Moreover, the puppetviewing infants were not “necessarily analyzing social categories,” as older people do, they added. “Infants needed only to evaluate single individuals” to respond as they did, though it’s unclear whether their motivation was “schadenfreude” (taking pleasure in others’ misfortune); the feeling that “the enemy of my enemy is my friend”; or maybe both.
Still, in conclusion, they wrote, “given the links between adults’ and children’s similarity preferences and group psychology, it seems likely that infants’ tendency to notice and prefer similarity is related to emergent intergroup biases... These tendencies are already operative in the first year of human life.”