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Article
USA Today, 8/7/06
Study: Ask With Care
Emotions rule brain’s decisions
By: Dan Vergano, USA Today
The evidence has been piling up throughout history, and now
neuroscientist has proved it’s true: The brain’s wiring emphatically
relies on emotion over intellect in decision-making.
A brain-imaging study reported in the current Science
examines “framing”, a hot topic among psychologists, economists, and
political hucksters.
Framing studies have shown that how a question is posed –
think negative ads, for instance – skews decision-making. But no one
showed exactly how this effect worked in the human brain until the
brain-imaging study led by Benedetto De Martino of University College
London.
De Martino and colleagues asked 20 men and women to undergo
three 17-minute brain scans while being asked to gamble – or not – with
an initial pot of English pounds worth about $95. When told they would
“keep” 40% of their money if they didn’t gamble, the volunteers chose to
gamble only 43% of the time. Told they could “lose” 60% of the money if
they didn’t gamble, they rolled the dice 62% of the time.
Their chances of winning the money were carefully explained
beforehand, and participants knew the odds were identical. But the
framing effect still skewed their decisions significantly.
The brain images revealed the amygdala, a neural region that
possessed strong negative emotions, such as fear, fired up vigorously in
response to each two-second (on average) gambling decision. Where people
resisted the framing effect, a brain region connected to positive
emotions such as empathy, and another that activates whenever people
face choices, lit up as well; seeming to duke it out over the decision.
“We found everyone showed emotional biases, more or less; no
one was totally free of them”, Dr Martino says. Even among the four
participants who were aware they were inconsistent in decision-making,
“they said, ‘I know, I just couldn’t help myself’”, he says.
The study comes amid a burst of research into neuroeconomics,
which studies the brain’s rode in buying and selling decisions.
Economists have embraced the idea in recent years that irrational
psychology, rather than cool calculation, plays as role in such
decisions. The brain study goes further and suggests that emotions rule
decisions almost completely.
“The study is a very mice application of recent knowledge
we’ve acquired about healthy cognition and emotion”, says neuroscientist
Antonio Damasio of the University of Southern California in Los Angeles,
who was not part of the study.
“As a neuroethicist, I’d urge caution about
over-interpreting this elegant study”, says Judy Illes of the Center for
Biomedical Ethics at Stanford University. In real life, decision-making
is “an extremely complex behavior with both rations and irrational
components”, she says, and it’s hard to capture completely in a lab
setting.
Still, Illes calls the study intriguing and predicts it will
lead to more work in the neuroeconomics arena.
Dr Martino acknowledges
the study’s limitations; the decisions described as rational in the
study were simply consistent ones, not a measure of intelligence or
correctness, he says. “I’m not sure you would really want someone like
Mr. Spock making all your decisions”.
In fact, people who lack emotions because of brain injuries,
often have difficult making decisions at all, notes Damasio. The brain
stores emotional memories of past decisions, and those are what drive
people’s choices in life, he suggests. “What makes you and me ‘rational’
is not suppressing our emotions, but tempering them in a positive way”,
he says.
Though neuroecononmics
is a hot field, with hundreds of researchers attending a recent meeting
in Paris on the topic, Damasio says brain imaging’s biggest potential
lies in teaching” “Our education system ignores the role of emotion in
learning and decision-making”.
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