MaqFACS(Macaque Facial Action Coding System) can be used to document facial movements in Barbary macaques (Macaca sylvanus)

Abstract

Human and non-human primates exhibit facial movements or displays to communicate with one another. The evolution of form and function of those displays could be better understood through multispecies comparisons. Anatomically based coding systems (Facial Action Coding Systems: FACS) are developed to enable such comparisons because they are standardized and systematic and aid identification of homologous expressions underpinned by similar muscle contractions. To date, FACS has been developed for humans, and subsequently modified for chimpanzees, rhesus macaques, orangutans, hylobatids, dogs, and cats. Here, we wanted to test whether the MaqFACS system developed in rhesus macaques (Macaca mulatta) could be used to code facial movements in Barbary macaques (M. sylvanus), a species phylogenetically close to the rhesus macaques. The findings show that the facial movement capacity of Barbary macaques can be reliably coded using the MaqFACS. We found differences in use and form of some movements, most likely due to specializations in the communicative repertoire of each species, rather than morphological differences.

Experience has a limited effect on humans’ ability to predict the outcome of social interactions in children, dogs and macaques

“…Clearly, NHP are phylogenetically closer to humans than dogs, and thus share more physical and functional similarities 33,34 . This might allow NHP to produce homologous facial expressions [65][66][67] , which might have allowed participants to more easily predict the outcome of their interactions. However, the use of facial expressions seems to be specific to the communicative repertoire of the species 66,68 , with some being morphologically similar in humans and NHPs, but corresponding to different emotional states 68,69 ; see 56 .…”

Rethinking primate facial expression: A predictive framework

“…Instead, an objective system for the quantification of animal facial expressions is necessary and can be found in the Facial Action Coding System (FACS: Ekman et al, 2002). Initially developed for humans, FACS has been modified for use with various primate species: chimpanzees (ChimpFACS: Vick et al, 2007), macaques (Julle-Danière et al, 2015;, gibbons (Waller et al, 2012) and orangutans (Caeiro et al, 2012). FACS is a standardised, objective method for recording facial movements based on the underlying anatomy (see Fig.…”

Morphological variants of silent bared‐teeth displays have different social interaction outcomes in crested macaques (Macaca nigra)

“…A classic example, the felt smile of enjoyment, known as the “Duchenne” smile, involves raising the cheek through a contraction of the orbicularis oculi muscle (Ekman, Davidson, & Friesen, 1990; Surakka & Hietanen, 1998), which is absent in many forced “non‐Duchenne” smiles (but see Krumhuber & Manstead, 2009); the contraction of orbicularis oculi is AU6 in the FACS, while the raising of the lip corners is AU12 and parting of the lips is AU25, hence a Duchenne smile comprises AU6 + 12 + 25 and a non‐Duchenne smile involves AU12 + 25 only. Subsequently, FACS has been adapted for use in other primates including chimpanzees (Parr, Waller, Vick, & Bard, 2007), macaques (Julle‐Danière et al, 2015; Parr, Waller, Burrows, Gothard, & Vick, 2010), gibbons (Waller, Lembeck, Kuchenbuch, Burrows, & Liebal, 2012), and orangutan (Caeiro, Waller, Zimmermann, Burrows, & Davila‐Ross, 2013). This has greatly improved our ability to examine the facial expressions of nonhuman primates in the same terms as those of humans, enabling both within‐species (e.g., Waller, Caeiro, & Davila‐Ross, 2015; Waller & Cherry, 2012) and between‐species (e.g., Waller, Misch, Whitehouse, & Hermann, 2014) comparisons of facial expression composition.…”