Insight is the sudden realization of a solution to a problem. The answer appears with a sense of clarity and often with the feeling that it should have been obvious all along.

Gestalt psychologists studied insight in apes and humans, contrasting it with gradual trial-and-error learning. A chimpanzee that suddenly uses a stick to reach a banana, or a person who suddenly sees how to rearrange the elements of a puzzle, is displaying insight. The solution is frequently preceded by a period of incubation in which the problem is set aside; the critical reorganization occurs outside immediate awareness.

Insight problems are typically those that require a change in representation—seeing the elements in a new relationship—rather than the routine application of a known procedure. Functional fixedness and mental set can block insight; techniques that encourage restructuring can facilitate it. Brain-imaging studies have associated moments of insight with brief bursts of activity in right-hemisphere temporal regions.

Insight is the experience of the pieces suddenly fitting. The path to that moment is often invisible until it arrives.