CalliFACS: The common marmoset Facial Action Coding System

Abstract

Facial expressions are subtle cues, central for communication and conveying emotions in mammals. Traditionally, facial expressions have been classified as a whole (e.g. happy, angry, bared-teeth), due to automatic face processing in the human brain, i.e., humans categorise emotions globally, but are not aware of subtle or isolated cues such as an eyebrow raise. Moreover, the same facial configuration (e.g. lip corners pulled backwards exposing teeth) can convey widely different information depending on the species (e.g. humans: happiness; chimpanzees: fear). The Facial Action Coding System (FACS) is considered the gold standard for investigating human facial behaviour and avoids subjective interpretations of meaning by objectively measuring independent movements linked to facial muscles, called Action Units (AUs). Following a similar methodology, we developed the CalliFACS for the common marmoset. First, we determined the facial muscular plan of the common marmoset by examining dissections from the literature. Second, we recorded common marmosets in a variety of contexts (e.g. grooming, feeding, play, human interaction, veterinary procedures), and selected clips from online databases (e.g. YouTube) to identify their facial movements. Individual facial movements were classified according to appearance changes produced by the corresponding underlying musculature. A diverse repertoire of 33 facial movements was identified in the common marmoset (15 Action Units, 15 Action Descriptors and 3 Ear Action Descriptors). Although we observed a reduced range of facial movement when compared to the HumanFACS, the common marmoset’s range of facial movements was larger than predicted according to their socio-ecology and facial morphology, which indicates their importance for social interactions. CalliFACS is a scientific tool to measure facial movements, and thus, allows us to better understand the common marmoset’s expressions and communication. As common marmosets have become increasingly popular laboratory animal models, from neuroscience to cognition, CalliFACS can be used as an important tool to evaluate their welfare, particularly in captivity.

Primate socio-ecology shapes the evolution of distinctive facial repertoires.

“…Many of the AUs found in both chimpanzees and gibbons are also found in a wide variety of mammals (Waller et al, 2020), such as orangutans (C. C. C. Caeiro, Waller, Zimmermann, et al, 2013), macaques (Parr et al, 2010), marmosets (Correia-Caeiro et al, 2022), horses (Wathan et al, 2015), dogs (Waller, Peirce, et al, 2013;Waller, Warmelink, et al, 2013), and cats (C. C. C. Caeiro, Waller, Zimmermann, et al, 2013).…”

“…The presence of shared AUs and AU combinations may well be the result of evolutionary continuity. Many of the AUs found in both chimpanzees and gibbons are also found in a wide variety of mammals (Waller et al, 2020), such as orangutans (C. Caeiro, Waller, & Burrows, 2013; C. C. Caeiro, Waller, Zimmermann, et al, 2013), macaques (Parr et al, 2010), marmosets (Correia-Caeiro et al, 2022), horses (Wathan et al, 2015), dogs (Waller, Peirce, et al, 2013; Waller, Warmelink, et al, 2013), and cats (C. Caeiro, Waller, & Burrows, 2013; C. C. Caeiro, Waller, Zimmermann, et al, 2013). This includes AU10, AU12, AU16, AU25, AU26, and AU27 (Waller et al, 2020).…”

Detection of Face Emotion and Music Recommendation System using Machine Learning

“…Preprocessing is used to extract the facial expression from the webcam image and turn it into a series of Action Units (AUs) [16]. Using combinations of the 64 AUs, the Face Action Coding System (FACS) characterizes every facial emotion [17]. Following feature extraction, the faces' emotions-such as happiness, anger, sadness, and surprise-are categorized.…”

A generalized classification and coding system of Human Disease Animal Model Resource data with a case study to show improving database retrieval efficiency

“…However, in some cases, it is very difficult to realize the data-based expression of animal models. A study on common marmoset facial action coding system shows that researchers have made great efforts to adopt objective measurement technology and avoid subjective interference in the process of animal facial expression coding [ 12 ]. Metabolomics is a powerful tool for developing traditional drugs.…”