by Linda DaVolls
Interest in the study of animal emotions is growing quickly, and is relevant to several disciplines, such as evolutionary zoology, affective neuroscience, comparative psychology, animal welfare science and psychopharmacology. Measurements of subjective emotional experiences are not possible in animals and researchers use neurophysiological, behavioural and cognitive indicators. However, reliable indicators, particularly of positive emotions, are lacking. One promising behavioural indicator of emotions is vocalization. The emotional state of the caller causes changes in the muscular tension and action of its vocal apparatus, which in turn impacts on vocal parameters of vocalizations. By considering the mode of production of vocalizations, we can understand and predict how vocal parameters should change according to the arousal (intensity) or valence (positive/negative) of emotional states. In this free paper, Elodie Briefer reviews the current state of knowledge on vocal correlates of emotions in mammals. Techniques recently developed to study animal emotions are presented and methods used to study animal vocalizations described. The paper concludes with the best/most likely vocal indicators of emotional valence and arousal in non-human mammals. Findings on vocal correlates of emotions in mammals could serve as a useful model for studies on humans, in which a greater motor control results in confounding factors influencing affective prosody.