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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.

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.

A series of experiments investigated the role of association and familiarity in the development of social recognition among lambs. In each experiment, lambs were tested successively with 2 different social partners. When separated from their mothers, lambs that were paired with a partner with which they had been housed for 17 or 5 days emitted fewer distress bleats than they did during tests with an unfamiliar lamb. However, this effect was only evident when the test with the unfamiliar partner preceded the test with the familiar partner. When lambs were first tested with an unfamiliar partner treated with the same artificial odorant that had previously been associated with members of their own group, they bleated more than they did during a second test with a partner whose odor was novel. This effect was not observed when the familiar- and novel-odor partners were encountered in the reverse order. Bleating frequencies by lambs paired with their twin did not differ reliably from those of lambs paired with a familiar non-twin. Nonetheless, there was a signficant correlation between the number of bleats by twins that were tested together. Overall, the results indicate that lambs become familiar with and recognize individuals (twins and non-twins) as a result of direct association. Lambs also discriminate between novel scents and artificial odorants associated with their familiar agemates, but such odors neither mask nor substitute effectively for lambs' individually recognizable phenotypes. Bleating frequency increases with the novelty of the social partner and of the test situation, and is therefore markedly affected by repeated testing.

Emotions are now largely recognised as a core element in animal welfare issues. However, convenient indicators to reliably infer emotions are still needed. As such, the availability of behavioural postures analogous to facial expressions in humans would be extremely valuable for animal studies of emotions. The purpose of this paper is to find out stable expressive postures in sheep and to relate these expressive postures with specific emotional contexts. In an initial experiment, we identified discrete ear postures from a comprehensive approach which integrates all theoretically distinguishable ear postures. Four main ear postures were identified: horizontal ears (P posture); ears risen up (R posture); ears pointed backward (B posture); and asymmetric posture (A posture). In a second experiment, we studied how these ear postures were affected by specific emotional states elicited by exposing sheep to experimental situations in which elementary characteristics (ie suddenness and unfamiliarity, negative contrast and controllability) were manipulated. We found that: i) the horizontal P posture corresponds to a neutral state; ii) sheep point their ears backward (B posture) when they face unfamiliar and unpleasant uncontrollable situations, hence likely to elicit fear; iii) they point their ears up (R posture) when facing similar negative situations but controllable, hence likely to elicit anger; and iv) they expressed the asymmetric A posture in very sudden situations, likely to elicit surprise. By cross-fostering psychological and ethological approaches, we are able to propose an interpretation of ear postures in sheep relative to their emotions.

Crossing a road intersection, a driver must collect a certain amount of visual information from various locations. The allocation of visual attention, which allows this collection, mainly relies on top-down processes. This study focuses on three top-down factors which inuence the collection of visual information: the value of visual information for the ongoing task, their bandwidth, and the familiarity with the environment. These factors are studied according to the priority rules at intersections (Give way, Stop or Priority), the expected trac density (Lower or Higher) and the number of passages (First or Second passage).Fourteen participants were installed in an instrumented vehicle equipped with an eye-tracker. They drove during 1h45 along a 80-km long route, mainly on rural roads, which included 19 intersections. Visual attention was studied by means of the head and gaze horizontal eccentricity. Eects were found for each of the three factors, in agreement with Wickens' theoretical framework and with previous studies, despite the important variability in the data due to the experimental situation.

The concept of quality of life in animals is closely associated with the concepts of animal sentience and animal welfare. It reflects a positive approach that inquires what animals like or prefer doing. The assessment of farm animal welfare requires a good understanding of the animals' affective experience, including their emotions. However, affective experience in animals is difficult to measure because of the absence of verbal communication. Recent studies in the field of cognitive psychology have shown that affective experience can be investigated without using verbal communication by examination of the interactions between emotions and cognition. On the one hand, appraisal theories provide a conceptual framework which suggests that emotions in humans are triggered by a cognitive process whereby the situation is evaluated on a limited number of elementary criteria such as familiarity and predictability. We have applied these appraisal theories to develop an experimental approach for studying the elementary criteria used by farm animals to evaluate their environment and the combinations of those criteria that trigger emotions. On the other hand, an increasing body of research, first in humans and then in other animals, suggests that emotions also influence cognitive processes by modifying attention, memory and judgement in a short- or long-term manner. Cognitive processes could therefore be manipulated and measured to provide new insights into how not only emotions but also more persistent affective states can be assessed in animals. Further work based on these cognitive approaches will offer new paradigms for improving our understanding of animal welfare, thus contributing to ‘a life of high quality’ in animals.

Animal welfare concerns stem from recognition of the fact that animals can experience emotions such as pain or joy. Nevertheless, discussion of animal emotions is often considered anthropomorphic, and there is a clear need to use explanatory frameworks to understand animals' emotions. We borrowed appraisal theories developed in cognitive psychology to study sheep emotions. Emotions are viewed as the result of how an individual evaluates a triggering situation, following a sequence of checks, including the relevance of the situation (its suddenness, familiarity, predictability, and intrinsic pleasantness), its implications for the individual (including consistency with the individual's expectations), the potential for control, and both internal and external standards. We assumed that if the outcome of checks has an impact on the animal's emotional responses, then animals do not only show emotional responses but also feel emotions. We showed that sheep use similar checks to those used by humans to evaluate their environment, ie suddenness, familiarity, predictability, consistency with expectations, and control. Furthermore, this evaluation affects their emotional responses (behavioural responses, such as startle, ear postures, and cardiac activity). It is concluded that sheep are able to experience emotions such as fear, anger, rage, despair, boredom, disgust and happiness because they use the same checks involved in such emotions as humans. For instance, despair is triggered by situations which are evaluated as sudden, unfamiliar, unpredictable, discrepant from expectations, and uncontrollable, whereas boredom results from an overly predictable environment, and all these checks have been found to affect emotional responses in sheep. These results have implications for animal welfare: although a completely invariable and totally predictable environment should be avoided to prevent boredom, sudden events should probably be minimised, the animals should be offered the possibility to control their environment, and care should be taken to ensure a degree of predictability concerning the various events.