Abstract: There is disagreement in the literature about the exact nature of the phenomenon of empathy. There are emotional, cognitive, and conditioning views, applying in varying degrees across species. An adequate description of the ultimate and proximate mechanism can integrate these views. Proximately, the perception of an object's state activates the subject's corresponding representations, which in turn activate somatic and autonomic responses. This mechanism supports basic behaviors (e.g., alarm, social facilitation, vicariousness of emotions, mother-infant responsiveness, and the modeling of competitors and predators) that are crucial for the reproductive success of animals living in groups. The Perception-Action Model (PAM), together with an understanding of how representations change with experience, can explain the major empirical effects in the literature (similarity, familiarity, past experience, explicit teaching, and salience). It can also predict a variety of empathy disorders. The interaction between the PAM and prefrontal functioning can also explain different levels of empathy across species and age groups. This view can advance our evolutionary understanding of empathy beyond inclusive fitness and reciprocal altruism and can explain different levels of empathy across individuals, species, stages of development, and situations.

Abstract: The efficacy of questionnaire-based personality assessment has been shown in a variety of animal and human personality studies. There has been a recent increase in questionnaire-based studies focussing on equine personality but with a lack of comparability to studies on other species. The aim of this study was to test the reliability of an assessment method originally developed for primates and demonstrate reliability using three criteria (1) assessments by independent observers must agree with one another, (2) these assessments must predict behaviours and real-world outcomes and (3) observer ratings must be shown to reflect genuine attributes of the individuals rated, not merely the observer's implicit personality theories about how traits co-vary. The personality of 61 horses (Equus caballus) was assessed using a questionnaire constructed of 30 behaviourally defined adjectives (BDAs). Horses were each assessed by three judges, in addition to a total of 2 h behaviour observations recorded per horse. Rater agreement was demonstrated for 72.1% of the horses and 25 of the BDAs. Principal component analysis was carried out on the rating data and revealed six underlying personality components that were labelled “dominance”, “anxiousness”, “excitability”, “protection”, “sociability” and “inquisitiveness”. Component scores for horses were correlated against behavioural observations for the same horses and revealed significant correlations with 20 of the recorded behaviour variables. Correlations between specific components and their associated behaviours were logical and consistent with the types of behaviours that would be expected to be linked with such personality types. The data were shown to meet all three criteria and provided strong evidence that the assessment method was reliably measuring horse personality.

Abstract: We studied the relationship of reciprocity, gender, and racial composition (Caucasian, African American, cross-race) of adolescent friendship dyads to similarity and proximity in 136 young adolescents. We found that adolescents selected friends who were of the same gender and race and that female dyads were more similar than male dyads on verbal achievement and several personality dimensions. Caucasian dyads were more similar than African American dyads on verbal achievement, mental alertness, and dominance. African American adolescents had more contact with their best friends outside school, whereas Caucasian adolescent friends had more in-school contact. African American students had fewer reciprocal relationships than the Caucasian students. Cross-race friendships were less reciprocal than same-race friendships. Race and gender were important in determining friendship patterns. Similarity and proximity were more important than reciprocity in understanding early adolescent friendships.

Abstract: Consistent individual differences in boldness, reactivity, aggressiveness, and other 'personality traits' in animals are stable within individuals but vary across individuals, for reasons which are currently obscure. Here, I suggest that consistent individual differences in growth rates encourage consistent individual differences in behavior patterns that contribute to growth-mortality tradeoffs. This hypothesis predicts that behavior patterns that increase both growth and mortality rates (e.g. foraging under predation risk, aggressive defense of feeding territories) will be positively correlated with one another across individuals, that selection for high growth rates will increase mean levels of potentially risky behavior across populations, and that within populations, faster-growing individuals will take more risks in foraging contexts than slower-growing individuals. Tentative empirical support for these predictions suggests that a growth-mortality perspective may help explain some of the consistent individual differences in behavioral traits that have been reported in fish, amphibians, reptiles, and other animals with indeterminate growth.

Abstract: Learning performances are influenced by many factors, not only breed, age and sex, but also temperament. The purpose of this study was to understand how different temperamental dimensions affect the learning performance of horses, Equus caballus. First, we carried out a series of behavioural tests on 36 Welsh ponies aged 5-7 years to measure five temperamental dimensions: fearfulness (novel area test and surprise test), gregariousness (social isolation test), reactivity to humans (passive human test), tactile sensitivity (von Frey filament test) and activity level (evaluation of locomotor activity during all the tests). We then presented them with two learning tasks (avoidance and backwards-forwards tasks). In the avoidance task they had to learn to jump over a fence when they heard a sound associated with an aversive stimulus (puff of air). In the backwards-forwards task they had to walk forwards or move backwards in response to a tactile or vocal command to obtain a food reward. There was no correlation between performances on the two learning tasks, indicating that learning ability is task-dependent. However, correlations were found between temperamental data and learning performance (Spearman correlations). The ponies that performed the avoidance task best were the most fearful and the most active ones. For instance, the number of trials required to perform 5 consecutive correct responses (learning criterion) was correlated with the variables aimed at measuring fearfulness (way of crossing a novel area: rs = -0.41, P = 0.01 and time to start eating again after a surprise effect: rs = -0.33, P = 0.05) and activity level (frequency of trotting during all the tests: rs = -0.40, P = 0.02). The animals that performed the backwards-forwards task best were the ones that were the least fearful and the most sensitive. For instance, the learning criterion (corresponding to the number of trials taken to achieve five consecutive correct responses) was correlated with the variables aimed at measuring fearfulness (latency to put one foot on the area: rs = 0.43, P = 0.01; way of crossing a novel area: rs = 0.31, P = 0.06; and time to start eating again after a surprise effect: rs = 0.43, P = 0.009) and tactile sensitivity (response to von Frey filaments: rs = -0.44, P = 0.008). This study revealed significant links between temperament and learning abilities that are highly task-dependent.