Nagging uncertainty: horses know when something’s amiss
Japanese study suggests the animals are smarter than we think. Andrew Masterson reports.
Horses, it seems, may have a sense of the incongruous.
Research led by cognitive scientist Kosuke Nakamura from the University of Tokyo in Japan examines the reaction of horses to visual and audio cues when the emotion expressed in one does not match that of the other.
The results, published in the journal Scientific Reports, is believed to be the first time this type of cognition has been tested in horses – a remarkable thing, given that the species was domesticated around 5000 years ago and has lived in close proximity to humans ever since.
To conduct their research, Nakamura and colleagues recruited 19 horses from their own institution and the nearby Tokyo University of Agriculture and Technology.
The animals were subjected to a test, known as the expectancy violation method, which was originally devised a means of examining cognition in infants.
The experimental protocol is simple. First, each animal was shown a visual stimulus – a photograph of a face expressing either happiness or anger. This was followed by a voice recording, which either matched the photograph in emotion, or contradicted it.
The results showed that the horses spent significantly longer looking at the faces when the vocal emotion did not match the visual one. In the same context, they also looked at the faces a lot faster.
“These results suggested that an expectancy violation occurred when the auditory stimulus had a different emotional value than the visual one because the horses were able to identify human emotions from the facial expressions,” the researchers conclude.
“Therefore, our results suggested that horses associate the emotional value of human facial expressions with the emotional value of human voices.”