This chapter explores our tendency to form us/them dichotomies from a biological perspective.

Many species bristle at the sight of strangers of the same species—outgroup members, or “Thems.” Some species, such as chimps, will fission into multiple sub-groups when the situation demands it, with previous conspecifics now belonging to different groups becoming hostile to each other. In humans, studies show we automatically associate outgroups with negative concepts and ingroup members with positive concepts. Such thinking emerges as early as three to four years old, suggesting it is not just culturally but also evolutionarily conditioned. Even infants recognize same-race faces better than different-race faces.

Us

Creating Us/Thems usually involved “inflating the merits of Us concerning core values—we are more correct, wise, moral and worthy” (393), and of inflating the importance of the arbitrary markers that indicate “Us”: our food, taboos, religion, parenting style, etc. Being an Us also means a shared expectation of reciprocity based on the cultural rules we know each other to participate in. Often, these codes of assistance to our in-group equal hostility to an out-group: It is “good” to kill in war.

Them

We tend to view “Thems,” as threatening, angry, and untrustworthy. This has serious social ramifications for our blended society: “White subjects become more likely to support juvenile criminals being tried as adults when primed to think about black (versus white) offenders” (398).