Eureka effect
There is some research on the Aha! insight. Aha! moments cannot be predicted. Insight is a psychological term describes the process in problem solving when a previously unsolvable puzzle becomes suddenly clear and obvious. Often this transition from not understanding to sudden comprehension is accompanied by an exclamation of joy or satisfaction, an Aha! moment. A person using insight to solve a problem is able to give accurate, clear, all-or-nothing type responses, whereas individuals not using the insight process are more likely to produce partial, incomplete responses.