Research on social learning in animals has revealed a rich variety of cases where animals--from caddis fly larvae to chimpanzees--acquire biologically important information by observing the actions of others. A great deal is known about the adaptive functions of social learning, but very little about the cognitive mechanisms that make it possible. Even in the case of imitation, a type of social learning studied in both comparative psychology and cognitive science, there has been minimal contact between the two disciplines. Social learning has been isolated from cognitive science by two longstanding assumptions: that it depends on a set of special-purpose modules--cognitive adaptations for social living; and that these learning mechanisms are largely distinct from the processes mediating human social cognition. Recent research challenges these assumptions by showing that social learning covaries with asocial learning; occurs in solitary animals; and exhibits the same features in diverse species, including humans. Drawing on this evidence, I argue that social and asocial learning depend on the same basic learning mechanisms; these are adapted for the detection of predictive relationships in all natural domains; and they are associative mechanisms--processes that encode information for long-term storage by forging excitatory and inhibitory links between event representations. Thus, human and nonhuman social learning are continuous, and social learning is adaptively specialized--it becomes distinctively "social"--only when input mechanisms (perceptual, attentional, and motivational processes) are phylogenetically or ontogenetically tuned to other agents.