Perception of dynamic facial expressions of emotion between dogs and humans

Abstract

Facial expressions are a core component of the emotional response of social mammals. In contrast to Darwin's original proposition, expressive facial cues of emotion appear to have evolved to be species-specific. Faces trigger an automatic perceptual process, and so, inter-specific emotion perception is potentially a challenge; since observers should not try to "read" heterospecific facial expressions in the same way that they do conspecific ones. Using dynamic spontaneous facial expression stimuli, we report the first inter-species eye-tracking study on fully unrestrained participants and without pre-experiment training to maintain attention to stimuli, to compare how two different species living in the same ecological niche, humans and dogs, perceive each other's facial expressions of emotion. Humans and dogs showed different gaze distributions when viewing the same facial expressions of either humans or dogs. Humans modulated their gaze depending on the area of interest (AOI) being examined, emotion, and species observed, but dogs modulated their gaze depending on AOI only. We also analysed if the gaze distribution was random across AOIs in both species: in humans, eye movements were not correlated with the diagnostic facial movements occurring in the emotional expression, and in dogs, there was only a partial relationship. This suggests that the scanning of facial expressions is a relatively automatic process. Thus, to read other species' facial emotions successfully, individuals must overcome these automatic perceptual processes and employ learning strategies to appreciate the inter-species emotional repertoire.

Dog faces exhibit anatomical differences in comparison to other domestic animals

“…While equivocal, accumulating evidence is demonstrating that humans and dogs are uniquely attuned to one another's facial expressions to the exclusion of other domestic mammals (Albuquerque et al, 2016;Schirmer, Seow, & Penney, 2013;Waller et al, 2013). Not only are humans good at reading facial expressions of dogs, but dogs are good at reading facial expressions of humans (Correira- Caeiro, Guo, & Mills, 2020). Does this mutual ability to read one another's facial expressions indicate that dogs and humans co-evolved and influenced one another's brain evolution?…”

Extending the MaqFACS to measure facial movement in Japanese macaques (Macaca fuscata) reveals a wide repertoire potential

“…facial expression length is context-dependent [ 23 ]). Researchers have also used the DogFACS alongside HumanFACS to investigate how these two unrelated species that have lived together and are thought to have coevolved social cognition [ 24 ], are able to influence [ 18 ] and perceive each other [ 25 ]. Furthermore, because animal FACS are built within a comparative framework, it is possible to compare facial repertoires across species; a comparison of EquiFACS and ChimpFACS demonstrated that horses have a larger potentiality for movement than chimpanzees [ 20 ].…”

Multivariate Analysis of Open Field Exploration Identifies Latent Spatial and Social Behavioral Axes in Domestic Dogs

“…In behavioral studies of domestic dogs, however, the challenges arise not from a paucity of characterization, but from a surfeit of it. A focus of majority of early dog behavior studies have been on subjective rating scales – although new research has seen increased use of quantitative variables ( Gerencsér et al, 2013 ; Huber, 2013 ; Correia-Caeiro et al, 2020 ). Most of these rating scales categorize dog behavior into “prosocial” and “reactive” categories.…”