This article from NYTimes.com
has been sent to you by khare@alumni.caltech.edu.
Axelrod, eh? "the E.coli of social psychology"? Nice to see our old friend still going strong -- Prisoner's Dilemma is old enough to qualify for AARP membership!
Regarding experimental design, it is interesting that 1) they used an all-female panel and 2) they included a mix of ages, from 20-60 and 3) they used humans, confederates, computers as well as imitations.
The last two paragraphs are a rare sign of editorialized humor by an NY Times bylined writer. Even still, note the very large fig leaf -- the CEO joke is introduced in an on-the-record quote.
Not that we're talking about anything nearly as colorful as the Economist :-)
RK
khare@alumni.caltech.edu
Why We're So Nice: We're Wired to Cooperate
July 23, 2002
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?
Hard 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.
Studying 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 to life.
And the longer the women engaged in a cooperative strategy,
the more strongly flowed the blood to the pathways of
pleasure.
The researchers, performing their work at Emory University
in Atlanta, used magnetic resonance imaging to take what
might be called portraits of the brain on hugs.
"The 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."
The researchers 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.
Instead, 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.
"It's reassuring," Dr. Berns said. "In some ways, it says
that we're wired to cooperate with each other."
The study 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.
It is 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?
Scientists 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.
"I've 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."
Dr. Ernst 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.
In her 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.
In laboratory 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.
In the 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.
But there is a vast body of non- imaging data that rely on
using the Prisoner's Dilemma.
"It's 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."
>>From past results, the researchers said, one can assume
that neuro- imaging studies of men playing the game would
be similar to their new findings with women.
The basic 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 player.
The monetary 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
earned $1.
Hence, mutual cooperation from start to finish was a far
more profitable strategy, at $40 a woman, than complete
mutual defection, which gave each $20.
The risk 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 the poorer.
In some 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.
In still 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.
The researchers 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.
"The 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."
As a 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.
Analyzing 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.
One is 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.
Another 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.
"Every round, you're confronted with the possibility of
getting an extra dollar by defecting," he said. "The choice
to cooperate requires impulse control."
Significantly, 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.
In concert 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
playing partners.
Assuming 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 our forebears.
Yet as 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 distributed.
"If we 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 at all."
A Prisoner's Dilemma indeed.
http://www.nytimes.com/2002/07/23/health/psychology/23COOP.html?ex=1028415440&ei=1&en=2face896773fa4ea
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