Cultural innovation and transmission of tool use in wild chimpanzees: evidence from field experiments

Abstract

Chimpanzees (Pan troglodytes) are the most proficient and versatile users of tools in the wild. How such skills become integrated into the behavioural repertoire of wild chimpanzee communities is investigated here by drawing together evidence from three complementary approaches in a group of oil-palm nut- ( Elaeis guineensis) cracking chimpanzees at Bossou, Guinea. First, extensive surveys of communities adjacent to Bossou have shown that population-specific details of tool use, such as the selection of species of nuts as targets for cracking, cannot be explained purely on the basis of ecological differences. Second, a 16-year longitudinal record tracing the development of nut-cracking in individual chimpanzees has highlighted the importance of a critical period for learning (3-5 years of age), while the similar learning contexts experienced by siblings have been found to result in near-perfect (13 out of 14 dyads) inter-sibling correspondence in laterality. Third, novel data from field experiments involving the introduction of unfamiliar species of nuts to the Bossou group illuminates key aspects of both cultural innovation and transmission. We show that responses of individuals toward the novel items differ markedly with age, with juveniles being the most likely to explore. Furthermore, subjects are highly specific in their selection of conspecifics as models for observation, attending to the nut-cracking activities of individuals in the same age group or older, but not younger than themselves. Together with the phenomenon of inter-community migration, these results demonstrate a mechanism for the emergence of culture in wild chimpanzees.

Primate archaeology reveals cultural transmission in wild chimpanzees (Pan troglodytes verus)

“…B 370: 20140348 remained difficult to ascertain due to the time consuming challenge of habituating several wild chimpanzee communities. Only a few immigration events have been observed in the past, which have added valuable information to understanding the transmission of social knowledge between chimpanzee communities [44,48,49,52]. Previous studies conducted in three neighbouring chimpanzee communities in the Taï National Park demonstrated that cultural traits were maintained in neighbouring groups despite regular individual transfer [42].…”

“…This could be a reason why innovations and also behaviour of immigrants does not seem to spread throughout the group. Only if innovators persist can they add to the behavioural pool by disseminating their innovations once they are older [48,76]. However, the ontogeny of cultural traits within a community remains a topic of investigation as only a few studies have reported the spread of new behaviours within a chimpanzee community [13,49].…”

“…Conformist transmission mechanisms in chimpanzees are supported by an increasing body of research that shows how conformity plays an important role in social learning strategies in a variety of wild ranging animal species [45][46][47]. Some studies have begun to thoroughly investigate how cultural transmission in wild chimpanzees may occur [42,48,49], yet how and why chimpanzees adopt certain behavioural traits and abandon their previous behaviour remain largely unknown [50,51]. With this study, we are aiming to investigate further whether immigrating females actively change their nut-cracking behaviour to match the tool selection of their new groups despite previously having acquired different preferences.…”

Faithful replication of foraging techniques along cultural transmission chains by chimpanzees and children

“…Matsuzawa and colleagues (8,10,25,26) have pioneered an ''outdoor laboratory'' to document the transmission of nut-cracking behavior in the wild, but the logistics of such studies have limited the application of control conditions possible in captive experiments, in which some chimpanzees see no model, allowing a more conclusive establishment of the role of social learning.…”

Escolha de alvos coespecíficos na observação do uso de ferramentas por macacos-prego (Cebus libidinosus) selvagens

“…Cerca 17% dos episódios foram observados por coespecíficos. Como em chimpanzés (Biro et al, 2003), os indivíduos observadores foram na maioria, mais jovens que os alvos.…”