What can behaviour really tell us about emotion? Integrating novel physiological and behavioural techniques to advance comparative affective science

Emotion research has gained enormous momentum through the emerging field of comparativeaffective science, which seeks to uncover important aspects about the emotional life ofnonhuman animals. This chapter reviews the limitations of relying solely on behaviouralinformation to derive information on affective states in animals. Instead, it emphasizes thevalue of combining behavioural coding methods with novel non-invasive physiologicalmethods. We specifically explore advances in automated behavioural tracking, facial actioncoding, infrared thermography (IRT), infrared videography (IR) and microwave radartechnologies. These promising new tools offer insights into internal states without restrainingor potentially harming animals, thus providing more ethical empirical assessment. We arguethat multi-dimensional approaches that combine behavioural and physiological data enablericher and more accurate interpretations of animal emotions. As future avenue, we propose“behaviour-physiology profiles” to uncover biological and evolutionary foundations ofaffective processes across species. We believe such an integrated framework holds greatpromise for advancing animal welfare, communication science and our understanding of thecomplex emotional life of animals.