Abstract: Current scores for equine personality traits assessed during performance tests are characterised by high means and inadequate variation, hampering genetic selection for these traits. A number of temperament and related behaviour tests have been developed in order to make assessment of equine personality more objective. However, rarely these tests have been validated for their use as a selection tool. Thus, as a first step the aim of the present study was to integrate a temperament tests into horse performance tests, in order to assess variability and repeatability of horses’ reactivity under the rider and the reliability of the judges’ assessment thereof. The temperament test was comprised of three novel stimuli, including a visual stimulus (BALL), a visual and tactile stimulus (GATE), and a visual and auditory stimulus (CANS). A total of 224 mares and stallions were subjected to the test during their participation in station performance tests for riding horses, and 133 of these horses were subjected to the test a second time either 2–3 weeks or 18 weeks after the first test. Horses were ridden in the test by professional riders, and their reactions to the stimuli were evaluated each by two judges and the rider using scores on a scale from 1 (task not concluded) to 10 (completely calm but attentive horse). Mean scores (±SD) ranged between 6.6 ± 2.4 (GATE) and 7.8 ± 2.1 (BALL), demonstrating lower means and considerably higher standard deviations than the same horses’ scores from present evaluation of the trait labelled temperament (8.1 ± 0.9) or related personality traits (e.g. character: 8.3 ± 0.8). Using variance components from mixed model analysis, inter-observer agreement between the two judges was for the individual stimuli very high (0.95 (BALL), 0.96 (GATE), 0.89 (CANS)), and there was likewise high agreement between the judges’ and the riders’ combined scores (0.93). Repeatabilities of horses’ scores were 0.72 (BALL), 0.75 (GATE), and 0.69 (CANS). Correlations to traits from the present evaluation of personality were low or non-existent, indicating that these traits are not a reflection of anxiety or fear reactivity as assessed by novel object tests. Horses’ improvement in judges’ combined scores from first to second test was not (P > 0.1) influenced by differences in time between tests, but differed between breed-types and individual riders. Also, not surprisingly, the higher horses’ scores in the first test were, the lower their improvement in the second test was (-0.45 ± 0.06 per additional score in the first test). Temperament tests using novel stimuli presented to horses under a rider may be a practical and valid tool for improving the current assessment of equine personality traits during performance tests. Considering a combination of absolute scores and horses’ improvement in scores of repeated tests, rather than measuring only absolute scores yields relevant information about horses’ personality, and at the same time it may prevent owners from deliberately training their horses for low reactions to the test-stimuli.

Abstract: The degree of lateralization (LI) indicates both the direction and strength of a paw preference. Here, a positive value is indicative of a right paw bias, and a negative value of a left paw bias. Higher numbers on the positive side of the scale and lower numbers on the negative side of the scale indicate a greater strength of that lateralization. The strength of motor lateralization (|LI|) is the absolute value of the LI. The use of absolute value removes directionality (i.e., does not indicate left or right paw bias) and instead indicates only the strength of the paw preference. Both LI and |LI| have been associated with behavioral differences in a range of species. The assessment of motor lateralization in the dog can be conducted by observing the paw used to perform motor tasks. Elevated cortisol concentrations have been associated with fearfulness in many species. Additionally, fearfulness and boldness can be assessed in response to so-called temperament tests. Consequently, in this study we examine the relationship between lateralization, temperament test results, and cortisol concentrations in 43 potential guide dogs, of which 38 were Labrador retrievers and 5 were golden retrievers. Over a 14-month period, the current study assessed motor lateralization and salivary cortisol concentrations 3 times (approximately 6 months of age, 14 months of age, and after the dogs' performance in the guide dog program had been determined) and behavior twice (approximately 6 and 14 months of age). This study is the first to examine the relationship between behavior, lateralization, and cortisol concentrations in dogs. It implemented an objective and quantifiable assessment of behavior that may be of use to a variety of dog-focused stakeholders. Findings show that during the Juvenile testing period (6 months of age), dogs with higher cortisol concentrations were typically less able to rest when exposed to the unfamiliar testing room. Results from both Juvenile and Adult Test (14 months of age) periods showed that a greater |LI| and LI were associated with more confident and relaxed behavior when dogs were exposed to novel stimuli and unfamiliar environments. Significant elevations of cortisol concentrations were found at the completion of guide dog training when compared with results from the 2 prior test periods. This finding may reflect maturation or the effect of the prolonged kenneling which occurred during this period.

Abstract: This paper demonstrates that the rhesus monkey provides an excellent model to study mechanisms underlying human anxiety and fear and emotion regulation. In previous studies with rhesus monkeys, stable, brain, endocrine, and behavioral characteristics related to individual differences in anxiety were found. It was suggested that, when extreme, these features characterize an anxious endophenotype and that these findings in the monkey are particularly relevant to understanding adaptive and maladaptive anxiety responses in humans. The monkey model is also relevant to understanding the development of human psychopathology. For example, children with extremely inhibited temperament are at increased risk to develop anxiety disorders, and these children have behavioral and biological alterations that are similar to those described in the monkey anxious endophenotype. It is likely that different aspects of the anxious endophenotype are mediated by the interactions of limbic, brain stem, and cortical regions. To understand the brain mechanisms underlying adaptive anxiety responses and their physiological concomitants, a series of studies in monkeys lesioning components of the neural circuitry (amygdala, central nucleus of the amygdala and orbitofrontal cortex) hypothesized to play a role are currently being performed. Initial findings suggest that the central nucleus of the amygdala modulates the expression of behavioral inhibition, a key feature of the endophenotype. In preliminary FDG positron emission tomography (PET) studies, functional linkages were established between the amygdala and prefrontal cortical regions that are associated with the activation of anxiety.

Abstract: REASONS FOR PERFORMING STUDY: Behavioural tests as well as observers' ratings have been used to study horses' temperament. However, the relationship between the ratings and the responses in behavioural tests has not yet been studied in detail. OBJECTIVES: The aim of the present study was to examine this relationship between ratings and responses. METHODS: Eighteen mature Swedish Warmblood horses were subjected to 2 behavioural tests, one relating to novelty (novel object test) and one to handling (handling test). Subsequently, 16 of these horses were ridden by 16 equally experienced students, having no former experience with the horses. Immediately after each ride, the students scored the horse for 10 temperamental traits using a line rating method. RESULTS: It was shown that for each temperamental trait all 16 riders agreed on the ranking of the horses (0.212<W<0.505, P < 0.001). CONCLUSIONS: Correlations between behavioural and heart rate variables in the behavioural tests revealed that horses with a high level of locomotion or much restlessness behaviour exhibited high mean heart rate and low heart rate variability. In particular, heart rate variables in the behavioural tests were found to correlate with riders' rating scores. Furthermore, the underlying components of the handling test, retrieved with a principal component analysis (PCA) correlated with riders' rating scores while the underlying components of the novel object test did not. POTENTIAL CLINICAL RELEVANCE: It is concluded that it is possible for a large panel of assessors to agree upon a horse's temperament and that objective measures from behavioural tests correlate significantly with temperamental traits assessed by a panel of assessors.

Abstract: Individual differences in the way persons respond to stimulation can have important consequences for their ability to learn and their choice of vocation. Temperament is the study of such individual differences, being thought of as the behavioral style of an individual. Common to all approaches in the study of temperament are the notions that it can be identified in infancy, is fairly stable across development, and influences adult personality. We have identified a specific temperament type in infancy that involves heightened distress to novel and unfamiliar stimuli. Infants who exhibit this temperament are likely, as they get older, to display behavioral inhibition-wariness and heightened vigilance of the unfamiliar-particularly in social situations. Our work has also described the underlying biology of this temperament and has linked it to neural systems supporting fear responses in animals. Children displaying behavioral inhibition are at-risk for behavioral problems related to anxiety and social withdrawal.