Facial displays of dominance in non-human primates

One approach for investigating the evolutionary history of human facial displays is to study those of our closest living relatives, non-human primates. Most non-human primates are social, and manage the conflicts inherent to social living through the construction of dominance hierarchies. Consequently, multiple ritualized forms of facial expressions and salient indicators of social status have evolved to decrease the frequency of agonistic interactions between group-mates. The form and function of facial displays of dominance in non-human primates are related to species-typical social interactions, and the importance of facial interpretation in primates is reflected in their neurobiology. Homologies in the form and function of human and non-human primate facial displays of dominance have been posited, with relevance to human facial color, shape, eye gaze, and expressions.