Personality and cognitive performance in western gorillas (Gorilla gorilla)

The relationship between personality, cognitive interest, and performance has received increasing attention in primates, as these variables contribute to explaining individual differences in behaviour. Numerous studies have indicated that specific personality traits may be associated with heightened motivation to explore or solve tasks. Nevertheless, this relationship remains unexplored within the genus Gorilla. In our study, we investigated the association between personality, interest, and performance in a cognitive enrichment task among 17 zoo-housed western gorillas (Gorilla gorilla). The experimental task involved retrieving food from a tube presented in a social context. Each session consisted of a 30-minute recording of a gorilla performing the task, with a total of three sessions per individual. We conducted personality assessments using the Gorilla Behavior Index questionnaire, which comprised 25 adjectives. Exploratory factor analysis revealed four factors that accounted for 76% of the variance. We found positive associations between Maternal factor and the variable of success (first success), and negative associations between Maternal and Extraversion with success rate. However, we did not find a link between the personality factors and interest. Additionally, we observed that repeated exposure to the task improved gorillas’ performance. Females showed greater efficiency in food extraction compared to males. Furthermore, younger individuals achieved higher success rates than older ones. Thus, our findings suggest that personality, sex and age play an important role in explaining gorillas' performance in solving tasks.