Abstract
In a previous study of laboratory housed common marmosets (Callithrix jacchus), we found that correlations among personality traits indicated the presence of factors that we labeled Dominance, Sociability, and a Neuroticism. Unlike two other studies of this species, we did not find a Conscientiousness, Openness, or Patience factor. Because this discrepancy may have been attributable to the fact that many purported markers of Conscientiousness were excluded because of concerns about reliability, we followed up this study by increasing the sample size from 77 to 128. In addition to this, as we did in our previous study, we gathered data on subjective well-being in these subjects. We also investigated polymorphisms related to the serotonin 1a receptor. We found three personality factors—Sociability, Dominance, and Negative Affect—like those found in our previous study and in other studies of this species. We also found an Openness factor and a factor that we labeled “Impulsiveness”, which resembled, but was not identical to, Conscientiousness. In addition, there was evidence for two higher-order factors: Pro-sociality and Boldness. Further analyses could not rule out the possibility that the higher-order factors represented a higher-level of personality organization. Correlations between the first- and higher-order factors and the subjective well-being measures were consistent with the definitions of the factors. There were no significant associations between personality and genotype. These results are consistent with the possibility that, perhaps because common marmosets are cooperative breeders, personality structure in this species is more labile than in other nonhuman primates and in humans.
Competing Interest Statement
The authors have declared no competing interest.
Footnotes
We have no known conflicts of interest to declare.
This work was supported by Brain/MINDS Beyond from the Japan Agency of Medical Research and Development (AMED) (JP21dm0307006h0002) to TH, KAKENHI Grant Numbers 19H04904 and 20H00420 to MI-M, 18H05090 and 18K06372 to CY. We wish to thank the Leading graduate program in Primatology and Wildlife Science.
We are grateful to Hiromi Kobayashi for technical support and to Mr. Akihiro Kawasaki, Mr. Takashi Fukuoka, and Ms. Chiho Takeda for rating the animals. AW thanks Kyoto University for inviting him to be a Visiting Professor at the Wildlife Research Center..
Chihiro Yokoyama is now at Department of Health Sciences, Faculty of Human Life and Environment, Nara Women’s University.
I updated one author's details related to funding.