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

Abstract

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.

Heart rate modulation in bystanding geese watching social and non-social events

“…Generally, suddenness, unfamiliarity and unpredictability of a stimulus have been found to be most effective HR modulators ( Weiss 1970;Désiré et al 2006). In our case, however, the social situations occurred much more frequently, regularly and predictably than non-social events.…”

“…Also, HR has been used in several studies to assess emotions in animals (Aureli et al 1999;Cabanac & Aizawa 2000;Bradley & Lang 2001;Preston & de Waal 2002;Désiré et al 2004). Affective responses, including physiological, behavioural and subjective components, are a result of the cognitive evaluation (not necessarily 'conscious') of an event in terms of its significance for the survival and well-being of the individual (Scherer 1999;Désiré et al 2006). Therefore, HR has been used as a parameter to judge the relevance of certain stimuli, for example, if individuals can differentiate between familiar and non-familiar animals ( Nakagawa et al 2001) or between conspecifics and heterospecifics Hauber et al 2002).…”

Validation of a fear test in sport horses using infrared thermography

“…Although repeated subjugation of undesirable fear responses may ultimately appear to solve the overt behavioral reaction, this method can cause short-or long-term stress (McGreevy and McLean, 2010) and can worsen the problem or lead to the development of alternative avoidance strategies such as abnormal behaviors (Hothersall and Casey, 2012). Besides possible problems caused by inappropriate human reactions to fear displays, a long-term negative emotional state related to fear can per se cause chronic stress and reduced welfare (Dantzer and Mormede, 1983;Désiré et al, 2006;Minch et al, 2008;Willner et al, 1992).…”

Assessing positive emotional states in dogs using heart rate and heart rate variability

“…Time domain indicators are insensitive to phase shifts that could potentially be introduced by stitching and the statistical properties of the variation are preserved [30]. In previous studies with lambs, time domain HRV indicators have been obtained from sequences of 10-60 s corresponding to beat-to-beat sequences of 20-120 beats [31,32,33]. Within the heart rate range of the individual dogs in this study (75-90 bpm), a 20 s stitched window would contain 25-30 beat-to-beat sequences, which is low, but sufficient for an estimation of time domain HRV indexes.…”