Joan Silk moved to ASU's School of Human Evolution and Social Change in 2012, from University of California, Los Angeles (UCLA). She is interested in how natural selection shapes the evolution of social behavior in primates. Most of her empirical work has focused on the form and adaptive function of social relationships among females in two Old World monkey species, bonnet macaques ( Macaca radiata) and baboons (Papio cynocephalus). She has also studied chimpanzees (Pan troglodytes) in the wild, and has recently completed a series of experiments to examine chimpanzees' prosocial preferences. Silk's work addresses questions that explicitly link studies of nonhuman primates to humans, attempting to probe the phylogenetic roots of capacities that play a crucial role in human societies, such as reconciliation, cooperation, friendship, cooperative signals, paternal investment, and the origins of prosocial sentiments.