Hundredth monkey effect

Last updated December 22, 2023

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.^[1]

Since it was first popularized, the effect has been discredited in many cases of research.^[1]^[2]^[3]^[4]^[5] One of the primary factors in the spread of this concept is that many authors quote secondary, tertiary, or post-tertiary sources that have themselves misrepresented the original observations.^[1]

History

The 'hundredth monkey' effect was popularized in the mid-to-late 1970s by Lyall Watson, who documented the findings of several Japanese primatologists from the 1950s.^[1]

Watson (1970s)

Between 1952 and 1953,^{[lower-roman 1]} primatologists conducted a behavioral study of a troop of Macaca fuscata (Japanese 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.^[1] An unanticipated byproduct of the study was that the scientists witnessed several innovative evolutionary behavioral changes by the troop, two of which were orchestrated by one young female, and the others by her sibling or contemporaries. The account of only one of these behavioral changes spread into a phenomenon (i.e., the 'hundredth monkey effect'), which Watson would then loosely publish as a story.^[1]

According to Watson, the scientists observed that some of the monkeys learned to wash sweet potatoes, initially through an 18-month-old female member (named "Imo" by the researchers) of the troop in 1953. Imo discovered that sand and grit could be removed from the potatoes by washing them in a stream or in the ocean. Gradually, this new potato-washing habit spread through the troop—in the usual fashion, through observation and repetition. (Unlike most food customs, this behavior was learned by the older generation of monkeys from younger ones.)^[1]

This behavior spread up until 1958, according to Watson, when a sort of group consciousness had suddenly developed among the monkeys, as a result of one last monkey learning potato washing by conventional means (rather than the one-monkey-at-a-time method prior). Watson 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.^[1]^[6]

Watson first published the story in a foreword to Lawrence Blair's Rhythms of Vision (1975);^[6] the story then spread with the appearance of Watson's 1979 book Lifetide: The Biology of the Unconscious .

Original research (1950s)

The original Koshima research was undertaken by a team of scientists as a secondary consequence of 1948 research on semi-wild monkeys in Japan. The Koshima troop was identified as segregated from other monkeys and, from 1950, used as a closed study group to observe wild Japanese macaque behavior. While studying the group, the team would drop sweet potatoes and wheat on the beach and observe the troop's behavior. In 1954, a paper was published indicating the first observances of one monkey, Imo, washing her sweet potatoes in the water.^[7]

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:

The young first teach their contemporaries and immediate family, who all benefit from the new behavior and teach it to their contemporaries.
If the parents or their contemporaries (or their parents) are too old, they do not adopt the behavior.
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.
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.
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.

Keyes (1984)

This story was further popularized by Ken Keyes Jr. with the publication of his book The Hundredth Monkey (1984). 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.^[8] 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.

Later research and criticism

In many cases of research since it was first popularized, the effect has been discredited.^[1]^[2]^[3]^[4]^[5] One of the primary factors in the spread of this concept is that many authors quote secondary, tertiary, or post-tertiary sources that have themselves misrepresented the original observations.^[1]

Separate papers make mention that, from 1960 onward, similar sweet potato-washing behaviors were noticed in other parts of the world, however this is not directly attributed to Koshima. Claims are made that a monkey swam from one island to another where he taught the resident monkeys how to wash sweet potatoes. No mention of the other behavioral improvements are made and no indication of how the monkey swam—the Koshima monkeys cannot swim. Therefore, although the question must be asked how the swimming monkey learned the sweet potato washing behavior if not from Koshima, no indication is made as to where the monkey learned the behavior.^{[ citation needed ]}

In 1985, Elaine Myers re-examined the original published research in an article for the journal In Context.^[3] In her review, she found that the original research reports by the Japan Monkey Centre in the 2nd, 5th, and 6th volumes of Primates were 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 troop 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, as well as becoming an urban legend and part of New Age mythology. Moreover, 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.^{[ citation needed ]}

In his book Why People Believe Weird Things (1997), Michael Shermer explains how the urban legend started, was popularized, and has since been discredited.

The original research continues to prove useful in the study of cultural transmission in animals.^[9]^[10]^[11]

An analysis of the appropriate literature by Ron Amundson, published by The Skeptics Society, revealed several key points that demystified the supposed effect.^[1] Claims that the practice spread suddenly to other isolated populations of monkeys may be called into question given the fact that the monkeys had the researchers in common. Amundson also notes that the sweet potato was not available to the monkeys prior to human intervention. Moreover, the number of monkeys in the colony was counted as 59 in 1962, indicating that even in numbers no "hundredth monkey" existed.^[1]^[4]^[5]

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 a learned skill, which is widespread in the animal kingdom;^[4] 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.^[4]

Notes

↑ Lawrence Blair, unlike Watson, does not assign the date 1952 to the observations.^{[ citation needed ]}

Related Research Articles

Ethology is a branch of zoology that studies the behaviour of non-human animals, usually with a scientific focus on behaviour under natural conditions, and viewing behaviour as an evolutionarily adaptive trait. Behaviourism as a term also describes the scientific and objective study of animal behavior, usually referring to measured responses to stimuli or to trained behavioral responses in a laboratory context, without a particular emphasis on evolutionary adaptivity. Throughout history, different naturalists have studied aspects of animal behaviour. Ethology has its scientific roots in the work of Charles Darwin and of American and German ornithologists of the late 19th and early 20th century, including Charles O. Whitman, Oskar Heinroth, and Wallace Craig. The modern discipline of ethology is generally considered to have begun during the 1930s with the work of Dutch biologist Nikolaas Tinbergen and Austrian biologists Konrad Lorenz and Karl von Frisch, the three recipients of the 1973 Nobel Prize in Physiology or Medicine. Ethology combines laboratory and field science, with a strong relation to some other disciplines such as neuroanatomy, ecology, and evolutionary biology. Ethologists typically show interest in a behavioral process rather than in a particular animal group, and often study one type of behavior, such as aggression, in a number of unrelated species.

The sweet potato or sweetpotato is a dicotyledonous plant that belongs to the bindweed or morning glory family, Convolvulaceae. Its large, starchy, sweet-tasting tuberous roots are used as a root vegetable. The young shoots and leaves are sometimes eaten as greens. Cultivars of the sweet potato have been bred to bear tubers with flesh and skin of various colors. Sweet potato is only distantly related to the common potato, both being in the order Solanales. Although darker sweet potatoes are often referred to as "yams" in parts of North America, the species is not a true yam, which are monocots in the order Dioscoreales.

Observational learning is learning that occurs through observing the behavior of others. It is a form of social learning which takes various forms, based on various processes. In humans, this form of learning seems to not need reinforcement to occur, but instead, requires a social model such as a parent, sibling, friend, or teacher with surroundings. Particularly in childhood, a model is someone of authority or higher status in an environment. In animals, observational learning is often based on classical conditioning, in which an instinctive behavior is elicited by observing the behavior of another, but other processes may be involved as well.

Edward Lee Thorndike was an American psychologist who spent nearly his entire career at Teachers College, Columbia University. His work on comparative psychology and the learning process led to the theory of connectionism and helped lay the scientific foundation for educational psychology. He also worked on solving industrial problems, such as employee exams and testing.

<span class="mw-page-title-main">John B. Watson</span> American psychologist (1878–1958)

John Broadus Watson was an American psychologist who popularized the scientific theory of behaviorism, establishing it as a psychological school. Watson advanced this change in the psychological discipline through his 1913 address at Columbia University, titled Psychology as the Behaviorist Views It. Through his behaviorist approach, Watson conducted research on animal behavior, child rearing, and advertising, as well as conducting the controversial "Little Albert" experiment and the Kerplunk experiment. He was also the editor of Psychological Review from 1910 to 1915. A Review of General Psychology survey, published in 2002, ranked Watson as the 17th most cited psychologist of the 20th century.

Primatology is the scientific study of primates. It is a diverse discipline at the boundary between mammalogy and anthropology, and researchers can be found in academic departments of anatomy, anthropology, biology, medicine, psychology, veterinary sciences and zoology, as well as in animal sanctuaries, biomedical research facilities, museums and zoos. Primatologists study both living and extinct primates in their natural habitats and in laboratories by conducting field studies and experiments in order to understand aspects of their evolution and behavior.

Cultural behavior is behavior exhibited by humans that is extrasomatic or extragenetic—in other words, learned.

An operant conditioning chamber is a laboratory apparatus used to study animal behavior. The operant conditioning chamber was created by B. F. Skinner while he was a graduate student at Harvard University. The chamber can be used to study both operant conditioning and classical conditioning.

<span class="mw-page-title-main">Giffen good</span> Product that people consume more of as the price rises

In economics and consumer theory, a Giffen good is a product that people consume more of as the price rises and vice versa—violating the basic law of demand in microeconomics. For any other sort of good, as the price of the good rises, the substitution effect makes consumers purchase less of it, and more of substitute goods; for most goods, the income effect reinforces this decline in demand for the good. But a Giffen good is so strongly an inferior good in the minds of consumers that this contrary income effect more than offsets the substitution effect, and the net effect of the good's price rise is to increase demand for it. This phenomenon is known as the Giffen paradox. A Giffen good is considered to be the opposite of an ordinary good.

In sociology, a tipping point is a point in time when a group—or many group members—rapidly and dramatically changes its behavior by widely adopting a previously rare practice.

The Japanese macaque, also known as the snow monkey, is a terrestrial Old World monkey species that is native to Japan. Colloquially, they are referred to as "snow monkeys" because some live in areas where snow covers the ground for months each year – no other non-human primate lives farther north, nor in a colder climate. Individuals have brownish grey fur, pinkish-red faces, and short tails. Two subspecies are known.

Imitation is a behavior whereby an individual observes and replicates another's behavior. Imitation is also a form of that leads to the "development of traditions, and ultimately our culture. It allows for the transfer of information between individuals and down generations without the need for genetic inheritance." The word imitation can be applied in many contexts, ranging from animal training to politics. The term generally refers to conscious behavior; subconscious imitation is termed mirroring.

<span class="mw-page-title-main">Lyall Watson</span> South African biologist

Lyall Watson was a South African botanist, zoologist, biologist, anthropologist, ethologist, and author of many books, among the most popular of which is the best seller Supernature. Lyall Watson tried to make sense of natural and supernatural phenomena in biological terms. He is credited with coining the "hundredth monkey" effect in his 1979 book, Lifetide; later, in The Whole Earth Review, he conceded this was "a metaphor of my own making".

Kinji Imanishi was a Japanese ecologist and anthropologist. He was the founder of Kyoto University's Primate Research Institute and, together with Junichiro Itani, is considered one of the founders of Japanese primatology.

The black-capped squirrel monkey is a species of New-World monkey native to the upper Amazon basin in Bolivia, western Brazil and eastern Peru. They weigh between 365 and 1,135 g and measure, from the head to the base of the tail, between 225 and 370 mm. Black-capped squirrel monkeys are primarily tree-dwelling and are found in both native and plantation forests as well as some farmed areas near running water. Their diet is omnivorous and mostly consists of flowers, fruit, leaves, nuts, seeds, insects, arachnids, eggs and small vertebrates. They mostly live in female-dominated troops of around 40 to 75 monkeys, with males having been observed to disperse to live in all-male troops after reaching sexual maturation. Their current conservation status according to the IUCN is 'Least Concern'. The species belongs to the genus Saimiri and has two subspecies, S. b. boliviensis and S. b. peruviensis.

Animal culture can be defined as the ability of non-human animals to learn and transmit behaviors through processes of social or cultural learning. Culture is increasingly seen as a process, involving the social transmittance of behavior among peers and between generations. It can involve the transmission of novel behaviors or regional variations that are independent of genetic or ecological factors.

Kōjima (幸島) is a small island in the Sea of Hyūga off the shore of the city of Kushima in Miyazaki Prefecture, Japan. The island is approximately 13 km ESE and 20 km by road from the central built-up area of Kushima. It is approximately 300 m offshore and 30 hectares in area, and mainly forested.

Satsue Mito was a Japanese school teacher and primate researcher. She helped with the Kyoto University Primatology group studying wild monkeys on an island called Kōjima, in Miyazaki Prefecture. She identified every monkey in the island and recorded their relationships. She discovered the origin and spreading of sweet potato washing by monkeys. She was an instructor of Kyoto University working with other researchers between 1970 and 1984.

Social learning refers to learning that is facilitated by observation of, or interaction with, another animal or its products. Social learning has been observed in a variety of animal taxa, such as insects, fish, birds, reptiles, amphibians and mammals.

American anthropology has culture as its central and unifying concept. This most commonly refers to the universal human capacity to classify and encode human experiences symbolically, and to communicate symbolically encoded experiences socially. American anthropology is organized into four fields, each of which plays an important role in research on culture:

biological anthropology
linguistic anthropology
cultural anthropology
archaeology

References

1 2 3 4 5 6 7 8 9 10 11 12 Amundson, Ron. 1985. "The Hundredth Monkey Phenomenon." Skeptical Inquirer 9(4):348–56. Also available via University of Hawaii (Archived on May 25, 2011).
1 2 Shermer, Michael. 1997. Why People Believe Weird Things .
1 2 3 Myers, Elaine. 1985. "The Hundredth Monkey Revisited." In Context 9(Spring 1985):10–10. Archived from the original on 2012-02-06.
1 2 3 4 5 Galef, B. G. (1992). "The question of animal culture". Human Nature. 3 (2): 157–178. doi:10.1007/BF02692251. PMID 24222403. S2CID 15087165.
1 2 3 Pössel, Markus, and Ron Amundson. 1996. "Senior Researcher Comments on the Hundredth Monkey Phenomenon in Japan." Skeptical Inquirer 20(3). Archived from the original on 2004-08-03.
1 2 Blair, Lawrence (1975). Rhythms of Vision: The Changing Patterns of Belief. London: Croom Helm Ltd. ISBN 978-0-8052-3610-1.
↑ "Herding Experiment: Hundredth Monkey Phenomenon : Networks Course blog for INFO 2040/CS 2850/Econ 2040/SOC 2090". Cornell University . 2021-10-29. Archived from the original on 2023-06-16. Retrieved 2023-06-16.
↑ Keyes, Ken (1984). The Hundredth Monkey . Camarillo: DeVorss & Co. ISBN 978-0-942024-01-2.
↑ 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. Bibcode:1999Natur.399..682W. doi:10.1038/21415. PMID 10385119. S2CID 4385871.
↑ Boesch, Christophe (2012). "31. Culture in primates. A - Culture as it Happens" (PDF). In Jaan Valsiner (ed.). The Oxford Handbook of Culture and Psychology. OUP. p. 678. ISBN 9780195396430.
↑ Trivedi, Bijal P. (February 6, 2004). ""Hot Tub Monkeys" Offer Eye on Nonhuman "Culture"". National Geographic Channel October 28, 2010/National Geographic. Archived from the original on 2004-04-04.