Abstract: Tests of self-awareness in nonhuman primates have to date been concerned almost entirely with the recognition of an animal's reflection in a mirror. By contrast, we know much less about non-human primates' perception of their place within a social network, or of their understanding of themselves as individuals with unique sets of social relationships. Here we review evidence that monkeys who fail the mirror test may nonetheless behave as if they recognize themselves as distinct individuals, each of whom occupies a unique place in society and has a specific set of relations with others. A free-ranging vervet monkey, baboon, or macaque recognizes other members of his group as individuals. He also recognizes matrilineal kin groups, linear dominance rank orders, and behaves as if he recognizes his own unique place within them. This sense of “social self” in monkeys, however, is markedly different from self-awareness in humans. Although monkeys may behave in ways that accurately place themselves within a social network, they are unaware of the knowledge that allows them to do so: they do not know what they know, cannot reflect on what they know, and cannot become the object of their own attention.

Abstract: The social intelligence hypothesis argues that competition and cooperation among individuals have shaped the evolution of cognition in animals. What do we mean by social cognition? Here we suggest that the building blocks of social cognition are a suite of skills, ordered roughly according to the cognitive demands they place upon individuals. These skills allow an animal to recognize others by various means; to recognize and remember other animals' relationships; and, perhaps, to attribute mental states to them. Some skills are elementary and virtually ubiquitous in the animal kingdom; others are more limited in their taxonomic distribution. We treat these skills as the targets of selection, and assume that more complex levels of social cognition evolve only when simpler methods are inadequate. As a result, more complex levels of social cognition indicate greater selective pressures in the past. The presence of each skill can be tested directly through field observations and experiments. In addition, the same methods that have been used to compare social cognition across species can also be used to measure individual differences within species and to test the hypothesis that individual differences in social cognition are linked to differences in reproductive success.