Horses appear to take emotional cues from their handlers when it comes to their response to novel objects, the findings of a German study suggest.
Researchers Anne Schrimpf, Marie-Sophie Single and Christian Nawroth say dogs and cats are known to use human emotional information in unfamiliar situations to guide their behavior. However, it is not clear whether other domestic species show similar abilities.
The human–horse relationship requires mutual interspecies communication and learning, including expressions such as posture, vocal signals, gazes, or emotional cues. But it is less clear how they respond to human emotional cues in uncertain situations.
The trio used 46 horses, comprising 19 Thoroughbreds, 20 Warmbloods and 7 ponies, in an experiment to determine whether they used human emotional information to adjust their behavior to a novel object.
The researchers also wanted to discover whether the behavior of the horses differed between breeds.
The horses, all used to daily handling, were randomly assigned to one of two groups.
In both scenarios, an experimenter positioned in the middle of a round pen directed her gaze and voice towards a novel object — a blue plastic bin covered with a blue-yellow shower curtain.
Under the positive scenario, the experimenter alternated her gaze between the bin and the horse. She used a positive facial expression and a relaxed body posture, during which she said “This is great” every 10 seconds in an upbeat tone.
Under the negative scenario, the experimenter adopted an anxious facial expression and a tense body posture. In a negative tone, she repeated: “This is terrifying”.
Each horse’s position in the arena in relation to the object and the person were analysed. Their gazing behavior and physical interactions with the object or experimenter were also monitored.
Horses who heard the positive tone spent more time between the experimenter and object compared to the horses who heard the negative tone. This indicated less avoidance behavior towards the object.
Horses who heard the negative tone gazed more often towards the object, indicating increased vigilance, compared to those who heard the positive voice.
Breed types differed in their behavior. Thoroughbreds directed less behavior toward the person than Warmbloods and ponies.
The study team also examined potential differences in behavior between the sexes.
Female horses spent more time behind the experimenter when compared to males, whereas male horses tended to stay longer in the area between the experimenter and the object as compared to females.
“These results are in line with previous research: mares have been found to be more suspicious and anxious than geldings, whereas geldings might be more easily desensitized during training than mares,” they said. “Mares have also been found to be less playful and curious than geldings.”
“Our results provide evidence that horses use emotional cues from humans to guide their behavior towards novel objects,” the trio concluded in their study, reported in the open-access journal Animals.
Discussing their findings, the researchers said horses’ abilities to guide their behavior according to the human emotional expression indicate their high responsiveness to human cues.
“This adds to the literature showing their sensitivity to human attentive states, pointing gestures, or auditory cues.
“A recent line of research also showed horses’ abilities to discriminate between human emotional facial and vocal expressions and to adjust behavior such as looking time and gaze following according to human facial emotional expressions.
“Future research should include handled and unhandled horses to compare their sensitivity to human emotional expressions in an ambiguous situation.”
Schrimpf is with Max Planck Institute for Human Cognitive and Brain Sciences in Leipzig; Single is with the Technical University of Munich; and Nawroth is with the Leibniz Institute for Farm Animal Biology, Institute of Behavioural Physiology, in Dummerstorf.
Social Referencing in the Domestic Horse
Anne Schrimpf, Marie-Sophie Single and Christian Nawroth
Animals 2020, 10(1), 164; https://doi.org/10.3390/ani10010164