Hundredth monkey effect
The hundredth monkey effect is a hypothetical phenomenon in which a new behavior or idea is claimed to spread rapidly by unexplained means from one group to all related groups once a critical number of members of one group exhibit the new behavior or acknowledge the new idea.
One of the primary factors in the promulgation of the story is that many authors quote secondary, tertiary or post-tertiary sources which have themselves misrepresented the original observations.
Popularisation of the effect
The story of the hundredth monkey effect was published in Lyall Watson's foreword to Lawrence Blair's Rhythms of Vision in 1975, and spread with the appearance of Watson's 1979 book Lifetide. The account is that unidentified scientists were conducting a study of macaque monkeys on the Japanese island of Koshima in 1952. These scientists observed that some of these monkeys learned to wash sweet potatoes, and gradually this new behavior spread through the younger generation of monkeys—in the usual fashion, through observation and repetition. Watson then concluded that the researchers observed that once a critical number of monkeys was reached, i.e., the hundredth monkey, this previously learned behavior instantly spread across the water to monkeys on nearby islands.
This story was further popularised by Ken Keyes, Jr. with the publication of his book The Hundredth Monkey. Keyes's book was about the devastating effects of nuclear war on the planet. Keyes presented the hundredth monkey effect story as an inspirational parable, applying it to human society and the effecting of positive change.
The original research
In 1985, Elaine Myers re-examined the original published research in "The Hundredth Monkey Revisited" in the journal In Context. In her review she found that the original research reports by the Japan Monkey Center in Vol. 2, 5, and 6 of the journal Primates are insufficient to support Watson's story. In short, she is suspicious of the existence of a hundredth monkey phenomenon; the published articles describe how the sweet potato washing behavior gradually spread through the monkey troupe and became part of the set of learned behaviors of young monkeys, but Myers does not agree that it serves as evidence for the existence of a critical number at which the idea suddenly spread to other islands.
The story as told by Watson and Keyes is popular among New Age authors and personal growth gurus and has become an urban legend and part of New Age mythology. Also, Rupert Sheldrake has cited that a phenomenon like the hundredth monkey effect would be evidence of morphic fields bringing about non-local effects in consciousness and learning. As a result, the story has also 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 the Committee in 1990.
The effect discredited
An analysis of the appropriate literature by Ron Amundson, published by the Skeptics Society, revealed several key points that demystified the supposed effect.
Unsubstantiated claims that there was a sudden and remarkable increase in the proportion of washers in the first population were exaggerations of a much slower, more mundane effect. Rather than all monkeys mysteriously learning the skill it was noted that it was predominantly younger monkeys that learned the skill from the older monkeys through observational learning, which is widespread in the animal kingdom; older monkeys who did not know how to wash tended not to learn. As the older monkeys died and younger monkeys were born the proportion of washers naturally increased. The time span between observations by the Japanese scientists was on the order of years so the increase in the proportion was not observed to be sudden.
Claims that the practice spread suddenly to other isolated populations of monkeys may be called into question given the fact that at least one washing monkey swam to another population and spent about four years there and also the monkeys had the researchers in common. Amundson also notes that the sweet potato was not available to the monkeys prior to human intervention. The number of monkeys in the colony was counted as 59 in 1962 indicating that even in numbers no "hundredth monkey" existed.
- Amundson, Ron (Summer 1985). Kendrick Frazier, ed. "The Hundredth Monkey Phenomenon". Skeptical Inquirer: 348–356.
- Blair, Lawrence (1975). Rhythms of Vision: The Changing Patterns of Belief. London: Croom Helm Ltd. ISBN 978-0-8052-3610-1.
- Blair, unlike Watson, does not assign the date 1952 to the observations.
- Keyes, Ken (1984). The Hundredth Monkey. Camarillo: DeVorss & Co. ISBN 0-942024-01-X.
- Whiten, Andrew; J. Goodall; W. C. McGrew; T. Nishida; V. Reynolds; Y. Sugiyama; C. E. G. Tutin; R. W. Wrangham; C. Boesch (1999). "Cultures in chimpanzees". Nature. 399 (6737): 682–685. PMID 10385119. doi:10.1038/21415.
- Boesch, Christophe (2012). "31. Culture in primates. A - Culture as it Happens". In Jaan Valsiner. The Oxford Handbook of Culture and Psychology (PDF). OUP. p. 678. ISBN 9780195396430. Retrieved Feb 2014. Check date values in:
- Trivedi, Bijal P. (February 6, 2004). ""Hot Tub Monkeys" Offer Eye on Nonhuman "Culture"". National Geographic Channel October 28, 2010/National Geographic. Retrieved Feb 2014. Check date values in:
- Galef, B. G. (1992). "The question of animal culture". Human Nature. 3 (2): 157–178. doi:10.1007/BF02692251.
- Carroll, Robert Todd (2005). "The Hundredth Monkey Phenomenon". Skeptic's Dictionary.
- Myers, Elaine (Spring 1985). "The Hundredth Monkey Revisited". In Context.
- Pössel, Markus; Amundson, Ron (May–June 1996). "Senior Researcher Comments on the Hundredth Monkey Phenomenon in Japan". Skeptical Inquirer. Archived from the original on 2004-08-03.
- Amundson, Ron (Summer 1985). Kendrick Frazier, ed. "The Hundredth Monkey Phenomenon". Skeptical Inquirer. Prometheus Books: 348–356. ISBN 0-87975-655-1.
Reprinted in The Hundredth Monkey—And Other Paradigms of the Paranormal (1991)(see online version under External links)
- Amundson, Ron (Spring 1987). Kendrick Frazier, ed. "Watson and the Hundredth Monkey Phenomenon,". Skeptical Inquirer. Prometheus Books: 303–304. ISBN 0-87975-655-1.
Reprinted in The Hundredth Monkey—And Other Paradigms of the Paranormal (1991)
- "The Hundredth Monkey Phenomenon", Ron Amundson's copy of his Skeptical Inquirer article of 1985