May 20, 2004

Aha! Scientists reveal brain processes

By Megan Fellman

Think Isaac Newton getting hit on the head with an apple or Alexander Graham Bell inventing the telephone. While these creative or “Aha!” moments often are associated with scientific discoveries and inventions, most people occasionally feel the thrill of insight when a solution that had eluded them suddenly becomes obvious.

But what is really going on in the brain when the light bulb goes off?

For one thing, a striking increase in neural activity in a specific area of the right hemisphere, according to a recent study by a team of cognitive neuroscientists including Mark Jung-Beeman and Edward Bowden of Northwestern and John Kounios of Drexel University. Their results appear online PLoS Biology, an open-access scientific journal published by the Public Library of Science.

“For thousands of years people have said that insight feels different from more straightforward problem solving,” said Jung-Beeman, an associate professor of psychology. “We believe this is the first research showing that distinct computational and neural mechanisms lead to these breakthrough moments.”

Princeton University Stuart Professor of Psychology Philip Johnson-Laird, who was not involved in the work, described the study as “one of the most original studies of insight that I have ever seen.”

Using two different brain imaging techniques, the team found an increase in neural activity in part of the brain’s right temporal lobe when people solved problems with insight that was not present when problems were solved without insight. This demonstrates that insight relies on at least one distinct brain mechanism, and the nature of that area also points to a specific cognitive process that makes insight special.

According to legend, after stepping into his bath Archimedes shouted “Eureka!” (“I have found it”) when an insight allowed him to determine whether or not his king’s crown was pure gold, a problem that had previously stumped him.

“As supposedly happened to Archimedes, prior to solving problems with insight people often reach an impasse and are not able to make any progress,” said Edward Bowden, a senior research associate at Northwestern. “They need to reinterpret the problem and integrate information in a new way. Sometimes the mind does this unconsciously, and then the solution suddenly appears in consciousness. To the solver, the solution seems to have come out of thin air, yet is obviously correct.”

In two experiments, Jung-Beeman and colleagues gave participants a series of word problems to solve. Each problem presented three words, such as fence, card and master, and asked participants to think of one word that would form a compound word or phrase for each of the words. (The answer? Post.) In addition to solving the problem, each person reported whether or not the solution felt like an insight. (The problems were designed to evoke a distinct “Aha!” moment about half the time they are solved.) Brain activity was assessed while participants tackled, and sometimes solved, these problems.