Thinking and Deciding

448 SOCIAL DILEMMAS: COOPERATION VERSUS DEFECTION
why should I be the only one to obey the “Keep Off the Grass” sign? I would only
decrease net benefit by hurting myself and helping nobody. (Let us put aside such
arguments as the fact that by being seen to walk around the grass I might encourage
others to do likewise. We have not counted such precedent setting as an outcome in
our analysis, and if we did count it, Figure 18.2 would look different.)
Schelling (1978, p. 236) gives another example of the conflict between the cooperative
theory and utility maximization. In summer, it is best for everyone if everyone
is on daylight saving time. By the cooperative theory, each of us ought to live according
to daylight saving time, even if everyone else around us is on standard time.
This example shows, again, that the effect of what we do depends on what others do.
In this case, it is best to conform.
The self-interest theory says that I should always do what is best for me and
ignore everyone else. Therefore I should always walk on the grass. Two different
forms of this theory are often confused. One form says that we should not care about
other people. Hardly anyone seriously holds this theory. The second form says that
it is best for everyone if individuals look out for their own interest. This theory is, in
fact, taken seriously by many as a moral theory, because it is concerned with what
is best for everyone. This theory seems to be the underlying justification for various
defenses of free enterprise, for example. It is often argued that the best society for
everyone is a society in which all individuals pursue their own self-interest.
The problem with this theory is that it essentially denies the existence of social
dilemmas. We may define such dilemmas as cases in which pursuit of narrow selfinterest
is not best for everyone. (We shall make this definition more precise later,
but it accounts for all the cases we have encountered so far, and it is consistent both
with the definition we shall give and with Dawes’s definition.) If there are any such
cases — and there surely are many — this theory simply ignores the problem that
they create; it gives up on the problem we are trying to solve. As a normative theory,
it amounts to saying that morality makes no claims on individual behavior. (It might
be more defensible as a prescriptive theory, but later I shall argue against that too.)
If we apply utilitarianism to the grass-walking problem, it says that I should
cooperate as long as the benefit to others from doing so is greater than the cost to
me. Therefore, I should cooperate when the number of other cooperators is about
50%, but not at either end of the percentage range. At the high end, I may not know
exactly how many cooperators there are; it would be difficult to determine whether I
will be the critical person who starts the decline of the grass. It seems sensible here to
compute expected utility, given my personal probabilities for the different numbers
of cooperators.
Utilitarianism seems to some to be too demanding. It seems to require people to
give away money whenever someone else could use the money more than they, for
example. (The cooperative theory has the same problem.) But it may not make such
impossible demands when it is taken as a theory of an entire life plan rather than
individual acts. People who always give their money away may not do as much good
in the long run as people who develop their talents in a way that is helpful to others
and then put their talents to use, maintaining a lifestyle that allows them to do this