Assessing chimpanzee personality and subjective well‐being in Japan

Abstract

We tested whether the cultural background of raters influenced ratings of chimpanzee personality. Our study involved comparing personality and subjective well-being ratings of 146 chimpanzees in Japan that were housed in zoos, research institutes, and a retirement sanctuary to ratings of chimpanzees in US and Australian zoos. Personality ratings were made on a translated and expanded version of a questionnaire used to rate chimpanzees in the US and Australia. Subjective well-being ratings were made on a translated version of a questionnaire used to rate chimpanzees in the US and Australia. The mean interrater reliabilities of the 43 original adjectives did not markedly differ between the present sample and the original sample of 100 zoo chimpanzees in the US. Interrater reliabilities of these samples were highly correlated, suggesting that their rank order was preserved. Comparison of the factor structures for the Japanese sample and for the original sample of chimpanzees in US zoos indicated that the overall structure was replicated and that the Dominance, Extraversion, Conscientiousness, and Agreeableness domains clearly generalized. Consistent with earlier studies, older chimpanzees had higher Dominance and lower Extraversion and Openness scores. Correlations between the six domain scores and subjective well-being were comparable to those for chimpanzees housed in the US and Australia. These findings suggest that chimpanzee personality ratings are not affected by the culture of the raters.

Evidence for a midlife crisis in great apes consistent with the U-shape in human well-being

“…Ratings on this questionnaire are consistent across raters and define a single dimension (30,31,33). In addition, like human subjective well-being questionnaires (6,26,34,35), scores on the present questionnaire are stable over time (31), associated with analogous personality traits (30,31,33), and both heritable and genetically correlated with personality (36,37). Finally, a study in orangutans (27) indicated that, like human well-being (26), higher scores on this wellbeing scale were associated with a longer lifespan.…”

“…We used three existing samples of great apes (22,27,30), each of which included individuals ranging from infancy to old adulthood. The study was not an experiment and there was no intervention.…”

“…The raters were zoo keepers, volunteers, researchers, and caretakers who knew the subjects, usually for at least 2 y (27,30,33). Ratings on the four items were made on 7-point scales.…”

Common marmoset (Callithrix jacchus) personality.

“…[1] (Weiss et al, 2009), which, together with its predecessors (King & Figueredo, 1997;Weiss et al, 2006), and offshoots (Konečná et al, 2008(Konečná et al, , 2012Iwanicki & Lehman, 2015), has been used to assess personality in several nonhuman primate species (Weiss, 2017). A further 12 items were taken from a questionnaire used to study Hanuman langurs (Konečná et al, 2008) and Barbary macaque personality (Konečná et al, 2012).…”

“…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).…”