Behavioral tests and social observations in adult capuchin monkeys

Contextualised behavioral measurements of personality differences obtained in behavioral tests and social observations in adult capuchin monkeys (Cebus apella)

Jana Uher *1, Elsa Addessi2, Elisabetta Visalberghi2

1 Comparative Differential and Personality Psychology, Department of Educational Science and Psychology, Freie Universität Berlin, Germany
2 Unit of Cognitive Primatology and Primate Centre, Institute of Cognitive Sciences and Technologies, National Research Council of Italy (ISTC-CNR), Rome, Italy


  • Personality differences studied with a new philosophy-of-science paradigm featuring a behavioural research framework.
  • A non-lexical taxonomic approach applied for comprehensive emic/bottom-up construct generation.
  • In 15 test and 2 group situations, 146 contextualised behaviours measured repeatedly.
  • This is the first comprehensive study on personality differences in capuchin monkeys.
  • Overall no age and sex differences found, but long-term effects of early life experiences.

We applied a new framework for behavioural research on personality differences in 26 adult tufted capuchin monkeys. Using the Behavioural Repertoire x Environmental Situations approach, we generated systematically 20 non-lexical emic personality constructs that have high ecological validity for this species.

For construct operationalisation, we obtained 146 contextualised behavioural measures repeatedly in 15 experimental situations and 2 group situations using computerised and video-assisted methods.

A complete repetition after a 2-3-week break within a 60-day period yielded significant test-retest reliability from individualoriente and variable-oriented viewpoints at different levels of aggregation. In accordance with well-established findings on cross-situational consistency, internal consistency was only moderate. This new and important finding highlights fundamental differences between behavioural approaches and judgment-based approaches to personality differences.

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