Chapter 17: Animal Models of Personality

The authors address the historical reluctance of many scientists to apply the term 'personality' to animals, often stemming from concerns regarding anthropomorphism, by proposing three stringent criteria for demonstrating personality existence: assessments must yield agreement among independent observers, ratings must successfully predict real-world outcomes and specific behaviors, and the observed structure must reflect genuine attributes of the animal rather than merely the implicit personality theories of the human observers. Empirical data supports these criteria, showing that inter-observer agreement correlations in animal studies are comparable to those found in human personality research. The primary motivations for studying animal personality fall into three interconnected areas: Behavioural Ecology, which explores how evolutionary pressures maintain consistent individual differences and adaptive variation in populations, often analyzing correlated behaviors known as behavioural syndromes; Animal Model Research, which provides unique advantages over human studies, including greater experimental control over genetic and environmental factors, accelerated life histories for longitudinal studies, and opportunities for detailed molecular and quantitative genetic investigation; and Practical Applications, encompassing improvements in animal welfare, aiding species conservation, and enhancing personnel selection processes, particularly for working animals like drug detection dogs. Research methods generally involve either detailed behavioral codings or subjective ratings derived from the accumulated experience of knowledgeable observers, with ratings often proving superior for reliably capturing personality consistencies. A structural review of traits indicates that dimensions resembling human Extraversion, Neuroticism, and Agreeableness are widely generalized across species, manifesting differently—for instance, as Sociability in pigs or bold approach versus avoidance in octopuses. Notably, the dimension of Conscientiousness is less general, having only been identified separately in humans and chimpanzees, which suggests that this complex trait evolved relatively recently, coinciding with the development of the frontal cortex associated with higher executive function. When performing cross-species comparisons, researchers must carefully establish the equivalence of seemingly similar traits by examining the behaviors in context and looking for shared underlying physiological, genetic, and biological commonalities, similar to methods used in cross-cultural psychology. The most appropriate species for study is determined by the specific research question, necessitating consideration of the species' environmental and social ecologies, their biology, and their phylogenetic distance from humans.