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Topic: Patterns?? Hogwash! It's all in your mind. |
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Junket King |
Posted: 28-Aug-08 18:12 |
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I think they could have saved all that study money if Ivan Petrovich
Pavlov were still around.
Source: Duke University
Date: 2002-04-08
Brain Center Searches For Patterns
DURHAM, N.C. -- Duke University Medical Center
researchers have discovered the brain region
that automatically watches for patterns in
sequences of events, even when the pattern
emerges by random happenstance.
According to the scientists, such compulsive
pattern-perception evolved to enable humans in
the natural world to escape danger, for example
by recognizing that a nearby twig snap and a
growl signaled a looming predator. However, they
said, in today's artificial world such pattern
perception also gives rise to maladaptive superstitions
such as the gambler's belief that a pair of dice is
"due" to roll a seven.
In an article posted online April 8, 2002, in
Nature Neuroscience, researchers Scott Huettel,
Beau Mack and Gregory McCarthy reported experiments
in which they asked subjects to watch simple random
sequences of a circle or a square flash onto a screen.
During the experiments, the scientists imaged the
subjects' brains using a high-resolution functional
MRI (fMRI) machine in the medical center's Brain Imaging
and Analysis Center. The center is a joint facility of
Duke and the University of North Carolina.
The analytical technique of fMRI works by using
magnetic pulses that produce telltale changes in the
molecules within brain tissues that are already under
a powerful-but-harmless static magnetic field. Since
even subtle differences in brain tissues cause them
to react distinctively under the magnetic fields, the
technique enables high-resolution mapping of the brain's
regions. Specifically, fMRI detects increased blood
flow to a particular region, and such increased
flow is triggered by increased activity of the brain
cells in that region.
In their experiments, Huettel and his colleagues
concentrated on the prefrontal cortex, a brain region
believed from previous studies to be involved in "working
memory." Such working memory is the dynamic memory
that people use to store information when engaged
in moment-to-moment tasks.
"We simply asked the subjects to press a button in
their left hand when they saw a circle, and the right
hand for a square," said Huettel. "We purposely kept the
experiment very simple.
"Then, in analyzing brain activity during those responses,
we took advantage of the fact that when you present a large
number of random events, some of the time there will be
short patterns, like a series of circles or a sequence of
alternating circles or squares," he said. "We concentrated
on discovering whether the subjects' brain activity in the
prefrontal cortex changed when these occasional patterns
were violated, as when a square would appear after a series
of circles, or an alternating circle-square pattern would
be disrupted.
"And even though our subjects knew they were seeing
random sequences, and they didn't behave in any explicit
way when they saw these occasional patterns, their
brains still reacted when the patterns were violated.
So, their brains couldn't help but look for these
patterns," said Huettel.
What's more, he said, in behavioral studies, the subjects
generally showed increased reaction time to violations of
longer patterns. This finding confirmed the fMRI results
revealing that the subjects were, indeed, perceiving patterns
in the sequences.
Also, he said, it required longer alternating circle-square
sequences to produce a response on the fMRI scans than it
did sequences of either circles or squares.
"The fact that there was no response until a relatively
long alternating series seems to tell us that humans can
pick up on simple repeating patterns rather quickly, but
it takes longer to perceive more complex patterns," said
Huettel. According to Huettel, the scientists' findings
offer new insight into the role of the prefrontal cortex.
"These findings suggest that the prefrontal cortex is
really actively and dynamically processing information
about the environment," he said. "It's preparing the
organism to change its behavior in response to something
that's happening, not just passively rehearsing."
Further studies, said Huettel, will seek to map how the
prefrontal cortex interacts with other areas of the brain
in processing such information. According to Huettel, the
scientists' findings reveal how brain functions that
evolved to cope with the natural world might not be optimal
in today's technological environment.
"Patterns in the modern world may be very different than
those perhaps twenty thousand years ago," he said. "In
a natural environment, almost all patterns are predictive,
in that the world obeys physical laws. For example, when
you hear a crash behind you, it's not something artificial;
it means that a branch is falling, and you need to get
out of the way. So, we evolved to look for these patterns,
an ability that worked well in a natural environment,
where these patterns mean something.
"But these causal relationships don't necessary hold
in the technological world that can produce irregularities,
and in which we look for patterns where none may exist,"
said Huettel. "A lot of superstitious behavior may
arise from this expectation of patterns.
These superstitions may range from a perceived connection
between washing the car and having it rain, to the belief
that rolling dice without getting a seven means that a
seven is due. Thus, brain processes that were perfectly
adaptive in a natural environment become maladaptive in
a technological environment," said Huettel.
The scientists' research was sponsored by the U.S.
Department of Veterans Affairs and the National Institutes
of Health. Huettel is an assistant professor of psychiatry;
Mack is a Duke undergraduate, and McCarthy is a professor
in radiology and psychology, a research career scientist
at the VA medical center and director of the Brain Imaging
and Analysis Center.
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This story has been adapted from a news release issued
by Duke University.
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