Chimps Can Learn and Teach Cultural Traditions

ST. ANDREWS, Scotland, June 11, 2007 (ENS) - Chimpanzee communities can adopt their own local customs and maintain their own "multiple-tradition cultures," an international team of researchers has found. The study demonstrates that chimpanzees, like people, can acquire new traditions, and spread those new "cultural practices" to other groups.

Led by primatologists at the University of St. Andrews, the researchers introduced novel forms of behavior into different chimpanzee communities to test the theory that behaviors such as foraging habits are passed on by observation and learning.

They found that, after a period of time, unique cultures developed within different communities and new traditions spread from one group to another.

Once chimps have learned a method of doing something, such as a unique way of finding food or using a tool, they have the ability to pass on this novel tradition to members of their own group as well as to neighboring communities, the scientists discovered.

"What makes any two human cultures different?" asked Andrew Whiten, a professor of evolutionary and developmental psychology at St. Andrews who led the study.

"Usually," he said, "the answer will lie in a set of traditional practices that set them apart. We have robust evidence that in chimpanzees there is a considerable capacity for cultural spread of innovations."

Chimpanzees at Edinburgh Zoo work on a version of one of the tool-using problems presented by researchers. (Photo courtesy University of St. Andrews)

It was in 1999 that an international collaboration led by St. Andrews researchers suggested that chimpanzees lead a rich cultural life with different traditions unique to each community.

Documented examples of behavioral differences among chimpanzees in the wild include various types of tool use, including hammers and pestles; social behaviors such as overhead hand-clasping during mutual grooming; courtship rituals involving leaves being noisily clipped with the teeth; and methods for eradicating parasites by either stabbing or squashing them.

While this discovery suggests that local cultures exist in different communities of chimpanzees across Africa, it has proved difficult to demonstrate that behaviors are passed on by observation and learning, as opposed to genetics or other environmental factors.

Dr. Andrew Whiten is professor of evolutionary and developmental psychology at University of St. Andrews.(Photo courtesy U. St. Andrews)

They tackled the problem by "seeding" novel forms of tool use and food extraction in chimpanzee communities at Yerkes and Texas. Over time, the researchers saw 10 of these new behaviors spread and become full-fledged, local "traditions."

As a result, the communities at Yerkes and the University of Texas now display their own unique cultures.

At the University of Texas, where several groups are next-door neighbors within sight of each other, four of the new traditions were passed on. The newly-learned foraging practices spread from one group to another, and then onto a third.

The findings have important implications for understanding the ability of primates to adapt over time.

"Our study proves that chimpanzees have the capacity to sustain the kinds of multiple-tradition cultures that field researchers believe exist in Africa, suggesting in turn that our common ancestor of five to six million years ago already had this level of cultural complexity.

"Social learning is important for evolutionary adaptation because it can be so much faster than that which occurs through genetic change; and, unlike learning by one's own efforts - for example, by trial and error - it can be very efficient because one is standing on the shoulders of what previous generations achieved," said Professor Whiten.

The research, which was supported by the Biotechnology and Biological Sciences Research Council and the Royal Society, is published by "Current Biology" online.

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