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

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.culture ͉ diffusion chain ͉ social learning ͉ tradition L ong-term observational studies of wild chimpanzees (Pan troglodytes) across Africa have revealed a diverse range of behavioral differences between populations, thought to represent local traditions (1-3). The inference that the differences are socially learned is based on (i) patterns of distribution that appear incompatible with genetic or simple environmental explanations; (ii) records of close observation of adults by infants as well as matching of mother-offspring foraging styles (4-7); and (iii) studies of both wild (8-10) and captive chimpanzees (11)(12)(13)(14)(15) showing that social learning from conspecifics can affect the acquisition of tool-use skills. Each wild chimpanzee community exhibits a distinct profile defined by several different kinds of putative traditions that have been described as cultures.

Limitations to the cultural ratchet effect in young children

“…across generations as well, and that the fidelity of transmission increases with age (see Flynn, 2008, for similar results with 2-and 3-year-olds, and see Horner et al, 2006, for a comparison of children to chimpanzees). In contrast, McGuigan and Graham (2009) found that 3-year-olds copied irrelevant actions in diffusion chains more robustly than did 5-year olds.…”

Cultural Evolution: A Review of Theory, Findings and Controversies

“…An initial suggestion that non-human species lack high-fidelity imitation, i.e. the copying of motor actions (Tomasello et al 1993), failed to find support when chimpanzees were shown able to faithfully transmit behaviours through captive groups (Horner et al 2006). Recent work has instead implicated multiple factors as being jointly necessary.…”

End state copying by humans (Homo sapiens): Implications for a comparative perspective on cumulative culture.

“…However, regardless of the mechanisms believed to be responsible, it is undisputed that the behaviors involved can transmit between chimpanzees with remarkably high fidelity (Tennie et al, 2009). Horner, Whiten, Flynn, & de Waal (2006), using a lift/slide door apparatus, found that chimpanzees were capable of copying the actions of conspecific models with such fidelity that the two alternative techniques were each faithfully transmitted along chains of task-naive chimpanzees, one of which was four "generations" long, and the other five. The remarkable copying by chimpanzees has also been shown to allow introduced behavioral variants to spread through social groups under more naturalistic conditions, creating captive behavioral traditions Whiten et al, 2007).…”