Horses’ cross-modal recognition of human emotions extends to fear vs joy

Domesticated animals are part of human societies, and understanding human-animal interactions is therefore of fundamental importance to improve animal welfare and our relationship. In particular, studying how animals perceive human emotions allows to better understand their reactions in human-animal interactions. In the past decade, domestic mammals have been indeed shown to perceive and react to human emotions, with a cognitive integration of both visual and vocal signals in their representation of human joy and anger. To date, few studies focused on animals’ perception of human fear, despite the ubiquity of this emotion across contexts and species. In this study, we investigated horses’ cross-modal recognition of human facial and vocal expressions of joy and fear. Thirty-three horses were subjected to two simultaneous soundless videos, showing respectively a fearful and a joyful human face. These videos were accompanied by a playback of either a fearful or a joyful voice. Horses looked significantly longer at the face expressing the emotion incongruent with the sound, demonstrating cross-modal recognition of human fear and joy. These results have implications for the human-horse relationship, as a deeper understanding of how horses respond to human emotions can improve communication and welfare in equestrian contexts. Moreover, these findings highlight domestic mammals’ advanced cognitive capacities toward humans.