The researchers used key indicators, such as heart rate and eye temperature when horses were at rest and when they were performing cognitive tasks.
20 horses took part in the study, during which researchers offered two targets. If the horse selected the correct target, they were rewarded with food. Once the horses had learned the task, it was reversed so that the other target was rewarded.
The team found that horses with a lower arousal at rest and during the challenge fared better, and had an increased temperature in the left eye. They suggested that this was due to increased blood flow to the left side of the brain, which is responsible for learning targeted responses and feeding.
Blink rate was also measured as this is known to cause dopamine production, which is known to boost learning in humans, but no correlation was found in horses.
“We regularly expect domesticated horses to learn different and complex behavioural responses as part of their working roles,” said lead researcher Louise Evans, from Nottingham Trent University’s School of Animal, Rural and Environmental Sciences.
She said: “In their day-to-day lives, horses require behavioural flexibility, the ability to adapt to changing environments, such as different riders and handlers. However, we also need horses to have excellent cognitive control so that we can safely rely on them to give consistent responses to important commands such as “slow down” or “stop”.
“This delicate balance between flexibility and control is what makes horses such good teammates. However, when things go wrong there can be dangerous consequences, so it’s vital that we understand how horses learn and can better predict their learning performance.
“This study has really helped aid our understanding to predict how well individual horses learn – and more relaxed horses clearly learn better. It’s important for us to recognise the impact that arousal in the home or training environment can have on horses’ learning.
“What’s also fascinating is that we may have found evidence of left brain hemisphere activity by measuring eye temperature differences during learning.
“This requires further investigation but, if a link can be demonstrated, this means we can for the first time measure hemispheric activity non-invasively and in real-time.”