The
Brain Loves a Surprise
NEW
YORK (Reuters Health) - Scientists know that basic pleasures like
good food and sex trigger the brain's ``reward system,'' but new
research suggests that a pleasant surprise really gets the brain
going.
The fact that
some people rely on an orderly routine, while others thrive on
never knowing what the day will bring, may have something to do
with the brain's ``pleasure centers,'' researchers have found.
In a brain-imaging study of 25 men and women, the investigators
discovered that the predictability of a situation determined whether
the brain's pleasure points were tweaked.
Dr. Gregory
S. Berns of Emory University in Atlanta, Georgia, led the study.
The findings are published in the April 15th issue of the Journal
of Neuroscience.
In the study,
Berns and his colleagues gave the participants drops of water
and fruit juice. Part of the time, the sequence of water and juice
drops was predictable, while at other points the sequence varied.
It was at this time of unpredictability that the researchers noticed
marked stimulation in the brain's pleasure centers in many, but
not all, of the participants.
Surprisingly,
Berns told Reuters Health, an individual's taste for water or
juice had no bearing on brain stimulation. Although more than
two thirds said after the tests that they preferred juice to water,
their brain activity did not reflect their preference. Nor did
water lovers show greater brain stimulation when they got their
beverage of choice.
Instead, only
the unpredictable drink sequence triggered a significant brain
response, on average. ``That's what really lit up the reward system,''
Berns said.
Although this
study could not delve into why a surprise dash of juice or water
would stimulate the brain, Berns speculated that the activity
in the brain's pleasure centers is linked to people's personalities.
For instance, a person who craves twists and turns in life might
show greater activity in response to a pleasant surprise than
would a person who needs consistency.
An unpleasant
surprise would have altogether different effects since it would
not stimulate the brain's pleasure centers, Berns noted.
He also speculated
that the brain's love of a surprise makes evolutionary sense.
Only a few basics--such as food, water and sex--are ``natural
rewards'' for animals, he said. It may be, according to Berns,
that the brain is also primed to consider unpredictable events
noteworthy. Being alert to out-of-the-ordinary conditions, he
noted, is important to survival.
SOURCE:
Journal of Neuroscience 2001;27.
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