Kiki E. Spoelstra, J. H. C. Vonk, Evy van Berlo, José Kok, Mariska E. Kret
Background Successful interpretation of emotion expressions is a critical aspect of communication in both solitary and group-living species, although it is seldom investigated in the former. Because of their flexible sociality, domestic cats ( Felis silvestris catus ) are an interesting species within which to study intraspecific emotion perception. Methods Adopting a multidimensional approach, we presented cats ( n = 24) with visual and auditory stimuli that represented two levels of valence and activity, which served as a proxy for arousal. Thus, each cat experienced four auditory and four visual stimulus presentations lasting 2 min each in which we measured the cats’ gaze duration and frequency, proximity duration, approach latency, and duration of stimulus interaction. Additionally, we applied a data-driven cluster analysis to investigate the occurrence of a wide range of other behaviours in response to the different stimuli. Results Valence and activity levels did not affect cats’ responses to auditory stimuli. However, cats gazed longer and more frequently at negatively valenced visual stimuli depicting higher levels of activity compared to all other stimulus categories. Stimulus interaction was longer for active stimuli, independent of valence. However, cats displayed more fear-related behaviours in response to the negatively compared to positively valenced active stimuli, indicating that they interpreted these as being fundamentally different from each other. Conclusion Our findings suggest that cat emotion perception in the visual domain is modulated by both valence and activity, highlighting the need to incorporate arousal in further emotion research.