30 JULY 2002: ENDING
THE SELF-INTEREST MYTH: T. HOBBES, A. SMITH TURNS OVER IN THEIR GRAVES.
From the July 23, 2002 NEW
Why We’re So Nice: We’re
Wired to Cooperate
By NATALIE ANGIER
What feels as good as chocolate
on the tongue or money in the bank but won’t make you fat or risk a subpoena
from the Securities and Exchange Commission?
as it may be to believe in these days of infectious greed and sabers unsheathed,
scientists have discovered that the small, brave act of cooperating with
another person, of choosing trust over cynicism, generosity over selfishness,
makes the brain light up with quiet joy.
neural activity in young women who were playing a classic laboratory game
called the Prisoner’s Dilemma, in which participants can select from a
number of greedy or cooperative strategies as they pursue financial gain,
researchers found that when the women chose mutualism over “me-ism,” the
mental circuitry normally associated with reward-seeking behavior swelled
longer the women engaged in a cooperative strategy, the more strongly flowed
the blood to the pathways of pleasure.
performing their work at Emory University in Atlanta, used magnetic resonance
imaging to take what might be called portraits of the brain on hugs.
results were really surprising to us,” said Dr. Gregory S. Berns, a psychiatrist
and an author on the new report, which appears in the current issue of
the journal Neuron. “We went in expecting the opposite.”
had thought that the biggest response would occur in cases where one person
cooperated and the other defected, when the cooperator might feel that
she was being treated unjustly.
the brightest signals arose in cooperative alliances and in those neighborhoods
of the brain already known to respond to desserts, pictures of pretty faces,
money, cocaine and any number of licit or illicit delights.
reassuring,” Dr. Berns said. “In some ways, it says that we’re wired to
cooperate with each other.”
is among the first to use M.R.I. technology to examine social interactions
in real time, as opposed to taking brain images while subjects stared at
static pictures or thought-prescribed thoughts.
also a novel approach to exploring an ancient conundrum, why are humans
so, well, nice? Why are they willing to cooperate with people whom they
barely know and to do good deeds and to play fair a surprisingly high percentage
of the time?
have no trouble explaining the evolution of competitive behavior. But the
depth and breadth of human altruism, the willingness to forgo immediate
personal gain for the long-term common good, far exceeds behaviors seen
even in other large-brained highly social species like chimpanzees and
dolphins, and it has as such been difficult to understand.
pointed out to my students how impressive it is that you can take a group
of young men and women of prime reproductive age, have them come into a
classroom, sit down and be perfectly comfortable and civil to each other,”
said Dr. Peter J. Richerson, a professor of environmental science and policy
at the University of California at Davis and an influential theorist in
the field of cultural evolution. “If you put 50 male and 50 female chimpanzees
that don’t know each other into a lecture hall, it would be a social explosion.”
Fehr of the University of Zurich and colleagues recently presented findings
on the importance of punishment in maintaining cooperative behavior among
humans and the willingness of people to punish those who commit crimes
or violate norms, even when the chastisers take risks and gain nothing
themselves while serving as ad hoc police.
survey of the management of so-called commons in small-scale communities
where villagers have the right, for example, to graze livestock on commonly
held land, Dr. Elinor Ostrom of Indiana University found that all communities
have some form of monitoring to gird against cheating or using more than
a fair share of the resource.
games that mimic small-scale commons, Dr. Richerson said, 20 to 30 percent
have to be coerced by a threat of punishment to cooperate.
Fear alone is not highly likely to inspire cooperative behavior to the
degree observed among humans. If research like Dr. Fehr’s shows the stick
side of the equation, the newest findings present the neural carrot people
cooperate because it feels good to do it.
new findings, the researchers studied 36 women from 20 to 60 years old,
many of them students at Emory and inspired to participate by the promise
of monetary rewards. The scientists chose an all-female sample because
so few brain-imaging studies have looked at only women. Most have been
limited to men or to a mixture of men and women.
is a vast body of non- imaging data that rely on using the Prisoner’s Dilemma.
a simple and elegant model for reciprocity,” said Dr. James K. Rilling,
an author on the Neuron paper who is at Princeton. “It’s been referred
to as the E. coli of social psychology.”
past results, the researchers said, one can assume that neuro- imaging
studies of men playing the game would be similar to their new findings
structure of the trial had two women meet each other briefly ahead of time.
One was placed in the scanner while the other remained outside the scanning
room. The two interacted by computer, playing about 20 rounds of the game.
In every round, each player pressed a button to indicate whether she would
“cooperate” or “defect.” Her answer would be shown on-screen to the other
awards were apportioned after each round. If one player defected and the
other cooperated, the defector earned $3 and the cooperator nothing. If
both chose to cooperate, each earned $2. If both opted to defect, each
mutual cooperation from start to finish was a far more profitable strategy,
at $40 a woman, than complete mutual defection, which gave each $20.
that a woman took each time she became greedy for a little bit more was
that the cooperative strategy would fall apart and that both would emerge
cases, both women were allowed to pursue any strategy that they chose.
In other cases, the non- scanned woman would be a “confederate” with the
researchers, instructed, unbeknown to the scanned subject, to defect after
three consecutive rounds of cooperation, the better to keep things less
rarefied and pretty and more lifelike and gritty.
other experiments, the woman in the scanner played a computer and knew
that her partner was a machine. In other tests, women played a computer
but thought that it was a human.
found that as a rule the freely strategizing women cooperated. Even occasional
episodes of defection, whether from free strategizers or confederates,
were not necessarily fatal to an alliance.
social bond could be reattained easily if the defector chose to cooperate
in the next couple of rounds,” another author of the report, Dr. Clinton
D. Kilts, said, “although the one who had originally been `betrayed’ might
be wary from then on.”
result of the episodic defections, the average per-experiment take for
the participants was in the $30’s. “Some pairs, though, got locked into
mutual defection,” Dr. Rilling said.
the scans, the researchers found that in rounds of cooperation, two broad
areas of the brain were activated, both rich in neurons able to respond
to dopamine, the brain chemical famed for its role in addictive behaviors.
the anteroventral striatum in the middle of the brain right above the spinal
cord. Experiments with rats have shown that when electrodes are placed
in the striatum, the animals will repeatedly press a bar to stimulate the
electrodes, apparently receiving such pleasurable feedback that they will
starve to death rather than stop pressing the bar.
region activated during cooperation was the orbitofrontal cortex in the
region right above the eyes. In addition to being part of the reward-processing
system, Dr. Rilling said, it is also involved in impulse control.
round, you’re confronted with the possibility of getting an extra dollar
by defecting,” he said. “The choice to cooperate requires impulse control.”
the reward circuitry of the women was considerably less responsive when
they knew that they were playing against a computer. The thought of a human
bond, but not mere monetary gain, was the source of contentment on display.
with the imaging results, the women, when asked afterward for summaries
of how they felt during the games, often described feeling good when they
cooperated and expressed positive feelings of camaraderie toward their
that the urge to cooperate is to some extent innate among humans and reinforced
by the brain’s feel-good circuitry, the question of why it arose remains
unclear. Anthropologists have speculated that it took teamwork for humanity’s
ancestors to hunt large game or gather difficult plant foods or rear difficult
children. So the capacity to cooperate conferred a survival advantage on
with any other trait, the willingness to abide by the golden rule and to
be a good citizen and not cheat and steal from one’s neighbors is not uniformly
put some C.E.O.’s in here, I’d like to see how they respond,” Dr. Kilts
said. “Maybe they wouldn’t find a positive social interaction rewarding