Automatic recognition of macaque facial expressions for detection of affective states

Anna Morozov, Lisa A. Parr, Katalin Gothard, Rony Paz, Raviv Pryluk

Research output: Contribution to journalArticlepeer-review

7 Scopus citations


Internal affective states produce external manifestations such as facial expressions. In humans, the Facial Action Coding System (FACS) is widely used to objectively quantify the elemental facial action units (AUs) that build complex facial expressions. A similar system has been developed for macaque monkeys—the Macaque FACS (MaqFACS); yet, unlike the human counterpart, which is already partially replaced by automatic algorithms, this system still requires labor-intensive coding. Here, we developed and implemented the first prototype for automatic MaqFACS coding. We applied the approach to the analysis of behavioral and neural data recorded from freely interacting macaque monkeys. The method achieved high performance in the recognition of six dominant AUs, generalizing between conspecific individuals (Macaca mulatta) and even between species (Macaca fascicularis). The study lays the foundation for fully automated detection of facial expressions in animals, which is crucial for investigating the neural substrates of social and affective states.

Original languageEnglish (US)
Article numberENEURO.0117-21.2021
Issue number6
StatePublished - Nov 1 2021

ASJC Scopus subject areas

  • General Neuroscience


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