Social Network Analysis Shows Direct Evidence for Social Transmission of Tool Use in Wild Chimpanzees
Catherine Hobaiter, Timothee Poisot, Klaus Zuberbühler, William Hoppitt & Thibaud Gruber
| Résumé |
Social network analysis methods have made it possible to test
whether novel behaviors in animals spread through individual or
social learning. To date, however, social network analysis of wild
populations has been limited to static models that cannot precisely
reflect the dynamics of learning, for instance, the impact of
multiple observations across time. Here, we present a novel dynamic
version of network analysis that is capable of capturing temporal
aspects of acquisition-that is, how successive observations by an
individual influence its acquisition of the novel behavior. We
apply this model to studying the spread of two novel tool-use
variants, "moss-sponging'' and "leaf-sponge re-use,'' in the Sonso
chimpanzee community of Budongo Forest, Uganda. Chimpanzees are
widely considered the most "cultural'' of all animal species, with
39 behaviors suspected as socially acquired, most of them in the
domain of tool-use. The cultural hypothesis is supported by
experimental data from captive chimpanzees and a range of
observational data. However, for wild groups, there is still no
direct experimental evidence for social learning, nor has there
been any direct observation of social diffusion of behavioral
innovations. Here, we tested both a static and a dynamic network
model and found strong evidence that diffusion patterns of
moss-sponging, but not leaf-sponge re-use, were significantly
better explained by social than individual learning. The most
conservative estimate of social transmission accounted for 85% of
observed events, with an estimated 15-fold increase in learning
rate for each time a novice observed an informed individual
moss-sponging. We conclude that group-specific behavioral variants
in wild chimpanzees can be socially learned, adding to the evidence
that this prerequisite for culture originated in a common ancestor
of great apes and humans, long before the advent of modern
humans. |
| Citation | Hobaiter, C., Poisot, T., Zuberbühler, K., Hoppitt, W., & Gruber, T. (2014). Social Network Analysis Shows Direct Evidence for Social Transmission of Tool Use in Wild Chimpanzees. Plos Biology, 12(9). |
| Type | Article de périodique (Anglais) |
| Date de publication | 2014 |
| Nom du périodique | Plos Biology |
| Volume | 12 |
| Numéro | 9 |