Assessing Eysenck's PEN model to describe personality in chimpanzees

Area of Science:

• Primate Psychology
• Comparative Cognition
• Animal Behavior

Background:

• Human personality models can be adapted for non-human primates.
• Previous research explored chimpanzee personality with smaller sample sizes.

Purpose of the Study:

• To test the applicability of an adapted Eysenck's Psychoticism-Extraversion-Neuroticism (PEN) model in a larger chimpanzee population.
• To identify and validate higher-order personality traits in chimpanzees.

Main Methods:

• Utilized a 12-item questionnaire based on the PEN model, rated on a 7-point Likert scale.
• Assessed personality in 37 chimpanzees across two facilities.
• Employed Principal Components Analysis and Robust Unweighted Least Squares for data reduction.

Main Results:

• Confirmed substantial inter-rater agreement using Intraclass Correlations (ICCs).
• Identified three personality factors: Extraversion, Neuropsychoticism, and a novel factor potentially representing Fearless Dominance.
• Factor analysis results supported the retention of three factors, aligning with previous findings and extending them.

Conclusions:

• The adapted PEN model reliably describes chimpanzee personality structure.
• Findings support the use of human personality frameworks in comparative psychology.
• This research provides a robust foundation for understanding primate personality.