Alan G. Sanfey

Independent Coding of Reward Magnitude and Valence in the Human Brain

Previous research has shown that two components of the event-related brain potential, the P300 and feedback negativity, are sensitive to information about rewards and penalties. The present study investigated the properties of these components in a simple gambling game that required participants to choose between cards that were unpredictably associated with monetary gains and losses of variable magnitude. The aim was to determine the sensitivity of each component to two critical features of reward stimuli: magnitude (small or large) and valence (win or loss). A double dissociation was observed, with the P300 sensitive to reward magnitude but insensitive to reward valence and the feedback negativity showing the opposite pattern, suggesting that these two fundamental features of rewarding stimuli are evaluated rapidly and separately in the human brain. Subsequent analyses provided additional evidence of functional dissociations between the feedback negativity and P300. First, the P300 (but not the feedback negativity) showed sensitivity to the reward value of alternative, nonselected stimuli. Second, individual differences in the amplitude of the feedback negativity correlated with individual differences in risk-taking behavior observed after monetary losses, whereas individual differences in P300 amplitude were related to behavioral adjustments observed in response to alternative, unchosen outcomes.

Testosterone Inhibits Trust but Promotes Reciprocity

The steroid hormone testosterone has been associated with behavior intended to obtain or maintain high social status. Although such behavior is typically characterized as aggressive and competitive, it is clear that high social status is achieved and maintained not only through antisocial behavior but also through prosocial behavior. In the present experiment, we investigated the impact of testosterone administration on trust and reciprocity using a double-blind randomized control design. We found that a single dose of 0.5 mg of testosterone decreased trust but increased generosity when repaying trust. These findings suggest that testosterone may mediate different types of status-seeking behavior. It may increase competitive, potentially aggressive, and antisocial behavior when social challenges and threats (i.e., abuse of trust and betrayal) need to be considered; however, it may promote prosocial behavior in the absence of these threats, when high status and good reputation may be best served by prosocial behavior.

Great expectations: neural computations underlying the use of social norms in decision-making

Social expectations play a critical role in everyday decision-making. However, their precise neuro-computational role in the decision process remains unknown. Here we adopt a decision neuroscience framework by combining methods and theories from psychology, economics and neuroscience to outline a novel, expectation-based, computational model of social preferences. Results demonstrate that this model outperforms the standard inequity-aversion model in explaining decision behavior in a social interactive bargaining task. This is supported by fMRI findings showing that the tracking of social expectation violations is processed by anterior cingulate cortex, extending previous computational conceptualizations of this region to the social domain. This study demonstrates the usefulness of this interdisciplinary approach in better characterizing the psychological processes that underlie social interactive decision-making.

The Herding Hormone Oxytocin Stimulates In-Group Conformity

People often conform to others with whom they associate. Surprisingly, however, little is known about the possible hormonal mechanisms that may underlie in-group conformity. Here, we examined whether conformity toward one’s in-group is altered by oxytocin, a neuropeptide often implicated in social behavior. After administration of either oxytocin or a placebo, participants were asked to provide attractiveness ratings of unfamiliar visual stimuli. While viewing each stimulus, participants were shown ratings of that stimulus provided by both in-group and out-group members. Results demonstrated that on trials in which the ratings of the in-group and out-group were incongruent, the ratings of participants given oxytocin conformed to the ratings of their in-group but not of their out-group. Participants given a placebo did not show this in-group bias. These findings indicate that administration of oxytocin can influence subjective preferences, and they support the view that oxytocin’s effects on social behavior are context dependent.

Reduced risk-taking behavior as a trait feature of anxiety

Affect can have a significant influence on decision-making processes and subsequent choice. One particularly relevant type of negative affect is anxiety, which serves to enhance responses to threatening stimuli or situations. In its exaggerated form, it can lead to psychiatric disorders, with detrimental consequences for quality of life, including the ability to make choices. This study investigated, for the first time, how pathological anxiety affects risk-taking behavior. In this study, 20 anxious participants meeting Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, criteria for either generalized anxiety disorder (n = 10) and for panic attack disorder (n = 10), as well as 20 matched nonanxious controls, performed a gambling task. To investigate the tendency toward either a risk-seeking or a risk-averse behavior, we employed a task that did not allow for learning from outcomes. Anxious participants made significantly fewer risky choices than matched nonanxious participants. Specifically, they become risk-avoidant after gains. Moreover, anxious participants not only were less happy after gains but were also less sad after losses, and they also evinced less desire to change their choices after losses than did nonanxious participants. Importantly, whereas the desire to switch choice was followed by actual choice switch for all participants, happiness directly predicted subsequent risky choices, particularly in the nonanxious participants. Further analyses revealed that the anxious participants risk-avoidance behavior was independent of different types of anxiety disorder (panic attack disorder and generalized anxiety disorder) as well as of the effects of psychotropic drugs treatment. This study demonstrates a specific role for anxiety in individual decision making. In particular, hypersensitivity to potential threats and pessimistic evaluation of future events reduced risk-taking behavior.

Reappraising social emotions: the role of inferior frontal gyrus, temporo-parietal junction and insula in interpersonal emotion regulation

Previous studies have reported the effect of emotion regulation (ER) strategies on both individual and social decision-making, however, the effect of regulation on socially driven emotions independent of decisions is still unclear. In the present study, we investigated the neural effects of using reappraisal to both up- and down-regulate socially driven emotions. Participants played the Dictator Game (DG) in the role of recipient while undergoing fMRI, and concurrently applied the strategies of either up-regulation (reappraising the proposers intentions as more negative), down-regulation (reappraising the proposers intentions as less negative), as well as a baseline “look” condition. Results showed that regions responding to the implementation of reappraisal (effect of strategy, that is, “regulating regions”) were the inferior and middle frontal gyrus, temporo parietal junction and insula bilaterally. Importantly, the middle frontal gyrus activation correlated with the frequency of regulatory strategies in daily life, with the insula activation correlating with the perceived ability to reappraise the emotions elicited by the social situation. Regions regulated by reappraisal (effect of regulation, that is, “regulated regions”) were the striatum, the posterior cingulate and the insula, showing increased activation for the up-regulation and reduced activation for down-regulation, both compared to the baseline condition. When analyzing the separate effects of partners behavior, selfish behavior produced an activation of the insula, not observed when subjects were treated altruistically. Here we show for the first time that interpersonal ER strategies can strongly affect neural responses when experiencing socially driven emotions. Clinical implications of these findings are also discussed to understand how the way we interpret others intentions may affect the way we emotionally react.

Testosterone biases the amygdala toward social threat approach

Testosterone administration in human participants increased amygdala responses during threat approach and decreased it during threat avoidance. Testosterone enhances amygdala reactions to social threat, but it remains unclear whether this neuroendocrine mechanism is relevant for understanding its dominance-enhancing properties; namely, whether testosterone biases the human amygdala toward threat approach. This pharmacological functional magnetic-resonance imaging study shows that testosterone administration increases amygdala responses in healthy women during threat approach and decreases it during threat avoidance. These findings support and extend motivational salience models by offering a neuroendocrine mechanism of motivation-specific amygdala tuning.

Norms and expectations in social decision-making

Recent research has shown that stimulating right lateral prefrontal cortex (rLPFC) via transcranial direct current stimulation (tDCS) changes social norm compliance in economic decisions, with different types of compliance affected in different ways. More broadly considering the norms involved in decision-making, and in particular expectations held by players, can help clarify the mechanisms underlying these results.

Exogenous testosterone in women enhances and inhibits competitive decision-making depending on victory–defeat experience and trait dominance

The present experiment tested the causal impact of testosterone on human competitive decision-making. According to prevailing theories about testosterones role in social behavior, testosterone should directly boost competitive decisions. But recent correlational evidence suggests that testosterones behavioral effects may depend on specific aspects of the context and person relevant to social status (win-lose context and trait dominance). We tested the causal influence of testosterone on competitive decisions by combining hormone administration with measures of trait dominance and a newly developed social competition task in which the victory-defeat context was experimentally manipulated, in a sample of 54 female participants. Consistent with the hypothesis that testosterone has context- and person-dependent effects on competitive behavior, testosterone increased competitive decisions after victory only among high-dominant individuals but testosterone decreased competitive decisions after defeat across all participants. These results suggest that testosterone flexibly modulates competitive decision-making depending on prior social experience and dominance motivation in the service of enhancing social status.

To play or not to play: A personal dilemma in pathological gambling

Research has shown that healthy people would rather avoid losses than gamble for even higher gains. On the other hand, research on pathological gamblers (PGs) demonstrates that PGs are more impaired than non-pathological gamblers in choice under risk and uncertainty. Here, we investigate loss aversion by using a rigorous and well-established paradigm from the field of economics, in conjunction with personality traits, by using self-report measures for PGs under clinical treatment. Twenty pathological gamblers, at the earlier and later stages of clinical treatment, were matched to 20 non-gamblers (NG). They played a flip coin task by deciding across 256 trials whether to accept or reject a 50-50 bet with a variable amount of gains and losses. They completed questionnaires aimed at assessing impulsivity. Compared to NG, pathological gamblers, specifically those in the later stages of therapy, were more loss averse and accepted a lower number of gambles with a positive expected value, whereas their impulsivity traits were significantly higher. This study shows for the first time that changes in loss aversion, but not in personality traits, are associated with the time course of pathology. These findings can be usefully employed in the fields of both gambling addiction and decision-making.