Appraisal process in sheep (Ovis aries): interactive effect of suddenness and unfamiliarity on cardiac and behavioral responses.

Appraisal theories state that an emotion results from an individual's evaluation of a stimulating event, which is based on a set of criteria. Each criterion triggers specific expressions that can be modulated by the outcome of other criteria. The authors analyzed the effects of the criteria of suddenness, unfamiliarity, and their combination on behavioral and cardiac responses in lambs (Ovis aries). Lambs were exposed to a visual stimulus that appeared either rapidly or slowly and was either unfamiliar or familiar. Suddenness induced a startle response and an increase in heart rate. Unfamiliarity induced an orientation response. The combination of suddenness and unfamiliarity enhanced both the heart rate increase and the behavioral orientation response. These results support the hypotheses of specificity and modulation of emotional expressions.

On the way to assess emotions in animals: do lambs (Ovis aries) evaluate an event through its suddenness, novelty, or unpredictability?

Appraisal theories provide a framework that gives insight into emotions and could allow comparisons across species. According to these theories, events are first evaluated on their suddenness, novelty, and unpredictability. The authors examined the ability of lambs (Ovis aries) to evaluate an event according to these 3 criteria through 3 tests. The lambs responded to suddenness with a startle response coupled with an increase in heart rate and to novelty with an orientation response coupled with an increase of vagal activity. There was no clear evidence that lambs can detect the predictability of an event. Those results support the usefulness of appraisal theories to assess emotion in animals.

Emotions in farm animals: a new approach to animal welfare in applied ethology.

One of the major topics of applied ethology is the welfare of animals reared by humans. Welfare can be defined as a state of harmony between an individual and its environment. Any marked deviation from this state, if perceived by the individual, results in a welfare deficit due to negative emotional experiences. In humans, verbal language helps to assess emotional experiences. In animals, only behavioural and physiological measurements help to detect emotions. However, how to interpret these responses in terms of emotional experiences remains an open question. The information on the cognitive abilities of farm animals, which are available but scattered, could help the understanding of their emotions. We propose a behavioural approach based on cognitive psychology: emotions can be investigated in farm animals in terms of the individual's appraisal of the situation. This evaluative process depends on: (a) the intrinsic characteristics of the eliciting event (suddenness, novelty, pleasantness); (b) the degree of conflict of that event with the individual's needs or expectations; and (c) the individual's coping possibilities offered by the environment. The result of such an evaluation determines the negative versus positive emotions. We propose an analysis of the emotional repertoire of farm animals in terms of the relationship between the evaluative process of the event on the one hand and the behavioural and physiological responses on the other hand.