Stress affects instrumental learning in domestic horses
In behavioral science a major question is how stress affects learning processes. It has been extensively studied in primates and rodents, but to a lesser extent in horses.
The main objective of this study is to understand how stressors related or unrelated to a task affect learning performance in horses. Earlier studies suggest that the learning performance may be different according to personality in the animal, especially for traits related to emotional reactivity. Therefore the influence of personality on learning performance is also explored.
The study was executed by assigning horses to 4 groups. Each group consisted of 15 horses and received training with negative or positive reinforcement in the presence or absence of stressors. The instrumental learning task consisted of the horse entering one of two compartments at the appearance of a visual signal given by the experimenter.
The results show that only when a stressor was present the learning was affected. However, learning was affected in a smaller amount when negative reinforcement was used. The negative reinforcement could have counterbalanced the impact of the stressor by focusing attention towards the learning task. Next to that, learning performance appears to differ between personalities. When negative reinforcement is used fearful horses are the best performers in the absence of stressors but the worst performers when stressors are present. On the contrary, when positive reinforcement is used, the fearful horses appear to be the worst performers with and without stressors.
Expert opinion by Anouk van Breukelen
This study provides fundamental and applied perspectives in understanding relationships between personalities and training abilities.
> From: Valenchon et al., PLOS ONE 12 (2017) e0170783. All rights reserved to Creative Commons Attribution License. Click here for the online summary.