Predicting Primate Behavior from Personality Ratings

Abstract

An important reason for measuring personality in any species is the determination of the predictive power between personality ratings and manifest behavior. In this chapter, I review what is known to date about the relationships between personality traits and overt behaviors in primates. The majority of studies that have found such links have done so at the factor level, so I also present new data from my own research with chimpanzees, gorillas and bonobos, where I test for relationships between specific trait terms and observed behavior within the broader overall dimensions (factors) of personality, along with associations between these factor scores and behaviors. Principal components analysis of chimpanzee personality ratings yielded six components accounting for 77.5% of the variance in ratings. Demonstrating convergent and discriminant validity, I illustrate links between factor scores on the top three factors (each accounting for more than 15% of the variance) concerned with Confidence (CI), Sociability (C2) and Excitability (C3), and behaviors—e.g.. Sociability (C2) scores correlate positively with several observed play indices. Examples of behaviors linked to discrete trait adjectives include significant correlations between rated playfulness and aggression and their respective observed behavioral frequencies. In addition, some relationships are specific to particular age or sex classes—e.g., the relationships between confidence and effectiveness and increased grooming are only evident among male chimpanzees, while immature individuals scoring higher on intelligent engage in more grooming. I also present preliminary findings of relationships between personality ratings and observed behaviors for the smaller samples of gorillas and bonobos. That the behavioral data here correlate significantly with both specific traits and with factor scores provides validation of the rating instrument and will benefit our understanding of nonhuman personality. (PsycINFO Database Record (c) 2012 APA, all rights reserved). (chapter)