Fairness Is a Hard-Wired Emotion
The belief that things should be divided fairly among members
of a group isn't just a matter of culture or reason -- it's
an emotion
that's built into the human brain.
That's the suggestion of a new study that posed the question:
Is it better to give food to some hungry children while others
go hungry? Or is it better that every child get a share, albeit
a smaller one?
"People prefer equity, when all things are equal, to efficiency,"
said study lead researcher Ming Hsu, a fellow at the University
of Illinois Beckman Institute for Advanced Science and
Technology.
And different regions
of the brain are involved when making decisions involving
fairness or efficiency, he said.
"In terms of the brain, we find areas of the insular cortex
are activated when people were choosing the equitable allocation
of food," Hsu said. "Given the involvement of the insular
cortex in emotions and fairness judgments, we conclude that emotions
are underlying equity judgments."
Other areas of the brain are activated when people are making
judgments about efficiency, he said.
But, not everyone is sensitive to equity, Hsu noted. "Some
people care less about equity, and that's associated with
a lower sensitivity in their insula," he said. "When
these people are confronted with inequitable situations, their
insula is activated less."
The study, by researchers at the University of Illinois and the
California Institute
of Technology, was published in the May 8 issue of Science.
For the study, the volunteers were hypothetically asked to distribute
food to children in an orphanage in Uganda.
The children would be given the cash equivalent of 24 meals, a
"gift" from the research team to the orphanage.
But, a number of meals would have to be cut for some of the children.
So, the volunteers were given two options to deal with the problem.
In one option, 15 meals could be taken from one child, or 13
from another child, or five from yet another child, for instance.
Choosing this option, the total number of meals lost would be
less, but one child would suffer from all cuts. Efficiency would
be maintained at the expense of equity.
The second option reduced efficiency, but promoted equity. In
this option, all the children would be fed, but they'd share
fewer meals.
The researchers found that the study participants overwhelmingly
chose the second option. This finding echoed other studies that
showed that most people are intolerant of inequity, Hsu said.
During the experiment, the volunteers underwent functional magnetic
resonance imaging. This allowed the researchers to determine which
parts of the brain were most affected during decision-making.
The researchers found that regions of the brain called the insula,
putamen and caudate were activated differently, and at different
times, during the experiment. The insula responded to changes
in equity, while the putamen responded to changes in efficiency.
The caudate appeared to blend both equity and efficiency, Hsu
said.
The insights involving the insula, which plays a key role in
emotions, supports the idea that emotion rather than reason is
at the base of people's attitudes about inequality, Hsu said.
Also, studies had found that the insula is involved in deciding
fairness. But, the putamen and the caudate are activated during
reward-related learning, the researchers noted.
"These results support the idea that people care about equity
at a very deep level," Hsu said.
Brian Knutson, an assistant professor of psychology and neuroscience
at Stanford University,
said the findings illustrate just how much emotion is involved
in decision-making.
"We are finding that similar brain regions seem to be involved
in individual economic well-being and also the well-being of others,"
he said.
Because the areas of the brain involved in such decisions are
located deep inside the brain, it suggests they have a role in
evolutionary survival function, Knutson said. "They are serving
some sort of survival and emotional function," he said.
Knutson noted that many economic theories assume that people
use reason to make decisions, but the areas of the brain involved
in equity and efficiency are really areas activated by emotion.
"When people see an unfair offer, they actually have a
negative emotional reaction to it," Knutson said. "They
have a visceral reaction to unfairness."
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