Today, let's activate a pleasure center. The
University of Houston's College of Engineering
presents this series about the machines that make
our civilization run, and the people whose
ingenuity created them.
Science Times writer Natalie
Angier tells about a new study of human cooperation
at Emory University. Investigators provide several
new wrinkles on the old Prisoner's Dilemma game.
They enlisted 36 players. They were all women, thus
reducing one dimension of variability. Each spent a
few moments meeting the person she'd be matched
with. Then each was put alone in a separate room
and shown two buttons. You push one button to
cooperate with the other player; you push
the other to defect from her.
If both players push cooperate, then each wins two
dollars (in real money). If both push defect, they
win only a dollar each. But: if one pushes
defect while the other pushes
cooperate, the defector wins three dollars
and the cooperator gets nothing at all.
So which button would you press? If you play only
one round, there's no learning curve; you might be
tempted to push defect and gamble on the other
person's response. But cooperation allows you both
to profit. In repeated rounds, some players
cooperate for a while, then they trick their
opponent by defecting.
In some rounds, players were told (or led to
believe) that they were playing a computer. Against
a computer (real or imagined) players became more
ruthless -- often at their own expense.
But they usually bonded with human opponents, even
though they were out of sight. Now and then,
players who decided they were up against a human
got themselves locked into repeated angry use of
their defect button. (Who among us hasn't
been led by anger into a lose-lose scenario?) But
cooperation, and a maximization of mutual profit,
was the norm. In fact, players often recovered from
those bouts of defection and restored their
Now the novel part of the study: One player from
each pair was subjected to an MRI brain scan while
she played. And here surfaced a far more basic
reason for cooperating than mere profit. Each
cooperative win-win play released dopamine. It, in
turn, lit up the same pleasure centers as, say,
eating chocolate does. Cooperation turns out to be
an authentic physical pleasure.
Angier includes one remark that powerfully strikes
home for me. She quotes a professor, who says,
I've pointed out to my students how impressive
it is that you can take a group of young men and
women ... have them come into a classroom, sit down
and be perfectly comfortable and civil to each
During fifty years of teaching, I've repeatedly
been struck by what a generally amicable place the
classroom is. Even in an inherently competitive
situation, students generally cooperate and seek
out the greater mutual good.
Now we know why. Cooperating is a pleasure. It's
one that we all forget, and deny to ourselves, from
time to time. But when we can engage it, it is
I'm John Lienhard, at the University of Houston,
where we're interested in the way inventive minds
Angier, N., Why We're So Nice: We're Wired to
Cooperate. New York Times, Tuesday, July 23,
2002, pp. D1, D8.
Owing to time constraints, I've been somewhat
simplistic about cooperation here. For more on the
subject, see http://www.uh.edu/engines/hisd.htm
The Engines of Our Ingenuity is
Copyright © 1988-2002 by John H.