Thinking and Deciding

SOLUTIONS TO SOCIAL DILEMMAS 465
each if both defected, and thirty-five and five, respectively, if one player defected
and the other cooperated. In a voting condition, subjects played the same game in
two groups of five. If a majority voted to cooperate, then everyone in the group was
counted as making a cooperative response, and likewise for defection. Subjects were
more likely to vote cooperatively in the voting condition than they were to cooperate
in the prisoner’s dilemma: cooperation declined essentially to zero in the dilemma
condition, over the course of twenty-five games, while it remained at about 20% in
the voting condition even at the end of the series of games.
One explanation of this result is that voting is low-cost. In the prisoner’s dilemma
condition, you gain ten points by defecting, regardless of what the other player does.
In the voting condition, the benefit of voting against cooperation depends on the
probability that your vote is critical, which is probably less than .5 (and is probably
perceived as low). The benefit of cooperating for others is also diluted in the
same way. A “weighted utilitarian,” who followed utilitarianism except for giving
himself a constant extra weight, would not behave differently in PD and DD. But
the expressive value of doing the right thing may be less dependent on its expected
consequences (Margolis, 1982).
Unfairness
Attempts to change the rules may also be affected by the perception of unfairness,
that is, by large differences in the amounts that players contribute. Samuelson, Messick,
Rutte, and Wilke (1984) studied the effects of departures from fairness in a
laboratory game. Six subjects sat at six different computer terminals and watched
displays showing the changing levels of a common resource pool. At the outset the
pool contained 300 units. On each trial, each player could take up to thirty units for
himself. After all players had taken what they wanted, a variable number of units
(about thirty) was added to the pool. (The units were worth real money.) Each subject
saw on the display the amounts that the other players took and the new level of
the pool after all players had consumed what they wanted. Subjects knew that if the
pool ran out, the experiment was over. Subjects were told both to try to get as many
points as possible and to make the resource pool last as long as possible.
In fact, the display was manipulated by the experimenter so that each subject
“saw” the other subjects behave in different ways. In some conditions, the other
subjects appeared to behave more or less the same way, leading to the appearance
of fairness. In other conditions, the subjects’ behavior differed drastically. Some
behaved like absolute pigs, and others were quite modest in their demands. The
average change in the size of the pool was also manipulated so as to make the pool
appear to increase, decrease, or stay about the same in size.
Subjects were more likely to take more for themselves when there appeared to
be no danger of the pool’s running out; when there was danger, subjects moderated
their demands, even if their demands had been minimal throughout. Subjects were
also asked whether they would like to elect a leader to apportion the resources for