Social Referencing in the Domestic Horse

SIMPLE SUMMARY: Daily horse handling is associated with a risk of injury. It is not clear how much (a) handlers’ emotional expressions (happy versus anxious) or (b) breed type influence horses’ behavior in new, potentially threatening situations and thus contribute to risks. We therefore assessed how horses responded to a novel object when a human handler introduced the object either with a positive (happy) or a negative (anxious) emotional expression. We found that horses in the positive condition seek more proximity to the object compared to horses in the negative condition. Furthermore, horses in the negative condition showed more vigilance towards the object (i.e., increased number of gazes) than horses in the positive condition. Independent of condition, we found in thoroughbreds less human-directed contact (interaction and gazes) than in warmbloods and ponies. We conclude that the handlers’ visual and acoustic emotional expressions affect horses’ responses to unfamiliar situations. ABSTRACT: Dogs and cats use human emotional information directed to an unfamiliar situation to guide their behavior, known as social referencing. It is not clear whether other domestic species show similar socio-cognitive abilities in interacting with humans. We investigated whether horses (n = 46) use human emotional information to adjust their behavior to a novel object and whether the behavior of horses differed depending on breed type. Horses were randomly assigned to one of two groups: an experimenter positioned in the middle of a test arena directed gaze and voice towards the novel object with either (a) a positive or (b) a negative emotional expression. The duration of subjects’ position to the experimenter and the object in the arena, frequency of gazing behavior, and physical interactions (with either object or experimenter) were analyzed. Horses in the positive condition spent more time between the experimenter and object compared to horses in the negative condition, indicating less avoidance behavior towards the object. Horses in the negative condition gazed more often towards the object than horses in the positive condition, indicating increased vigilance behavior. Breed types differed in their behavior: thoroughbreds showed less human-directed behavior than warmbloods and ponies. Our results provide evidence that horses use emotional cues from humans to guide their behavior towards novel objects.