Curiosity may ultimately kill the cat, but in horses it seems to benefit their learning performance.
Researchers in Denmark found that exploratory behaviour towards novel objects in young horses is associated with enhanced learning.
Aarhus University researcher Janne Winther Christensen and her colleagues, reporting in the journal Scientific Reports, said the mechanisms underlying individual variation in learning are key to understanding the development of cognitive abilities.
“In humans and primates, curiosity has been suggested as an important intrinsic factor that enhances learning, whereas in domesticated species research has primarily identified factors with a negative effect on cognitive abilities, such as stress and fearfulness.”
In their study, Christensen and her colleagues exposed 44 young horses to standardised novel object tests. There was one test at five months and two performed on the same day at one year of age.
Novel objects were placed in the middle of an arena and the young horses had to pass these objects to go to their feed containers. Their reactions, such as their alertness and whether they approached and touched it, were monitored, as were their heart rates.
The first test was conducted before weaning, with their mother present, who served as a motivator to go past the object to the food.
The two later tests were after weaning. The researchers said they found consistency in their horses’ responses. There were no differences between males and females on four variables measured in their response to the novel object tests.
The authors also detected some consistency between behavioural parameters in the pre-weaning test and how individuals performed in the later tests, without their mothers.
The horses were also trained in two learning tasks when 10 to 12 months old. In the first, involving negative reinforcement, they had to learn to move away from pressure applied at an increasing rate on their hindquarter in 10 attempts. Half succeeded.
The positive reinforcement test was a visual discrimination task. The horse had to learn that only one of two distinct containers (differing in size, shape, colour and pattern) contained food, with the container’s positions switched. Nearly all the horses (39) passed.
Standard indicators of fearfulness in the novel objects tests — for example, heart rate and alertness — were found to be unrelated to learning performance, whereas exploratory behaviour towards the novel objects correlated to performance in the two learning tasks.
The study team said the exploratory behaviour in the novel object tests likely reflects the animal’s intrinsic motivation and curiosity, suggesting that this trait is favourable for learning performance.
“Young horses’ intrinsic motivation to explore novel objects was positively associated to learning performance in both a positively and a negatively reinforced task,” they reported, “whereas traditional measures of fearfulness, such as alertness and heart rate responses, were unrelated to learning performance.”
Discussing their findings, the researchers said they were surprised to find no association between traditional measures of fearfulness in horses and performance in the two learning tasks.
“Previous studies on adult horses reported a negative effect of fearfulness on performance in learning tasks under stressful conditions, which could be caused by fearful animals becoming more aroused and thus paying less attention to the task.”
“Our learning tasks were conducted separately and under low-stress conditions where a negative impact of fearfulness on learning performance may be less likely. However, horses that approached and manipulated novel objects at one year of age performed better in both learning tasks.
“For the negatively reinforced learning task, this trend was already apparent at five months of age.
“Thus, the tendency to show exploratory behaviour appears central to cognitive abilities in horses, as also shown in humans, non-human primates and rodents.”
The authors said their results are the first to suggest that novel object-directed curiosity could be central to cognitive performance in horses across different types of learning tasks; an association that has previously been demonstrated mainly in humans and primates.
“The result raises interesting questions in relation to fostering of curiosity and the impact of such manipulations on cognitive processes in domesticated animals.”
They said their study provides the first evidence of a link between object-directed curiosity and learning performance in young horses in two very different learning tasks (visual discrimination and pressure-release).
The study team comprised Christensen, Line Peerstrup Ahrendt and Jens Malmkvist, all with Aarhus University in Denmark; and Christine Nicol, with the Royal Veterinary College in England.
Christensen, J.W., Ahrendt, L.P., Malmkvist, J. et al. Exploratory behaviour towards novel objects is associated with enhanced learning in young horses. Sci Rep 11, 1428 (2021). https://doi.org/10.1038/s41598-020-80833-w