A number of studies in humans and other animals has confirmed the amygdala's role in modulating cognition and behavior on the basis of a stimulus' motivational, emotional, and social attributes. This raises the question of how these attributes are related: is social information processing reducible to motivational processing? Some recent data suggest the possibility that the amygdala's primitive function may be motivational processing that is domain-general, but that its function in primates, and especially humans, may have evolved to process social information specifically. While the issue is unresolved, future experiments could provide additional support.