Recognising the facial expression of frustration in the horse during feeding period

The aim of this research project was to promote better human horse relationships through improved recognition and understanding of their emotions.

During feeding, the wait for food can lead to different emotions such as positive anticipation, a positive emotional state, or two negative emotional states when expectations are not met: frustration (a high arousal state) and disappointment (a low arousal state).

30 horses, aged 2-23 years old, (11 males and 19 females) were used in this research.

Firstly, the horses were trained to expect a reward after 10 seconds. Then, data were collected during three situations: positive anticipation – when the horse expects food, i.e. 10 seconds before accessing the reward, frustration – when they do not get access to the food after 10 seconds, and disappointment – when the food is lost (get access to an empty bucket instead). The videos recorded during the experiment have allowed to measure the horses’ facial expression using the Horse Facial Action Coding System (EquiFACS), an objective system for coding facial movements on the basis of the contraction of underlying muscles.

Surprisingly, the waiting for food period does not seem to show signs of being a positive experience for the horses and so the positive emotional state of anticipation may be much less common than generally believed.

However, consistent differences in the facial expressions and behaviour between frustration and disappointment situations were found. Frustration was characterised by an increase in the white of the eye, the ears turned backward, the head turned towards the food supply and the horse biting the feeding device (e.g. bucket, manger, etc.). While in disappointment situations, the most common facial expressions and behaviours were increased blinking, a flare of at least one nostril, an appearance of the tongue, and the chewing or licking of the feeding device.

The results of this research emphasise the importance of feeding horse promptly and the ease with which they may become frustrated if kept waiting, and will also help owners to recognise the differences between two negative emotional states: the frustration and the disappointment.

This project has been funded by the Horse Trust.

Facial expressions and behaviours typical of frustration and disappointment.