Individual acquisition of “stick pounding” behavior by naïve chimpanzees

• Published in: American journal of primatology Vol. 81; no. 6; pp. e22987 - n/a
• Main Authors: Bandini, Elisa, Tennie, Claudio
• Format: Journal Article
• Language: English
• Published: United States Wiley Subscription Services, Inc 01.07.2019
• Subjects: Ability; Accuracy; Animal behavior; Animals; Behavior; chimpanzee behavior; Chimpanzees; Fidelity; Hypotheses; individual learning; Innovations; Learning; Observational learning; Pan troglodytes; Pan troglodytes - psychology; Populations; Pounding; Primates; Social Behavior; Social discrimination learning; Social learning; Tool Use Behavior; tool‐use; Wildlife; zone of latent solutions; social learning; zone of latent solutions; chimpanzee behavior; individual learning; tool-use
• ISSN: 0275-2565; 1098-2345; 1098-2345
• DOI: 10.1002/ajp.22987

Many studies investigating culture in nonhuman animals tend to focus on the inferred need of social learning mechanisms that transmit the form of a behavior to explain the population differences observed in wild animal behavioral repertoires. This research focus often results in studies overlooking the possibility of individuals being able to develop behavioral forms without requiring social learning. The disregard of individual learning abilities is most clearly observed in the nonhuman great ape literature, where there is a persistent claim that chimpanzee behaviors, in particular, require various forms of social learning mechanisms. These special social learning abilities have been argued to explain the acquisition of the relatively large behavioral repertoires observed across chimpanzee populations. However, current evidence suggests that although low‐fidelity social learning plays a role in harmonizing and stabilizing the frequency of behaviors within chimpanzee populations, some (if not all) of the forms that chimpanzee behaviors take may develop independently of social learning. If so, they would be latent solutions—behavioral forms that can (re‐)emerge even in the absence of observational opportunities, via individual (re)innovations. Through a combination of individual and low‐fidelity social learning, the population‐wide patterns of behaviors observed in great ape species are then established and stably maintained. This is the Zone of Latent Solutions (ZLS) hypothesis. The current study experimentally tested the ZLS hypothesis for pestle pounding, a wild chimpanzee behavior. We tested the reinnovation of this behavior in semi‐wild chimpanzees at Chimfunshi Wildlife Orphanage in Zambia, Africa, (N = 90, tested in four social groups). Crucially, all subjects were naïve to stick pounding before testing. Three out of the four tested groups reinnovated stick pounding—clearly demonstrating that this behavioral form does not require social learning. These findings provide support for the ZLS hypothesis alongside further evidence for the individual learning abilities of chimpanzees. Chimpanzees spontaneously use stick tools and pounding action to retrieve food from a testing apparatus. HIGHLIGHTS Naïve chimpanzees were provided the materials for wild pestle pounding behavior. Chimpanzees spontaneously demonstrated the same behavioral form as wild counterparts. Individual learning, contra to previous claims, is sufficient to drive this behavioral form in chimpanzees.