to a food through repeated exposure to its taste, texture or appearance. This was found to be an effective technique for learning about foods, especially for children at the younger end of our age range. (2 Observational learning of food choice. Imitation of others' eating behavior was also found to play an important role in the first years of life. (3 Associative learning through flavor-nutrient and flavor-flavor learning (FFL. Although the subject of much investigation, conditioning techniques were not found to play a major role in shaping the food preferences of infants in the post-weaning and toddler periods. (4 Categorization of foods. The direct effects of the ability to categorize foods have been little studied in this age group. However, the literature suggests that what infants are willing to consume depends on their ability to recognize items on their plate as

Learning by cases in food technology

DEFF Research Database (Denmark)

Løje, Hanne

2012-01-01

The purpose of this paper is to evaluate the use of the method learning by cases for teaching food technology students at the technical university of Denmark (DTU) and to clarify if the method can be used to improve the motivation and make the students more active and thereby be more in control...... of their own learning process, to feel more secure and less frustrated. The applying of the learning by cases method at the food technology course can make the students to learn in a significantly way, where they will be more actively involved in the learning process than previous. The work with real life...... cases with engineering topics, can develop the students knowledge and understanding, which gives the students a more conceptual understanding of engineering tasks, and can improve their skills to analyze and deal with complex situations and furthermore to be more confident with the course curriculum....

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.

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

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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.

Deciding for Future Selves Reduces Loss Aversion

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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.

Deciding for Future Selves Reduces Loss Aversion.

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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.

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.

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)

Glucocorticoids Enhance Taste Aversion Memory via Actions in the Insular Cortex and Basolateral Amygdala

Science.gov (United States)

Miranda, Maria Isabel; Quirarte, Gina L.; Rodriguez-Garcia, Gabriela; McGaugh, James L.; Roozendaal, Benno

2008-01-01

It is well established that glucocorticoid hormones strengthen the consolidation of hippocampus-dependent spatial and contextual memory. The present experiments investigated glucocorticoid effects on the long-term formation of conditioned taste aversion (CTA), an associative learning task that does not depend critically on hippocampal function.…

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...

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....

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...

Learned helplessness at fifty: Insights from neuroscience.

Science.gov (United States)

Maier, Steven F; Seligman, Martin E P

2016-07-01

Learned helplessness, the failure to escape shock induced by uncontrollable aversive events, was discovered half a century ago. Seligman and Maier (1967) theorized that animals learned that outcomes were independent of their responses-that nothing they did mattered-and that this learning undermined trying to escape. The mechanism of learned helplessness is now very well-charted biologically, and the original theory got it backward. Passivity in response to shock is not learned. It is the default, unlearned response to prolonged aversive events and it is mediated by the serotonergic activity of the dorsal raphe nucleus, which in turn inhibits escape. This passivity can be overcome by learning control, with the activity of the medial prefrontal cortex, which subserves the detection of control leading to the automatic inhibition of the dorsal raphe nucleus. So animals learn that they can control aversive events, but the passive failure to learn to escape is an unlearned reaction to prolonged aversive stimulation. In addition, alterations of the ventromedial prefrontal cortex-dorsal raphe pathway can come to subserve the expectation of control. We speculate that default passivity and the compensating detection and expectation of control may have substantial implications for how to treat depression. (PsycINFO Database Record (c) 2016 APA, all rights reserved).

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

Cannabinoid transmission in the prelimbic cortex bidirectionally controls opiate reward and aversion signaling through dissociable kappa versus μ-opiate receptor dependent mechanisms.

Science.gov (United States)

Ahmad, Tasha; Lauzon, Nicole M; de Jaeger, Xavier; Laviolette, Steven R

2013-09-25

Cannabinoid, dopamine (DA), and opiate receptor pathways play integrative roles in emotional learning, associative memory, and sensory perception. Modulation of cannabinoid CB1 receptor transmission within the medial prefrontal cortex (mPFC) regulates the emotional valence of both rewarding and aversive experiences. Furthermore, CB1 receptor substrates functionally interact with opiate-related motivational processing circuits, particularly in the context of reward-related learning and memory. Considerable evidence demonstrates functional interactions between CB1 and DA signaling pathways during the processing of motivationally salient information. However, the role of mPFC CB1 receptor transmission in the modulation of behavioral opiate-reward processing is not currently known. Using an unbiased conditioned place preference paradigm with rats, we examined the role of intra-mPFC CB1 transmission during opiate reward learning. We report that activation or inhibition of CB1 transmission within the prelimbic cortical (PLC) division of the mPFC bidirectionally regulates the motivational valence of opiates; whereas CB1 activation switched morphine reward signaling into an aversive stimulus, blockade of CB1 transmission potentiated the rewarding properties of normally sub-reward threshold conditioning doses of morphine. Both of these effects were dependent upon DA transmission as systemic blockade of DAergic transmission prevented CB1-dependent modulation of morphine reward and aversion behaviors. We further report that CB1-mediated intra-PLC opiate motivational signaling is mediated through a μ-opiate receptor-dependent reward pathway, or a κ-opiate receptor-dependent aversion pathway, directly within the ventral tegmental area. Our results provide evidence for a novel CB1-mediated motivational valence switching mechanism within the PLC, controlling dissociable subcortical reward and aversion pathways.

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.

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.

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.

Implementation of Real-World Experiential Learning in a Food Science Course Using a Food Industry-Integrated Approach

Science.gov (United States)

Hollis, Francine H.; Eren, Fulya

2016-01-01

Success skills have been ranked as the most important core competency for new food science professionals to have by food science graduates and their employers. It is imperative that food science instructors promote active learning in food science courses through experiential learning activities to enhance student success skills such as oral and…

Long term effects of aversive reinforcement on colour discrimination learning in free-flying bumblebees.

Directory of Open Access Journals (Sweden)

Miguel A Rodríguez-Gironés

Full Text Available The results of behavioural experiments provide important information about the structure and information-processing abilities of the visual system. Nevertheless, if we want to infer from behavioural data how the visual system operates, it is important to know how different learning protocols affect performance and to devise protocols that minimise noise in the response of experimental subjects. The purpose of this work was to investigate how reinforcement schedule and individual variability affect the learning process in a colour discrimination task. Free-flying bumblebees were trained to discriminate between two perceptually similar colours. The target colour was associated with sucrose solution, and the distractor could be associated with water or quinine solution throughout the experiment, or with one substance during the first half of the experiment and the other during the second half. Both acquisition and final performance of the discrimination task (measured as proportion of correct choices were determined by the choice of reinforcer during the first half of the experiment: regardless of whether bees were trained with water or quinine during the second half of the experiment, bees trained with quinine during the first half learned the task faster and performed better during the whole experiment. Our results confirm that the choice of stimuli used during training affects the rate at which colour discrimination tasks are acquired and show that early contact with a strongly aversive stimulus can be sufficient to maintain high levels of attention during several hours. On the other hand, bees which took more time to decide on which flower to alight were more likely to make correct choices than bees which made fast decisions. This result supports the existence of a trade-off between foraging speed and accuracy, and highlights the importance of measuring choice latencies during behavioural experiments focusing on cognitive abilities.

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...

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...

Robust portfolio choice with ambiguity and learning about return predictability

DEFF Research Database (Denmark)

Larsen, Linda Sandris; Branger, Nicole; Munk, Claus

2013-01-01

We analyze the optimal stock-bond portfolio under both learning and ambiguity aversion. Stock returns are predictable by an observable and an unobservable predictor, and the investor has to learn about the latter. Furthermore, the investor is ambiguity-averse and has a preference for investment...... strategies that are robust to model misspecifications. We derive a closed-form solution for the optimal robust investment strategy. We find that both learning and ambiguity aversion impact the level and structure of the optimal stock investment. Suboptimal strategies resulting either from not learning...... or from not considering ambiguity can lead to economically significant losses....

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.

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.

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.

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)

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)

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.

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....

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....

ASIC1a regulates insular long-term depression and is required for the extinction of conditioned taste aversion.

Science.gov (United States)

Li, Wei-Guang; Liu, Ming-Gang; Deng, Shining; Liu, Yan-Mei; Shang, Lin; Ding, Jing; Hsu, Tsan-Ting; Jiang, Qin; Li, Ying; Li, Fei; Zhu, Michael Xi; Xu, Tian-Le

2016-12-07

Acid-sensing ion channel 1a (ASIC1a) has been shown to play important roles in synaptic plasticity, learning and memory. Here we identify a crucial role for ASIC1a in long-term depression (LTD) at mouse insular synapses. Genetic ablation and pharmacological inhibition of ASIC1a reduced the induction probability of LTD without affecting that of long-term potentiation in the insular cortex. The disruption of ASIC1a also attenuated the extinction of established taste aversion memory without altering the initial associative taste learning or its long-term retention. Extinction of taste aversive memory led to the reduced insular synaptic efficacy, which precluded further LTD induction. The impaired LTD and extinction learning in ASIC1a null mice were restored by virus-mediated expression of wild-type ASIC1a, but not its ion-impermeable mutant, in the insular cortices. Our data demonstrate the involvement of an ASIC1a-mediated insular synaptic depression mechanism in extinction learning, which raises the possibility of targeting ASIC1a to manage adaptive behaviours.

Serotonin affects association of aversive outcomes to past actions.

Science.gov (United States)

Tanaka, Saori C; Shishida, Kazuhiro; Schweighofer, Nicolas; Okamoto, Yasumasa; Yamawaki, Shigeto; Doya, Kenji

2009-12-16

Impairment in the serotonergic system has been linked to action choices that are less advantageous in a long run. Such impulsive choices can be caused by a deficit in linking a given reward or punishment with past actions. Here, we tested the effect of manipulation of the serotonergic system by tryptophan depletion and loading on learning the association of current rewards and punishments with past actions. We observed slower associative learning when actions were followed by a delayed punishment in the low serotonergic condition. Furthermore, a model-based analysis revealed a positive correlation between the length of the memory trace for aversive choices and subjects' blood tryptophan concentration. Our results suggest that the serotonergic system regulates the time scale of retrospective association of punishments to past actions.

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.

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

The effects of specified chemical meals on food intake.

Science.gov (United States)

Koopmans, H S; Maggio, C A

1978-10-01

Rats received intragastric infusions of various specified chemical meals and were subsequently tested for a reduction in food intake. A second experiment, using a novel technique, tested for conditioned aversion to the meal infusions. The nonnutritive substances, kaolin clay and emulsified fluorocarbon, had no significant effect on food intake. Infusions of 1 M glucose and 1 M sorbitol reduced feeding behavior, but the 1 M sorbitol infusion also produced a conditioned aversion to flavored pellets paired with the sorbitol infusion, showing that the reduced feeding could have been caused by discomfort. Infusion of a high-fat meal consisting of emulsified triolein mixed with small amounts of sugar and protein or the rat's normal liquid diet, Nutrament, also reduced food intake, and both infusions failed to produce a conditioned aversion. The use of specified meals to understand the chemical basis of satiety requires a sensitive behavioral test to establish that the meal does not cause discomfort or other nonspecific effects.

Region-Specific Involvement of Actin Rearrangement-Related Synaptic Structure Alterations in Conditioned Taste Aversion Memory

Science.gov (United States)

Bi, Ai-Ling; Wang, Yue; Li, Bo-Qin; Wang, Qian-Qian; Ma, Ling; Yu, Hui; Zhao, Ling; Chen, Zhe-Yu

2010-01-01

Actin rearrangement plays an essential role in learning and memory; however, the spatial and temporal regulation of actin dynamics in different phases of associative memory has not been fully understood. Here, using the conditioned taste aversion (CTA) paradigm, we investigated the region-specific involvement of actin rearrangement-related…

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.

Dissociable Learning Processes Underlie Human Pain Conditioning.

Science.gov (United States)

Zhang, Suyi; Mano, Hiroaki; Ganesh, Gowrishankar; Robbins, Trevor; Seymour, Ben

2016-01-11

Pavlovian conditioning underlies many aspects of pain behavior, including fear and threat detection [1], escape and avoidance learning [2], and endogenous analgesia [3]. Although a central role for the amygdala is well established [4], both human and animal studies implicate other brain regions in learning, notably ventral striatum and cerebellum [5]. It remains unclear whether these regions make different contributions to a single aversive learning process or represent independent learning mechanisms that interact to generate the expression of pain-related behavior. We designed a human parallel aversive conditioning paradigm in which different Pavlovian visual cues probabilistically predicted thermal pain primarily to either the left or right arm and studied the acquisition of conditioned Pavlovian responses using combined physiological recordings and fMRI. Using computational modeling based on reinforcement learning theory, we found that conditioning involves two distinct types of learning process. First, a non-specific "preparatory" system learns aversive facial expressions and autonomic responses such as skin conductance. The associated learning signals-the learned associability and prediction error-were correlated with fMRI brain responses in amygdala-striatal regions, corresponding to the classic aversive (fear) learning circuit. Second, a specific lateralized system learns "consummatory" limb-withdrawal responses, detectable with electromyography of the arm to which pain is predicted. Its related learned associability was correlated with responses in ipsilateral cerebellar cortex, suggesting a novel computational role for the cerebellum in pain. In conclusion, our results show that the overall phenotype of conditioned pain behavior depends on two dissociable reinforcement learning circuits. Copyright © 2016 The Authors. Published by Elsevier Ltd.. All rights reserved.

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.

Genetic Dissection of Aversive Associative Olfactory Learning and Memory in Drosophila Larvae

OpenAIRE

Widmann, Annekathrin; Artinger, Marc; Biesinger, Lukas; Boepple, Kathrin; Peters, Christina; Schlechter, Jana; Selcho, Mareike; Thum, Andreas S.

2016-01-01

Memory formation is a highly complex and dynamic process. It consists of different phases, which depend on various neuronal and molecular mechanisms. In adult Drosophila it was shown that memory formation after aversive Pavlovian conditioning includes-besides other forms-a labile short-term component that consolidates within hours to a longer-lasting memory. Accordingly, memory formation requires the timely controlled action of different neuronal circuits, neurotransmitters, neuromodulators a...

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...

Genetic Dissection of Aversive Associative Olfactory Learning and Memory in Drosophila Larvae

Science.gov (United States)

Widmann, Annekathrin; Artinger, Marc; Biesinger, Lukas; Boepple, Kathrin; Schlechter, Jana; Selcho, Mareike; Thum, Andreas S.

2016-01-01

Memory formation is a highly complex and dynamic process. It consists of different phases, which depend on various neuronal and molecular mechanisms. In adult Drosophila it was shown that memory formation after aversive Pavlovian conditioning includes—besides other forms—a labile short-term component that consolidates within hours to a longer-lasting memory. Accordingly, memory formation requires the timely controlled action of different neuronal circuits, neurotransmitters, neuromodulators and molecules that were initially identified by classical forward genetic approaches. Compared to adult Drosophila, memory formation was only sporadically analyzed at its larval stage. Here we deconstruct the larval mnemonic organization after aversive olfactory conditioning. We show that after odor-high salt conditioning larvae form two parallel memory phases; a short lasting component that depends on cyclic adenosine 3’5’-monophosphate (cAMP) signaling and synapsin gene function. In addition, we show for the first time for Drosophila larvae an anesthesia resistant component, which relies on radish and bruchpilot gene function, protein kinase C activity, requires presynaptic output of mushroom body Kenyon cells and dopamine function. Given the numerical simplicity of the larval nervous system this work offers a unique prospect for studying memory formation of defined specifications, at full-brain scope with single-cell, and single-synapse resolution. PMID:27768692

Genetic Dissection of Aversive Associative Olfactory Learning and Memory in Drosophila Larvae.

Science.gov (United States)

Widmann, Annekathrin; Artinger, Marc; Biesinger, Lukas; Boepple, Kathrin; Peters, Christina; Schlechter, Jana; Selcho, Mareike; Thum, Andreas S

2016-10-01

Memory formation is a highly complex and dynamic process. It consists of different phases, which depend on various neuronal and molecular mechanisms. In adult Drosophila it was shown that memory formation after aversive Pavlovian conditioning includes-besides other forms-a labile short-term component that consolidates within hours to a longer-lasting memory. Accordingly, memory formation requires the timely controlled action of different neuronal circuits, neurotransmitters, neuromodulators and molecules that were initially identified by classical forward genetic approaches. Compared to adult Drosophila, memory formation was only sporadically analyzed at its larval stage. Here we deconstruct the larval mnemonic organization after aversive olfactory conditioning. We show that after odor-high salt conditioning larvae form two parallel memory phases; a short lasting component that depends on cyclic adenosine 3'5'-monophosphate (cAMP) signaling and synapsin gene function. In addition, we show for the first time for Drosophila larvae an anesthesia resistant component, which relies on radish and bruchpilot gene function, protein kinase C activity, requires presynaptic output of mushroom body Kenyon cells and dopamine function. Given the numerical simplicity of the larval nervous system this work offers a unique prospect for studying memory formation of defined specifications, at full-brain scope with single-cell, and single-synapse resolution.

Genetic Dissection of Aversive Associative Olfactory Learning and Memory in Drosophila Larvae.

Directory of Open Access Journals (Sweden)

Annekathrin Widmann

2016-10-01

Full Text Available Memory formation is a highly complex and dynamic process. It consists of different phases, which depend on various neuronal and molecular mechanisms. In adult Drosophila it was shown that memory formation after aversive Pavlovian conditioning includes-besides other forms-a labile short-term component that consolidates within hours to a longer-lasting memory. Accordingly, memory formation requires the timely controlled action of different neuronal circuits, neurotransmitters, neuromodulators and molecules that were initially identified by classical forward genetic approaches. Compared to adult Drosophila, memory formation was only sporadically analyzed at its larval stage. Here we deconstruct the larval mnemonic organization after aversive olfactory conditioning. We show that after odor-high salt conditioning larvae form two parallel memory phases; a short lasting component that depends on cyclic adenosine 3'5'-monophosphate (cAMP signaling and synapsin gene function. In addition, we show for the first time for Drosophila larvae an anesthesia resistant component, which relies on radish and bruchpilot gene function, protein kinase C activity, requires presynaptic output of mushroom body Kenyon cells and dopamine function. Given the numerical simplicity of the larval nervous system this work offers a unique prospect for studying memory formation of defined specifications, at full-brain scope with single-cell, and single-synapse resolution.

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...

Bitter receptor gene (TAS2R38) P49A genotypes and their associations with aversion to vegetables and sweet/fat foods in Malaysian subjects.

Science.gov (United States)

Ooi, Shee-Xuen; Lee, Pui-Leng; Law, Huey-Yi; Say, Yee-How

2010-01-01

Recently, the bitter receptor gene (TAS2R38) was identified to be responsible for phenylthiocarbamide (PTC) bitter sensitivity. Its two predominant haplotypes at three Single Nucleotide Polymorphisms (SNPs) are found to be definitive for the PTC status, which the ProAlaVal and AlaValIle haplotypes are associated with tasters and non-tasters, respectively. TAS2R38 haplotypes have been reported to influence food preferences (like cruciferous vegetables and fat foods) and cardiovascular disease risk factors. We examined, in 215 Malaysian subjects (100 males, 115 females), the association of the P49A SNP of TAS2R38 with anthropometric measurements and aversion to a list of 36 vegetables, 4 soy products, green tea and 37 sweet/fat foods. The subjects were successfully genotyped as 110 PA, 81 PP and 24 AA (with the A49 allelic frequency of 0.37), by Polymerase Chain Reaction-Restriction Fragment Length Polymorphism (PCR-RFLP). Ethnicity (Malay, Chinese or Indian), but not gender, was associated with the P49A TAS2R38 genotypes (pfoods, were associated with the P49A genotypes (pfoods in the sampled Malaysian subjects, and this suggests the existence of other possible factors influencing food selection among Malaysians.

Cerebral Giant Cells are Necessary for the Formation and Recall of Memory of Conditioned Taste Aversion in Lymnaea.

Science.gov (United States)

Sunada, Hiroshi; Lukowiak, Ken; Ito, Etsuro

2017-02-01

The pond snail Lymnaea stagnalis can acquire conditioned taste aversion (CTA) as a long-term memory. CTA is caused by the temporal pairing of a stimulus, such as sucrose (the conditioned stimulus; CS), with another stimulus, such as electric shock (the unconditioned stimulus; US). Previous studies have demonstrated changes in both cellular and molecular properties in a pair of neurons known as the cerebral giant cells (CGCs), suggesting that these neurons play a key role in CTA. Here we examined the necessity of the pair of CGC somata for the learning, memory formation and memory recall of CTA by using the soma ablation technique. There was no difference in the feeding response elicited by the CS before and after ablation of the CGC somata. Ablation of the CGC somata before taste-aversion training resulted in the learning acquisition, but the memory formation was not observed 24 h later. We next asked whether memory was present when the CGC somata were ablated 24 h after taste-aversion training. The memory was present before performing the somata ablation. However, when we tested snails five days after somata ablation, the memory recall was not present. Together the data show that: 1) the somata of the CGCs are not necessary for learning acquisition; 2) the somata are necessary for memory formation; and 3) the somata are necessary for memory recall. That is, these results demonstrate that the CGCs function in the long-term memory of CTA in Lymnaea.

Learning Styles of Mexican Food Science and Engineering Students

Science.gov (United States)

Palou, Enrique

2006-01-01

People have different learning styles that are reflected in different academic strengths, weaknesses, skills, and interests. Given the almost unlimited variety of job descriptions within food science and engineering, it is safe to say that students with every possible learning style have the potential to succeed as food scientists and engineers.…

Serotonin and dopamine in the parabrachial nucleus of rats during conditioned taste aversion learning

Czech Academy of Sciences Publication Activity Database

Zach, P.; Křivánek, Jiří; Valeš, Karel

2006-01-01

Roč. 170, č. 2 (2006), s. 271-276 ISSN 0166-4328 R&D Projects: GA MŠk(CZ) 1M0517 Institutional research plan: CEZ:AV0Z5011922 Keywords : taste aversion * microdialysis * parabrachial nucleus Subject RIV: FH - Neurology Impact factor: 2.591, year: 2006

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

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.

Acute Social Stress Engages Synergistic Activity of Stress Mediators in the VTA to Promote Pavlovian Reward Learning

OpenAIRE

Kan, Russell; Pomrenze, Matthew; Tovar-Diaz, Jorge; Morikawa, Hitoshi; Drew, Michael; Pahlavan, Bahram

2017-01-01

Stressful events rapidly trigger activity-dependent synaptic plasticity in certain brain areas, driving the formation of aversive memories. However, it remains unclear how stressful experience affects plasticity mechanisms to regulate learning of appetitive events, such as intake of addictive drugs or palatable foods. Using rats, we show that two acute stress mediators, corticotropin-releasing factor (CRF) and norepinephrine (NE), enhance plasticity of NMDA receptor-mediated glutamatergic tra...

The endocannabinoid system and associative learning and memory in zebrafish.

Science.gov (United States)

Ruhl, Tim; Moesbauer, Kirstin; Oellers, Nadine; von der Emde, Gerhard

2015-09-01

In zebrafish the medial pallium of the dorsal telencephalon represents an amygdala homolog structure, which is crucially involved in emotional associative learning and memory. Similar to the mammalian amygdala, the medial pallium contains a high density of endocannabinoid receptor CB1. To elucidate the role of the zebrafish endocannabinoid system in associative learning, we tested the influence of acute and chronic administration of receptor agonists (THC, WIN55,212-2) and antagonists (Rimonabant, AM-281) on two different learning paradigms. In an appetitively motivated two-alternative choice paradigm, animals learned to associate a certain color with a food reward. In a second set-up, a fish shuttle-box, animals associated the onset of a light stimulus with the occurrence of a subsequent electric shock (avoidance conditioning). Once fish successfully had learned to solve these behavioral tasks, acute receptor activation or inactivation had no effect on memory retrieval, suggesting that established associative memories were stable and not alterable by the endocannabinoid system. In both learning tasks, chronic treatment with receptor antagonists improved acquisition learning, and additionally facilitated reversal learning during color discrimination. In contrast, chronic CB1 activation prevented aversively motivated acquisition learning, while different effects were found on appetitively motivated acquisition learning. While THC significantly improved behavioral performance, WIN55,212-2 significantly impaired color association. Our findings suggest that the zebrafish endocannabinoid system can modulate associative learning and memory. Stimulation of the CB1 receptor might play a more specific role in acquisition and storage of aversive learning and memory, while CB1 blocking induces general enhancement of cognitive functions. Copyright © 2015 Elsevier B.V. All rights reserved.

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.

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.

The Yerkes-Dodson law and appropriate stimuli for conditioned taste aversion in Lymnaea.

Science.gov (United States)

Ito, Etsuro; Yamagishi, Miki; Takigami, Satoshi; Sakakibara, Manabu; Fujito, Yutaka; Lukowiak, Ken

2015-02-01

The pond snail Lymnaea stagnalis can learn conditioned taste aversion and then consolidate it into long-term memory (LTM). A high-voltage electric shock was used as the unconditioned stimulus, where we have previously used KCl. We varied the strength of both the conditioned and unconditioned stimuli to determine whether the so-called Yerkes-Dodson law prevailed. This is an empirical relationship between the state of arousal and LTM formation, showing that there is an optimal level of arousal leading to memory formation. However, too little or too much arousal results in poorer LTM. We found here that the most appropriate stimuli to use in taste aversion training in Lymnaea were a 10 mmol l(-1) sucrose solution as the conditioned stimulus and a 3 s electric shock as the unconditioned stimulus. © 2015. Published by The Company of Biologists Ltd.

Ecological origins of object salience: reward, uncertainty, aversiveness and novelty

Directory of Open Access Journals (Sweden)

Ali Ghazizadeh

2016-08-01

Full Text Available Among many objects around us, some of them are more salient than others (i.e., attract our attention automatically. Some objects may be inherently salient (e.g., brighter, but others may become salient by virtue of their ecological relevance through experience. However, the importance of ecological experience in guiding attention has not been studied systematically. To address this question, we let subjects (macaque monkeys view a large number of complex objects (>300, each experienced repeatedly (>5 days with rewarding, aversive or no outcome association (mere-perceptual exposure. Test of salience was done on separate days using free viewing with no outcome. We found that gaze was biased among the objects from the outset, affecting saccades to objects or fixations within objects. When the outcome was rewarding, gaze preference was stronger (i.e. positive for objects with larger or equal but uncertain rewards. The effects of aversive outcomes were variable. Gaze preference was positive for some outcome associations (e.g. airpuff, but negative for others (e.g. time-out, possibly due to differences in threat levels. Finally, novel objects attracted gaze, but mere perceptual exposure of objects reduced their salience (learned negative salience. Our results show that, in primates, object salience is strongly influenced by previous ecological experience and is supported by a large memory capacity. Owing to such learned salience, the capacity to rapidly choose important objects can grow during the entire life to promote biological fitness.

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.

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.

The Antimetabolite ara-CTP Blocks Long-Term Memory of Conditioned Taste Aversion

OpenAIRE

Wang, Jianpeng; Ren, Keqin; Pérez, Javier; Silva, Alcino J.; Peña de Ortiz, Sandra

2003-01-01

We examined the hypothesis that processes related to DNA recombination and repair are involved in learning and memory. Rats received intracerebroventricular (icv) infusions of the antimetabolite 1-beta-D-arabinofuranosylcytosine triphosphate (ara-CTP) or its precursor cytosine arabinoside (ara-C) 30 min prior to conditioned taste aversion (CTA) training. Both ara-CTP and ara-C caused significant impairments in long-term memory (LTM) of CTA. Control experiments indicate that the effect of ara-...

Effects of consumer-producer interactions in alternative food networks on consumers’ learning about food and agriculture

Directory of Open Access Journals (Sweden)

Opitz Ina

2017-09-01

Full Text Available In the recent literature, Alternative Food Networks (AFN are discussed as a promising approach, at the urban-rural interface, to meeting the challenges of the current agri-food system. Consumer-producer collaboration is seen as a characteristic feature in this context. What is lacking, however, are general concepts for describing the topics of consumer-producer interactions (CPI. The present study aims (1 to develop an analytical framework relying on six CPI domains and (2 to apply it to investigate CPI effects on consumers’ learning about and appreciation of agriculture. We conducted 26 guided interviews with consumers and producers of the three most frequent AFN types in Germany: community-supported agriculture (CSA, food coops, and self-harvest gardens. The results show that AFN participation enhances consumers’ learning about food (seasonality, cooking/nutrition, housekeeping aspects and agricultural production (farmers’ perspectives, cultivation. Our results show that consumer’s learning is influenced by certain CPI domains, and each AFN type can be described by distinctive CPI domains. This led to the conclusion that specific AFN types open up specific learning channels and contents, with consumers learning from producers. AFNs at the urban-rural interface exploit knowledge of rurality.

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

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.

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.

Long-Term Visuo-Gustatory Appetitive and Aversive Conditioning Potentiate Human Visual Evoked Potentials

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Gert R. J. Christoffersen

2017-09-01

Full Text Available Human recognition of foods and beverages are often based on visual cues associated with flavors. The dynamics of neurophysiological plasticity related to acquisition of such long-term associations has only recently become the target of investigation. In the present work, the effects of appetitive and aversive visuo-gustatory conditioning were studied with high density EEG-recordings focusing on late components in the visual evoked potentials (VEPs, specifically the N2-P3 waves. Unfamiliar images were paired with either a pleasant or an unpleasant juice and VEPs evoked by the images were compared before and 1 day after the pairings. In electrodes located over posterior visual cortex areas, the following changes were observed after conditioning: the amplitude from the N2-peak to the P3-peak increased and the N2 peak delay was reduced. The percentage increase of N2-to-P3 amplitudes was asymmetrically distributed over the posterior hemispheres despite the fact that the images were bilaterally symmetrical across the two visual hemifields. The percentage increases of N2-to-P3 amplitudes in each experimental subject correlated with the subject’s evaluation of positive or negative hedonic valences of the two juices. The results from 118 scalp electrodes gave surface maps of theta power distributions showing increased power over posterior visual areas after the pairings. Source current distributions calculated from swLORETA revealed that visual evoked currents rose as a result of conditioning in five cortical regions—from primary visual areas and into the inferior temporal gyrus (ITG. These learning-induced changes were seen after both appetitive and aversive training while a sham trained control group showed no changes. It is concluded that long-term visuo-gustatory conditioning potentiated the N2-P3 complex, and it is suggested that the changes are regulated by the perceived hedonic valence of the US.

Risk-Averse Newsvendor Model with Strategic Consumer Behavior

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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.

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....

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…

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...

Enhancing Adaptive Capacity in Food Systems: Learning at Farmers' Markets in Sweden

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Rebecka Milestad

2010-09-01

Full Text Available This article examines how local food systems in the form of farmers' markets can enhance adaptive capacity and build social-ecological resilience. It does this by exploring the learning potential among farmers and customers. Learning can enable actors to adapt successfully and thus build adaptive capacity. Three forms of learning are investigated: instrumental, communicative, and emancipatory. These forms of learning constitute the foundation for lasting changes of behaviors. Local food systems are characterized by close links and opportunities for face-to-face interactions between consumers and producers of food, and are also institutions where farmers and customers can express and act upon their ethical values concerning food. However, local food systems are still a marginal phenomenon and cannot be accessed by all consumers. Interviews were held with customers and farmers, and the interactions between farmers and customers were observed at two farmers' markets in Sweden. Customers and farmers were found to learn and adapt to each other due to the opportunities offered by the farmers' markets. We found that farmers and customers learned in the instrumental and communicative domains, but could not confirm emancipatory learning. We concluded that the feedback between customers and farmers offers the potential for learning, which in turn contributes to adaptive capacity. This can be a driving force for building resilience in the food system.

Memory reconsolidation in aversive and appetitive settings

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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.

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.

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.

Systemic 5-Bromo-2-Deoxyuridine Induces Conditioned Flavor Aversion and C-Fos in the Visceral Neuraxis

Science.gov (United States)

Kimbrough, Adam; Kwon, Bumsup; Eckel, Lisa A.; Houpt, Thomas A.

2011-01-01

5-bromo-2-deoxyuridine (BrdU) is often used in studies of adult neurogenesis and olfactory learning, but it can also have toxic effects on highly proliferative tissue. We found that pairing Kool-Aid flavors with acute systemic injections of BrdU induced strong conditioned flavor aversions. Intermittent injections during Kool-Aid-glucose…

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.

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.

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.

Orexin/hypocretin system modulates amygdala-dependent threat learning through the locus coeruleus

Science.gov (United States)

Sears, Robert M.; Fink, Ann E.; Wigestrand, Mattis B.; Farb, Claudia R.; de Lecea, Luis; LeDoux, Joseph E.

2013-01-01

Survival in a dangerous environment requires learning about stimuli that predict harm. Although recent work has focused on the amygdala as the locus of aversive memory formation, the hypothalamus has long been implicated in emotional regulation, and the hypothalamic neuropeptide orexin (hypocretin) is involved in anxiety states and arousal. Nevertheless, little is known about the role of orexin in aversive memory formation. Using a combination of behavioral pharmacology, slice physiology, and optogenetic techniques, we show that orexin acts upstream of the amygdala via the noradrenergic locus coeruleus to enable threat (fear) learning, specifically during the aversive event. Our results are consistent with clinical studies linking orexin levels to aversive learning and anxiety in humans and dysregulation of the orexin system may contribute to the etiology of fear and anxiety disorders. PMID:24277819

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

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

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.

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

Lesions of the lateral habenula increase voluntary ethanol consumption and operant self-administration, block yohimbine-induced reinstatement of ethanol seeking, and attenuate ethanol-induced conditioned taste aversion.

Directory of Open Access Journals (Sweden)

Andrew K Haack

Full Text Available The lateral habenula (LHb plays an important role in learning driven by negative outcomes. Many drugs of abuse, including ethanol, have dose-dependent aversive effects that act to limit intake of the drug. However, the role of the LHb in regulating ethanol intake is unknown. In the present study, we compared voluntary ethanol consumption and self-administration, yohimbine-induced reinstatement of ethanol seeking, and ethanol-induced conditioned taste aversion in rats with sham or LHb lesions. In rats given home cage access to 20% ethanol in an intermittent access two bottle choice paradigm, lesioned animals escalated their voluntary ethanol consumption more rapidly than sham-lesioned control animals and maintained higher stable rates of voluntary ethanol intake. Similarly, lesioned animals exhibited higher rates of responding for ethanol in operant self-administration sessions. In addition, LHb lesion blocked yohimbine-induced reinstatement of ethanol seeking after extinction. Finally, LHb lesion significantly attenuated an ethanol-induced conditioned taste aversion. Our results demonstrate an important role for the LHb in multiple facets of ethanol-directed behavior, and further suggest that the LHb may contribute to ethanol-directed behaviors by mediating learning driven by the aversive effects of the drug.

Failure to produce taste-aversion learning in rats exposed to static electric fields and air ions

Energy Technology Data Exchange (ETDEWEB)

Creim, J.A.; Lovely, R.H.; Weigel, R.J.; Forsythe, W.C.; Anderson, L.E. [Pacific Northwest Labs., Richland, WA (United States)

1995-12-01

Taste-aversion (TA) learning was measured to determine whether exposure to high-voltage direct current (HVdc) static electric fields can produce TA learning in male Long Evans rats. Fifty-six rats were randomly distributed into four groups of 14 rats each. All rats were placed on a 20 min/day drinking schedule for 12 consecutive days prior to receiving five conditioning trials. During the conditioning trials, access to 0.1% sodium saccharin-flavored water was given for 20 min, followed 30 min later by one of four treatments. Two groups of 14 rats each were individually exposed to static electric fields and air ions, one group to +75 kV/m (+2 {times} 10{sup 5} air ions/cm{sup 3}) and the other group to {minus}75 kV/m ({minus}2 {times} 10{sup 5} air ions/cm{sup 3}). Two other groups of 14 rats each served as sham-exposed controls, with the following variation in one of the sham-exposed groups: this group was subdivided into two subsets of seven rats each, so that a positive control group could be included to validate the experimental design. The positive control group (n = 7) was injected with cyclophosphamide 25 mg/kg, i.p., 30 min after access to saccharin-flavored water on conditioning days, whereas the other subset of seven rats was similarly injected with an equivalent volume of saline. Access to saccharin-flavored water on conditioning days was followed by the treatments described above and was alternated daily with water recovery sessions in which the rats received access to water for 20 min in the home cage without further treatment. Following the last water-recovery session, a 20 min, two-bottle preference test (between water and saccharin-flavored water) was administered to each group. The positive control group did show TA learning, thus validating the experimental protocol.

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

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...

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

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.

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.

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.

Learning and Memory

OpenAIRE

1999-01-01

Under various circumstances and in different species the outward expression of learning varies considerably, and this has led to the classification of different categories of learning. Just as there is no generally agreed on definition of learning, there is no one system of classification. Types of learning commonly recognized are: Habituation, sensitization, classical conditioning, operant conditioning, trial and error, taste aversion, latent learning, cultural learning, imprinting, insight ...

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.

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.

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.

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

Directory of Open Access Journals (Sweden)

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.

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.

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.

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

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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

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

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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.

Enhanced striatal sensitivity to aversive reinforcement in adolescents versus adults.

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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.

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...

Food security: what the community wants. Learning through focus groups.

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Hargrove, D; Dewolfe, J A; Thompson, L

1994-01-01

We used focus groups to learn the range of issues threatening food security of low income residents in our community. Five major themes emerged from the discussions: literacy, money, time, mental health and self-esteem, suggesting several approaches that could help ensure food security: 1) education, 2) sharing of resources, 3) coalition building, and 4) advocacy. Education programs have to be practical, allowing for demonstrations and hands-on learning while emphasizing skill building and problem solving. Incorporating a social aspect into learning may compensate for the social isolation and would capitalize on the impressive mutual support we witnessed. Strategies based on self-help and peer assistance may counteract low self-esteem and overcome suspicion of health professionals. A community-wide effort is needed to address the factors contributing to food insecurity. We envision the formation of a coalition of professionals, agencies, and low income people to develop a comprehensive strategy for achieving food security.

Endowment effects for hedonic and utilitarian food products

NARCIS (Netherlands)

Cramer, L.; Antonides, G.

2011-01-01

Part of consumer food habits may be explained by reference effects, status quo bias and loss aversion, but little research has focused on these processes in food choices. This paper is a first attempt at understanding the impact of these effects in consumer decision making with respect to hedonic

Glia protein aquaporin-4 regulates aversive motivation of spatial memory in Morris water maze.

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Zhang, Ji; Li, Ying; Chen, Zhong-Guo; Dang, Hui; Ding, Jian-Hua; Fan, Yi; Hu, Gang

2013-12-01

Although extensive investigation has revealed that an astrocyte-specific protein aquaporin-4 (AQP4) participates in regulating synaptic plasticity and memory, a functional relationship between AQP4 and learning processing has not been clearly established. This study was designed to test our hypothesis that AQP4 modulates the aversive motivation in Morris water maze (MWM). Using hidden platform training, we observed that AQP4 KO mice significantly decreased their swimming velocity compared with wild-type (WT) mice. To test for a relationship between velocities and escape motivation, we removed the platform and subjected a new group of mice similar to the session of hidden platform training. We found that KO mice exhibited a gradual reduction in swimming velocity, while WT mice did not alter their velocity. In the subsequent probe trial, KO mice after no platform training significantly decreased their mean velocity compared with those KO mice after hide platform training. However, all of KO mice were not impaired in their ability to locate a visible, cued escape platform. Our findings, along with a previous report that AQP4 regulates memory consolidation, implicate a novel role for this glial protein in modulating the aversive motivation in spatial learning paradigm. © 2013 John Wiley & Sons Ltd.

Aversive properties of negative incentive shifts in Fischer 344 and Lewis rats

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Brewer, Adam; Johnson, Patrick; Stein, Jeff; Schlund, Michael; Williams, Dean C.

2018-01-01

Research on incentive contrast highlights that reward value is not absolute but rather is based upon comparisons we make to rewards we have received and expect to receive. Both human and nonhuman studies on incentive contrast show that shifting from a larger more-valued reward to a smaller less-valued reward is associated with long periods of nonresponding—a negative contrast effect. In this investigation, we used two different genetic rat strains, Fischer 344 and Lewis rats that putatively differ in their sensitivity to aversive stimulation, to assess the aversive properties of large-to-small reward shifts (negative incentive shifts). Additionally, we examined the extent to which increasing cost (fixed-ratio requirements) modulates negative contrast effects. In the presence of a cue that signaled the upcoming reward magnitude, lever pressing was reinforced with one of two different magnitudes of food (large or small). This design created two contrast shifts (small-to-large, large-to-small) and two shifts used as control conditions (small-to-small, large-to-large). Results showed a significant interaction between rat strain and cost requirements only during the negative incentive shift with the emotionally reactive Fischer 344 rats exhibiting significantly longer response latencies with increasing cost, highlighting greater negative contrast. These findings are more consistent with emotionality accounts of negative contrast and results of neurophysiological research that suggests shifting from a large to a small reward is aversive. Findings also highlight how subjective reward value and motivation is a product of gene-environment interactions. PMID:27864048

Dietary GABA and food selection by rats.

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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.

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.

Differential participation of temporal structures in the consolidation and reconsolidation of taste aversion extinction.

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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.

Work-related lifelong learning for entrepreneurs in the agri-food sector

NARCIS (Netherlands)

Lans, T.; Wesselink, R.; Biemans, H.J.A.; Mulder, M.

2004-01-01

This article presents a study on work-related lifelong learning for entrepreneurs in the agri-food sector. Accordingly, learning needs, learning preferences, learning motivation and conditions in the context of lifelong learning were identified. The results indicate that technology, IT and

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...

Memory of conditioned taste aversion is erased by inhibition of PI3K in the insular cortex.

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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.

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.

Salivary peptide tyrosine-tyrosine 3-36 modulates ingestive behavior without inducing taste aversion.

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Hurtado, Maria D; Sergeyev, Valeriy G; Acosta, Andres; Spegele, Michael; La Sala, Michael; Waler, Nickolas J; Chiriboga-Hurtado, Juan; Currlin, Seth W; Herzog, Herbert; Dotson, Cedrick D; Gorbatyuk, Oleg S; Zolotukhin, Sergei

2013-11-20

Hormone peptide tyrosine-tyrosine (PYY) is secreted into circulation from the gut L-endocrine cells in response to food intake, thus inducing satiation during interaction with its preferred receptor, Y2R. Clinical applications of systemically administered PYY for the purpose of reducing body weight were compromised as a result of the common side effect of visceral sickness. We describe here a novel approach of elevating PYY in saliva in mice, which, although reliably inducing strong anorexic responses, does not cause aversive reactions. The augmentation of salivary PYY activated forebrain areas known to mediate feeding, hunger, and satiation while minimally affecting brainstem chemoreceptor zones triggering nausea. By comparing neuronal pathways activated by systemic versus salivary PYY, we identified a metabolic circuit associated with Y2R-positive cells in the oral cavity and extending through brainstem nuclei into hypothalamic satiety centers. The discovery of this alternative circuit that regulates ingestive behavior without inducing taste aversion may open the possibility of a therapeutic application of PYY for the treatment of obesity via direct oral application.

e-Learning Course on Food Irradiation

International Nuclear Information System (INIS)

Hénon, Yves

2016-01-01

Since May 2015, an online, interactive, multi-media and self-study course on Food Irradiation - Technology, Applications and Good Practices has been made available by the Food and Environmental Protection Section. This e-learning Course on Food Irradiation was initiated during a project (RAS/05/057) of the Regional Cooperative Agreement (RCA) Implementing Best Practices of Food Irradiation for Sanitary and Phytosanitary Purposes. Each module contains: • A lesson, largely based on the Manual of Good Practice in Food except for the first part (Food Irradiation) for which expanding the contents and addressing frequently asked questions seemed necessary. The latest chapters will help operators of irradiation facilities to appreciate and improve their practices. • A section called ‘Essentials’ that summarizes the key points. • A quiz to assess the knowledge acquired by the user from the course material. The quiz questions take a variety of forms: answer matching, multiple choice, true or false, picture selection, or simple calculation. Videos, Power Point presentations, pdf files and pictures enrich the contents. The course includes a glossary and approximately 80 downloadable references. These references cover safety of irradiated food, effects of irradiation on the nutritional quality of food, effects of irradiation on food microorganisms, insects and parasites, effects of irradiation on parasites, sanitary and phytosanitary applications of irradiation, packaging of irradiated food, food irradiation standards and regulations, history of food irradiation, and communication aspects.

Commercial Foods and Culinary Arts. Student Learning Guide.

Science.gov (United States)

Palm Beach County Board of Public Instruction, West Palm Beach, FL.

This student learning guide contains one module for completing a course in commercial foods and culinary arts. It is designed especially for use in secondary schools in Palm Beach County, Florida. The module covers one task, and consists of a purpose, performance objective, enabling objectives, learning activities keyed to resources, information…

The Small GTPase Rac1 Contributes to Extinction of Aversive Memories of Drug Withdrawal by Facilitating GABAA Receptor Endocytosis in the vmPFC.

Science.gov (United States)

Wang, Weisheng; Ju, Yun-Yue; Zhou, Qi-Xin; Tang, Jian-Xin; Li, Meng; Zhang, Lei; Kang, Shuo; Chen, Zhong-Guo; Wang, Yu-Jun; Ji, Hui; Ding, Yu-Qiang; Xu, Lin; Liu, Jing-Gen

2017-07-26

Extinction of aversive memories has been a major concern in neuropsychiatric disorders, such as anxiety disorders and drug addiction. However, the mechanisms underlying extinction of aversive memories are not fully understood. Here, we report that extinction of conditioned place aversion (CPA) to naloxone-precipitated opiate withdrawal in male rats activates Rho GTPase Rac1 in the ventromedial prefrontal cortex (vmPFC) in a BDNF-dependent manner, which determines GABA A receptor (GABA A R) endocytosis via triggering synaptic translocation of activity-regulated cytoskeleton-associated protein (Arc) through facilitating actin polymerization. Active Rac1 is essential and sufficient for GABA A R endocytosis and CPA extinction. Knockdown of Rac1 expression within the vmPFC of rats using Rac1-shRNA suppressed GABA A R endocytosis and CPA extinction, whereas expression of a constitutively active form of Rac1 accelerated GABA A R endocytosis and CPA extinction. The crucial role of GABA A R endocytosis in the LTP induction and CPA extinction is evinced by the findings that blockade of GABA A R endocytosis by a dynamin function-blocking peptide (Myr-P4) abolishes LTP induction and CPA extinction. Thus, the present study provides first evidence that Rac1-dependent GABA A R endocytosis plays a crucial role in extinction of aversive memories and reveals the sequence of molecular events that contribute to learning experience modulation of synaptic GABA A R endocytosis. SIGNIFICANCE STATEMENT This study reveals that Rac1-dependent GABA A R endocytosis plays a crucial role in extinction of aversive memories associated with drug withdrawal and identifies Arc as a downstream effector of Rac1 regulations of synaptic plasticity as well as learning and memory, thereby suggesting therapeutic targets to promote extinction of the unwanted memories. Copyright © 2017 the authors 0270-6474/17/377096-15$15.00/0.

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

Development switch in neural circuitry underlying odor-malaise learning.

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Shionoya, Kiseko; Moriceau, Stephanie; Lunday, Lauren; Miner, Cathrine; Roth, Tania L; Sullivan, Regina M

2006-01-01

Fetal and infant rats can learn to avoid odors paired with illness before development of brain areas supporting this learning in adults, suggesting an alternate learning circuit. Here we begin to document the transition from the infant to adult neural circuit underlying odor-malaise avoidance learning using LiCl (0.3 M; 1% of body weight, ip) and a 30-min peppermint-odor exposure. Conditioning groups included: Paired odor-LiCl, Paired odor-LiCl-Nursing, LiCl, and odor-saline. Results showed that Paired LiCl-odor conditioning induced a learned odor aversion in postnatal day (PN) 7, 12, and 23 pups. Odor-LiCl Paired Nursing induced a learned odor preference in PN7 and PN12 pups but blocked learning in PN23 pups. 14C 2-deoxyglucose (2-DG) autoradiography indicated enhanced olfactory bulb activity in PN7 and PN12 pups with odor preference and avoidance learning. The odor aversion in weanling aged (PN23) pups resulted in enhanced amygdala activity in Paired odor-LiCl pups, but not if they were nursing. Thus, the neural circuit supporting malaise-induced aversions changes over development, indicating that similar infant and adult-learned behaviors may have distinct neural circuits.

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.

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

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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

Neurocognitive development of risk aversion from early childhood to adulthood

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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.

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

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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.

Dopamine and octopamine influence avoidance learning of honey bees in a place preference assay.

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Maitreyi Agarwal

Full Text Available Biogenic amines are widely characterized in pathways evaluating reward and punishment, resulting in appropriate aversive or appetitive responses of vertebrates and invertebrates. We utilized the honey bee model and a newly developed spatial avoidance conditioning assay to probe effects of biogenic amines octopamine (OA and dopamine (DA on avoidance learning. In this new protocol non-harnessed bees associate a spatial color cue with mild electric shock punishment. After a number of experiences with color and shock the bees no longer enter the compartment associated with punishment. Intrinsic aspects of avoidance conditioning are associated with natural behavior of bees such as punishment (lack of food, explosive pollination mechanisms, danger of predation, heat, etc. and their association to floral traits or other spatial cues during foraging. The results show that DA reduces the punishment received whereas octopamine OA increases the punishment received. These effects are dose-dependent and specific to the acquisition phase of training. The effects during acquisition are specific as shown in experiments using the antagonists Pimozide and Mianserin for DA and OA receptors, respectively. This study demonstrates the integrative role of biogenic amines in aversive learning in the honey bee as modeled in a novel non-appetitive avoidance learning assay.

Trends and consequences of consumption of food and non-food items (pica by pregnant women in Western Kenya

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Lucy Kariuki

2016-12-01

Food cravings, aversions and pica practices should be assessed in antenatal care of pregnant women. Attention should be paid to pregnant women who have had a history of child death and women with low education level.

Work-Related Lifelong Learning for Entrepreneurs in the Agri-Food Sector

Science.gov (United States)

Lans, Thomas; Wesselink, Renate; Biemans, Harm J. A.; Mulder, Martin

2004-01-01

This article presents a study on work-related lifelong learning for entrepreneurs in the agri-food sector. Accordingly, learning needs, learning preferences, learning motivation and conditions in the context of lifelong learning were identified. The results indicate that technology, IT and entrepreneurial competencies will become of increasing…

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 ...

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.

Effects of area postrema lesions on taste aversions produced by treatment with WR-2721 in the rat

International Nuclear Information System (INIS)

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

1986-01-01

The conditioned taste aversion procedure was used to further assess some behavioral effects of treatment with the putative radioprotectant WR-2721 and the role of the area postrema in mediating the behavioral effects of treatment. Treatment with 40, 150 or 300 mg/kg WR-2721 produced dose-dependent changes in sucrose intake in both control rats and rats with area postrema lesions. The effectiveness of the lesion in disrupting the acquisition of an aversion varied as a function of the dose administered, with the lesions producing the greatest disruption of aversion learning at the lowest dose and little disruption at the highest dose tested. At all dose levels, sucrose intake was greater for the rats with area postrema lesions than for the sham-operated control rats. Treatment with WR-2721 also produced significant decreases in total fluid intake, particularly at the higher dose levels. The results are discussed as indicating that treatment with WR-2721 produces highly toxic effects on behavior and that the use of the compound as a radioprotectant for radiotherapy requires additional assessment of its effects on brain function and behavior

Flavor Dependent Retention of Remote Food Preference Memory.

Science.gov (United States)

Singh, Aditya; Kumar, Suraj; Singh, Vikram Pal; Das, Asish; Balaji, J

2017-01-01

Social Transmission of Food Preference (STFP) is a single trial non-aversive learning task that is used for testing non-spatial memory. This task relies on an accurate estimate of a change in food preference of the animals following social demonstration of a novel flavor. Conventionally this is done by providing two flavors of powdered food and later estimating the amount of food consumed for each of these flavors in a defined period of time. This is achieved through a careful measurement of leftover food for each of these flavors. However, in mice, only a small (~1 g) amount of food is consumed making the weight estimates error prone and thereby limiting the sensitivity of the paradigm. Using multiplexed video tracking, we show that the pattern of consumption can be used as a reliable reporter of memory retention in this task. In our current study, we use this as a measure and show that the preference for the demonstrated flavor significantly increases following demonstration and the retention of this change in preference during remote testing is flavor specific. Further, we report a modified experimental design for performing STFP that allows testing of change in preference among two flavors simultaneously. Using this paradigm, we show that during remote testing for thyme and basil demonstrated flavors, only basil demonstrated mice retain the change in preference while thyme demonstrated mice do not.

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.

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.

Rapid, Labile, and Protein Synthesis– Independent Short-Term Memory in Conditioned Taste Aversion

OpenAIRE

Houpt, Thomas A.; Berlin, RoseAnn

1999-01-01

Short-term memory is a rapid, labile, and protein-synthesis-independent phase of memory. The existence of short-term memory in conditioned taste aversion (CTA) learning has not been demonstrated formally. To determine the earliest time at which a CTA is expressed, we measured intraoral intake of sucrose at 15 min, 1 hr, 6 hr, or 48 h after contingent pairing of an intraoral infusion of 5% sucrose (6.6 ml over 6 min) and toxic lithium chloride injection (76 mg/kg). Rats were implanted with int...

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.

Failure to Find Ethanol-Induced Conditioned Taste Aversion in Honey Bees (Apis mellifera L.).

Science.gov (United States)

Varnon, Christopher A; Dinges, Christopher W; Black, Timothy E; Wells, Harrington; Abramson, Charles I

2018-04-24

Conditioned taste aversion (CTA) learning is a highly specialized form of conditioning found across taxa that leads to avoidance of an initially neutral stimulus, such as taste or odor, that is associated with, but is not the cause of, a detrimental health condition. This study examines if honey bees (Apis mellifera L.) develop ethanol (EtOH)-induced CTA. Restrained bees were first administered a sucrose solution that was cinnamon scented, lavender scented, or unscented, and contained either 0, 2.5, 5, 10, or 20% EtOH. Then, 30 minutes later, we used a proboscis extension response (PER) conditioning procedure where the bees were taught to associate either cinnamon odor, lavender odor, or an air-puff with repeated sucrose feedings. For some bees, the odor of the previously consumed EtOH solution was the same as the odor associated with sucrose in the conditioning procedure. If bees are able to learn EtOH-induced CTA, they should show an immediate low level of response to odors previously associated with EtOH. We found that bees did not develop CTA despite the substantial inhibitory and aversive effects EtOH has on behavior. Instead, bees receiving a conditioning odor that was previously associated with EtOH showed an immediate high level of response. While this demonstrates bees are capable of one-trial learning common to CTA experiments, this high level of response is the opposite of what would occur if the bees developed a CTA. Responding on subsequent trials also showed a general inhibitory effect of EtOH. Finally, we found that consumption of cinnamon extract reduced the effects of EtOH. The honey bees' lack of learned avoidance to EtOH mirrors that seen in human alcoholism. These findings demonstrate the usefulness of honey bees as an insect model for EtOH consumption. Copyright © 2018 by the Research Society on Alcoholism.

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...

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).

Vocal learning in the functionally referential food grunts of chimpanzees.

Science.gov (United States)

Watson, Stuart K; Townsend, Simon W; Schel, Anne M; Wilke, Claudia; Wallace, Emma K; Cheng, Leveda; West, Victoria; Slocombe, Katie E

2015-02-16

One standout feature of human language is our ability to reference external objects and events with socially learned symbols, or words. Exploring the phylogenetic origins of this capacity is therefore key to a comprehensive understanding of the evolution of language. While non-human primates can produce vocalizations that refer to external objects in the environment, it is generally accepted that their acoustic structure is fixed and a product of arousal states. Indeed, it has been argued that the apparent lack of flexible control over the structure of referential vocalizations represents a key discontinuity with language. Here, we demonstrate vocal learning in the acoustic structure of referential food grunts in captive chimpanzees. We found that, following the integration of two groups of adult chimpanzees, the acoustic structure of referential food grunts produced for a specific food converged over 3 years. Acoustic convergence arose independently of preference for the food, and social network analyses indicated this only occurred after strong affiliative relationships were established between the original subgroups. We argue that these data represent the first evidence of non-human animals actively modifying and socially learning the structure of a meaningful referential vocalization from conspecifics. Our findings indicate that primate referential call structure is not simply determined by arousal and that the socially learned nature of referential words in humans likely has ancient evolutionary origins. Copyright © 2015 Elsevier Ltd. All rights reserved.

Incidental learning and memory for food varied in sweet taste in children

NARCIS (Netherlands)

Laureati, M.; Pagliarini, E.; Mojet, J.; Köster, E.P.

2011-01-01

This experiment investigated incidental learning and memory in children (age 7–10 years) for three different foods (fruit juice, fruit purée and biscuit), varied in sweetness. Children (N = 286) were exposed to three target foods and 24 h later their incidental learning was tested for one of the

Comparative effects of pulmonary and parenteral Δ⁹-tetrahydrocannabinol exposure on extinction of opiate-induced conditioned aversion in rats.

Science.gov (United States)

Manwell, Laurie A; Mallet, Paul E

2015-05-01

Evidence suggesting that the endogenous cannabinoid (eCB) system can be manipulated to facilitate or impair extinction of learned behaviours has important consequences for opiate withdrawal and abstinence. We demonstrated that the fatty acid amide hydrolase (FAAH) inhibitor URB597, which increases eCB levels, facilitates extinction of a naloxone-precipitated morphine withdrawal-induced conditioned place aversion (CPA). The potential of the exogenous CB1 ligand, Δ(9)-tetrahydrocannabinol (Δ(9)-THC), to facilitate extinction of this CPA was tested. Effects of both pulmonary and parenteral Δ(9)-THC exposure were evaluated using comparable doses previously determined. Rats trained to associate a naloxone-precipitated morphine withdrawal with a floor cue were administered Δ(9)-THC-pulmonary (1, 5, 10 mg vapour inhalation) or parenteral (0.5, 1.0, 1.5 mg/kg intraperitoneal injection)-prior to each of 20 to 28 extinction/testing trials. Vapourized Δ(9)-THC facilitated extinction of the CPA in a dose- and time-dependent manner: 5 and 10 mg facilitated extinction compared to vehicle and 1 mg Δ(9)-THC. Injected Δ(9)-THC significantly impaired extinction only for the 1.0-mg/kg dose: it prolonged the CPA fourfold longer than the vehicle and 0.5- and 1.5-mg/kg doses. These data suggest that both dose and route of Δ(9)-THC administration have important consequences for its pharmacokinetic and behavioural effects; specifically, pulmonary exposure at higher doses facilitates, whereas pulmonary and parenteral exposure at lower doses impairs, rates of extinction learning for CPA. Pulmonary-administered Δ(9)-THC may prove beneficial for potentiation of extinction learning for aversive memories, such as those supporting drug-craving/seeking in opiate withdrawal syndrome, and other causes of conditioned aversions, such as illness and stress.

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.

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.

Dissecting neural pathways for forgetting in Drosophila olfactory aversive memory.

Science.gov (United States)

Shuai, Yichun; Hirokawa, Areekul; Ai, Yulian; Zhang, Min; Li, Wanhe; Zhong, Yi

2015-12-01

Recent studies have identified molecular pathways driving forgetting and supported the notion that forgetting is a biologically active process. The circuit mechanisms of forgetting, however, remain largely unknown. Here we report two sets of Drosophila neurons that account for the rapid forgetting of early olfactory aversive memory. We show that inactivating these neurons inhibits memory decay without altering learning, whereas activating them promotes forgetting. These neurons, including a cluster of dopaminergic neurons (PAM-β'1) and a pair of glutamatergic neurons (MBON-γ4>γ1γ2), terminate in distinct subdomains in the mushroom body and represent parallel neural pathways for regulating forgetting. Interestingly, although activity of these neurons is required for memory decay over time, they are not required for acute forgetting during reversal learning. Our results thus not only establish the presence of multiple neural pathways for forgetting in Drosophila but also suggest the existence of diverse circuit mechanisms of forgetting in different contexts.

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.

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...

Food cleaning in gorillas: Social learning is a possibility but not a necessity.

Directory of Open Access Journals (Sweden)

Damien Neadle

Full Text Available Food cleaning is widespread in the animal kingdom, and a recent report confirmed that (amongst other behaviours wild western lowland gorillas also show food cleaning. The authors of this report conclude that this behaviour, based on its distribution patterns, constitutes a potential candidate for culture. While different conceptualisations of culture exist, some more and some less reliant on behavioural form copying, all of them assign a special role to social learning processes in explaining potentially cultural behaviours. Here we report the results of an experiment that tested to what extent food cleaning behaviour in a group of captive Western lowland gorillas (Gorilla gorilla gorilla relies on social learning processes. Subjects were provided with clean and dirty apples. When they were provided with dirty apples, all subjects showed evidence of food cleaning in at least 75% of trials. Preferred cleaning techniques differed between individuals, four out of five of subjects expressed a behaviour analogous to that reported in wild conspecifics. Given this occurrence of food cleaning in a culturally unconnected population of gorillas, we conclude that social learning is unlikely to play a central role in the emergence of the food cleaning behavioural form in Western lowland gorillas; instead, placing a greater emphasis on individual learning of food cleaning's behavioural form.

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.

Learning in an exotic social wasp while relocating a food source.

Science.gov (United States)

Lozada, Mariana; D'Adamo, Paola

2014-01-01

In this paper we review several studies on Vespulagermanica behavioral plasticity while relocating a food source in natural environments. This exotic social wasp, which has become established in many parts of the world, displays diverse cognitive abilities when foraging. Given its successful invasiveness worldwide, our initial hypothesis was that this species has great behavioral plasticity, which enables it to face environmental uncertainty. In our work we have analyzed foraging behavior associated with undepleted resources. Throughout several experiments, rapid learning was observed in this species; after few learning experiences they associate diverse contextual cues with a food source. However, by exploring wasp behavior when food suddenly disappeared, either because it had been removed or displaced, we found that they continued searching over a no longer rewarding site for a considerable period of time, suggesting that past experience can hinder new learning. Particularly surprising is the fact that when food was displaced nearby, wasps persisted in searching over the empty dish, ignoring the presence of food close by. We propose that this species could be a suitable model for studying cognitive plasticity in relation to environmental uncertainty. Copyright © 2014 Elsevier Ltd. All rights reserved.

Escape and avoidance learning in the earthworm Eisenia hortensis

Directory of Open Access Journals (Sweden)

W. Jeffrey Wilson

2014-01-01

Full Text Available Interest in instrumental learning in earthworms dates back to 1912 when Yerkes concluded that they can learn a spatial discrimination in a T-maze. Rosenkoetter and Boice determined in the 1970s that the “learning” that Yerkes observed was probably chemotaxis and not learning at all. We examined a different form of instrumental learning: the ability to learn both to escape and to avoid an aversive stimulus. Freely moving “master” worms could turn off an aversive white light by increasing their movement; the behavior of yoked controls had no effect on the light. We demonstrate that in as few as 12 trials the behavior of the master worms comes under the control of this contingency.

Palatable food avoidance and acceptance learning with different stressors in female rats.

Science.gov (United States)

Liang, N-C; Smith, M E; Moran, T H

2013-04-03

Stress activates the hypothalamus-pituitary-adrenal (HPA) axis leading to the release of glucocorticoids (GC). Increased activity of the HPA axis and GC exposure has been suggested to facilitate the development of obesity and metabolic syndrome. Nonetheless, different stressors can produce distinct effects on food intake and may support different directions of food learning e.g. avoidance or acceptance. This study examined whether interoceptive (LiCl and exendin-4) and restraint stress (RS) support similar or distinct food learning. Female rats were exposed to different stressors after their consumption of a palatable food (butter icing). After four palatable food-stress pairings, distinct intakes of the butter icing were observed in rats treated with different stressors. Rats that received butter icing followed by intraperitoneal injections of LiCl (42.3mg/kg) and exendin-4 (10μg/kg) completely avoided the palatable food with subsequent presentations. In contrast, rats experiencing RS paired with the palatable food increased their consumption of butter icing across trials and did so to a greater degree than rats receiving saline injections. These data indicate that interoceptive and psychosocial stressors support conditioned food avoidance and acceptance, respectively. Examination of c-Fos immunoreactivity revealed distinct neural activation by interoceptive and psychosocial stressors that could provide the neural basis underlying opposite direction of food acceptance learning. Published by Elsevier Ltd.

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.

Acute stress affects risk taking but not ambiguity aversion.

Science.gov (United States)

Buckert, Magdalena; Schwieren, Christiane; Kudielka, Brigitte M; Fiebach, Christian J

2014-01-01

Economic decisions are often made in stressful situations (e.g., at the trading floor), but the effects of stress on economic decision making have not been systematically investigated so far. The present study examines how acute stress influences economic decision making under uncertainty (risk and ambiguity) using financially incentivized lotteries. We varied the domain of decision making as well as the expected value of the risky prospect. Importantly, no feedback was provided to investigate risk taking and ambiguity aversion independent from learning processes. In a sample of 75 healthy young participants, 55 of whom underwent a stress induction protocol (Trier Social Stress Test for Groups), we observed more risk seeking for gains. This effect was restricted to a subgroup of participants that showed a robust cortisol response to acute stress (n = 26). Gambling under ambiguity, in contrast to gambling under risk, was not influenced by the cortisol response to stress. These results show that acute psychosocial stress affects economic decision making under risk, independent of learning processes. Our results further point to the importance of cortisol as a mediator of this effect.

Intracellular calcium chelation and pharmacological SERCA inhibition of Ca2+ pump in the insular cortex differentially affect taste aversive memory formation and retrieval.

Science.gov (United States)

Miranda, María Isabel; González-Cedillo, Francisco J; Díaz-Muñoz, Mauricio

2011-09-01

Variation in intracellular calcium concentration regulates the induction of long-term synaptic plasticity and is associated with a variety of memory/retrieval and learning paradigms. Accordingly, impaired calcium mobilization from internal deposits affects synaptic plasticity and cognition in the aged brain. During taste memory formation several proteins are modulated directly or indirectly by calcium, and recent evidence suggests the importance of calcium buffering and the role of intracellular calcium deposits during cognitive processes. Thus, the main goal of this research was to study the consequence of hampering changes in cytoplasmic calcium and inhibiting SERCA activity by BAPTA-AM and thapsigargin treatments, respectively, in the insular cortex during different stages of taste memory formation. Using conditioned taste aversion (CTA), we found differential effects of BAPTA-AM and thapsigargin infusions before and after gustatory stimulation, as well as during taste aversive memory consolidation; BAPTA-AM, but not thapsigargin, attenuates acquisition and/or consolidation of CTA, but neither compound affects taste aversive memory retrieval. These results point to the importance of intracellular calcium dynamics in the insular cortex during different stages of taste aversive memory formation. Copyright © 2011 Elsevier Inc. All rights reserved.

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.

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.

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.

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

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)

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.

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.

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.

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

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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.

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.

The effect of BLA GABAB receptors in anxiolytic-like effect and aversive memory deficit induced by ACPA

Directory of Open Access Journals (Sweden)

Katayoon Kangarlu Haghighi

2016-07-01

Full Text Available Background: As a psychoactive plant, Cannabis sativa (Marijuana is widely used throughout the world. Several investigations have indicated that administration of Marijuana affects various cognitive and non-cognitive behaviors. These include anxiety-like behaviors and learning and memory deficit. It has been shown that three main cannabinoid receptors [i.e. CB1, CB2 and CB3 are involved in cannabinoids’ functions. CB1 receptors are abundantly expressed in the central nervous system regions such as hippocampus, amygdala, cerebellum and the cortex. Therefore, the neuropsychological functions of endocannabinoids are thought to be more linked to CB1 receptors. Among other brain regions, CB1 is highly expressed in the amygdala which is an integral component of the limbic circuitry. The amygdala plays a major role in the control of emotional behavior, including conditioned fear and anxiety. In present study we examined the possible roles of basolateral amygdala (BLA GABAB receptors in arachydonilcyclopropylamide (ACPA-induced anxiolytic-like effect and aversive memory deficit in adult male mice. Methods: This experimental study was conducted from September 2013 to December 2014 in Institute for Studies in Theoretical Physics and Mathematics, School of Cognitive Sciences, Tehran and Male albino NMRI mice (Pasture Institute, Iran, weighting 27-30 g, were used. Bilateral guide-cannulae were implanted to allow intra BLA microinjection of the drugs. We used Elevated Plus Maze (EPM to examine memory and anxiety behavior (test-retest protocol. ACPA administrate intra-peritoneal and GABAB agonist and antagonist administrated intra-amygdala. Results: Data showed that pre-test treatment with ACPA induced anxiolytic-like and aversive memory deficit The results revealed that pre-test intra-BLA infusion of baclofen (GABAB receptor agonist impaired the aversive memory while phaclofen (GABAB receptor antagonist improved it. Interestingly, pretreatment with a sub

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.

Establishing a learned-helplessness effect paradigm in C57BL/6 mice: behavioural evidence for emotional, motivational and cognitive effects of aversive uncontrollability per se.

Science.gov (United States)

Pryce, Christopher R; Azzinnari, Damiano; Sigrist, Hannes; Gschwind, Tilo; Lesch, Klaus-Peter; Seifritz, Erich

2012-01-01

Uncontrollability of major life events has been proposed to be central to depression onset and maintenance. The learned helplessness (LH) effect describes a deficit in terminating controllable aversive stimuli in individuals that experienced aversive stimuli as uncontrollable relative to individuals that experienced the same stimuli as controllable. The LH effect translates across species and therefore can provide an objective-valid readout in animal models of depression. Paradigms for a robust LH effect are established and currently applied in rat but there are few reports of prior and current study of the LH effect in mouse. This includes the C57BL/6 mouse, typically the strain of choice for application of molecular-genetic tools in pre-clinical depression research. The aims of this study were to develop a robust paradigm for the LH effect in BL/6 mice, provide evidence for underlying psychological processes, and study the effect of a depression-relevant genotype on the LH effect. The apparatus used for in/escapable electro-shock exposure and escape test was a two-way shuttle arena with continuous automated measurement of locomotion, compartment transfers, e-shock escapes, vertical activity and freezing. Brother-pairs of BL/6 mice were allocated to either escapable e-shocks (ES) or inescapable e-shocks (IS), with escape latencies of the ES brother used as e-shock durations for the IS brother. The standard two-way shuttle paradigm was modified: the central gate was replaced by a raised divider and e-shock escape required transfer to the distal part of the safe compartment. These refinements yielded reduced superstitious, pre-adaptive e-shock transfers in IS mice and thereby increased the LH effect. To obtain a robust LH effect in all brother pairs, pre-screening for minor between-brother ES differences was necessary and did not confound the LH effect. IS mice developed reduced motor responses to e-shock, consistent with a motivational deficit, and absence of a

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

Aversive conditioning in prenatally gamma-irradiated rats

International Nuclear Information System (INIS)

Tamaki, Yoshitaka; Hoshino, Kiyoshi; Kameyama, Yoshiro

1987-01-01

To examine how intrauterine exposure to gamma rays would exert on four kinds of aversive conditioning, rat fetuses were irradiated with 0.27, 0.48, or 1.46 Gy at Day 15 post conception. When ordinary avoidance conditioning was given to the groups with 0.27 and 0.48 Gy, there was no significant difference between the irradiated groups and the control group in the rate of positive avoidance response. Nor was this different in the irradiated groups and the control group, when the rate of baseline response was examined in avoidance conditioning. In positive avoidance conditioning to two kinds of anticipatory electric stimuli, the acquisition of avoidance was significantly inferior in all irradiated groups to that in the control group. When giving succesive discrimination learning, the group with 1.46 Gy tended to have higher rate of positive avoidance response and remarkably lower rate of passive avoidance response than the control group. (Namekawa, K.)

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...

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…

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

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

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

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.

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.

Cognitive emotion regulation enhances aversive prediction error activity while reducing emotional responses.

Science.gov (United States)

Mulej Bratec, Satja; Xie, Xiyao; Schmid, Gabriele; Doll, Anselm; Schilbach, Leonhard; Zimmer, Claus; Wohlschläger, Afra; Riedl, Valentin; Sorg, Christian

2015-12-01

Cognitive emotion regulation is a powerful way of modulating emotional responses. However, despite the vital role of emotions in learning, it is unknown whether the effect of cognitive emotion regulation also extends to the modulation of learning. Computational models indicate prediction error activity, typically observed in the striatum and ventral tegmental area, as a critical neural mechanism involved in associative learning. We used model-based fMRI during aversive conditioning with and without cognitive emotion regulation to test the hypothesis that emotion regulation would affect prediction error-related neural activity in the striatum and ventral tegmental area, reflecting an emotion regulation-related modulation of learning. Our results show that cognitive emotion regulation reduced emotion-related brain activity, but increased prediction error-related activity in a network involving ventral tegmental area, hippocampus, insula and ventral striatum. While the reduction of response activity was related to behavioral measures of emotion regulation success, the enhancement of prediction error-related neural activity was related to learning performance. Furthermore, functional connectivity between the ventral tegmental area and ventrolateral prefrontal cortex, an area involved in regulation, was specifically increased during emotion regulation and likewise related to learning performance. Our data, therefore, provide first-time evidence that beyond reducing emotional responses, cognitive emotion regulation affects learning by enhancing prediction error-related activity, potentially via tegmental dopaminergic pathways. Copyright © 2015 Elsevier Inc. All rights reserved.

Different levels of food restriction reveal genotype-specific differences in learning a visual discrimination task.

Directory of Open Access Journals (Sweden)

Kalina Makowiecki

Full Text Available In behavioural experiments, motivation to learn can be achieved using food rewards as positive reinforcement in food-restricted animals. Previous studies reduce animal weights to 80-90% of free-feeding body weight as the criterion for food restriction. However, effects of different degrees of food restriction on task performance have not been assessed. We compared learning task performance in mice food-restricted to 80 or 90% body weight (BW. We used adult wildtype (WT; C57Bl/6j and knockout (ephrin-A2⁻/⁻ mice, previously shown to have a reverse learning deficit. Mice were trained in a two-choice visual discrimination task with food reward as positive reinforcement. When mice reached criterion for one visual stimulus (80% correct in three consecutive 10 trial sets they began the reverse learning phase, where the rewarded stimulus was switched to the previously incorrect stimulus. For the initial learning and reverse phase of the task, mice at 90%BW took almost twice as many trials to reach criterion as mice at 80%BW. Furthermore, WT 80 and 90%BW groups significantly differed in percentage correct responses and learning strategy in the reverse learning phase, whereas no differences between weight restriction groups were observed in ephrin-A2⁻/⁻ mice. Most importantly, genotype-specific differences in reverse learning strategy were only detected in the 80%BW groups. Our results indicate that increased food restriction not only results in better performance and a shorter training period, but may also be necessary for revealing behavioural differences between experimental groups. This has important ethical and animal welfare implications when deciding extent of diet restriction in behavioural studies.

The role of dopamine D2 receptors in the nucleus accumbens during taste-aversive learning and memory extinction after long-term sugar consumption.

Science.gov (United States)

Miranda, María Isabel; Rangel-Hernández, José Alejandro; Vera-Rivera, Gabriela; García-Medina, Nadia Edith; Soto-Alonso, Gerardo; Rodríguez-García, Gabriela; Núñez-Jaramillo, Luis

2017-09-17

The nucleus accumbens (NAcc) is a forebrain region that may significantly contribute to the integration of taste and visceral signals during food consumption. Changes in dopamine release in the NAcc have been observed during consumption of a sweet taste and during compulsive consumption of dietary sugars, suggesting that NAcc dopaminergic transmission is strongly correlated with taste familiarity and the hedonic value content. NAcc core and shell nuclei are differentially involved during and after sugar exposure and, particularly, previous evidence suggests that dopamine D2 receptors could be related with the strength of the latent inhibition (LI) of conditioned taste aversion (CTA), which depends on the length of the taste stimulus pre-exposure. Thus, the objective of this work was to evaluate, after long-term exposure to sugar, the function of dopaminergic D2 receptors in the NAcc core during taste memory retrieval preference test, and during CTA. Adult rats were exposed during 14days to 10% sugar solution as a single liquid ad libitum. NAcc core bilateral injections of D2 dopamine receptor antagonist, haloperidol (1μg/μL), were made before third preference test and CTA acquisition. We found that sugar was similarly preferred after 3 acute presentations or 14days of continued sugar consumption and that haloperidol did not disrupt this appetitive memory retrieval. Nevertheless, D2 receptors antagonism differentially affects aversive memory formation after acute or long-term sugar consumption. These results demonstrate that NAcc dopamine D2 receptors have a differential function during CTA depending on the degree of sugar familiarity. Copyright © 2017 IBRO. Published by Elsevier Ltd. All rights reserved.

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.

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...

Understanding infants' and children's social learning about foods: previous research and new prospects.

Science.gov (United States)

Shutts, Kristin; Kinzler, Katherine D; DeJesus, Jasmine M

2013-03-01

Developmental psychologists have devoted significant attention to investigating how children learn from others' actions, emotions, and testimony. Yet most of this research has examined children's socially guided learning about artifacts. The present article focuses on a domain that has received limited attention from those interested in the development of social cognition: food. We begin by reviewing the available literature on infants' and children's development in the food domain and identify situations in which children evidence both successes and failures in their interactions with foods. We focus specifically on the role that other people play in guiding what children eat and argue that understanding patterns of successes and failures in the food domain requires an appreciation of eating as a social phenomenon. We next propose a series of questions for future research and suggest that examining food selection as a social phenomenon can shed light on mechanisms underlying children's learning from others and provide ideas for promoting healthy social relationships and eating behaviors early in development.

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

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

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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

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

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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.

Aversive Stimulation -- Criteria for Application.

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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…

Essays on the Economics of Climate Change, Biofuel and Food Prices

Science.gov (United States)

Seguin, Charles

Climate change is likely to be the most important global pollution problem that humanity has had to face so far. In this dissertation, I tackle issues directly and indirectly related to climate change, bringing my modest contribution to the body of human creativity trying to deal with climate change. First, I look at the impact of non-convex feedbacks on the optimal climate policy. Second, I try to derive the optimal biofuel policy acknowledging the potential negative impacts that biofuel production might have on food supply. Finally, I test empirically for the presence of loss aversion in food purchases, which might play a role in the consumer response to food price changes brought about by biofuel production. Non-convexities in feedback processes are increasingly found to be important in the climate system. To evaluate their impact on the optimal greenhouse gas (GHG) abate- ment policy, I introduce non-convex feedbacks in a stochastic pollution control model. I numerically calibrate the model to represent the mitigation of greenhouse gas (GHG) emissions contributing to global climate change. This approach makes two contributions to the literature. First, it develops a framework to tackle stochastic non-convex pollu- tion management problems. Second, it applies this framework to the problem of climate change. This approach is in contrast to most of the economic literature on climate change that focuses either on linear feedbacks or environmental thresholds. I find that non-convex feedbacks lead to a decision threshold in the optimal mitigation policy, and I characterize how this threshold depends on feedback parameters and stochasticity. There is great hope that biofuel can help reduce greenhouse gas emissions from fossil fuel. However, there are some concerns that biofuel would increase food prices. In an optimal control model, a co-author and I look at the optimal biofuel production when it competes for land with food production. In addition oil is not

Lesions of the lateral habenula facilitate active avoidance learning and threat extinction.

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Song, Mihee; Jo, Yong Sang; Lee, Yeon-Kyung; Choi, June-Seek

2017-02-01

The lateral habenula (LHb) is an epithalamic brain structure that provides strong projections to midbrain monoaminergic systems that are involved in motivation, emotion, and reinforcement learning. LHb neurons are known to convey information about aversive outcomes and negative prediction errors, suggesting a role in learning from aversive events. To test this idea, we examined the effects of electrolytic lesions of the LHb on signaled two-way active avoidance learning in which rats were trained to avoid an unconditioned stimulus (US) by taking a proactive shuttling response to an auditory conditioned stimulus (CS). The lesioned animals learned the avoidance response significantly faster than the control groups. In a separate experiment, we also investigated whether the LHb contributes to Pavlovian threat (fear) conditioning and extinction. Following paired presentations of the CS and the US, LHb-lesioned animals showed normal acquisition of conditioned response (CR) measured with freezing. However, extinction of the CR in the subsequent CS-only session was significantly faster. The enhanced performance in avoidance learning and in threat extinction jointly suggests that the LHb normally plays an inhibitory role in learning driven by absence of aversive outcomes. Copyright © 2016 Elsevier B.V. All rights reserved.

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

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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

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...

Gender Differences in Risk Aversion Among Chinese University Students.

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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.

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...

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

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.

Appetitive but Not Aversive Olfactory Conditioning Modifies Antennal Movements in Honeybees

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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…

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

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

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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.

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

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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.

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

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.

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.

The Development and Public Health Implications of Food Preferences in Children

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Jacob P. Beckerman

2017-12-01

Full Text Available Food preferences are a primary determinant of dietary intake and behaviors, and they persist from early childhood into later life. As such, establishing preferences for healthy foods from a young age is a promising approach to improving diet quality, a leading contributor to cardiometabolic health. This narrative review first describes the critical period for food preference development starting in utero and continuing through early childhood. Infants’ innate aversion to sour and bitter tastes can lead them to initially reject some healthy foods such as vegetables. Infants can learn to like these foods through exposures to their flavors in utero and through breastmilk. As solid foods are introduced through toddlerhood, children’s food preferences are shaped by parent feeding practices and environmental factors such as food advertising. Next, we discuss two key focus areas to improve diet quality highlighted by the current understanding of food preferences: (1 promoting healthy food preferences through breastfeeding and early exposures to healthy foods and (2 limiting the extent to which innate preferences for sweet and salty tastes lead to poor diet quality. We use an ecological framework to summarize potential points of intervention and provide recommendations for these focus areas, such as worksite benefits that promote breastfeeding, and changes in food retail and service environments. Individuals’ choices around breastfeeding and diet may ultimately be influenced by policy and community-level factors. It is thus crucial to take a multilevel approach to establish healthy food preferences from a young age, which have the potential to translate into lifelong healthy diet.

How does pattern of feeding and rate of nutrient delivery influence conditioned food preferences?

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Duncan, A J; Elwert, C; Villalba, J J; Yearsley, J; Pouloupoulou, I; Gordon, I J

2007-09-01

Ruminant herbivores have been shown to learn about food properties by associating food flavours with the food's post-ingestive consequences. Previous experimentation supporting the conditioned food aversion/preference hypothesis has generally employed very simple diet learning tasks which do not effectively represent the wide range of foods selected within single bouts typical of wild, free-ranging ruminant herbivores. We tested the ability of a ruminant herbivore to associate a food with artificially administered nutrient rewards in a designed experiment where we altered the temporal pattern of encounter with the food as well as the nature (fast or slow reward) of the post-ingestive outcome. Twenty-four goats were offered branches of Sitka spruce (SS) and Norway spruce (NS) for 4 h per day on two days per week for five weeks. The pattern of feeding varied with treatment such that the species on offer changed every hour (short) or every 2 h (long). The energy treatment altered the reward delivered during Sitka consumption so that animals were dosed either with predominantly sugar (rapidly fermented), predominantly starch (slower fermentation rate), or with water (placebo). Preference was measured on the day following each learning day. We expected that goats would find it easier to associate SS with post-ingestive rewards when the duration of encounter was longest, and that associations would be stronger with the most rapidly digested post-ingestive reward. In the event, goats did not alter their consumption of SS in response to the treatments. Our results suggest that at the scale of temporal resolution of encounters with different plant species (1-2 h), and at the different rates of experiencing post-ingestive consequences tested in this experiment, ruminants do not appear to discriminate the nutritive properties of foods predominantly through a post-ingestive feedback mechanism. They must, instead, use a range of cues-including post-ingestive consequences

Impairment of context memory by β-amyloid peptide in terrestrial snail

Directory of Open Access Journals (Sweden)

2008-09-01

Full Text Available We examined influence of the β-amyloid peptide (25-35 neurotoxic fragment (βAP on Helix lucorum food-aversion learning. Testing with aversively conditioned carrot showed that 2, 5, and 14 days after training the βAP-injected group responded in a significantly larger number of cases and with a significantly smaller latency than the sham-injected control group. The results demonstrate that the amyloid peptide partially impairs the learning process. In an attempt to specify what component of memory is impaired we compared responses in a context in which the snails were aversively trained, and in a neutral context. It was found that the sham-injected learned snails significantly less frequently took the aversively conditioned food in the context in which the snails were shocked, while the βAP-injected snails remembered the aversive context 2 days after associative training, but were not able to distinguish two contexts 5, and 14 days after training. In a separate series of experiments a specific context was associated with electric shock, and changes in general responsiveness were tested in two contexts several days later. It was found that the βAP-injected snails significantly increased withdrawal responses in all tested contexts, while the sham-injected control animals selectively increased responsiveness only in the context in which they were reinforced with electric shocks. These results demonstrate that the β-amyloid peptide (25-35 interferes with the learning process, and may play a significant role in behavioral plasticity and memory by selectively impairing only one

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.

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

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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…

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.

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.

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

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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.

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.

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.

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.

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.

Recruits of the stingless bee Scaptotrigona pectoralis learn food odors from the nest atmosphere

Science.gov (United States)

Reichle, Christian; Jarau, Stefan; Aguilar, Ingrid; Ayasse, Manfred

2010-05-01

The ability to learn food odors inside the nest and to associate them with food sources in the field is of essential importance for the recruitment of nestmates in social bees. We investigated odor learning by workers within the hive and the influence of these odors on their food choice in the field in the stingless bee Scaptotrigona pectoralis. During the experiments, recruited bees had to choose between two feeders, one with an odor that was present inside the nest during the recruitment process, and one with an unknown odor. In all experiments with different odor combinations (linalool/phenylacetaldehyde, geraniol/eugenol) a significant majority of bees visited the feeder with the odor they had experienced in their nest ( χ 2-tests; p bees showed no preference for one of two feeders when they were either baited with the same odor (linalool) or contained no odor. Our results clearly show that naïve workers of S. pectoralis can learn the odor of a food source during the recruitment process from the nest atmosphere and that their subsequent food search in the field is influenced by the learned odor.

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

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...

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...

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…

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.

Perceived ambiguity as a barrier to intentions to learn genome sequencing results.

Science.gov (United States)

Taber, Jennifer M; Klein, William M P; Ferrer, Rebecca A; Han, Paul K J; Lewis, Katie L; Biesecker, Leslie G; Biesecker, Barbara B

2015-10-01

Many variants that could be returned from genome sequencing may be perceived as ambiguous-lacking reliability, credibility, or adequacy. Little is known about how perceived ambiguity influences thoughts about sequencing results. Participants (n = 494) in an NIH genome sequencing study completed a baseline survey before sequencing results were available. We examined how perceived ambiguity regarding sequencing results and individual differences in medical ambiguity aversion and tolerance for uncertainty were associated with cognitions and intentions concerning sequencing results. Perceiving sequencing results as more ambiguous was associated with less favorable cognitions about results and lower intentions to learn and share results. Among participants low in tolerance for uncertainty or optimism, greater perceived ambiguity was associated with lower intentions to learn results for non-medically actionable diseases; medical ambiguity aversion did not moderate any associations. Results are consistent with the phenomenon of "ambiguity aversion" and may influence whether people learn and communicate genomic information.

Food Gardening and Intergenerational Learning in Times of ...

African Journals Online (AJOL)

The focus of discussion is the intergenerational interactions and learning ... pastoralism and, to a lesser degree, cultivation (Mayer, 1971; Mostert, 1992). ... discouraged about the hard physical work and rather limited economic ... in the Amanzi for Food project, a middle-aged female participant, Mrs Peters, has involved a.

Food Gardening and Intergenerational Learning in Times of ...

African Journals Online (AJOL)

Uncertainty is a universal phenomenon, a lived experience, an unease about acting ... uncertainty through mediations of knowledge, the formation of new social relations and ... Environmental Affairs and Tourism, 53% of young people in the country are ... Bubomi learning network connected to the Amanzi for Food project.

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

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...

"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

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.

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

Memory block: a consequence of conflict resolution.

Science.gov (United States)

Ito, Etsuro; Yamagishi, Miki; Hatakeyama, Dai; Watanabe, Takayuki; Fujito, Yutaka; Dyakonova, Varvara; Lukowiak, Ken

2015-06-01

Food deprivation for 1 day in the pond snail Lymnaea stagnalis before aversive classical conditioning results in optimal conditioned taste aversion (CTA) and long-term memory (LTM) formation, whereas 5-day food deprivation before training does not. We hypothesize that snails do in fact learn and form LTM when trained after prolonged food deprivation, but that severe food deprivation blocks their ability to express memory. We trained 5-day food-deprived snails under various conditions, and found that memory was indeed formed but is overpowered by severe food deprivation. Moreover, CTA-LTM was context dependent and was observed only when the snails were in a context similar to that in which the training occurred. © 2015. Published by The Company of Biologists Ltd.

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.

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...

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.

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.

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.

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…

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.

Learning Entrepreneurial Leadership among Nascent Food Entrepreneurs in Denmark and New Zealand

DEFF Research Database (Denmark)

Ramsgaard, Michael Breum; Warren, Lorraine

This paper examines the process of learning entrepreneurial leadership in small food businesses in the early stages. It draws on the growing body of research around entrepreneurial leadership that deals with leadership in ventures but overlooks the importance of entrepreneurial leadership...... in the nascent phases. We analyse the factors constituting the processes of learning entrepreneurial leadership among nascent food entrepreneurs. The primary source of data derives from four in-depth interviews in each country with founders of SME food businesses with no more than 5 years of company history....... Further we discuss whether regional differences in the conception of entrepreneurial leadership can be identified through comparison between qualitative data from Denmark and New Zealand....

Behavioural memory reconsolidation of food and fear memories.

Science.gov (United States)

Flavell, Charlotte R; Barber, David J; Lee, Jonathan L C

2011-10-18

The reactivation of a memory through retrieval can render it subject to disruption or modification through the process of memory reconsolidation. In both humans and rodents, briefly reactivating a fear memory results in effective erasure by subsequent extinction training. Here we show that a similar strategy is equally effective in the disruption of appetitive pavlovian cue-food memories. However, systemic administration of the NMDA receptor partial agonist D-cycloserine, under the same behavioural conditions, did not potentiate appetitive memory extinction, suggesting that reactivation does not enhance subsequent extinction learning. To confirm that reactivation followed by extinction reflects a behavioural analogue of memory reconsolidation, we show that prevention of contextual fear memory reactivation by the L-type voltage-gated calcium channel blocker nimodipine interferes with the amnestic outcome. Therefore, the reconsolidation process can be manipulated behaviourally to disrupt both aversive and appetitive memories. © 2011 Macmillan Publishers Limited. All rights reserved.

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

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.

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.

Influences of β-endorphins in Ethanol Consumption Patterns and Acquisition of a Conditioned Taste Aversion Mediated by the Drug

Directory of Open Access Journals (Sweden)

Juan Carlos Molina

2009-09-01

Full Text Available Rewarding effects of ethanol may be mediated in part by endogenous opioids. Ethanol alters β-endorphin synthesis and release. β-endorphin heterozygous (HT and knockout (KO mice consume higher levels of a low-concentrated alcohol solution and show heightened predisposition to self-administer ethanol in comparison with wild-type (WT mice (Grisel et al., 1999. This study was conducted in order to: i re-analyze and extend previous results in terms of ethanol consumption profiles of β-endorphin deficient mice; and ii analyze conditioned aversive learning mediated by ethanol postabsorptive effects as a function of genetic capabilities to synthesize β-endorphin. In Experiment 1, mice were evaluated in terms of consumption of a low (7% ethanol solution in a two-bottle free choice paradigm. Ethanol concentration was then increased to 10 % and voluntary intake consumption was tested. WT mice displayed significantly higher consumption levels and ethanol-preference scores than did KO mice, independently from ethanol concentration. HT mice drank more ethanol than did KO mice. In Experiment 2, mice (KO, HT and WT were tested in a conditioned taste aversion paradigm in which a sodium chloride (NaCl solution was paired with a 2-g/kg ethanol dose. Only HT and KO displayed a conditioned aversion when using 2-g/kg ethanol as unconditioned stimulus. The present results indicate that total or partial deficiency of β-endorphin synthesis reduces ethanol preference and consumption. Furthermore, this study indicates that the lack of β-endorphin synthesis exacerbates ethanol’s aversive postabsorptive effects which can in turn modulate self-administration patterns of the drug.

Enhancing Student Learning in Food Engineering Using Computational Fluid Dynamics Simulations

Science.gov (United States)

Wong, Shin Y.; Connelly, Robin K.; Hartel, Richard W.

2010-01-01

The current generation of students coming into food science and engineering programs is very visually oriented from their early experiences. To increase their interest in learning, new and visually appealing teaching materials need to be developed. Two diverse groups of students may be identified based on their math skills. Food science students…

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.

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

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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.

Aversive viscerally referred states and thirst accompanying the sating of hunger motivation by rapid digestion of glucosaccharides.

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Booth, David A; O'Leary, Gemma; Li, Lixiang; Higgs, Suzanne

2011-03-01

Associative conditioning of satiety indicates that concentrated maltodextrin (cMD) may induce a mildly aversive visceral signal within 20 min of its ingestion, as well as satiating normally. Individuals' awareness of this adverse state was tested on ratings of statistically distinct descriptions of factors liable to suppress hunger, whether distressing or comfortably satisfying. Wanted amount of a food and the pleasantness of eating it correlated highly for each of five foods, once again refuting the widespread presumption that "pleasant" refers to sensory pleasure; hence, as in previous reports, suppression of hunger was measured as a reduction of the averaged pleasantness of functionally related foods. At 20 min after the start of ingestion of a small meal on a near-empty stomach, cMD reliably reduced hunger. The greatest influence on hunger, besides normal sating, was thirst, but there were also tendencies to nausea and bloat, although all less than after a full sized meal. Visceral processes shortly after a meal can create dissociable conscious states, only one of which is satiety for food. 2010 Elsevier Inc. All rights reserved.

Pedagogy Lost? Possibilities for Adult Learning and Solidarity in Food Activism

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Kepkiewicz, Lauren

2015-01-01

In this paper, I examine the potential for solidarity between indigenous and non-indigenous peoples within food movements working in the context of a settler colony such as Canada. I argue that it is necessary to engage with narratives provided by indigenous food activists and indigenous studies scholars and that learning from these narratives…

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)

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...

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

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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.

Loss aversion and duration of residence

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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.

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

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

Students' Perception of Interdisciplinary, Problem-Based Learning in a Food Biotechnology Course

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Ng, Betsy L. L.; Yap, Kueh C.; Hoh, Yin K.

2011-01-01

Abstract: Students' perception of 8 criteria (rationale of the problem; interdisciplinary learning; facilitator asked essential questions; learner's skills; assessments; facilitation procedures; team's use of resources [team collaboration], and facilitator within a problem-based learning context) were assessed for a food biotechnology course that…

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

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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.

Gastrin-releasing peptide signaling plays a limited and subtle role in amygdala physiology and aversive memory.

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Frederique Chaperon

Full Text Available Links between synaptic plasticity in the lateral amygdala (LA and Pavlovian fear learning are well established. Neuropeptides including gastrin-releasing peptide (GRP can modulate LA function. GRP increases inhibition in the LA and mice lacking the GRP receptor (GRPR KO show more pronounced and persistent fear after single-trial associative learning. Here, we confirmed these initial findings and examined whether they extrapolate to more aspects of amygdala physiology and to other forms of aversive associative learning. GRP application in brain slices from wildtype but not GRPR KO mice increased spontaneous inhibitory activity in LA pyramidal neurons. In amygdala slices from GRPR KO mice, GRP did not increase inhibitory activity. In comparison to wildtype, short- but not long-term plasticity was increased in the cortico-lateral amygdala (LA pathway of GRPR KO amygdala slices, whereas no changes were detected in the thalamo-LA pathway. In addition, GRPR KO mice showed enhanced fear evoked by single-trial conditioning and reduced spontaneous firing of neurons in the central nucleus of the amygdala (CeA. Altogether, these results are consistent with a potentially important modulatory role of GRP/GRPR signaling in the amygdala. However, administration of GRP or the GRPR antagonist (D-Phe(6, Leu-NHEt(13, des-Met(14-Bombesin (6-14 did not affect amygdala LTP in brain slices, nor did they affect the expression of conditioned fear following intra-amygdala administration. GRPR KO mice also failed to show differences in fear expression and extinction after multiple-trial fear conditioning, and there were no differences in conditioned taste aversion or gustatory neophobia. Collectively, our data indicate that GRP/GRPR signaling modulates amygdala physiology in a paradigm-specific fashion that likely is insufficient to generate therapeutic effects across amygdala-dependent disorders.

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

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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

Personality, risk aversion and speeding: an empirical investigation.

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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.

Loss Aversion, Adaptive Beliefs, and Asset Pricing Dynamics

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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.

Sensitivity of the brain to loss aversion during risky gambles.

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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).

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…

Commercial Foods and Culinary Arts. Student Learning Guides.

Science.gov (United States)

Ridge Vocational-Technical Center, Winter Haven, FL.

These 13 learning guides are self-instructional packets for 13 tasks identified as essential for performance on an entry-level job in commercial foods and culinary arts. Each guide is based on a terminal performance objective (task) and 1-4 enabling objectives. For each enabling objective, some or all of these materials may be presented: learning…

The rural school meal as a site for learning about food.

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Torres, Irene; Benn, Jette

2017-10-01

The aim of the article is to contribute to the understanding of the school meal as a site for learning about food, nutrition and the wider determinants of health in three small rural schools of Ecuador. Based on a year-long qualitative fieldwork, the multiple case study associates Vygotsky's sociocultural theory of learning with Noddings' theory of care to analyze the findings. In the study, elements of care in the relationships between children and adults seemed to promote dialogue and, in this way, adults were able to model what is required to care for others and oneself. This entails that a focus solely on food or limitations on social interaction during the school meal may reduce its learning opportunities. The study concurs with the research that the food is better received when it is more aligned with the students' expectations. In addition, the findings support the view that rural school meal programs should address the views of parents and teachers because of their influence on how the meal is prepared and provided. The article proposes that schools work within a flexible framework emphasizing attention to the caring aspects of the meal, as a means to develop this dimension of the school meal. The study also contends that a collaborative reshaping of conditions formally set by school food policy is consistent with a critical approach to food and nutrition. In connection with this, the study concludes by highlighting the value of revisiting Noddings' perspective of care as deriving from the practice of opening up and meeting the other. Copyright © 2017 Elsevier Ltd. All rights reserved.

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

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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.

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

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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.

Learning about the energy density of liquid and semi-solid foods.

Science.gov (United States)

Hogenkamp, P S; Stafleu, A; Mars, M; de Graaf, C

2012-09-01

People learn about a food's satiating capacity by exposure and consequently adjust their energy intake. To investigate the effect of energy density and texture on subsequent energy intake adjustments during repeated consumption. In a randomized crossover design, participants (n=27, age: 21±2.4 years, body mass index: 22.2±1.6 kg m(-2)) repeatedly consumed highly novel foods that were either low-energy-dense (LE: 30 kcal per 100 g) or high-energy-dense (HE: 130 kcal per 100 g), and either liquid or semi-solid, resulting in four product conditions. In each condition, a fixed portion of test food was consumed nine times as an obligatory part of breakfast, lunch and dinner on 3 consecutive days. All meals continued with an ad libitum buffet; food items for evening consumption were provided and the intake (kcal per day) was measured. Buffet intake depended on energy density and day of consumption of the test foods (day*energy interaction: P=0.02); daily buffet intake increased from day 1 (1745±577 kcal) to day 3 (1979±567 kcal) in the LE conditions; intake did not change in the HE conditions (day 1: 1523±429 kcal, day 3: 1589±424 kcal). Food texture did not affect the intake (P=0.56). Intake did depend on energy density of the test foods; participants increased their buffet intake over days in response to learning about the satiating capacity of the LE foods, but did not change buffet intake over days when repeatedly consuming a HE food as part of their meal. The adjustments in intake were made irrespective of the food texture.

Is there evidence of learned helplessness in horses?

Science.gov (United States)

Hall, Carol; Goodwin, Deborah; Heleski, Camie; Randle, Hayley; Waran, Natalie

2008-01-01

Learned helplessness is a psychological condition whereby individuals learn that they have no control over unpleasant or harmful conditions, that their actions are futile, and that they are helpless. In a series of experiments in which dogs were exposed to inescapable shocks, this lack of control subsequently interfered with the ability to learn an avoidance task. There is evidence that both neural adaptations and behavioral despair occur in response to uncontrollable aversive experiences in rodents, although this has yet to be demonstrated in other species such as horses. However, certain traditional methods of horse training and some behavioral modification techniques--it has been suggested--may involve aversive conditions over which the horse has little or no control. When training and management procedures are repeatedly unpleasant for the horse and there is no clear association between behavior and outcome, this is likely to interfere with learning and performance-in addition to compromising welfare. This article reviews published literature and anecdotal evidence to explore the possibility that the phenomenon, learned helplessness, occurs in the horse.

Risk Aversion and the Value of Information.

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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)

Modern 'junk food' and minimally-processed 'natural food' cafeteria diets alter the response to sweet taste but do not impair flavor-nutrient learning in rats.

Science.gov (United States)

Palframan, Kristen M; Myers, Kevin P

2016-04-01

Animals learn to prefer and increase consumption of flavors paired with postingestive nutrient sensing. Analogous effects have been difficult to observe in human studies. One possibility is experience with the modern, processed diet impairs learning. Food processing manipulates flavor, texture, sweetness, and nutrition, obscuring ordinary correspondences between sensory cues and postingestive consequences. Over time, a diet of these processed 'junk' foods may impair flavor-nutrient learning. This 'flavor-confusion' hypothesis was tested by providing rats long-term exposure to cafeteria diets of unusual breadth (2 or 3 foods per day, 96 different foods over 3 months, plus ad libitum chow). One group was fed processed foods (PF) with added sugars/fats and manipulated flavors, to mimic the sensory-nutrient properties of the modern processed diet. Another group was fed only 'natural' foods (NF) meaning minimally-processed foods without manipulated flavors or added sugars/fats (e.g., fresh fruits, vegetables, whole grains) ostensibly preserving the ordinary correspondence between flavors and nutrition. A CON group was fed chow only. In subsequent tests of flavor-nutrient learning, PF and NF rats consistently acquired strong preferences for novel nutrient-paired flavors and PF rats exhibited enhanced learned acceptance, contradicting the 'flavor-confusion' hypothesis. An unexpected finding was PF and NF diets both caused lasting reduction in ad lib sweet solution intake. Groups did not differ in reinforcing value of sugar in a progressive ratio task. In lick microstructure analysis the NF group paradoxically showed increased sucrose palatability relative to PF and CON, suggesting the diets have different effects on sweet taste evaluation. Copyright © 2016 Elsevier Inc. All rights reserved.

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

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

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

Aboriginal health learning in the forest and cultivated gardens: building a nutritious and sustainable food system.

Science.gov (United States)

Stroink, Mirella L; Nelson, Connie H

2009-01-01

Sustainable food systems are those in which diverse foods are produced in close proximity to a market. A dynamic, adaptive knowledge base that is grounded in local culture and geography and connected to outside knowledge resources is essential for such food systems to thrive. Sustainable food systems are particularly important to remote and Aboriginal communities, where extensive transportation makes food expensive and of poorer nutritional value. The Learning Garden program was developed and run with two First Nation communities in northwestern Ontario. With this program, the team adopted a holistic and experiential model of learning to begin rebuilding a knowledge base that would support a sustainable local food system. The program involved a series of workshops held in each community and facilitated by a community-based coordinator. Topics included cultivated gardening and forest foods. Results of survey data collected from 20 Aboriginal workshop participants are presented, revealing a moderate to low level of baseline knowledge of the traditional food system, and a reliance on the mainstream food system that is supported by food values that place convenience, ease, and price above the localness or cultural connectedness of the food. Preliminary findings from qualitative data are also presented on the process of learning that occurred in the program and some of the insights we have gained that are relevant to future adaptations of this program.

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

Creating a Learning Environment to Promote Food Sustainability Issues in Primary Schools? Staff Perceptions of Implementing the Food for Life Partnership Programme

Directory of Open Access Journals (Sweden)

Judy Orme

2013-03-01

Full Text Available There is increasing interest in the role that schools can play in promoting education for sustainable development (ESD, and evidence is emerging that schools can be influential in the emerging agenda around the ecological, ethical and social aspects of food, diet and nutrition. With regard to such food sustainability issues, this paper analyses the role of the Food for Life Partnership national programme in supporting garden and farm-based learning activities in 55 primary schools in England, UK. Using a mixed methods approach, the study examined the programme’s implementation through staff perceptions and a range of school change indicators. The study found that the programme delivery was associated with widespread institutional reforms. According to staff, implementation of the programme provided a range of opportunities for pupils to learn about food production and sustainability, but addressing these issues was challenging for teachers and raised a number of questions concerned with effective, equitable and on-going implementation. At a pedagogical level, teachers also reflected on conceptually challenging aspects of food sustainability as a topic for primary school education. The study identified ways that ESD programmes could support schools to think about and implement learning opportunities as well as identifying significant barriers related to resourcing such programmes.

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

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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.

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

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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.

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

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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.

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

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...