A Wandering Mind Heads Straight Toward Insight
Researchers Map the Anatomy of the Brain's Breakthrough Moments and Reveal the Payoff of Daydreaming
By ROBERT LEE HOTZ

It happened to Archimedes in the bath. To Descartes it took place in bed while watching flies on his ceiling. And to Newton it occurred in an orchard, when he saw an apple fall. Each had a moment of insight. To Archimedes came a way to calculate density and volume; to Descartes, the idea of coordinate geometry; and to Newton, the law of universal gravity.
Eureka Moments
Five light-bulb moments of understanding that revolutionized science.
In our fables of science and discovery, the crucial role of insight is a cherished theme. To these epiphanies, we owe the concept of alternating electrical current, the discovery of penicillin, and on a less lofty note, the invention of Post-its, ice-cream cones, and Velcro. The burst of mental clarity can be so powerful that, as legend would have it, Archimedes jumped out of his tub and ran naked through the streets, shouting to his startled neighbors: "Eureka! I've got it."
In today's innovation economy, engineers, economists and policy makers are eager to foster creative thinking among knowledge workers. Until recently, these sorts of revelations were too elusive for serious scientific study. Scholars suspect the story of Archimedes isn't even entirely true. Lately, though, researchers have been able to document the brain's behavior during Eureka moments by recording brain-wave patterns and imaging the neural circuits that become active as volunteers struggle to solve anagrams, riddles and other brain teasers.
Following the brain as it rises to a mental challenge, scientists are seeking their own insights into these light-bulb flashes of understanding, but they are as hard to define clinically as they are to study in a lab.
To be sure, we've all had our "Aha" moments. They materialize without warning, often through an unconscious shift in mental perspective that can abruptly alter how we perceive a problem. "An 'aha' moment is any sudden comprehension that allows you to see something in a different light," says psychologist John Kounios at Drexel University in Philadelphia. "It could be the solution to a problem; it could be getting a joke; or suddenly recognizing a face. It could be realizing that a friend of yours is not really a friend."
These sudden insights, they found, are the culmination of an intense and complex series of brain states that require more neural resources than methodical reasoning. People who solve problems through insight generate different patterns of brain waves than those who solve problems analytically. "Your brain is really working quite hard before this moment of insight," says psychologist Mark Wheeler at the University of Pittsburgh. "There is a lot going on behind the scenes."
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Daydreaming is more demanding than it seems, researchers reported in "Experience Sampling During fMRI Reveals Default Network and Executive System Contributions to Mind Wandering" in Proceedings of The National Academy of Sciences.
A positive mood makes an insight more likely, Northwestern University researchers reported in "A Brain Mechanism for Facilitation of Insight by Positive Affect" in the March edition of Journal of Cognitive Neuroscience.
In the journal Neuropsychologia, Drexel University scientists reported on "The Origins of Insight in Resting State Brain Activity."
Together, the two research teams reported that people who solved problems through insight had different brain wave patterns than people who don't. In PLoS Biology, they documented "Neural Activity When People Solve Verbal Problems with Insight" and the "Neural Basis of Solving Problems with Insight."
At the University of London's Goldsmith College, researchers reported in the Journal of Cognitive Neuroscience that brain waves heralding an insight can be detected 8 seconds before we become conscious of it.
In fact, our brain may be most actively engaged when our mind is wandering and we've actually lost track of our thoughts, a new brain-scanning study suggests. "Solving a problem with insight is fundamentally different from solving a problem analytically," Dr. Kounios says. "There really are different brain mechanisms involved."
By most measures, we spend about a third of our time daydreaming, yet our brain is unusually active during these seemingly idle moments. Left to its own devices, our brain activates several areas associated with complex problem solving, which researchers had previously assumed were dormant during daydreams. Moreover, it appears to be the only time these areas work in unison.
"People assumed that when your mind wandered it was empty," says cognitive neuroscientist Kalina Christoff at the University of British Columbia in Vancouver, who reported the findings last month in the Proceedings of the National Academy of Sciences. As measured by brain activity, however, "mind wandering is a much more active state than we ever imagined, much more active than during reasoning with a complex problem."
She suspects that the flypaper of an unfocused mind may trap new ideas and unexpected associations more effectively than methodical reasoning. That may create the mental framework for new ideas. "You can see regions of these networks becoming active just prior to people arriving at an insight," she says.
In a series of experiments over the past five years, Dr. Kounios and his collaborator Mark Jung-Beeman at Northwestern University used brain scanners and EEG sensors to study insights taking form below the surface of self-awareness. They recorded the neural activity of volunteers wrestling with word puzzles and scanned their brains as they sought solutions.
Some volunteers found answers by methodically working through the possibilities. Some were stumped. For others, even though the solution seemed to come out of nowhere, they had no doubt it was correct.
In those cases, the EEG recordings revealed a distinctive flash of gamma waves emanating from the brain's right hemisphere, which is involved in handling associations and assembling elements of a problem. The brain broadcast that signal one-third of a second before a volunteer experienced their conscious moment of insight -- an eternity at the speed of thought.
The scientists may have recorded the first snapshots of a Eureka moment. "It almost certainly reflects the popping into awareness of a solution," says Dr. Kounios.
In addition, they found that tell-tale burst of gamma waves was almost always preceded by a change in alpha brain-wave intensity in the visual cortex, which controls what we see. They took it as evidence that the brain was dampening the neurons there similar to the way we consciously close our eyes to concentrate.
"You want to quiet the noise in your head to solidify that fragile germ of an idea," says Dr. Jung-Beeman at Northwestern.
At the University of London's Goldsmith College, psychologist Joydeep Bhattacharya also has been probing for insight moments by peppering people with verbal puzzles.
By monitoring their brain waves, he saw a pattern of high frequency neural activity in the right frontal cortex that identified in advance who would solve a puzzle through insight and who would not. It appeared up to eight seconds before the answer to a problem dawned on the test subject, Dr. Bhattacharya reported in the current edition of the Journal of Cognitive Neuroscience.
"It's unsettling," says Dr. Bhattacharya. "The brain knows but we don't."
So far, no one knows why problems sometimes trigger an insight or what makes us more inclined to the Eureka experience at some moments but not at others. Insight does favor a prepared mind, researchers determined.
Even before we are presented with a problem, our state of mind can affect whether or not we will likely resort to insightful thinking. People in a positive mood were more likely to experience an insight, researchers at Drexel and Northwestern found. "How you are thinking beforehand is going to affect what you do with the problems you get," Dr. Jung-Beeman says.
By probing the anatomy of 'aha,' researchers hope for clues to how brain tissue can manufacture a new idea. "Insight is crucial to intellect," Dr. Bhattacharya says.
Taken together, these findings highlight a paradox of mental life. They remind us that much of our creative thought is the product of neurons and nerve chemistry outside our awareness and beyond our direct control.
"We often assume that if we don't notice our thoughts they don't exist," says Dr. Christoff in Vancouver, "When we don't notice them is when we may be thinking most creatively."
Robert Lee Hotz shares recommended reading on this topic and responds to reader comments at WSJ.com/Currents. Email him at sciencejournal@wsj.com