The Hundredth Monkey is an urban legend referring to the instantaneous, supernatural spread of a learned behaviour, from one isolated group of animals to all related animals, all across the world.

The popular version of the story originated with Lyall Watson in his 1979 book Lifetide. In it he claimed to describe the observations of scientists studying macaques (a type of monkey) on the Japanese island of Koshima in 1952. Some of these monkeys learned to wash sweet potatoes, and gradually this new behavior spread through the younger generation of monkeys in a normal fashion; through observation and repetition. However, according to Watson the researchers noted that once a critical mass of monkeys was reached - the so-called hundredth monkey - this previously learned behaviour instantly and supernaturally spread across the water to monkeys on nearby islands.

This story was further popularized by Ken Keyes with the publication of his book The Hundredth Monkey. Keyes used the hundredth monkey story as an inspirational and perhaps paranormal parable of cultural transformation and social change. Since then, this story has become widely accepted as fact, and has even appeared in books written by some educators.

In 1985, Elaine Myers revisited the original published research in 'The Hundredth Monkey Revisited' in the journal In Context. Although she reports the first part of the story as true, she found that the original research by the Japan Monkey Center in vol. 2, 5 and 6 of the journal Primates differs from Watson's story in significant ways. The hundredth monkey phenomenon does not exist. The published articles only describe how the sweet potato washing behavior gradually spread through the monkey troop and became part of the set of learned behaviors of young monkeys. There is no evidence at all of a magical number where the idea suddenly spread through the whole troop, let alone to other islands. None of the original researchers ever made any such claim. [1]

The story has become a favorite target of the Committee for the Scientific Investigation of Claims of the Paranormal and was used as the title essay in The Hundredth Monkey: And Other Paradigms of the Paranormal published by them in 1991.

But despite the factual inaccuracies in the story as told by Watson and Keyes, it is still popular among New Age authors and personal growth gurus and has become a permanent part of the cultural lexicon and mythology. The story lives on and continues to inspire positive social and environmental change. This was likely its original intent, and is certainly its most important legacy.

External links

• The Hundredth Monkey Phenomenon article from the Skeptic's Dictionary
• The Hundredth Monkey Revisited - article by Elaine Myers
• Senior Researcher Comments on the Hundredth Monkey Phenomenon in Japan - article in the Skeptical Inquirer