In unfair monetary deals, the negative emotion part of our brain becomes more active while the logical part of our brain plays less of a role.
By
Colin Allen, published on June 16, 2003 - last reviewed on June 26, 2008
From the piggy bank to Wall Street, we don't always manage our
money rationally. Despite our best efforts, economic decisions can be
influenced by emotion. Researchers offer a neurological explanation:
The part of the brain that controls negative thinking can often override
logical thought.
Alan Sanfey, Ph.D, and Jim Rilling, Ph.D, at Princeton University,
had participants perform a decision-making experiment known as the
"Ultimatum Game." In it, two strangers have a chance to split ten
dollars. The "proposer" offers the "receiver" a portion of the money,
then keeps the rest. If the receiver accepts the offer from the proposer,
both keep their profits. If he rejects the offer, neither receives any
money.
Rationally, the receiver should always accept—even if offered one
dollar out of the ten—but this is not the case. People often forgo
profit when they sense an unfair proposal. The study confirmed previous
research that receivers will forgo profit to prevent proposers from
getting a disproportionate amount of the reward.
Sanfey and Rilling monitored brain scans of 19 receivers during the
experiment as they participated in 10 games with different proposers.
While rejecting an offer, increased brain activity was observed in the
anterior insula, which is associated with negative emotions such as
disgust. Brain activity decreased in the dorsolateral prefrontal cortex,
which is associated with deliberative thought. The reverse occurred when
subjects accepted offers.
"People's emotions are so riled up that it overrides the happiness
of getting one or two dollars," explains Sanfey. "People are willing to
sacrifice this amount of money to punish the person who they think is
treating them badly."
