Personality dimensions in nonhuman animals: A cross-species review

The evolutionary continuity between humans and other animals suggests that some dimensions of personality may be common across a wide range of species. Unfortunately, there is no unified body of research on animal personally, studies are dispersed across multiple disciplines and diverse journals. To review 19 studies of personality factors in 12 nonhuman species, we used the human Five-Factor Model plus Dominance and activity as a preliminary framework. Extraversion, Neuroticism, and Agreeableness showed the strongest cross-species generality, followed by Openness; a separate Conscientiousness dimension appeared only in chimpanzees, humans' closest relatives. Cross-species evidence was modest for a separate Dominance dimension but scant for activity. The comparative approach taken here offers a fresh perspective on human personality and should facilitate hypothesis-driven research on the social and biological bases of personality.