What is ChimpFACS?

Welcome to ChimpFACS, an observational, scientific tool to record and analyse facial expressions in chimpanzees.

Scientists have observed that facial expressions are similar between primate species for many years, but until now we have had no common language with which to assess similarity between species. Here we present an anatomically based system that can assess similarity at the level of facial musculature. ChimpFACS is based on the widely used Facial Action Coding System (FACS) by Paul Ekman & Walter Friesen (1978; updated version in CDRom: Ekman, Friesen & Hager, 2002).


ChimpFACS is a standardized system that requires certification to use. The ChimpFACS Manual identifies each muscle movement that causes visible changes in facial appearance. These are called Action Units (AUs) and each AU is listed in the manual with a numerical code. For each AU, the muscular basis is described along with a list of observable appearance changes and subtle differences between AUs.


The ChimpFACS Manual and the ChimpFACS Test are freely available through this website. Please contact us for the passwords. We keep a record of who is using the system so we can maintain standardisation.

For a correct visualization of the ChimpFACS Manual, please install the latest version of Adobe Reader on your computer. To decompress the files (manual and test), please install WinRar.

Click here for the ChimpFACS manual


To use the system you need to take a test after training. This ensures that all users are coding in the same way, and so maintains the standardisation of the system.

Once you have completed the training, you may wish to become certified to use ChimpFACS. The ChimpFACS certification test is available online, with a password given upon request.

How to use it?

ChimpFACS is a technical guide that explains how to categorize chimpanzee facial behaviours in terms of muscle movement. Detailed research of facial movement in both chimpanzees and humans was previously conducted to verify this system, and in the manual these movements are illustrated using written descriptions, still images, and digital video examples. 

If you wish to make comparisons between human and chimpanzee facial expressions we recommend that you become certified in FACS also. To become certified in FACS you need to obtain materials directly from the FACS website.

The people behind it

ChimpFACS was developed with the support of The Leverhulme Trust. Research Interchange Grant (F/00678/E) “Chimpanzee emotions: Development of a Chimpanzee Facial Action Coding System” was awarded to Kim A. Bard (University of Portsmouth)

with Research Partners Marcia Smith Pasqualini (Avila University) and Lisa Parr (Yerkes National Primate Research Center)

and Research Fellows, Sarah-Jane Vick (Stirling University) and Bridget Waller (University of Portsmouth).


The idea for this project blossomed while Kim A. Bard, Marcia Smith Pasqualini and Lisa Parr attended the conference, ‘Feelings and Emotions: The Amsterdam Symposium’, in May of 2001. With the considerable support of Paul Ekman and Frans de Waal as independent referees, we were successful in obtaining financial support from The Leverhulme Trust

In 2002, Sarah-Jane Vick and Bridget Waller began the process of developing ChimpFACS. Along the way, we received warm and essential support from Paul EkmanSusanne Kaiser, and Harriet Oster. The anatomical basis for ChimpFACS was made possible by enthusiastic collaborations with Anne BurrowsAndrew Fuglevand and Katalin Gothard , and the Yerkes National Primate Center. The essential images of chimpanzee faces were collected with the generous assistance of Chester Zoo, Samuel Fernandez-Carriba and William D. Hopkins (the Yerkes National Primate Research Center of Emory University, and the Madrid Zoo), Charles Menzel (Language Research Center of Georgia State University) and The Primate Research Institute, Kyoto University

In March 2005, with the support of the Centre for the Study of Emotion, and Vasudevi Reddy, Head of Department of Psychology, we held an international conference and workshop to display our accomplishments. Special thanks to Anne Pusey and The Jane Goodall Institute for use of videoarchives of the Gombe Stream chimpanzees. 

In April 2006, with the invaluable assistance of Paul Marshman and the Department of Psychology at Portsmouth, we disseminate the ChimpFACS via this website.


In March 2005, we held a Leverhulme Trust funded workshop at The University of Portsmouth to disseminate the initial progress of the ChimpFACS project (click to view programme). We invited international scholars to hear about this new tool for studying chimpanzee facial expression, and present their work on other aspects of primate communication and cognition. The conference was a huge success and we are grateful to all who attended!

From l to r– Francine Dolins, Josep Call, Debbie Custance, Harriet Oster, Lisa Lane, Lisa Parr, Kirsty Brown, Marc Mehu, Augusta Gaspar. Kim Bard, Vasu Reddy, Gwenda Simons, Issy Scott, Fillipo Aureli, Emily Bethell, Suzanne Kaiser, Charlie Menzel, Bridget Waller, Marcia Smith Pasqualini and Sarah-Jane Vick.

Contact us

Psychology Department

University of Portsmouth

Portsmouth, UK

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