Thinking and Deciding

VOTERS’ ILLUSIONS 459
what is best for everyone. They may think that they should vote their own narrow
self-interest. If enough people did this, the needs of those who cannot wield power
through voting, such as children, minorities, people in the future, or people in other
countries, would be neglected. It might be better for everyone if people who voted
out of self-interest just decided that voting was not worthwhile — although the rest
of us would then have to look out for them.
There is, however, another incorrect reason for voting, which is less insidious.
People may think that their own choice affects others’ choices. Of course, this is
true, in that a vote supports a social norm favoring voting, but the belief in question
may go beyond that. Voters may reason, “If people on my side vote, I’ll probably
vote too. My voting will thus be linked with theirs. Hence, I’d better vote, because if
I don’t, they won’t either.” The same reasoning could apply to any social dilemma, of
course. The essential confusion here is between diagnostic and causal relationships.
Their own voting is diagnostic of the overall turnout on their side, but it does not
affect the turnout, except for their own vote. (The same reasoning is involved in the
Quattrone and Tversky experiment on self-deception described in Chapter 9.)
Quattrone and Tversky (1984) told subjects about a hypothetical election in a
country with 4 million supporters of party A, 4 million supporters of party B, and 4
million nonaligned voters. Subjects were told that they were supporters of party A.
Some subjects were told that the election depended on whether more of the supporters
of party A or the supporters of party B turned out to vote. These subjects said
that their side (party A) was substantially more likely to win if they voted than if they
did not vote. They were also quite willing to vote. Other subjects were told that the
election depended on whether more of the nonaligned voters voted for party A or for
party B. These subjects thought that the probability of their side’s winning was not
much different whether they voted or not. They were less willing to vote than the
subjects who were told that the election depended on the turnout of party supporters.
Of course, one vote is one vote; in fact, these latter subjects would have just as much
influence on the election whether it was “determined” by the party supporters or by
the nonaligned voters. In short, people may think that their vote affects other people,
when in fact they are only themselves affected by the same factors that affect other
people.
A related demonstration of this effect concerns the prisoner’s dilemma itself
(Shafir and Tversky, 1992). When subjects in a two-person prisoner’s dilemma were
told that their partner had defected, 97% of the subjects defected too. When they
were told that their partner had cooperated, 84% still defected. But when they did
not know what their partner had done, 37% cooperated and only 63% defected. Apparently,
many subjects did not think through the uncertainty about what their partner
had done: “If she cooperates, I will defect; if she defects, I will defect; so I don’t
need to know what she does, I should defect anyway.” Perhaps it is a good thing that
people do not think so logically in this case!
A second illusion that makes people vote is the confusion of morality and selfinterest.
It is as though people resist the very idea of a social dilemma, which is
a conflict between self and others. People try to reduce this conflict by convincing