title: Functionally relevant responses to human facial expressions of emotion in the domestic horse (Equus caballus).
abstract: Whether non-human animals can recognize human signals, including emotions, has both scientific and applied importance, and is particularly relevant for domesticated species. This study presents the first evidence of horses' abilities to spontaneously discriminate between positive (happy) and negative (angry) human facial expressions in photographs. Our results showed that the angry faces induced responses indicative of a functional understanding of the stimuli: horses displayed a left-gaze bias (a lateralization generally associated with stimuli perceived as negative) and a quicker increase in heart rate (HR) towards these photographs. Such lateralized responses towards human emotion have previously only been documented in dogs, and effects of facial expressions on HR have not been shown in any heterospecific studies. Alongside the insights that these findings provide into interspecific communication, they raise interesting questions about the generality and adaptiveness of emotional expression and perception across species.
authors: Mammal Vocal Communication and Cognition Research Group, School of Psychology, University of Sussex, Brighton BN1 9QH, UK a.v.smith@sussex.ac.uk.
authors: Amy Victoria
authors: 0000-0003-4219-7406
authors: AV
authors: Smith
authors: Mammal Vocal Communication and Cognition Research Group, School of Psychology, University of Sussex, Brighton BN1 9QH, UK.
authors: Leanne
authors: 0000-0002-8661-1229
authors: L
authors: Proops
authors: Mammal Vocal Communication and Cognition Research Group, School of Psychology, University of Sussex, Brighton BN1 9QH, UK.
authors: Kate
authors: K
authors: Grounds
authors: Mammal Vocal Communication and Cognition Research Group, School of Psychology, University of Sussex, Brighton BN1 9QH, UK.
authors: Jennifer
authors: J
authors: Wathan
authors: Mammal Vocal Communication and Cognition Research Group, School of Psychology, University of Sussex, Brighton BN1 9QH, UK karenm@sussex.ac.uk.
authors: Karen
authors: 0000-0003-2744-6101
authors: K
authors: McComb
mesh_terms: D000818:Animals; D001362:Avoidance Learning; D004644:Emotions; D005149:Facial Expression; D005260:Female; D006339:Heart Rate; D006736:Horses / Q000502:physiology* / Q000523:psychology; D006801:Humans; D008297:Male; D010364:Pattern Recognition, Visual
keywords: emotion recognition; facial expression; heart rate; interspecific communication; lateralization; stress-related behaviours