Olfactory communication of emotions between animal and human – Emodour

Growing evidence demonstrates that emotional communication takes place between humans and domestic animals, but most studies have focused on the visual and acoustic channels, neglecting olfactory communication, the most primitive and widespread channel. Recent studies of our teams show that equids and bovidae can perceive human olfactory signals associated with different emotional states, and these chemical cues have begun to be characterized. These first results lead us to investigate further the chemical communication of emotions from humans to animals but also from animals to humans. We propose a project on two domestic livestock species, equids (Equus caballus) and bovidae (Ovis aries), with three aims: (1) To determine whether these species discriminate between different human emotional odours and whether these odours induce emotions in animals; (2) To investigate reciprocity, namely are humans able to discriminate animal emotional odours and how do they react emotionally to these odors? (3) To analyze the chemical composition of emotional odours produced by humans, horses and sheep to confirm whether chemical differences exist between odours from different emotional states in a species, and determine whether the three species share chemical signatures linked to emotional states. Regarding methods, collection of human emotional odours will be based on well-established and published protocols. The participants will watch emotion-charged film extracts (displaying fear, joy, sadness or inspiring disgust) while equipped with under-arm gauze pads. Animal emotional odours will be collected following the same principle. Horses and sheep will experience situations of contrasting emotional valence (positive, such as pleasant touch contact, and more negative, such as a novel environment), while equipped with gauze pads placed under abdominal belts. These odours will then be tested on receiver subjects in appropriate tests for each species. Thus, horses and sheep will participate in ‘habituation/ discrimination’ tests which will enable us to demonstrate whether they can discriminate different human emotional odours. They will then undergo a battery of tests to evaluate their emotional reactivity (e.g., a neophobia test) according to whether they are exposed or not to human emotional odours. The human subjects will take part in specific tests to determine whether or not they can evaluate implicitly or explicitly the animal odours (e.g., standardized laboratory tests in which they will self-evaluate their emotional state before and after smelling an odour). The consortium is well-experienced in the battery of tests the animal and human participants will perform. Finally, to describe the chemical composition of the emotional signals in human and animal sweat, the organic volatile compound extracts will be analyzsed through gas chromatography -mass spectrometry. This inter disciplinary project will group fields such as cognitive ethology, human psychology and chemical ecology. It should improve understanding of how animals and humans mutually communicate their emotions through chemicals. Four different scientific teams will collaborate on the project, which will be supported by scientists recognized in the domains of animal cognition, emotions and welfare, the human-animal relationship, olfactory processing in animals and humans, and chemical ecology.