Comparison of "personality" differences between
four monkey species: A novel methodology to unravel communalities
Press release in PDF-Version
"Personality" differences have already been demonstrated in the
behaviour of many species. But how similar or distinct are the
"personality" differences described for different species? In her new
study, Jana Uher introduces a comprehensive research methodology for
systematic cross-species comparisons. Their application in four monkey
species from four different continents reveals many commonalities but also
exiting species differences.
(© Photos: Dr Jana Uher, Primate Personality Net,
London School of Economics & Free University Berlin)
For a long time, "personality" was thought to be one of the last
domains of human uniqueness that would differentiate humans
fundamentally from other animals. Meanwhile, however, individual
differences that occur in similar ways repeatedly over time-commonly
called "personality" differences-were shown in many species'
In her recent research, Jana Uher has adapted and refined approaches
and methods of cross-cultural "personality" psychology to develop a
comprehensive methodology for systematic comparisons of
"personality" differences across species. She demonstrates the
application of this methodology in a study on four monkey species
that are endemic to three different continents: Weeper capuchins
originate from South America, Mandrills from Africa, and toque
macaques and rhesus macaques from Asia. Over several weeks, her team
observed monkeys housed at the Berlin Zoo and the Animal Shelter of
Berlin, Germany, and recorded their individual behaviours
meticulously-each individual for in total 60 to 80 hours.
The findings are fascinating. In all four species, individuals differ
in their degrees of social orientation; thus, some individuals spent
more time with group members and grooming than did other
individuals. These individual differences were not just random but
occurred in similar ways and repeatedly over time; that is, they
reflect "personality" differences. In all four species, stable
individual differences also occurred in aggressiveness and
dominance. Thus, these individual differences can be considered as
universal for these four primate species.
This universality allowed for making direct comparisons in the degrees
to which individuals of the different species showed particular
behaviours. These comparisons yielded interesting
species-differences. Capuchin individuals generally spent much less
time with their group than did the individuals of the other three
species. But interestingly, the four species did not differ in the
average frequencies by which their individuals showed aggressive
The same was true for dominance behaviours. But in dominance,
pronounced species differences occurred in the magnitude of the
individual differences. The differences between individuals were
most pronounced in the mandrills: some males and some females showed
dominant behaviours very often whereas other individuals hardly ever
did and showed a lot of subordination behaviours instead. This
reflects the well-known finding that, in species with a despotic
social system like Mandrills, the social hierarchy is much steeper
than in species with a more egalitarian social system, such as
Such differences in the magnitude of individual differences may have
an important impact on the dynamics of social groups that could also
influence speciation. The new research methodologies are therefore
important tools for comparing "personality" differences in the
entire behavioural repertoire systematically between species.
This research is part of a project funded by the German Research
Foundation (DFG, UH249/1-1).
Contact person: Dr. Jana
Uher, J. (2015e). Comparing individuals within and across
situations, groups and species: Metatheoretical and methodological
foundations demonstrated in primate behaviour. In D. Emmans & A.
Laihinen (Eds.). Comparative neuropsychology and brain imaging
(Vol. 2), Series Neuropsychology: An interdisciplinary approach.
(chapter 14, pp. 223-284). Berlin: Lit Verlag.
Last update: 18.09.2015
Keywords: Weeper capuchin (Cebus olivaceus), Mandrill (Mandrillus
sphinx), Toque macaque (Macaca sinica), Rhesus monkey (Macaca mulatta),
macaques, personality, rating, judgement, personality questionnaire,
individual differences, species differences, species comparisons,
personality dimensions, personality traits, individual behaviour,
individual-specific behaviour, individual behavior, despotic, egalitarian,
dominance hierarchy, aggressiveness, social behavior, social orientation.