Influence of personality, age, sex, and estrous state on chimpanzee problem-solving success

Abstract

Despite the importance of individual problem solvers for group- and individual-level fitness, the correlates of individual problem-solving success are still an open topic of investigation. In addition to demographic factors, such as age or sex, certain personality dimensions have also been revealed as reliable correlates of problem-solving by animals. Such correlates, however, have been little-studied in chimpanzees. To empirically test the influence of age, sex, estrous state, and different personality factors on chimpanzee problem-solving, we individually tested 36 captive chimpanzees with two novel foraging puzzles. We included both female (N = 24) and male (N = 12) adult chimpanzees (aged 14–47 years) in our sample. We also controlled for the females’ estrous state—a potential influence on cognitive reasoning—by testing cycling females both when their sexual swelling was maximally tumescent (associated with the luteinizing hormone surge of a female’s estrous cycle) and again when it was detumescent. Although we found no correlation between the chimpanzees’ success with either puzzle and their age or sex, the chimpanzees’ personality ratings did correlate with responses to the novel foraging puzzles. Specifically, male chimpanzees that were rated highly on the factors Methodical, Openness (to experience), and Dominance spent longer interacting with the puzzles. There was also a positive relationship between the latency of females to begin interacting with the two tasks and their rating on the factor Reactivity/Undependability. No other significant correlations were found, but we report tentative evidence for increased problem-solving success by the females when they had detumescent estrous swellings.

Stability of the guinea pigs personality – cognition – linkage over time

“…An analysis of the linkage between personality traits and performance in cognitive tasks in animals has recently started and to date some results are available across species (e.g. Benus et al 1987;Hopper et al 2014;Tebbich et al 2012;Verbeek et al 1994). …”

Chimpanzees demonstrate individual differences in social information use

“…It is somewhat surprising that we did not find evidence that age had an effect upon social learning, given the evidence that young individuals undergo an enhanced “sensitive period” in social learning behaviour (Biro et al 2003) and elderly individuals decline in social cognition (Lacreuse et al 2014, although see; Hopper et al 2014). Perhaps while there may be an early sensitive period in chimpanzees’ proclivity for social learning, once passed, social learning may remain relatively stable over the rest of their lives.…”

“…Furthermore, wild baboons that were scored most highly on ‘boldness’ or ‘anxious’ traits were found to show a greater improvement on a foraging task after observing a demonstrator (Carter et al 2014). In addition, Hopper et al (2014) found that certain chimpanzee personality traits (‘methodical’, ‘openness’ and ‘dominance’) are associated with success in asocial learning paradigms. Examining personality in parallel with performance across a broad range of social learning tasks would be useful in exploring how proclivity for social information use fits into the broader tapestry of chimpanzee personality traits.…”

“…Whiten et al 2005; Watson et al 2017; Kendal et al 2015) demonstrating that social learning occurs throughout chimpanzee lifespans (for a review, see Whiten and van de Waal 2018). Moreover, it should also be noted that a chimpanzees’ age has been found not to correlate with success in problem-solving in non-social contexts (Hopper et al 2014). …”

Personality influences responses to inequity and contrast in chimpanzees

“…In particular, studies of nonhuman primate species show that they have stable, consistent personalities (Massen et al, 2013; Morton et al, 2013; for a review in nonhuman primates see Freeman & Gosling, 2010), which also correlate with their responses in behavioural experiments (e.g. Hopper, Price, et al, 2014; Massen et al, 2013). The personality dimensions that have been identified to apply to nonhuman primates include some dimensions that are more social (e.g.…”