Personality in wild bonobos (Pan paniscus)

Abstract

To understand the evolution of personality structure requires examining personality dimensions in multiple species using a common set of traits. Little research has been conducted on personality in wild populations of nonhuman primates. Using behavioral observations and questionnaire ratings, we examined factors influencing personality in 16 wild bonobos (Pan paniscus) at Wamba, Luo Scientific Reserve, Democratic Republic of the Congo. We extracted five factors from 31 of the items from the Hominoid Personality Questionnaire (HPQ) and three factors from observed behaviors. The HPQ factors were labeled Unemotionality , Friendliness , Aggressiveness , Irritability , and Activity . The behavioral factors were labeled Grooming , Playfulness , and Introversion . We established the convergent and divergent validity of these factors by obtaining correlations between the HPQ and behavioral factors. We tested for sex differences and found that males were significantly higher on Introversion and significantly lower in Irritability . We then tested for age differences and found that Friendliness was lower and Aggressiveness was higher in older individuals. Finally, we found that, among males, hierarchical rank was associated with higher Aggressiveness . These findings contrast with findings in chimpanzees in ways consistent with known species differences. For one, consistent with the more egalitarian structure of bonobo society, we did not identify a clear Dominance factor. Also, the results related to sex differences were consistent with previous findings that reveal closer bonds between female bonobos than female chimpanzees. These findings highlight the importance of studying personality in closely related species and the need to consider species' socioecology when studying personality. Am. J. Primatol. 78:1178-1189, 2016. © 2016 Wiley Periodicals, Inc.

A human model for primate personality

“…The culture from which raters come also appears to have little influence on the personality domains that emerge from ratings of chimpanzees [86]. Note that there are possible exceptions: the differences between the personality domains of bonobos in zoos [65] and those in the wild is fairly pronounced [87]. Additional indirect evidence comes from studies that show that, although there is some overlap, closely related species, such as white-faced and brown capuchin monkeys [88], various macaque species [53], and humans, chimpanzees and bonobos [65,89], differ with respect to the personality domains that they possess.…”

Common marmoset (Callithrix jacchus) personality.

“…Research on nonhuman primate personality bucks this trend (e.g., Koski, 2011a;Massen et al, 2013;Neumann et al, 2013;Konečná et al, 2008Konečná et al, , 2012Morton et al, 2013;Garai et al, 2016;Weiss et al, 2006Weiss et al, , 2007Weiss et al, , 2009Weiss et al, , 2011Weiss et al, , 2012aWeiss et al, ,b, 2015Eckardt et al, 2015;Neumann et al, 2013;Adams et al, 2015;Uher & Visalberghi, 2016).…”

“…Another feature of human personality is that agreeableness is defined by positive associations with traits related to helpfulness and prosociality and negative associations with traits related to aggression and competitiveness (Costa & McCrae, 1992). Its counterparts in chimpanzees (King & Figueredo, 1997;Freeman et al, 2013), bonobos Garai et al, 2016), orangutans (Weiss et al, 2006), and gorillas (Gold & Maple, 1994), on the other hand, are defined only by traits related to sociopositivity.…”

Bonobo personality: Age and sex effects and links with behavior and dominance

“…We therefore expect similar differences to be reflected in their personality. Unfortunately, despite the large number of chimpanzee personality studies, few studies have focused on bonobos, and those that did, involved small sample sizes (Uher and Asendorpf, 2008, Murray, 2011, Garai et al, 2016 or focused on measuring single traits, such as boldness (Herrmann et al, 2011). To complement this existing literature, we obtained personality ratings on154 bonobos.…”