Chimps show “social conformity,” researchers find
Aug. 22, 2005
and World Science staff
Social conformity—a desire
to act, talk, dress and even think like everyone else—is a human tendency that
has helped glue societies together for ages, while perennially irritating some
of the greatest philosophers, scientists, artists and other thinkers.
Now, researchers have found
we share this monkey-see-monkey-do tendency with—perhaps unsurprisingly—chimps.
This shows conformity has deep evolutionary roots, the researchers claim.
The research, conducted by U.S. and British
scientists, is published in the current online edition of the research journal Nature.
During the study, three groups of chimpanzees at the Yerkes National Primate Research Center of Emory
University in Atlanta, Ga., were presented with a problem also known to their wild cousins: an attractive food item was stuck just out of reach, behind a blockage.
This was achieved by a system of tubes the researchers called the
Unseen by their group-mates, one chimpanzee from each of two of the groups was shown a different way to use a stick to retrieve the food. One chimpanzee was taught to use the tool to lift the blockage up so the food fell towards her, while the other was trained instead to poke the blockage, pushing it so the food fell backwards and rolled down another pipe into her waiting hand.
These two chimpanzees were then reunited with their respective groups and soon started to apply their newly-learned techniques to the Pan-pipes task.
The researchers said they wanted to find out whether the other chimpanzees would learn by observation the technique used by their local expert, and thus establish different traditions in the two groups.
“Chimpanzees in the wild show numerous local traditions described as ‘ape culture’, but it is almost impossible to prove that these traditions are actually passed on by each chimpanzee learning from others,” as is the case in humans,
said Andrew Whiten of the University of St. Andrews in Fife, U.K, one of the
researchers. “It is hard to do the necessary experiments with wild chimpanzees.”
The chimpanzees proved keen observational learners, according to the scientists.
Members of a chimp group gathered around the local expert, watched attentively and were then successful when allowed to try the task on their own.
The third group of chimpanzees, which did not have the benefit of a local expert and was left to solve the task on its own, was
unable to retrieve food from the pipes.
In contrast, in the first experimental group the expert’s ‘Lift’ technique was soon adopted, while the ‘Poke’ method spread in the second group. When tested two months later, this difference in group traditions was still in
place, the researchers found. This is the first experimental evidence for the spread and maintenance of traditions in any
primate, they claimed.
Chimps “ copy members of their own species and they develop different traditions by doing so,” said
the university’s Victoria Horner, another of the researchers.
“It makes it likely differences in tool use between wild chimpanzee communities in Africa indeed reflect a form of culture and establishes another link between human and chimpanzee societies.”
Finding a conformity bias was an unexpected, but important, result of the culture study, according to the researchers.
A few members of each group independently discovered the alternative method for freeing food from the Pan-pipes, but this knowledge did not endanger the groups’ traditions because most of these chimpanzees reverted back to the norm set by their local expert. “Choosing the group norm over the alternative method shows a level of conformity we usually associate only with our own species,” said Horner.
“These results suggest an ancient origin for the cultural conformism that is so evident in humans,”
said Emory University’s Frans de Waal, another member of the research team. “Further research may reveal this tendency to be more widespread in the animal kingdom.”
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