The hundredth monkey effect is an esoteric idea claiming that a new behavior or idea is 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. The behavior was said to propagate even to groups that are physically separated and have no apparent means of communicating with each other.

Since it was first popularized, the effect has been discredited in many cases of research. One of the primary factors in the spread of this claim is that many authors quote secondary, tertiary, or post-tertiary sources that have themselves misrepresented the original observations. primatologists conducted a behavioral study of a troop of Macaca fuscata (Japanese macaque or snow monkeys) on the island of Kōjima. The researchers would supply these troops with such foods as sweet potatoes and wheat in open areas, often on beaches.

Watson first published the story in a foreword to Lawrence Blair's Rhythms of Vision (1975);

Her changed behavior led to several feeding behavior changes over the course of the next few years, all of which was of great benefit in understanding the process of teaching and learning in animal behavior. A brief account of the behavioral changes can be seen below:

  1. The young first teach their contemporaries and immediate family, who all benefit from the new behavior and teach it to their contemporaries.
  2. If the parents or their contemporaries (or their parents) are too old, they do not adopt the behavior.
  3. Once the initial group have children, a change occurs in the dynamic of the behavior from teaching previous and current generations, to a new dynamic where the next generation learns by observation. The behavior is no longer actively taught but passively observed and mimicked.
  4. The first innovator continues to innovate. The young monkey who started potato washing also learned how to sift wheat grains out of the sand by throwing handfuls of sand and wheat into the water, then catching the wheat that floated to the top. This invention was also copied using the above teaching and learning process until there were too many monkeys on the island with too little wheat apportioned, which is when competition became too fierce and the stronger monkeys would steal the collected wheat from the weaker ones, so they stopped the learned behavior in self-preservation.
  5. The innovator's sibling started another innovation whereas the monkeys were initially fearful of the ocean, only deigning to put their hands and feet into it, the wheat straining innovation led to monkeys submerging more of their bodies in the water, or play-splashing in the ocean. This behavior was again copied using the above teaching and learning processes.

The study does not indicate a catalyst ratio at which all the Koshima monkeys started washing sweet potatoes, or a correlation to other monkey studies where similar behavior started. To the contrary, it indicated that certain age groups in Koshima would not learn the behavior. Unfortunately, Keyes combined two items of truth: that the Koshima monkeys learned to wash sweet potatoes, and that the phenomenon was observed on neighboring islands. He did not provide substantiating evidence for his claims, diluting the importance of both studies and potentially discrediting the scientists involved. Combining this science with his political views may also have damaged the research credibility, leading to many reporters attempting to "debunk" the Japanese team's research without doing sufficient research themselves. This lead to the discovery of the 100 th monkey.

Later research and criticism

In many cases of research since it was first popularized, the effect has been discredited.

Ron Amundson's analysis of the pertinent literature, published by the Skeptics Society, revealed several key points that demystified the supposed effect. 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.

See also

  • Confirmation bias
  • Decline effect
  • Infinite monkey theorem
  • Meme
  • Multiple discovery
  • Tipping point (sociology)

Notes

References

Further reading

  • Amundson, Ron (1991). The Hundredth Monkey—And Other Paradigms of the Paranormal. Prometheus Books. . Includes:
  • 1985. "The Hundredth Monkey Phenomenon." Skeptical Inquirer 9(4):348–56. Also available via University of Hawaii (Archived on May 25, 2011).
  • 1987. "Watson and the Hundredth Monkey Phenomenon." Skeptical Inquirer 11(3):303–04.
  • Myers, Elaine (1985). "The Hundredth Monkey Revisited." In Context 9(Spring 1985):10–10. Archived from the original on 2012-02-06.