The strength of Us/Them-ing is shown by its emergence in kids. By age three to four, kids already group people by race and gender, have more negative views of such Thems, and perceive other-race faces as being angrier than same-race faces.8 And even earlier. Infants learn same-race faces better than other-race. (How can you tell? Show an infant a picture of someone repeatedly; she looks at it less each time. Now show a different face--if she can't tell the two apart, she barely glances at it. But if it's recognized as being new, there's excitement, and longer looking).9 Four important thoughts about kids dichotomizing: Are children learning these prejudices from their parents? Not necessarily. Kids grow in environments whose nonrandom stimuli tacitly pave the way for dichotomizing. If an infant sees faces of only one skin color, the salient thing about the first face with a different skin color will be the skin color. Racial dichotomies are formed during a crucial developmental period. As evidence, children adopted before age eight by someone of a different race develop the expertise at face recognition of the adoptive parent's race.10