Social Categorization
Kinship
In humans, family resemblance can be judged from the face, without ever having seen individuals interact with one another. This would be extremely beneficial in primate groups in which dominance follows family lines, such as in macaques, baboons, and to some degree in capuchins. When a male enters a new social group, it is advantageous to be able to recognize related family members without having to observe all possible behavioral interactions before determining who is related to whom and the corresponding rank order. An alternative strategy to phenotype matching for judging kin relations would be to learn through associations, as nonhuman primates appear to have knowledge of close associates, and in matrilineal primates, individuals primarily associate with those who are related. Experimental work in nonhuman primates has found support for both hypotheses: phenotype matching and association, though there are methodological concerns with each, such as available background cues due to cropping of the image and presenting only familiar mother-offspring pairs. Studies are underway which will test both kin recognition strategies in our capuchins.
