The Hundredth Monkey Phenomenon
(c) Ron Amundson 1985

First published in Skeptical Inquirer vol. 9, 1985, 348-356.

. . . One has to gather the rest of the story from personal anecdotes and bits of folklore among primate researchers, because most of them are still not quite sure what happened. And those who do suspect the truth are reluctant to publish it for fear of ridicule. So I am forced to improvise the details, but as near as I can tell, this is what seems to have happened. In the autumn of that year an unspecified number of monkeys on Koshima were washing sweet potatoes in the sea. . . . Let us say, for argument's sake, that the number was ninety-nine and that at eleven o'clock on a Tuesday morning, one further convert was added to the fold in the usual way. But the addition of the hundredth monkey apparently carried the number across some sort of threshold, pushing it through a kind of critical mass, because by that evening almost everyone was doing it. Not only that, but the habit seems to have jumped natural barriers and to have appeared spontaneously, like glycerine crystals in sealed laboratory jars, in colonies on other islands and on the mainland in a troop at Takasakiyama.
A sort of group consciousness had developed among the monkeys, Watson tells us. It had developed suddenly, as a result of one last monkey's learning potato washing by conventional means. The sudden learning of the rest of the Koshima troop was not attributable to the normal one-monkey-at-a-time methods of previous years. The new phenomenon of group consciousness was responsible not only for the sudden learning on Koshima but for the equally sudden acquisition of the habit by monkeys across the sea. Watson admits that he was forced to "improvise" some of the details - the time of the day, the day of the week, and the exact number of monkeys required for the "critical mass" were not specified in the scientific literature. But by evening (or at least in a very short period of time) almost everyone (or at least a large number of the remaining monkeys) in the colony had suddenly acquired the custom. This is remarkable in part because of the slow and gradual mode of acquisition that had typified the first five years after Imo's innovation. Even more remarkable was the sudden jumping of natural boundaries, apparently caused by the Koshima miracle.
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In this section I investigate the relations between Watson's description of the Hundredth Monkey Phenomenon and the scientific sources by which he validates it. To be sure, we must not expect too much from the sources. Watson has warned us that the complete story was not told and that he was 'forced to improvise the details." But we should expect to find some evidence of the mysteriousness of the Koshima events of 1958. In particular, we should expect to find evidence of an episode of sudden learning within the troop at this time (though perhaps not in one afternoon) and evidence of the sudden appearance of potato washing on other troops sometime soon after the Koshima event. We also have a negative expectation of the literature; it should fail to report certain important details. It will not (we expect) tell us the exact number of monkeys washing potatoes prior to or after the event of 1958, nor will it provide us with an explanation of how the post-event Koshima learners were able to acquire their knowledge. After all, it is Watson's claim that the event produced paranormal learning of potato washing. These three expectations will be tested against the literature. Was there a sudden event at Koshima? Did acquisition at other colonies follow closely the Koshima event? Does Watson improvise details only when the cited literature fails to provide adequate information? The following comments will be restricted to the literature on macaques actually cited by Watson.
Almost all of the information about the Koshima troop appears in a journal article by Masao Kawai (1965); the other articles are secondary on this topic. Kawai's article is remarkably detailed in its description of the Koshima events. The troop numbered 20 in 1952 and grew to 59 by 1962. (At least in the numerical sense, there was never a "hundredth monkey" on Koshima.) Watson states that "an unspecified number" of monkeys on Koshima had acquired the potato-washing habit by 1958. Actually this number was far from unspecified. Kawai's data allowed the reader to determine the dates of acquisition of potato washing (and two other food behaviors), as well as the dates of birth and genealogical relationships, of every monkey in the Koshima troop from 1949 to 1962 (Figure 1, pp. 2-3, and elsewhere in the paper). In March 1958, exactly 2 of 11 monkeys over 7 years old had learned potato washing, while exactly 15 of 19 monkeys between 2 and 7 had the habit (p.3). This amounts to 17 of 30 non-infant monkeys. There is no mention in this paper (or in any other) of a sudden learning event in the fall of 1958. However, it is noted that by 1962, 36 of the 49 non-infant monkeys had acquired the habit. So both the non-infant population and the number of potato washers had increased by 19 during this four-year period. Perhaps this is what suggested to Watson that a sudden event occurred in the fall of 1958. And perhaps (since one can only surmise) this idea was reinforced in Watson's mind by the following statement by Kawai: "The acquisition of [potato washing] behavior can be divided into two periods; before and after 1958"(p.5).
So Kawai does not give a time of year, a day of the week, or even the season for any sudden event in 1958. But he does at least identify the year. And is Kawai mystified about the difference between pre- and post-1958 acquisition? Is he "not quite sure what happened"? Is he reluctant to publish details "for fear of ridicule?" No. He publishes the whole story, in gothic detail. The post-1958 learning period was remarkable only for its normalcy. The period from 1953 to 1958 had been a period of exciting innovation. The troop encountered new food sources, and the juveniles invented ways of dealing with these sources. But by 1958 the innovative youth had become status quo adults; macaques mature faster than humans. The unusual juvenile-to-adult teaching methods reverted to the more traditional process of learning one's food manners at one's mother's knee. Imo's first child, a male named "Ika," was born in 1957 (pp.5,7). Imo and her former playmates brought up their children as good little potato-washers. One can only hope that Ika has been less trouble to his Mom than Imo was to hers. Kawai speaks of the innovative period after 1958 as "pre-cultural propagation" (p.8). (This latter term does not indicate anything unusual for the monkey troops. The troops under normal circumstances have behavior as genuinely "cultural".)
So there was nothing left unsaid in Kawai's description. There was nothing mysterious, or even sudden, in the events of 1958. Nineteen fifty-eight and 1959 were the years of maturation of a group of innovative youngsters. The human hippies of the 1960s now know that feeling. In fact 1958 was a singularly poor year for habit acquisition on Koshima. Only two monkeys learned to wash potatoes during that year, young females named Zabon and Nogi. An average of three a year had learned potato washing during the previous five years (Table 1, p.4). There is no evidence that Zabon and Nogi were psychic or in any other way unusual.
Let us try to take Watson seriously for a moment longer. Since only two monkeys learned potato washing during 1958 (according to Watson's own citation), one of them must have been the "Hundredth Monkey." Watson leaves "unspecified" which monkey it was, so I am "forced to improvise" and "say, for argument's sake" that it was Zabon. This means that poor little Nogi carries the trim metaphysical burden of being the "almost everyone in the colony" who, according to Watson, suddenly and miraculously began to wash her potatoes on that autumn afternoon.
Watson claims that the potato-washing habit "spontaneously" leaped natural barriers. Is there evidence of this? Well, two sources report that the behavior was observed off Koshima, in at least five different colonies (Kawai 1965, 23; Tsumori 1967, 219). These reports specifically state that the behaviors was observed only among a few individual monkeys and that it had not spread throughout the colony. There is no report of when these behaviors occurred. They must have been observed sometime between 1953 and 1967. But there is nothing to indicate that they followed closely upon some supposed miraculous event on Koshima during the autumn of 1958, or that they occurred suddenly at any other time, or that they were in any other way remarkable.
In fact there is absolutely no reason to believe in the 1958 miracle on Koshima. There is every reason to deny it. Watson's description of the event is refuted in great detail by the very sources he cites to validate it. In contrast to Watson's claims of a sudden and inexplicable event, "Such behavior patterns seen to be smoothly transmitted among individuals in the troop and handed down to the next generation" (Tsumori 1967, 207).
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Methodology of Pseudoscience
The factual issue ends here. Watson's claim of a "Hundredth Monkey Phenomenon" is conclusively refuted by the very sources he cites in its support. He either failed to read or misreported the information in these scientific articles. But Watson's own mode of reasoning and reporting, as well as the responses he has inspired in the popular literature, deserve attention. They exemplify the pseudoscientific tradition. Consider the following:
1. Hidden sources of information: Watson informs us that the scientific reports leave important data "unspecified." This is simply false. But, more subtly, he tells us that most of the researchers are still unsure of what happened and that those who "so suspect the truth are reluctant to publish it for fear of ridicule." In one fell swoop Watson brands himself as courageous, explains why no one else has dared report these miraculous phenomenon, and discourages us from checking the cited literature for corroboration. Watson got the real story from "personal anecdotes and bits of folklore among primate researchers. . . ."Those of us who don't hobnob with such folks must trust Watson. The technique was effective. Of the commentaries I have found on the Hundredth Monkey Phenomenon, not one shows evidence of having consulted the scientific sources cited by Watson. Nonetheless, each presents Watson's fantasy as a scientifically authenticated fact. Nor is additional information available from Watson. I have written both to Watson and to his publishers requesting such information and have received no reply.
2. Aversion to naturalistic explanations: The fact is that potato washing was observed on different islands. Watson infers that it had traveled in some paranormal way from one location to another. Like other aficionados of the paranormal, Watson ignores two plausible explanations of the concurrence of potato washing. First, it could well have been an independent innovation - different monkeys inventing the same solution to a common problem. This process is anathema to the pseudoscientist. The natives of the Americas simply could not have invented the pyramids independent of the Egyptians - they just didn't have the smarts. In more extreme cases (von Daniken, for example) a human being is just too dumb to invent certain clever things - extraterrestrial must have done it.
Watson assumes that Imo was the only monkey capable of recognizing the usefulness of washing potatoes. In his words, Imo was "a monkey genius" and potato washing is "comparable almost to the invention of the wheel." Monkeys on other islands were too dumb for this sort of innovation. But keep in mind that these monkeys didn't even have potatoes to wash before 1952 or 1953, when provisioning began. Monkeys in at least five locations had learned potato washing by 1962. This suggests to me that these monkeys are clever creatures. It suggests to Watson that one monkey was clever and that the paranormal took care of the rest. A second neglected explanation is natural diffusion. And indeed Kawai reports that in 1960 a potato washer named "Jugo" swam from Koshima to the island on which the Takasakiyama troop lives. Jugo returned in 1964 (Kawai 1965, 17). Watson does not mention this. The Japanese monkeys are known to be both clever and mobile, and either characteristic might explain the interisland spread of potato washing. Watson ignores both explanations, preferring to invent a new paranormal power.
3. Inflation of the miracle: As myths get passed along, everyone puffs them up a bit. The following two examples come from second-generation commentaries that quote extensively from Watson. Nevertheless, even Watson's claims are beginning to bulge. First, the primatologists' reports had mentioned that only a few isolated cases of off-Koshima potato-washing were observed. Watson reports this as the habit's having "appeared spontaneously . . . in colonies on other islands. . . ." Not actually false, since the few individuals were indeed in other colonies (though only individuals and not whole colonies adopted the behavior. Following Watson, Ken Keyes reported that, after the hundredth Koshima monkey, "colonies of monkeys on other islands . . . began washing their sweet potatoes"! (Keyes 1982, p.16). From Keyes, one gets the image of spontaneous mass orgies of spud-dunking. A second example: Regarding the primatologists' attitudes toward the events of 1958, Watson reports only that they are "still not quite sure what happened." But the primatological confusion quickly grows, for Science Digest (1981) reports "a mystery which has stumped scientists for nearly a quarter of a century." In these two particular cases, Watson's own statements are at least modest. They're not what one would call accurate, but not exorbitantly false either. By the second generation we find that "not quite sure what happened" becomes "stumped for nearly a quarter of a century," and the habit that appeared in individuals within colonies of monkeys become a habit of colonies of monkeys. Please keep in mind that the second generation relies only on Watson for its information; even Watson's none-too-accurate report has been distorted - and not, needless to say, in the direction of accuracy.
4. The paranormal validates the paranormal: The validity of one supernatural report is strengthened by its consistency with other such reports. Watson's commentators show how this works. Keyes supports the Hundredth Monkey Phenomenon by its consistency with J.B. Rhine's word at Duke, which "demonstrated" telepathy between individual humans. "We now know that the strength of this extrasensory communication can be amplified to a powerfully effective level when the consciousness of the 'hundredth person' is added" (Keyes 1982, 18). Elda Hartley's film "The Hundredth Monkey" invokes Edgar Cayce. And in a remarkable feat of group consciousness, four of the five secondary sources emphasize the similarities between Watson's Hundredth Monkey Phenomenon and Rupert Sheldrake's notion of the "morphogenetic field." The spontaneous recognition of the similarities between Watson and Sheldrake seems to have leaped the natural boundaries between the four publications! Now there's a miracle! (Surely independent invention or natural diffusion couldn't account for such a coincidence.)
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I must admit sympathy for some of the secondary sources on the Hundredth Monkey Phenomenon. This feeling comes from the purpose for which the phenomenon was cited. Ken Keyes's book uses the phenomenon as a theme, but the real topic of the book is nuclear disarmament. Arthur Stein's article and (to a lesser extent) the Hartley film are inspired by Keye's hope that the Hundredth Monkey Phenomenon may help may help prevent nuclear war. The message is that "you may be the Hundredth Monkey" whose contribution to the collective consciousness turns the world away from nuclear holocaust. It is hard to find fault in this motive. For these same reasons, one couldn't fault the motives of a child who wrote to Santa Claus requesting world nuclear disarmament as a Christmas present. We can only hope that Santa Claus and the Hundredth Monkey are not our best chances to avoid nuclear war.
Watson's primary concern is not prevention of war but sheer love of the paranormal. His book begins with a description of a child who, before Watson's eyes, and with a "short implosive sound, very soft, like a cork being drawn in the dark," psychically turned a tennis ball inside out - fuzz side in, rubber side out - without loosing air pressure (p.18). Just after the Hundredth Monkey discussion, Watson makes a revealing point. He quotes with approval a statement attributed to Lawrence Blair: "When a myth is shared by a large number of people, it becomes a reality" (p. 148). This sort of relativist epistemology is not unusual in New Age thought. I would express Blair's thought somewhat differently: "Convince enough people of a lie, and it becomes the truth." I suggest that someone who accepts this view of truth is not to be trusted as a source of knowledge. He may, of course, be a marvelous source of fantasy, rumor, and pseudoscientific best-sellers.
I prefer epistemological realism to this sort of relativism. Truth is not dependent on the number of believers or on the frequency of published repetition. My preferred epistemology can be expressed simply: Facts are facts. There is no Hundredth Monkey Phenomenon.
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I began investigating the "Hundredth Monkey Phenomenon" in August 1984 with a letter to Lyall Watson, the author of the "phenomenon," addressed in care of his publisher, Simon and Schuster. I asked for more information about the group consciousness of monkeys reported by Watson in Lifetide. Neither this nor a later letter to the publisher has ever received a reply. My study was published in the Summer 1985 Skeptical Inquirer. Boyce Rensberger, a Washington Post science writer, and subsequently a recipient of CSIOCP's 1986 Responsibility in Journalism Award, picked up the story. He also approached Simon and Schuster, who declined to put him in touch with Watson. Rensberger (1985) quoted Watson's editor as saying that Watson "is a distinguished and eminent scholar who, I have to say, does have some weird ideas." No news there.
Watson has now broken the silence. Ted Schultz, an editor for Whole Earth Review, managed to contact him. According to Schultz, Watson was "quite happy to respond to Amundson's analysis of his monkey tale." The response was published, in the Fall 1986 "Fringes of Reason" issue of Whole Earth Review (and reprinted in Schultz 1989). Although he begins with a swipe at "self-appointed committees for the suppression of curiosity," Watson deals "in good humor" with my critique of the Hundredth Monkey. My article was "lucid, amusing, and refreshingly free of the emotional dismissals" that, he says, CSICOP is prone to. I wish I could be proud of this distinction.
Watson continues: "I accept Amundson's analysis of the origin and evolution of the Hundredth Monkey without reservation. It is a metaphor of my own making, based--as he rightly suggests--on very slim evidence and a great deal of hearsay. I have never pretended otherwise. . . . I based none of my conclusions on the five sources Amundson uses to refute me. I was careful to describe the evidence for the phenomenon as strictly anecdotal and included citations in Lifetide, not to validate anything, but in accordance with my usual practice of providing tools, of giving access to useful background information."
It should be remembered that the "five sources" I used to "refute" him were the identical five sources that Watson provides as "tools" and "access" in his original discussion of the phenomenon.
Watson goes on to complain about my conclusion that the Hundredth Monkey Phenomenon does not exist. He still thinks the phenomenon is real but admitting that it didn't happen on Koshima. This is like saying that the "Geller Effect" is real, while claiming that Uri Geller himself has no special powers. Well, okay. Show us a real example.
Watson is unhappy about my description of his work as "pseudoscience." He admitted all along, he says, that the Hundredth Monkey story was anecdotal. This is approximately a half truth. Watson did admit in Lifetide that he had to "gather the rest of the story from personal anecdotes and bits of folklore." (This was because, he said, the scientists were afraid to publish the truth "for fear of ridicule.") He then specifically stated that certain crucial details were missing from the scientific reports. He went on to describe the events on Koshima, "improvising" the detail. The miraculous result were stated in two sentences, followed by a citation reference.
The details said by Watson to be missing were not missing. He falsely reported on the scientific evidence available--available, in fact, in his own citations.
Watson responds to my claim that his own documentation refutes him by explaining that his citation references were not meant as documentation at all, but as "tools." (Perhaps being refuted by your own tool is less painful than being refuted by your own documentation.) Here it should be noted that the citations were presented in exactly the format used to provide documentation for factual claims, both in scientific and in informal writing. Lifetide is peppered with raised reference numbers, each following a factual statement made in the text. The Chicago Manual of Style refers to this format as "notes documenting the text, and corresponding to reference numbers in the text." Does Watson anywhere warn us that his citations do not document the text--that they actually contradict the text? Does he warn us that they are merely "tools"? No. We are told only that the raised numbers "refer to numbered items in the bibliography."
As an "eminent scholar" and "holder of degrees in anthropology, ethology, and marine biology" (Whole Earth Review's description), Watson must be assumed to understand the use of scientific citations. The meaning of a reference citation is not something each author simply invents for himself. It does not mean "documentation" for some writers and "tools" for others. Watson uses a format that implies documented support for a factual claim. He now says that he didn't really mean it that way.
I submit that this technique is pseudoscientific in the strictest sense. It falsely presents the appearance of science. Watson could have admitted that he made a mistake in his citations (or that he never read them in the first place). Instead he excuses himself by saying that the references were merely "tools." They just looked like scholarly citations.
Watson owes an apology to the thousands of people who took his claims to be reports of fact, rather than "hearsay" and "anecdotes." None of Watson's published commentators thought he was presenting "hearsay" about potato-washing monkeys. If I made a mistake by taking him seriously, so did everyone else. Let it be known that the hundreds of scientific-looking citations in Watson's books are not intended to support his factual claims. They are "tools." They look, for all the world, like scientific documentation. But it is all an illusion.
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My only regret in the writing of 'Hundredth Monkey Phenomenon" is that I didn't have the nerve to call it something like "Spud-Dunking Monkey Theory Debunked," Boyce Rensberger's priceless title in the Washington Post.
Reaction to the paper amazed me. I had underestimated the influence of the Skeptical Inquirer, and Rensberger's article certainly helped to spread the word. But besides that, I had no idea that the Hundredth Monkey had become such a compelling image in New Age thought, not only in the United States but around the world. The article has been reprinted in Australia and in Sweden (where it was translated into "Der Hundreden Apen"). It was discussed in the British science magazine New Scientist (1985), and I was interviewed on Australian Public Radio (an interview arranged by the good people of the Australian Skeptics). It has even received friendly attention from sources one would normally expect to be sympathetic to the New Age, such as East-West Journal (1985) and Whole Earth Review. (Discussion and related articles from the Fall 1986 Whole Earth Review were reprinted in Fringes of Reason, Schultz 1989). There was even a kindly word from Douglas Groothuis (1988) in a book advising conservative Christians about how to confront New Age beliefs. To my knowledge, the only negative reaction was Lyall Watson's gentle scolding of my narrow-mindedness (in Schultz 1989). The moral of the story seems to be that many of the thousands of people who heard the Hundredth Monkey myth were already skeptical about it. Nevertheless, practically no one had bothered to chase down its origin and check its credentials.
The notable exception to this complacency was Maureen O'Hara, a humanistic psychologist who had independently critiqued the Hundredth Monkey (see O'Hara 1986). She was more tolerant than I of Watson's myth-making, laying most of the blame on Watson's commentators. But she eloquently exposed a crucial fallacy in the New Age acceptance of mass consciousness, a fallacy I had missed. New Age aficionados consider mass consciousness to be "empowering" to individuals, since "you may be the Hundredth Monkey." O'Hara points out the foolishness of this "empowerment." An individual whose beliefs are in the minority is already out-Hundredth-Monkeyed by the opinion of the majority. Moreover, the conviction that beliefs alone can affect social change provides a perfect excuse for complacency. Why bother to engage in political activism when it's just as effective to sit comfortably at home and believe things? I was especially gratified to see the same point recognized in a local Kansas newspaper; my refutation of Watson was celebrated by the Wellington News in an editorial entitled "Individually Responsible."
As I already confessed, I'm no heroic crusader for rationality. I studied the Hundredth Monkey Phenomenon because my students forced me into it. Our complacency in the face of such nonsense simply allows the nonsense to spread. Other myths may not be as easy to burst as the Hundredth Monkey Phenomenon, but we'll never know until we try.
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Brain/Mind Bulletin. 1982. The Hundredth Monkey. In "Updated Special Issue: 'A New Science of Life.'"
East-West Journal. 1985. Monkey Business, November, p.13.
Groothuis, Douglas R. 1988. Confronting the New Age. Downers Grove, IL: InterVarsity Press.
Hartley, Elda (producer). 1983. The Hundredth Monkey (film and videotape). Hartly Film Foundation, Inc. Cos Cob, Conn.
Imanishi, Kinji. 1963. Social behavior in Japanese monkeys. In Primate Social Behavior, Charles A Southwick, ed. Toronto: Van Nostrand.
Kawai, Masao. 1963. On the Newly-acquired behaviors of the natural troop of Japanese monkeys on Koshima island. Primates, 4:113-115.
Kawai, Masao. 1965. On the newly-acquired pre-cultural behavior of the natural troop of Japanese monkeys on Koshima Islet. Primates, 6:1-30.
Kawamura, Syunzo. 1963. Subcultural propagation among Japanese macaques. In Primate Social Behavior, Charles A. Southwick, ed. Toronto: Van Nostrand.
Keyes, Ken, Jr. 1982. The Hundredth Monkey. Coos Bay, OR: Vision Books.
New Scientist. 1985. Making a monkey out of Lyall Watson. July 11, p.21.
O'Hara, Maureen. 1986. Of myths and monkeys. Whole Earth Review, Fall. Reprinted in Schultz, 1989.
Rensberger, Boyce. 1985. Spud-dunking monkey theory debunked. Washington Post, July 6.
Schultz, Ted, ed. 1989. Fringes of Reason: A Whole Earth Catalog. New York: Harmony Books.
Science Digest. 1981. The quantum monkey. Vol.8: 57.
Sheldrake, Rupert. 1981. A New Science Life. Los Angeles: J.P. Tarcher.
Stein Arthur. 1983. The "Hundredth Monkey" and Humanity's Quest for Survival. Phoenix Journal of Transpersonal Anthropology, 7: 29-40.
Tsumori, Atsuo. 1967. Newly acquired behavior and social interactions of Japanese monkeys. In Social Communication Among Primates. Stuart Altman, ed. Chicago: University of Chicago Press.
Watson, Lyall. 1979. Lifetide. New York: Simon and Schuster.
Watson, Lyall. 1986. Lyall Watson responds. Whole Earth Review, Fall. Reprinted in Schultz, 1989.
Wellington (Kansas) News. 1985. Individually Responsible, July 22.

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