Between 1952 and 1953,[i] 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. 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.
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.
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. 1e1e36bf2d