Document type : Scientific review

In order to achieve the objective evaluation of emotions in farm animals, the Agri-Bien-Être Animal network (an interdisciplinary group created by INRA in 1998, www6.inra.fr/agri_bien_etre_animal) has proposed experimental strategies based on cognitive evaluation theory in human psychology (Boissy et al 2007, Box 1). According to this conceptual framework, emotions are generated by the cognitive evaluation of a situation confronting the animal. Although the characterisation of these situations is complex (Forkman et al 2007), it is suggested that the animal would evaluate them using basic criteria for relevance (suddenness, novelty, etc) and involvement (predictability, etc), the degree to which they correspond to  expectations, and according to its own adaptive capacities (controllability of the situation). At the end of this evaluation phase, the emotion felt by the animal is translated into emotional expression. It is the latter that can be assessed by the objective measurement of behavioural and physiological emotional responses (Box 2). By applying this conceptual framework to research in the neurobiology of emotions, the representation of the neural circuit of emotions can be built around those structures involved in the perception of the environment, information processing and the expression of emotional responses (Figure 1). From an experimental point of view, this theoretical framework requires the characterisation and standardisation of situations likely to serve as a trigger and the characterisation of the emotional responses expressed by individual animals in relation to the neurobiological actors studied.