The 100th Monkey Theory is a concept suggesting that once a critical number of individuals in a population adopt a new behavior or idea, it can spontaneously spread to the rest of the population, even across separated groups, as if the knowledge transcends direct communication. Originating from observations of Japanese macaques learning to wash sweet potatoes, proponents of the theory argue that cultural or behavioral shifts can reach a tipping point, leading to rapid, collective transformation. While widely cited in popular culture to illustrate social contagion and consciousness-driven change, scientific scrutiny questions the literal interpretation, emphasizing instead its metaphorical power to highlight the potential of small actions to create large-scale social impact.