Herding Experiment: Hundredth Monkey Phenomenon
The Hundredth Monkey Phenomenon was first baptized by Lyall Watson in 1979, who documents the case with references to five high reputable Japanese primatologists, and has thus been cited as the sole source of information in subsequent articles. These monkeys in question are Japanese macaques, or Macaca fuscata, who habit in groups on several islands in Japan.
Macaques have been long under observation, and in 1952 and 1953, some primatologists began to provide them with food, including sweet potatoes and wheat. They delivered and left the food in open areas, usually on beaches. As a result of this provision, the monkeys developed various innovative behaviors. Particularly in 1953, one monkey, an 18-month-old female whom observers named “Imo,” unearthed a strategy that she could remove the sand and grit from the sweet potatoes by washing them in a stream or ocean. Soon, Imo’s mother and playmates learned this trick and began to do it as well (opposite of the typical flow of knowledge passed from parents to offspring). This strategy soon spread gradually to other monkeys of the same troop up until 1958.
In the fall of 1958, a remarkable event happened on Koshima, which later came to be known as the “Hundredth Monkey Phenomenon.” An unspecified number of monkeys were washing their sweet potatoes. Let us assume that there were 99 monkeys already doing that and 1 additional monkey also developed this strategy in the usual way. All of a sudden, as if that one additional monkey pushed the strategy through some form of threshold and critical mass, almost all of the monkeys in the same troop were doing it. Moreover, this strategy transcended natural barriers and have suddenly appeared in other groups on other islands.
Watson theorized that some sort of group consciousness had developed suddenly among the monkeys upon the one last monkey’s development of washing potatoes, which was dissimilar to the one-monkey-at-a-time distribution method in previous years. It was not only applicable instantaneously to the entire troop at the end of the day but also spread to other groups across the sea rapidly. This was ground-breaking because it broke the pattern on the slow and gradual mode of acquisition that characterized the first five years after Imo’s discovery and it broke through natural barriers by spreading across seas.
The “Hundredth Monkey Phenomenon” described above is similar to the herding experiment illustrated in class where students are told that an urn contains 3 balls and either it is majority-red (MR) or majority-blue (MB). After 2 people in front of them announce the same choice, either MR or MB, the third person will also follow and make the same choice regardless of the color they picked up. Everyone following the third person would also follow the decision of the first 2 people, which results in an information cascade. The threshold of 100 monkeys in the phenomenon is similar to the third person in the herding experiment as once it reaches that number, everyone else following would do the same thing regardless of their own information.
These two phenomena are highly applicable to the real world as well in terms of fashion or social media trends. Once a certain number of people decide to follow the trend, an exponential number of people will follow as well, breaking the slow and gradual spread initially. For example, TikTok was first created in 2016 but had a sudden burst of popularity in 2019, and now almost everyone uses or at least has the app downloaded because everyone has it. As depicted above, both the “Hundredth Monkey Phenomenon” and the herding experiment can be used to explain trends by how quickly information can spread on a global basis once they hit a certain level of acceptance in our modern society.
Sources:
https://hilo.hawaii.edu/~ronald/HMP.htm
https://simplicable.com/new/information-cascade