A comparison of personality in the common and Bolivian squirrel monkey (Saimiri sciureus and Saimiri boliviensis).

Abstract

Personality has been studied in all of the great apes, many Old World monkey species, but only a handful of New World monkey species. Because understanding the personalities of New World monkeys is crucial to understanding personality evolution in primates, we used the Hominoid Personality Questionnaire to assess personality in 55 common squirrel monkeys () and 40 Bolivian squirrel monkeys (). We found 4 personality components in each species, and labeled them Openness, Neuroticism, Assertiveness, and Agreeableness. We then, in a genus-level analysis, found 5 components, which we labeled Neuroticism, Openness, Assertiveness, Agreeableness, and Decisiveness. Comparisons of the genus- and species-level structures revealed that common squirrel monkeys had a personality structure that more closely resembled the genus-level structure than did Bolivian squirrel monkeys. We then compared the personality structures of common and Bolivian squirrel monkeys with that of brown capuchin monkeys, Sapajus apella. The personality structure of Bolivian squirrel monkeys more closely resembled that of brown capuchins. These findings suggest that the Bolivian squirrel monkey personality structure is ancestral and that Assertiveness and Openness are ancestral to both the Saimiri genus and brown capuchins; Agreeableness and Neuroticism seem to be derived in Saimiri. We discuss these findings in relation to differences in the social structures and ecologies of these species. (PsycINFO Database Record

Individual differences in zoo‐housed squirrel monkeys' (Saimiri sciureus) reactions to visitors, research participation, and personality ratings

“…Interestingly, the remaining relevant personality traits for the two behaviors fell on opposite spectrums. While for the window approaching behaviors the significant predictive personality scores (correlated with less time spent at the window) were for solitude and depression, both of which are highly loading on the “Neuroticism” factor (Wilson et al, in prep.), for predicting the monkeys' participation in research, it was the traits that were highly loading on the “Agreeableness” factor (gentle, affectionate, and friendly) that proved to be significant. The suggestion that more neurotic animals do not come to the observation window more frequently when there are visitors present could have welfare implications.…”

“…The personality traits were chosen based on high loadings found in a previous personality assessment of squirrel monkeys using the full 54‐item Hominoid Personality Questionnaire. In that study, four components (“Assertiveness,” “Impulsiveness,” “Neuroticism,” and “Agreeableness”) were derived from 46 reliable items and were validated across 57 animals from eight international zoos (Wilson et al, in prep; Wilson, ). Three high‐loading traits were chosen from each of the four components.…”

“…This can lead to the monkeys being enriched by human presence, or at the very least having a non‐aversive relationship with them (Hosey, ). Research concerning individual differences in the squirrel monkeys has been ongoing (Wilson et al, in prep; Wilson, ), but thus far has not been investigated with regards to either reactions to visitors or participation in research.…”

Personality, Subjective Well-Being, and the Serotonin 1a Receptor Gene in Common Marmosets (Callithrix jacchus)

“…Pan (17), the genera Saimiri, Sapajus, and Cebus (18)(19)(20), and of Callitrichidae (21) indicate that species socioecology influences personality structure evolution. This appears to also be true for common marmosets, that is, cooperative breeding appears to have influence how personality traits are organized in this species.…”

Regularized Exploratory Bifactor Analysis With Small Sample Sizes

“…Regularized exploratory factor analysis (REFA) (Jung and Takane, 2008;Jung and Lee, 2011) has been introduced as an alternative approach of conducting exploratory factor analysis with small sample sizes. The applications for REFA have been increasing rapidly in many fields such as behavior science due to its usefulness in handling the limited sample size problems, resulting in more stable parameter estimates (e.g., Wilson et al, 2018).…”