April 20, 2004
Aha! Cognitive Neuroscientists Reveal Creative
Brain Processes
EVANSTON, Ill.
--- 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 University and John Kounios of Drexel
University. Their results appear online in this month’s edition
of 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 his colleagues gave study 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.
In the first experiment, functional magnetic resonance imaging
(fMRI) revealed increased activity in a small part of the right
temporal lobe (the anterior superior temporal gyrus) during insight
solutions and little activity during non-insight solutions. No
insight effect was observed anywhere within the temporal lobe of
the left hemisphere. Prior evidence suggests that the right temporal
area, which is associated with insight, may be important for drawing
distantly related information together when comprehending complex
language.
“Archimedes’ sudden observation that water displacement
could be used to calculate density resulted from his connecting
known concepts in new ways,” said Jung-Beeman. “This
is the nature of many insights, the recognition of new connections
across existing knowledge.”
In the second experiment, an electroencephalogram (EEG) tracked
brainwave activity during insight and non-insight solutions. About
one-third of a second before the subjects indicated solutions achieved
through insight, there was a sudden burst of high-frequency (gamma
band) activity, relative to solutions achieved without insight.
This neural activity, often associated with complex cognitive processing,
was observed at scalp electrodes over the same right temporal area
observed with fMRI, replicating the effect with new participants
and a different measure of brain activity.
A second,
unexpected EEG effect also was observed: About 1.5 seconds prior
to insight solutions, an increase in lower frequency
(alpha band) activity appeared over the right posterior cortex.
This effect disappeared precisely when the high-frequency activity
began over the right temporal lobe. The researchers interpreted
the posterior effect as evidence of “gating,” or attenuation,
of visual input, and suggested that this occurs to allow initially
weak solution-related activity to gain strength, then burst into
consciousness as an insight.
“This is like closing your eyes so you can concentrate
when you are trying to solve a difficult problem,” said Kounios,
professor of psychology at Drexel. “But in this case, your
brain is blocking out just the visual inputs to your right hemisphere.”
Success in
solving insight problems is associated with creative thinking. “If there is one human trait that would seem impervious
to scientific study, it is intuition or insight -- that seemingly
nonrational ‘Aha!’ that accompanies sudden recognition
or solution,” said Howard Gardner, Hobbs Professor of Education
and Cognition at the Harvard Graduate School of Education, who
was not involved in the study. “In showing that distinctive
cortical activity characterizes self reports of insight, while
being absent on solutions bereft of insight, Jung-Beeman and his
colleagues have helped to demystify the creative process.”
In addition to Jung-Beeman, Bowden and Kounios, other authors
on the PLoS Biology paper are Jason Haberman, Stella Arambel-Liu
and Paul J. Reber, from Northwestern University; Jennifer L. Frymiare,
from Drexel University; and Richard Greenblatt, from Source Signal
Imaging, Inc.
The research was supported by the National Institute of Deafness
and Other Communication Disorders. |