An important feature of adaptive social behavior is the ability to flexibly modify future actions based on the successes or failures of past experiences. The ventral striatum (VS) occupies a central role in shaping behavior by using feedback to evaluate actions and guide learning. The current studies tested whether feedback indicating the need to update social knowledge would engage the VS, thereby facilitating subsequent learning. We also examined the sensitivity of these striatal signals to the value associated with social group membership. Across two fMRI studies, participants answered questions testing their knowledge about the preferences of personally relevant social groups who were high (in-group) or low (out-group) in social value. Participants received feedback indicating whether their responses were correct or incorrect on a trial-by-trial basis. After scanning, participants were given a surprise memory test examining memory for the different types of feedback. VS activity in response to social feedback correlated with subsequent memory, specifying a role for the VS in encoding and updating social knowledge. This effect was more robust in response to in-group than out-group feedback, indicating that the VS tracks variations in social value. These results provide novel evidence of a neurobiological mechanism adaptively tuned to the motivational relevance of the surrounding social environment that focuses learning efforts on the most valuable social outcomes and triggers adjustments in behavior when necessary.

The human brain is remarkably adept at integrating complex information to form unified psychological representations of agents, objects, and events in the environment. Two domains in which this ability is particularly salient are the processing of social and valence information and are supported by common cortical areas in the medial pFC (MPFC). Because social information is often embedded within valenced emotional contexts, it is possible that activation patterns within the MPFC may represent both of these types of cognitive processes when presented simultaneously. The current study tested this possibility by employing a large-scale automated meta-analysis tool, together with multivoxel pattern analysis to investigate the representational similarity of social and valence information in the MPFC during fMRI. Using a representational similarity analysis, we found a high degree of representational similarity both within social dimensions and within valence dimensions, but not across them (e.g., positive social information was highly dissimilar to negative nonsocial information), in a ventral portion of the MPFC. These results were significantly correlated with a behaviorally measured similarity structure of the same stimuli, suggesting that a psychologically meaningful representation of social and valence information is reflected by multivoxel activation patterns in the ventral MPFC.

As a social species, humans are acutely aware of cues that signal inclusionary status. This study characterizes behavioral and neural responses when individuals anticipate social feedback. Across two fMRI studies, participants ( n = 42) made social judgments about supposed peers and then received feedback from those individuals. Of particular interest was the neural activity occurring when participants were awaiting social feedback. During this anticipatory period, increased neural activity was observed in the ventral striatum, a central component of the brain's reward circuitry, and dorsomedial pFC, a brain region implicated in mentalizing about others. Individuals high in rejection sensitivity exhibited greater responses in both the ventral striatum and dorsomedial pFC when anticipating positive feedback. These findings provide initial insight into the neural mechanisms involved in anticipating social evaluations as well as the cognitive processes that underlie rejection sensitivity.

Experiencing negative affect frequently precedes lapses in self-control for dieters, smokers, and drug addicts. Laboratory research has similarly shown that inducing negative emotional distress increases the consumption of food or drugs. One hypothesis for this finding is that emotional distress sensitizes the brain's reward system to appetitive stimuli. Using functional neuroimaging, we demonstrate that inducing negative affect in chronic dieters increases activity in brain regions representing the reward value of appetitive stimuli when viewing appetizing food cues. Thirty female chronic dieters were randomly assigned to receive either a negative ( n = 15) or neutral mood induction ( n = 15) immediately followed by exposure to images of appetizing foods and natural scenes during fMRI. Compared with chronic dieters in a neutral mood, those receiving a negative mood induction showed increased activity in the OFC to appetizing food images. In addition, activity to food images in the OFC and ventral striatum was correlated with individual differences in the degree to which the negative mood induction decreased participants' self-esteem. These findings suggest that distress sensitizes the brain's reward system to appetitive cues, thereby offering a mechanism for the oft-observed relationship between negative affect and disinhibited eating.

Numerous studies have demonstrated that consuming high-calorie food leads to subsequent overeating by chronic dieters. The present study investigates the neural correlates of such self-regulatory failures using fMRI. Chronic dieters ( n = 50) and non-dieters ( n = 50) consumed either a 15-oz glass of cold water or a 15-oz milkshake and were subsequently imaged while viewing pictures of animals, environmental scenes, people, and appetizing food items. Results revealed a functional dissociation in nucleus accumbens and amygdala activity that paralleled well-established behavioral patterns of eating observed in dieters and non-dieters. Whereas non-dieters showed the greatest nucleus accumbens activity in response to food items after water consumption, dieters showed the greatest activity after consuming the milkshake. Activity in the left amygdala demonstrated the reverse interaction. Considered together with previously reported behavioral findings, the present results offer a suggested neural substrate for diet failure.

The current study examined the neural substrates of facial attractiveness judgments. Based on the extant behavioral literature, it was hypothesized that brain regions involved in identifying the potential reward value of a stimulus would be more active when men viewed attractive women than when women viewed attractive men. To test this hypothesis, we conducted an event-related functional magnetic resonance imaging experiment during which participants provided explicit attractiveness judgments for faces of the opposite sex. These individual ratings were subsequently used to perform analyses aimed at identifying the brain regions preferentially responsive to attractive faces for both sex groups. The results revealed that brain regions comprising the putative reward circuitry (e.g., nucleus accumbens [NAcc], orbito-frontal cortex [OFC]) showed a linear increase in activation with increased judgments of attractiveness. However, further analysis also revealed sex differences in the recruitment of OFC, which distinguished attractive and unattractive faces only for male participants.