Abstract
Animal-assisted interventions (AAIs) have become increasingly popular, with horses being one of the most commonly used species. While the effects of equine-assisted interventions (EAIs) have been widely studied in humans, research focusing on animals involved in such work is limited. Understanding how animals perceive their world is ethically important because their perception reflects the valence of their underlying mood. We investigated the cognitive judgement bias (pessimistic vs. optimistic) and perception of humans (negative vs. positive) in horses from three different facilities, divided into two groups: horses involved only in riding school lessons (RS, N = 14) and horses participating in both riding school and EAI lessons (EAI-RS, N = 16). We hypothesised that horses engaged in both types of work would be more negatively impacted than RS horses because the two activities may be demanding. No significant effects of work on pessimistic bias and negative perception of humans were found. However, a modulating effect was found in the interaction between work type and facility management. These findings highlight the impact of both the type of work and facility management on the cognition and underlying affective states of EAI-RS horses.