Facial appearance is a salient source of social information that affects various social interactions. Humans are inclined to infer personality, health, and behavioral tendencies of others from facial appearance, although this inference is not necessarily accurate. This article reviews recent human and nonhuman primate research to understand the evolution and origin of face-based trait inferences. This review revealed that the tendency to make trait inferences from facial appearance can occur in nonhuman primates, which indicate that face-based trait inferences are not unique to humans. Moreover, nonhuman primates also appear to utilize facial features unique to their own species when making social judgments. Despite the paucity of nonhuman primate studies, the phylogenetic comparison of face-based trait inferences provides valuable insights into the evolution and origin of human social perception.
