Much like people, chimpanzees are inveterate conformists whose copycat tendencies enable them to develop cultural traditions, a new study suggests.
Andrew Whiten of the University of St. Andrews in Fife, Scotland, and his colleagues trained a high-ranking female in each of two chimpanzee groups to use a stick to release a food pellet from a ramp in a rectangular box.
One animal learned how to push the stick through an opening and against a block inside the box, knocking the food off the ramp so that it could roll out through a chute. The other chimp learned to manipulate the stick to lift a hook that moved the block and allowed the food to roll into the chute.
Each dominant female was then returned to her home group. Over the next 21/2 months, 30 of the remaining 32 chimps in the two groups mastered and primarily employed the stick-wielding technique that they observed in the trained animal in their group, Whiten’s group reports in an upcoming issue of Nature. The few chimps in each group that had independently discovered a method different from the one that their group adopted eventually conformed.
A third set of chimps lacking a member with stick training didn’t develop any tool-use styles during the study.
Wild chimps exhibit local traditions in tool use and social behavior (SN: 6/19/99, p. 388). The new report provides the first experimental evidence that chimps transmit traditions by copying the behavior of their peers, Whiten says.