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

• Authors: Victoria Horner, Emory University; Andrew Whiten, University of St. Andrews; Emma Flynn, University of St. Andrews; Frans B M De Waal, Emory University
• Journal Title: Proceedings of the National Academy of Sciences
• Volume: Volume 103, Number 37
• Publisher: National Academy of Sciences | 2006-09-12, Pages 13878-13883
• Type of Work: Article | Post-print: After Peer Review
• Publisher DOI: http://doi.org/10.1073/pnas.0606015103
• Subjects: Psychology, General
• Keywords: culture; diffusion chain; social learning; tradition

Abstract

Observational studies of wild chimpanzees (Pan troglodytes) have revealed population-specific differences in behavior, thought to represent cultural variation. Field studies have also reported behaviors indicative of cultural learning, such as close observation of adult skills by infants, and the use of similar foraging techniques within a population over many generations. Although experimental studies have shown that chimpanzees are able to learn complex behaviors by observation, it is unclear how closely these studies simulate the learning environment found in the wild. In the present study we have used a diffusion chain paradigm, whereby a behavior is passed from one individual to the next in a linear sequence in an attempt to simulate intergenerational transmission of a foraging skill. Using a powerful three-group, two-action methodology, we found that alternative methods used to obtain food from a foraging device (“lift door” versus “slide door”) were accurately transmitted along two chains of six and five chimpanzees, respectively, such that the last chimpanzee in the chain used the same method as the original trained model. The fidelity of transmission within each chain is remarkable given that several individuals in the no-model control group were able to discover either method by individual exploration. A comparative study with human children revealed similar results. This study is the first to experimentally demonstrate the linear transmission of alternative foraging techniques by non-human primates. Our results show that chimpanzees have a capacity to sustain local traditions across multiple simulated generations.