We review emerging research on the psychological and biological factors that underlie social group formation, cooperation, and conflict in humans. Our aim is to integrate the intergroup neuroscience literature with classic theories of group processes and intergroup relations in an effort to move beyond merely describing the effects of specific social out-groups on the brain and behavior. Instead, we emphasize the underlying psychological processes that govern intergroup interactions more generally: forming and updating our representations of "us" and "them" via social identification and functional relations between groups. This approach highlights the dynamic nature of social identity and the context dependent nature of intergroup relations. We argue that this theoretical integration can help reconcile seemingly discrepant findings in the literature, provide organizational principles for understanding the core elements of intergroup dynamics, and highlight several exciting directions for future research at the interface of intergroup relations and neuroscience. (146 words)The neuroscience of intergroup relations 3The neuroscience of intergroup relations:
An integrative reviewThe human brain is "truly social", which is to say specialized for group living (Caporeal, 1997;Dunbar, 1998). People who accurately identify, value, and cooperate with in-group members enjoy numerous benefits, including the fulfillment of many basic psychological needs (Allport, 1954;Correll & Park, 2005;Kurzban & Neuberg, 2005;Wilson & Wilson, 2007). The value humans place on group membership is illustrated by the ease with which humans form groups and favor in-group members. The propensity to prefer one's in-group has been observed in every culture on earth (Brown, 1991) and in children as young as five (Dunham et al., 2011;Fehr, Bernhard, & Rockenbach, 2008). Extensive research has shown that even arbitrary assignment to a group elicits preferences for in-group relative to out-group members across a wide variety of indices, and does so in the absence of factors typically thought to account for intergroup discrimination, such as prior contact with in-group or out-group members and competition over resources (Tajfel, 1970).The functional benefits of group membership notwithstanding, group life is also a source of social strife and destruction (e.g., pressure to conform within groups, protracted conflict between groups; Brewer, 1999;Cosmides, 1989;Hewstone et al., 2002;Neuberg & Cottrell, 2006). Intergroup conflict, in particular, has been described as "one of the greatest problems facing the world today" (Cohen & Insko, 2008). For example, it has been estimated that over 200 million people were killed in the last century due to genocide, war, and other forms of group conflict (Woolf & Hulsizer, 2004). The social and economic obstacles of group living have attracted the attention of scholars and scientists from social, developmental, evolutionary, and cognitive psychology, social neuroscience, biological and cultural anthropology,...