If you're one of those insufferable people who can finish the Saturday New York Times crossword puzzle, you probably have a gift for insight. The puzzles always have an underlying hint to solving them, but on Saturdays that clue is insanely obtuse. If you had all day, you could try a zillion different combinations and eventually figure it out. But with insight, you'd experience the usual clueless confusion, until--voilà--the fog clears and you get the clue, which suddenly seems obvious. The sudden flash of insight that precedes such "Aha!" moments is characteristic of many types of cognitive processes besides problem-solving, including memory retrieval, language comprehension, and various forms of creativity. Now, researchers from Northwestern and Drexel Universities report on studies revealing a unique neural signature of such insight solutions.
Mark Jung-Beeman and colleagues mapped both the location and electrical signature of neural activity using functional magnetic resonance imaging (fMRI) and the electroencephalogram (EEG). Neural activity was mapped with fMRI while the participants were given word problems--which can be solved quickly with or without insight, and evoke a distinct Aha! moment about half the time they're solved. Subjects pressed a button to indicate whether they had solved the problem using insight, which they had been told leads to an Aha! experience characterized by suddenness and obviousness.
While several regions in the cerebral cortex showed about the same heightened activity for both insight and noninsight-derived solutions, only an area known as the anterior Superior Temporal Gyrus (aSTG) in the right hemisphere (RH) showed a robust insight effect. The researchers also found that 0.3 seconds before the subjects indicated solutions achieved through insight, there was a burst of neural activity of one particular type: high-frequency (gamma band) activity that is often thought to reflect complex cognitive processing. This activity was also mapped to the aSTG of the RH, providing compelling convergence across experiments and methods.
Problem-solving involves a complex network of brain regions to encode, retrieve, and evaluate information, but these results show that solving verbal problems with insight requires at least one additional component. Further, the fact that the effect occurred in RH aSTG suggests what that process may be: integration of distantly related information. Distinct neural processes, the authors conclude, underlie the sudden flash of insight that allows people to "see connections that previously eluded them."
citation: Jung-Beeman M, Bowden EM, Haberman J, Frymiare JL, Arambel-Liu S, et al. (2004) Neural activity when people solve verbal problems with insight. PLoS Biol 2(4): e97 DOI: 10.1371/journal.pbio.0020097
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