What is MaqFACS?

The Macaque Facial Action Coding System (MaqFACS) is a scientific observational tool for identifying and coding facial movements in rhesus macaques. The system is based on the facial anatomy of rhesus macaques and has been adapted from the original FACS system used for humans created by Ekman and Friesen (1978). The MaqFACS manual details how to use the system and code the facial movements of macaques objectively. The manual is freely available to the scientific community.

MaqFACS is not an ethogram of rhesus macaques facial expressions and does not detect emotions per se. Instead, the system allows the user to code the unitary facial movements of rhesus macaques in detail, with no a priori assumptions about what represents a facial expression in this species.


MaqFACS is a standardized system that requires certification to use. The 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.


The MaqFACS Manual and the MaqFACS 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 MaqFACS Manual, please install the latest version of Adobe Reader on your computer. To decompress the files (manual and test), please install WinRar.


Click here to download the MaqFACS 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.


To access the MaqFACS Test clips click here. Please contact us for the passwords.

Please notice that you can attempt the MaqFACS Test several times if you don't pass initially. For each additional attempt, however, you may need to wait for several weeks to receive your scores, especially during busy periods. It is also important that the trainee takes enough time to revise the Manual before a second attempt.

How to use it?

After becoming MaqFACS certified, the coder will be able to reliably code facial movements in videos and pictures of macaques. High quality close-ups of the face should ideally be recorded and pictures must be compared with the neutral face of each macaque, accounting for individual variation. Depending on the purpose of coding, two or more cameras should be used in synchrony (e.g. one camera zoomed in on the face and other camera recording body and context behaviours).

The MaqFACS can be applied to investigate communication and emotion in macaques through the analyses of the individual facial behaviour.

The MaqFACS system can be used to investigate facial movements in rhesus macaques, Barbary macaques, and crested macaques.

The people behind it

MaqFACS was developed thanks to the joint effort of:

  • Lisa A. ParrEmory University - Yerkes National Primate Research Center
  • Bridget M. Waller, Department of Psychology, University of Portsmouth
  • Anne M. Burrows, Department of Physical Therapy, Duquesne University (PA, USA)
  • Katalin M. GothardDepartment of Physiology, University of Arizona (AZ, USA)
  • Sarah-Jane VickUniversity of Stirling


This project was supported by a grant from the National Institute of Mental Health.


This investigation was supported by RR-00165 from the NIH/NCRR to the Yerkes National Primate Research Center, and R03-MH082282 to L.A. Parr. The Yerkes National Primate Research Center is fully accredited by the American Association for Accreditation of Laboratory Animal Care.

Thanks to Dr. Andy Fuglevand and Dr.Fumihiro Kano for assistance with the development of the MaqFACS manual, and Ryan Huang and Prisca Zimmerman for assistance with video editing.

Contact us

Psychology Department

University of Portsmouth

Portsmouth, UK

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