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The Imitation Factor

Imo the Amazing

Imo the Japanese macaque holds a special place in the hearts of those who study the cultural transmission of behavior. Her story starts innocently enough on Koshima Islet, Japan, in September 1953, when Imo, only a year old, added a new behavior to her repertoire: she washed the sweet potatoes that researchers provided her in a nearby brook before she ate them. Soon enough, many of Imo's peers and relatives had learned the art of potato washing from out pioneer Epicurean. By 1959, most infants in Imo's group intently watched their moms, many of whom had acquired Imo's habit, and learned to wash their own sweet potatoes at early ages.

Imo was more than a shooting star that had a brief moment of glory, only to fade into obscurity. When she was four, she outdid herself by introducing an even more complicated new behavior into her group. In addition to the sweet potatoes that monkeys on Koshima Islet were given, they were also occasionally treated to wheat. The problem was that wheat was usually provisioned to the monkeys on a sandy beach, and wheat and sand mixed together is not nearly as tasty as a plain helping of wheat. So Imo came up with a novel solution: she tossed her wheat and sand mixture into the water. The sand sank, the wheat floated. Imo had done it again! as with the sweet potatoes, it was only a matter of time before her groupmates learned this handy trick from Imo. It took a bit longer for this trait to spread through the population, but, of course, it was trickier than washing sweet potatoes, at least from a monkey's perspective. Monkeys aren't good at letting go of food once they get their paws on it, so it was tough to learn to throw the wheat and sand combination into the water. But eventually this new behavioral trait was spread to many group members by imitation and cultural transmission.

Imo's escapades, and the cultural transmission of behaviors she fostered, garnered worldwide attention. This was one of the first examples of a newly introduced behavior's spreading through a population of animals. In addition, primates are clever, and so although many didn't believe we would ever find evidence of culture in animals, we could be somewhat comforted that the first strong evidence came from a smart animal. But perhaps just as important, the new behavior - washing food - seemed eerily human-like. It doesn't take much imagination to picture our human ancestors learning the same trait, in a similar manner, hundreds of thousands of years ago.

I think I picked up The Imitation Factor from the New York Times book section, as well. This little, not so well-written book was a fascinating read and made me think a lot.

©2005 karenika.com