Face perception

Overview
Face perception refers to the cognitive processes involved in recognizing and interpreting facial features in order to make judgments about identity, attractiveness, emotion, and other qualities. This ability is intrinsically linked to social interaction and has evolved in humans and non-human primates alike. In humans, the evaluation of facial attributes plays a significant role in mate choice, as attractive features are often considered indicative of good health and genetic fitness.

Attractiveness across cultures and species
The judgments we make about human faces may also influence how we perceive non-human primate faces, suggesting a shared evolutionary basis for face perception across species https://www.frontiersin.org/articles/10.3389/fpsyg.2020.00643/full+-. The consistency of facial attractiveness ratings across different cultures and the emergence of such preferences early in development challenge the idea that these preferences are the result of arbitrary standards of beauty dictated by cultural influences https://www2.psych.ubc.ca/~schaller/Psyc591Readings/Rhodes2006.pdf+-.

A critical review and meta-analysis found that certain facial features, specifically symmetry, averageness, and sexual dimorphism, are consistently rated as attractive in both male and female faces across cultures https://www.annualreviews.org/doi/10.1146/annurev.psych.57.102904.190208+-. These findings support the idea that some aspects of facial attractiveness may reflect evolutionary adaptations for mate choice.

Evolutionary implications of face perception
The capacity to perceive faces accurately and efficiently is thought to have evolved due to the significant advantages it provides in social interactions, particularly in terms of recognizing friends, foes, and potential mates. Some researchers have posited that our preferences for specific facial features may be driven by adaptations in the human brain for mate choice and social cooperation, as these features could signal important aspects of an individual's mate quality, such as health https://www.frontiersin.org/articles/10.3389/fpsyg.2020.00643/full+-.

Face pareidolia, the phenomenon of perceiving faces in inanimate objects or abstract patterns, is another indication of the evolutionary importance placed on this ability. Face pareidolia has been observed in monkeys, adding further support to the notion that the brain's capacity to recognize faces may have been inherited from primates https://newsroom.unsw.edu.au/news/science-tech/why-brain-programmed-see-faces-everyday-objects+-.

Factors influencing face perception
Several factors are known to influence how faces are perceived and evaluated, such as symmetry, averageness, and sexual dimorphism.


 * Symmetry: Symmetrical faces are considered more attractive than asymmetrical faces, possibly because facial symmetry is indicative of developmental stability and resistance to illness or injury https://www.annualreviews.org/doi/10.1146/annurev.psych.57.102904.190208+-.
 * Averageness: More average or prototypical faces tend to be rated as more attractive than those with exaggerated features. This preference could reflect a bias towards faces that are indicative of a diverse gene pool with an increased resistance to disease https://journals.sagepub.com/doi/abs/10.1111/1467-8721.00190+-.
 * Sexual dimorphism: Faces that display pronounced gender-specific features, such as a strong jawline in men and full lips in women, are considered more attractive. This preference may be linked to perceptions of mate quality and reproductive fitness, given that sex hormones influence these features https://www.annualreviews.org/doi/10.1146/annurev.psych.57.102904.190208+-.

Conclusion
Face perception is a crucial aspect of human and non-human primate social interaction. The evolutionary roots of this ability are evidenced through cross-cultural and cross-species similarities in judgments of facial attractiveness, as well as the consistency with which certain facial features are regarded as attractive. These preferences likely play a significant role in mate choice, as features considered attractive often signal aspects of mate quality and genetic fitness.