Human facial expressions as adaptations: Evolutionary questions in facial expression research
Article first published online: 4 JAN 2002
Copyright © 2001 Wiley-Liss, Inc.
American Journal of Physical Anthropology
Supplement: Yearbook of Physical Anthropology
Volume 116, Issue Supplement 33, pages 3–24, 2001
How to Cite
Schmidt, K. L. and Cohn, J. F. (2001), Human facial expressions as adaptations: Evolutionary questions in facial expression research. Am. J. Phys. Anthropol., 116: 3–24. doi: 10.1002/ajpa.20001
- Issue published online: 4 JAN 2002
- Article first published online: 4 JAN 2002
- NIH. Grant Numbers: MH12579, MH56193
- nonverbal communication;
- social intelligence;
- signaling systems
The importance of the face in social interaction and social intelligence is widely recognized in anthropology. Yet the adaptive functions of human facial expression remain largely unknown. An evolutionary model of human facial expression as behavioral adaptation can be constructed, given the current knowledge of the phenotypic variation, ecological contexts, and fitness consequences of facial behavior. Studies of facial expression are available, but results are not typically framed in an evolutionary perspective. This review identifies the relevant physical phenomena of facial expression and integrates the study of this behavior with the anthropological study of communication and sociality in general. Anthropological issues with relevance to the evolutionary study of facial expression include: facial expressions as coordinated, stereotyped behavioral phenotypes, the unique contexts and functions of different facial expressions, the relationship of facial expression to speech, the value of facial expressions as signals, and the relationship of facial expression to social intelligence in humans and in nonhuman primates. Human smiling is used as an example of adaptation, and testable hypotheses concerning the human smile, as well as other expressions, are proposed. Yrbk Phys Anthropol 44:3–24, 2001. © 2001 Wiley-Liss, Inc.