Emotions in horses: Identifying and validating behavioural indicators of horses' emotional valence

Accumulating evidence across a range of species indicates that cognitive bias is a promising measure of emotional valence in animals. However, current tests are invasive and time-consuming as animals have to be trained extensively before they can be tested. Therefore, an important goal of future research will be to identify reliable and valid behavioural indicators of emotional valence for the assessment of animal welfare in different situations (e.g. housing, transport, training, work). The aim of this project is to detect and validate such indicators of emotional valence in horses, and to use these indicators to study the effects of different operant training methods on the emotional state of horses. Furthermore, horses will also be used as model animals to examine the general approach of detecting and validating behavioural indicators of emotional valence through investigating the associations between different measures of behavior and cognitive bias. The conventional way of looking for behavioural indicators of emotional states is to assess behaviour quantitatively by recording frequencies and durations of behavioural elements in specific situations. Depending on the direction (positive, negative) and intensity of cognitive bias, the expression of specific behavioural elements may change in consistent ways. Besides such changes in the expression of specific behavioural elements, an animal’s emotional state may become apparent in the manner the individual expresses its behaviour in terms of body language and postures, and in the dynamic interaction with the environment. This can be assessed by the methodology of Qualitative Behaviour Assessment (QBA). QBA is a complementary approach to conventional quantitative ethology describing behaviour qualitatively by adjectives such as ‘frightened’, ‘confident’ or ‘playful’. When applied systematically (Free Choice Profiling, FCP) and analysed with appropriate statistical tests (Generalised Procrustes Analysis, GPA), QBA may provide additional information about animals’ emotional state. It has been shown that QBA is sensitive to different treatments and that the results are correlated with quantitative behavioural data as well as physiological measurements. Moreover, QBA shows high repeatability for individual observers as well as a high agreement among observers from different backgrounds.

Using quantitative ethological methods and QBA in combination with cognitive bias tests to detect and validate reliable behavioural indicators predicting the direction and intensity of cognitive bias is a promising step towards the on-site monitoring of animals’ emotional states and may, therefore, greatly advance the assessment of animal welfare. There have not been any comparable systematic studies with horses or other species so far.