When life’s got you down, do you tend to be pessimistic? According to a new study, horses sure seem to be. French researchers have learned that suboptimal living conditions, such as 24-hour individual stabling and restricted feeding, can make horses less optimistic.
“The use of cognitive bias testing—checking a horse’s level of optimism—is a useful way to ‘ask’ the horse about its own perceptions of its living conditions and even working conditions,” said Séverine Henry, PhD, of the University of Rennes in France.
“This constitutes an indispensable step in establishing management practices or working conditions which contribute toward an improvement of the horse’s quality of life or toward better prophylactic care such as treatment for back pain,” she said. Henry presented her study on equine optimism at the 2016 French Equine Research Day held in March in Paris.
In their study, the horses with the highest levels of welfare also had the highest levels of optimism in their experiments, Henry said. By contrast, however, poor welfare was always associated with pessimism in the study horses.
We first reported on optimism studied in horses in 2013 when Swiss researchers compared the effects of positive and negative reinforcement on a horse’s outlook (as optimistic or pessimistic).
In both the 2013 experiment and the current study, the test horses were first trained to recognize that only one of two widely spaced buckets in an arena contained treats. The “treat” bucket was always placed in the same location, as was the empty one. Later, researchers added three more buckets in between these first two buckets. They could judge the horse’s optimism by seeing whether that horse bothered looking for treats in the three in-between buckets. The more the horse looked in the buckets approaching the empty bucket, the more optimistic they considered him.
Henry and her colleagues performed their study on 34 horses—25 from two riding clubs and nine from two leisure-riding farms. The riding club horses lived in individual box stalls and received three grain or concentrate rations and one hay ration per day. Students rode them six days a week in a variety of activities, including outdoor hacks. The leisure horses lived in permanent groups of two to four in large pastures with shelters and were ridden occasionally with loose reins.
Before performing the optimism experiment, Henry’s team evaluated each horse’s welfare level using previously defined techniques, such as monitoring the horses’ behavior (including stereotypies), observing their posture, and determining their health status (especially in regard to back pain).
They found that the horses with the lowest welfare scores were also the horses that showed the least amount of optimism during the bucket experiment, Henry said. As welfare levels increased, so did optimism.
Just as importantly, these findings were significantly related to the place where the horses lived and worked, she added.
“Our results revealed an important effect of site,” said Henry. “The horses in the two riding clubs lived in restrained conditions, with more signs of poor welfare (stereotypies, aggression towards humans, back pain, etc.) and more pessimistic responses to the cognitive bias tests, thereby anticipating a negative event.
“On the other hand, the horses living in semi-natural conditions in the leisure farms were exempt of health and behavior problems, and these horses had a more optimistic approach to our experiment, thus anticipating a positive event,” she said.
“It therefore seems that the accumulation of negative experiences in horses in certain situations (with restricted access to food, space, and other horses, plus working conditions leading to pain) can lead to these horses interpreting their environment in a negative way,” said Henry.