Original Paper

Journal of Nonverbal Behavior

, Volume 31, Issue 1, pp 1-20

First online:

Open Access This content is freely available online to anyone, anywhere at any time.

A Cross-species Comparison of Facial Morphology and Movement in Humans and Chimpanzees Using the Facial Action Coding System (FACS)

  • Sarah-Jane VickAffiliated withScottish Primate Research Group, Department of Psychology, University of Stirling Email author 
  • , Bridget M. WallerAffiliated withCentre for the Study of Emotion, Department of Psychology, University of Portsmouth
  • , Lisa A. ParrAffiliated withDivison of Psychiatry and Behavioral Sciences, Yerkes National Primate Research Center, Emory University
  • , Marcia C. Smith PasqualiniAffiliated withDepartment of Psychology, Avila University
  • , Kim A. BardAffiliated withCentre for the Study of Emotion, Department of Psychology, University of Portsmouth


A comparative perspective has remained central to the study of human facial expressions since Darwin’s [(1872/1998). The expression of the emotions in man and animals (3rd ed.). New York: Oxford University Press] insightful observations on the presence and significance of cross-species continuities and species-unique phenomena. However, cross-species comparisons are often difficult to draw due to methodological limitations. We report the application of a common methodology, the Facial Action Coding System (FACS) to examine facial movement across two species of hominoids, namely humans and chimpanzees. FACS [Ekman & Friesen (1978). Facial action coding system. CA: Consulting Psychology Press] has been employed to identify the repertoire of human facial movements. We demonstrate that FACS can be applied to other species, but highlight that any modifications must be based on both underlying anatomy and detailed observational analysis of movements. Here we describe the ChimpFACS and use it to compare the repertoire of facial movement in chimpanzees and humans. While the underlying mimetic musculature shows minimal differences, important differences in facial morphology impact upon the identification and detection of related surface appearance changes across these two species.


Comparative anatomy Chimpanzees Facial action coding system (FACS) Facial morphology