Fission-Fusion Dynamics, Behavioral Flexibility, and Inhibitory Control in Primates

Abstract

The Machiavellian Intelligence or Social Brain Hypothesis explains the evolution of increased brain size as mainly driven by living in complex organized social systems in which individuals represent "moving targets" who can adopt multiple strategies to respond to one another. Frequently splitting and merging in subgroups of variable composition (fission-fusion or FF dynamics) has been proposed as one aspect of social complexity ( compare with) that may be associated with an enhancement of cognitive skills like inhibition, which allows the suppression of prepotent but ineffective responses in a changing social environment. We compared the performance of primates experiencing high levels of FF dynamics (chimpanzees, bonobos, orangutans, and spider monkeys) to that of species living in more cohesive groups (gorillas, capuchin monkeys, and long-tailed macaques) on five inhibition tasks. Testing species differing in diet, phylogenetic relatedness, and levels of FF dynamics allowed us to contrast ecological, phylogenetic, and socioecological explanations for interspecific differences. Spider monkeys performed at levels comparable to chimpanzees, bonobos, and orangutans, and better than gorillas. A two-cluster analysis grouped all species with higher levels of FF dynamics together. These findings confirmed that enhanced inhibitory skills are positively associated with FF dynamics, more than to phylogenetic relations or feeding ecology.

Variation in withholding of information in three monkey species

“…Such a good level of inhibition may seem to be at odds with previous studies, indicating that macaques perform worse than other primates in tasks requiring inhibition (AlbiachSerrano et al 2007;Amici et al 2008). One possible explanation is that although macaques perform relatively poorly in non-social-inhibition tasks, they might excel at inhibition in the social domain.…”

Triadic social interactions operate across time: a field experiment with wild chimpanzees

“…Taking these two cognitive tasks together, the increase in the number of potential bonding partners and the relative transience of distantly related bonded relationships compared with close kin relationships, we suggest that for chimpanzees, keeping track of others' less conspicuous bonded relationships is likely to require more frequent monitoring effort of their social environment than in species that predominantly rely on close kin bonds. The monitoring task is further complicated, however, by the fission -fusion nature of the chimpanzee's social structure, where not everybody can be monitored all the time [44,56].…”

“…Evidence that triadic interventions can be delayed over time implies that social events that happen hours apart, and even involving different individuals, may nonetheless be connected in an animals' mind. Whether this capacity has evolved in species where group members are not always visible to each other, such as for animals living in fission-fusion social groups [44,56], or is more widespread, remains to be tested. Nonetheless, these results have considerable implications when examining animal behaviour and social cognition.…”

Evolutionary pressures on primate intertemporal choice

“…established indifference) between the two options. Other studies either used different reward amounts (one versus three food rewards [29]) or used other adjusting procedures to calculate discounting functions from which I could estimate an indifference point [32,33]. Rhesus macaque experiments [32,33] used liquid food rewards (water or juice), whereas all other experiments involved solid food rewards.…”