The Effect of Prior Abuse on Behavioural Responses to Emotional Expression in the Domestic Horse (Equus caballus)

Abstract

Several domestic species have shown discriminatory abilities when judging the level of affect in human faces. In other words, they can distinguish between positive (happy) and negative (angry) human facial expressions. As a species that relies heavily upon humans for survival, such recognition abilities aid domestic species in their interactions with human handlers. What has yet to be explored is whether former experiences of neglect or abuse influences subsequent behaviours in response to varying degrees of human emotion, expressed through facial expressions. Previous research suggests that poor welfare conditions, such as former experiences of abuse and neglect, can affect subsequent judgments of future events. Such that abused horses may have a diminished expectation of positive events, which often leads to an enhanced awareness of threatening stimuli, thereby, eliciting avoidance behaviour. The present study aims to add to the current literature by examining differences in behavioural responses to positive (happy) and negative (angry) human facial expressions, between horses with and without former experiences of abuse and neglect. Eleven horses were assigned to one of two experimental groups; 5 horses with known, prior experiences of abuse, and the remaining 6 horses served as the control group, with no prior experiences of abuse. Horses were presented with counterbalanced photographs of positive and negative human facial expressions, and their behavioural responses were recorded. Our results indicated that horses with previous experiences of abuse were more likely to hold a pessimistic bias, involving a diminished anticipation of positive events (decreased optimism), and an increased occurrence of stress-related behaviours. Alongside the insights that these findings provide into inter-specific communication, they highlight the impact of welfare conditions on domestic horses well-being, cognition, and related behaviours.

Presented in absentia on April 27, 2020 at "Student Research Day" at MacEwan University in Edmonton, Alberta. (Conference cancelled)

Faculty Mentor: Shannon Digweed

Department: Psychology