Snort acoustic structure codes for positive emotions in horses

International audienceWhile the vocal coding of human and animal internal states has been widely studied, the possible acoustic expression of “positive” emotions remains poorly known. Recent studies suggest that snorts (non-vocal sounds produced by the air expiration through the nostrils) appear to be reliable indicators of positive internal states in several ungulate species. Here, we hypothesised in horses that the acoustic structure of the snort could vary with the subjects’ current emotional state. Indeed, a preliminary sound analysis of snorts let us suggest structure variations related to the presence of pulsations. We recorded snorts from 20 horses living in a riding center. Auditory playbacks run with 20 humans first confirmed the existence of two snort subtypes, i.e. one pulsed and one non-pulsed. Observations were then conducted to compare the distribution of these two subtypes according to the location (stall/pasture) of the signaller as a contextual determinant of its internal state and to its ears’ position as a reflection of its emotional state. We found that both subtypes were preferentially observed in positive contexts, but that pulsed snorts were even more associated with highly appreciated situations (in pasture and with ears forward). This study is a step further in the identification of indicators of positive emotions in horses and more generally in the understanding of the acoustic emotions’ coding

The regulatory effect of choice in Situation Selection reduces experiential, exocrine and respiratory arousal for negative emotional stimulations

Abstract Situation selection is a seldom studied emotion regulation strategy that entails choosing an upcoming emotional situation. Two mechanisms may drive its regulatory effect on emotional responses. One relates to the evaluation of the chosen option, people generally selecting the most positive. The other one implies that having the choice regarding the upcoming emotional situation is already regulatory, independently of what we choose. This research aimed at investigating this latter hypothesis. In a within-subject design, we compared emotional responses of 65 participants when they viewed negative and positive images they could select (use of Situation selection) vs. when they were imposed the exact same images (Situation selection not used). Results show that having the choice in negative contexts decreased negative experience, skin conductance, and respiration reactivity, while enhancing expressivity and cardiovascular reactivity. In positive contexts, choosing generally reinforced the image calming effect. Thus, contrary to other strategies that are efficient for negative but usually impair positive reactions (e.g., distraction), Situation selection may be used widely to reduce negative experience, while avoiding depletion of positive responses. This is particularly notable in emotion experience. Remarkably, these effects are not driven by the content of the situations, but by the act of choosing itself