Event-related potentials support the mnemonic effect of spontaneous insight solution

The mnemonic effect of insight refers to the situation in which experiencing an "aha" moment when solving problems could improve memory performance for both the question and its solution. The aha experience can be triggered either by external stimuli or by internal solution attempts, namely "induced" or "spontaneous" insight, respectively. Tests of the neural correlates of the insightful memory effect are typically conducted in induced insight paradigms. The neural mechanism of the mnemonic effect of spontaneous insight is unclear. In the present study, the mnemonic effect for spontaneous insight was examined by the event-related potentials (ERPs) technique and behavioral measures. Subjects were required to solve a set of Chinese verbal compound remote-associated tasks (CRA), and performed a recognition test 10 min later. The results showed that the spontaneous insight solution elicited a more negative deflection than did the non-insight solution before the button reaction (- 800 to - 400 ms) in the study phase. In the recognition test phase, items which elicited insight during study were recognized faster, compared with non-insight study items. And spontaneous insight solution elicited a more positive deflection than did non-insight solution in the time window from 400 to 700 ms after onset of the answer. Moreover, brain-behavior correlations revealed a relationship between N400 amplitude during study and later memory performance which revealed a double-dissociation between items solved with and without insight during study. The different predictions for recognition indicate that the encoding of spontaneous insight may differ from that of non-insight, suggesting that different encoding mechanisms may mediate the encoding of items and solutions found by insight versus non-insight.