From observations of individual behaviour to social representations of personality: Developmental pathways, attribution biases, and limitations of questionnaire methods

•New philosophy-of-science paradigm to systematically study both individual-specific behaviours and pertinent representations.•A non-lexical taxonomic approach used to generate emic personality constructs.•Over 3 years and 6 waves, 104 crab-eating macaques (Macaca fascicularis) and 99 human observers, experts and novices, studied.•Attribution biases reflecting socio-cultural stereotypes about age, sex, and social rank demonstrated in personality ratings.•Important implications for methodology and research methods, in particular limitations of questionnaire methods, illuminated.

Socio-cognitive abilities to recognise and to represent individual-specificity—even in some nonhuman species—are central to human life. Using a novel philosophy-of-science paradigm, we explored these abilities over 3 years in 6 waves by investigating individual-specific behaviours of 104 crab-eating macaques (Macaca fascicularis) and the representations that 99 human observers—experts and novices—developed of them. By applying the non-lexical Behavioural Repertoire × Environmental Situations Approach, we generated 18 macaque-specific personality constructs. They were operationalised with behavioural measures to study the macaques and with two rating formats to study the observers’ representations. Analyses of reliability, cross-method coherence, taxonomic structures, associations with demographic factors, and 12–24-month stabilities highlighted essential differences between individual-specific behaviours and pertinent representations, explored developmental pathways of representations, and illuminated attribution biases and limitations of questionnaire methods.