The Japanese monkey, Macaca fuscata, had been observed in the wild for a
                      period of over 30 years.

                      In 1952, on the island of Koshima, scientists were providing monkeys with
                      sweet potatoes dropped in the sand. The monkeys liked the taste of the raw
                      sweet potatoes, but they found the dirt unpleasant.

                      An 18-month-old female named Imo found she could solve the problem by
                      washing the potatoes in a nearby stream. She taught this trick to her mother.
                      Her playmates also learned this new way and they taught their mothers too.

                      This cultural innovation was gradually picked up by various monkeys before the
                      eyes of the scientists. Between 1952 and 1958 all the young monkeys learned
                      to wash the sandy sweet potatoes to make them more palatable. Only the
                      adults who imitated their children learned this social improvement. Other adults
                      kept eating the dirty sweet potatoes.

                      Then something startling took place. In the autumn of 1958, a certain number
                      of Koshima monkeys were washing sweet potatoes -- the exact number is not
                      known. Let us suppose that when the sun rose one morning there were 99
                      monkeys on Koshima Island who had learned to wash their sweet potatoes.
                      Let's further suppose that later that morning, the hundredth monkey learned to
                      wash potatoes.

                      THEN IT HAPPENED! By that evening almost everyone in the tribe was washing
                      sweet potatoes before eating them. The added energy of this hundredth
                      monkey somehow created an ideological breakthrough!

                      But notice: A most surprising thing observed by these scientists was that the
                      habit of washing sweet potatoes then jumped over the sea...Colonies of
                      monkeys on other islands and the mainland troop of monkeys at Takasakiyama
                      began washing their sweet potatoes.

                      Thus, when a certain critical number achieves an awareness, this new awareness
                      may be communicated from mind to mind.

                      Although the exact number may vary, this Hundredth Monkey Phenomenon
                      means that when only a limited number of people know of a new way, it may
                      remain the conscious property of these people.

                      But there is a point at which if only one more person tunes-in to a new
                      awareness, a field is strengthened so that this awareness is picked up by
                      almost everyone!

                      The Hundredth Monkey by Ken Keyes