Thinking and Deciding

454 SOCIAL DILEMMAS: COOPERATION VERSUS DEFECTION
of which the subject could contribute to a common pool. All subjects received bonus
points that depended on these contributions.
There were two conditions of interest, which differed in terms of the system used
for determining the number of bonus points. In the minimum condition, the number
of bonus points was determined by the size of the contribution of the subject who
had contributed the least; if only one subject contributed nothing, there would be
no bonus at all. This is analogous to preserving the reputation of a group. One “bad
apple,” it is said, can spoil things for everyone. Here, fear would prevent people from
contributing if they thought that someone else would contribute less. A contributor
would be a sucker, losing for no good reason. Greed, however, would make no
sense here, because a small contribution would destroy the possibility of any benefit
from the contributions of others. Thus, the minimum condition was assumed to be
sensitive to fear.
In the maximum condition, the bonus depended on the amount given by the highest
contributor. This is like volunteering for a dangerous mission on behalf of a
group, when only a few volunteers are required. Here, one is little affected by a
few defectors, so fear of someone else’s defecting plays little role. You do not lose
if others contribute less. Greed, however, may play a larger role, for one’s own
contribution also matters little, except in the unlikely event that one is the highest
contributor. The maximum condition was thus assumed to be sensitive to greed. 3
Yamagishi and Sato found that friends cooperated more than strangers in the
minimum condition but not in the maximum condition. Presumably friends were
less afraid that they would cheat on each other by giving less money, but friendship
had no effect on personal greed. Subjects were also given a questionnaire about their
attitudes toward public questions, with items designed to assess both fear and greed
as general motives in the subjects. Here are some “fear” items (pp. 69–70):
Help to developing nations should be limited to the minimum, because
it is only exploited by a small group of people.
During the oil shock, people rushed to stores to buy a stock of toilet
paper because people are concerned only with their own interest and not
with the benefit of society.
There will be more people who will not work, if the social security system
is developed further.
Here are some greed items (p. 70):
In order to be a successful person in this society, it is important to make
use of every opportunity.
It is not morally bad to think first of one’s own benefit and not of other
people’s.
3 Yamagishi and Sato called the two conditions “conjunctive” and “disjunctive,” respectively.