Stress Impairs Horses’ Learning Abilities
By Christa Lesté-Lasserre, MA Jun 30, 2016
Under stress fearful horses were the worst learners in the negative reinforcement group. In the positive reinforcement group, fearful horses were the worst performers, regardless of their stress level.
Be it in horses or humans, stress can affect learning ability. Some of us actually appear to learn better with a little bit of stress. But in a new study, French researchers have shown that, at least in horses, stress seems to consistently impair learning. And the degree of that impairment depends on training method and the individual horse.
“Our study is the first to demonstrate that stress affects equine learning differentially according to the type of reinforcement in interaction with personality,” said Mathilde Valenchon, PhD, of the University of Strasbourg, of her research conducted at the French National Institute for Agricultural Research Val de Loire. Valenchon presented her work during the 2016 International Society for Equitation Science conference, held June 23-25 in Saumur, France.
Specifically, stress impaired learning more when the horses learned a task through positive reinforcement as opposed to negative reinforcement, Valenchon said. In positive reinforcement, handlers reward horses’ behavior by giving them something they enjoy, such as a treat. In negative reinforcement, handlers reward behavior by removing something unpleasant, such as pressure. Furthermore, horses with fearful personality traits tended to be more impaired by stress when learning a task, regardless of the kind of reinforcement, she added. In their study, Valenchon and her fellow researchers assigned 60 horses to four groups: negative reinforcement without stress, negative reinforcement with stress, positive reinforcement without stress, and positive reinforcement with stress. The stress resulted from being separated from other horses for a short period before the learning task.
The researchers taught all the horses to enter one of two compartments of a small enclosure after receiving a visual signal from a handler. In the study, the team rewarded the positive reinforcement groups with handfuls of grain and rewarded the negative reinforcement groups by removing pressure.
There was no noticeable difference in the learning performance between the unstressed negative and positive reinforcement groups, Valenchon said. However, stress caused both groups to have diminished results, taking longer to learn the task. That difference was much more pronounced in the positive reinforcement group, she added. Negative reinforcement horses’ learning performance was only slightly lower when they were stressed compared to not stressed.
“The negative reinforcement could be conceived as a stressor in and of itself, and so that fact might have counteracted the effect of the extrinsic stressor we gave them before the learning task,” Valenchon said. “It might have caused the horses to focus more (than the positive reinforcement horses) on the learning task despite the extrinsic stress. The stress might also have simply reduced their food motivation, making the positive reinforcement less efficient.” The scientists also used the Lansade Test to determine each study horse’s personality traits. The one trait that appeared related to learning performance under stress was fearfulness, said Valenchon.
Without stress, fearful horses were the best learners in the negative reinforcement group, she said. But under stress they were the worst learners. In the positive reinforcement group, fearful horses were the worst performers, regardless of their stress level, she added.
These results suggest that trainers should use more individualized approach based on the horse and the situation, Valenchon said. “There are no good or bad learners,” she relayed. “We need to recognize that and personalize our training to each individual horse.”
ABOUT THE AUTHOR Christa Lesté-Lasserre, MA Christa Lesté-Lasserre is a freelance writer based in France. A native of Dallas, Texas, Lesté-Lasserre grew up riding Quarter Horses, Appaloosas, and Shetland Ponies. She holds a master’s degree in English, specializing in creative writing, from the University of Mississippi in Oxford and earned a bachelor’s in journalism and creative writing with a minor in sciences from Baylor University in Waco, Texas. She currently keeps her two Trakehners at home near Paris. Follow Lesté-Lasserre on Twitter @christalestelas.
From PATH International Equine Welfare blog.