“The brain appears to be an efficient superhighway that gets you from Point A to Point B” when it comes to intelligence, Dr. Jung explained. “But in the regions of the brain related to creativity, there appears to be lots of little side roads with interesting detours, and meandering little byways.”

Although intelligence and skill are generally associated with the fast and efficient firing of neurons, subjects who tested high in creativity had thinner white matter and connecting axons that have the effect of slowing nerve traffic in the brain. This slowdown in the left frontal cortex, a region where emotional and cognitive abilities are integrated, Dr. Jung suggested, “might allow for the linkage of more disparate ideas, more novelty and more creativity.”

Dr. Kounios, of Drexel, said that Dr. Jung was doing original and interesting work, but he maintained that trying to find a correlation between creativity and a single area of the brain is an “old-fashioned approach.”

Image Left, before an insight, activity drops in the visual cortex; right, in the “aha! moment,” activity in the right temporal lobe spikes. Credit... John Kounios, Drexel University

“Creativity is a collection of different processes that work in different areas of the brain,” Dr. Kounios said, so the creative act must be broken down into tiny pieces. He also rejects utility as part of the definition, arguing that there can be brilliant and creative failures — what he calls near misses.

Last year he and Mark Beeman, a psychologist at Northwestern University, published a paper on what he calls the “Aha! moment,” the sudden insight that solves a problem, reinterprets a situation or explains a joke. In their test, they used simple word puzzles that could be solved either with an instant creative insight or a quick analysis.

For example, here are three words: crab, pine and sauce.

Now, think of a single word that could be combined with each of the three to form a familiar term.