Humans learn about people and objects through positive and negative experiences, yet they can also look beyond the immediate reward of an interaction to encode trait-level attributes. We found that perceivers encoded both reward and trait-level information through feedback in an instrumental learning task, but relied more heavily on trait representations in cross-context decisions. Both learning types implicated ventral striatum, but trait learning also recruited a network associated with social impression formation.

No abstract

No abstract

People frequently engage in more prosocial behavior toward members of their own groups, as compared to other groups. Such group-based prosociality may reflect either strategic considerations concerning one's own future outcomes or intrinsic value placed on the outcomes of in-group members. In a functional magnetic resonance imaging experiment, we examined vicarious reward responses to witnessing the monetary gains of in-group and out-group members, as well as prosocial behavior towards both types of individuals. We found that individuals’ investment in their group—a motivational component of social identification—tracked the intensity of their responses in ventral striatum to in-group (vs out-group) members’ rewards, as well as their tendency towards group-based prosociality. Individuals with strong motivational investment in their group preferred rewards for an in-group member, whereas individuals with low investment preferred rewards for an out-group member. These findings suggest that the motivational importance of social identity—beyond mere similarity to group members—influences vicarious reward and prosocial behavior. More broadly, these findings support a theoretical framework in which salient social identities can influence neural representations of subjective value, and suggest that social preferences can best be understood by examining the identity contexts in which they unfold.

No abstract

Cooperation is necessary for solving numerous social issues, including climate change, effective governance and economic stability. Value-based decision models contend that prosocial tendencies and social context shape people’s preferences for cooperative or selfish behavior. Using functional neuroimaging and computational modeling, we tested these predictions by comparing activity in brain regions previously linked to valuation and executive function during decision-making—the ventromedial prefrontal cortex (vmPFC) and dorsolateral prefrontal cortex (dlPFC), respectively. Participants played Public Goods Games with students from fictitious universities, where social norms were selfish or cooperative. Prosocial participants showed greater vmPFC activity when cooperating and dlPFC-vmPFC connectivity when acting selfishly, whereas selfish participants displayed the opposite pattern. Norm-sensitive participants showed greater dlPFC-vmPFC connectivity when defying group norms. Modeling expectations of cooperation was associated with activity near the right temporoparietal junction. Consistent with value-based models, this suggests that prosocial tendencies and contextual norms flexibly determine whether people prefer cooperation or defection.

Reciprocity and reputation are powerful tools for encouraging cooperation on a broad scale. Here, we highlight a potential side effect of these social phenomena: exacerbating economic inequality. In two novel economic games, we manipulated the amount of money with which participants were endowed and then gave them the opportunity to share resources with others. We found that people reciprocated more toward higher-wealth givers, compared with lower-wealth givers, even when those givers were equally generous. Wealthier givers also achieved better reputations than less wealthy ones and therefore received more investments in a social marketplace. These discrepancies were well described by a formal model of reinforcement learning: Individuals who weighted monetary outcomes, rather than generosity, when learning about interlocutors also most strongly helped wealthier individuals. This work demonstrates that reciprocity and reputation-although globally increasing prosociality-can widen wealth gaps and provides a precise account of how inequality grows through social processes.

Throughout human history, food consumption has been deeply tied to cultural groups. Past models of food preference have assumed that social concerns are dissociated from basic appetitive qualities-such as tastiness-in food choice. Providing a counter to this notion, we tested and found support for the novel idea that social identities can shape the evaluation of food pleasantness. Specifically, individual differences in social identification (Study 1) as well as experimentally manipulated identity salience (Study 2) were associated with the anticipated tastiness of identity-relevant foods. We also found that identity salience influenced perceived food pleasantness during consumption (Study 3). These results suggest social identity may shape evaluations of food pleasantness, both through long-term motivational components of identification as well as short-term identity salience. Thus, the influence of social identity on cognition appears to extend beyond social evaluation, to hedonic experience. We discuss implications for theories of identity, decision-making, and food consumption.