Thinking and Deciding

MOTIVES IN SOCIAL DILEMMAS 451
dollars). If we describe this as a change in the utilities of each subject, then the task
is no longer a social dilemma when this weight is exceeded.
As Smith suggested, emotional empathy, the tendency for people to experience
emotions that they observe others experiencing, is a source of altruism. This could
be the reason why pictures or films of famine victims inspire an outpouring of contributions
in the United States and Europe. To measure such empathy in the laboratory,
Krebs (1975) asked one subject to watch another subject (actually a confederate) performing
a task. In some conditions, the confederate either won money or appeared to
receive an electrical shock, as a result of the spin of a roulette wheel. Krebs had convinced
the observers that they were either similar (or dissimilar) to the confederate
by showing them, in advance, a questionnaire that the confederate had supposedly
filled out, which agreed (or disagreed) with the subjects’ opinions on various issues.
When the confederate was perceived as similar, the observers demonstrated more
physiological response (increased heart rate and the like) as a function of the outcome
experienced by the confederate. Also, when the confederate was perceived as
similar, subjects were more likely to sacrifice some of their own reward for the confederate,
when given an opportunity to do so. Krebs concluded that the feelings of
empathy made the subjects behave more altruistically.
Cultures seem to differ in their emphasis on cooperation. Parks and Vu (1994)
found that cooperation in social dilemmas was much greater in Vietnamese immigrants
to the United States than in U.S. college students. Vietnam is thought of as a
“collectivist” culture, in which group cohesion is highly valued.
It would seem that empathy and the desire to form and maintain groups are helpful
for altruistic behavior (behavior that helps another at one’s own expense), but they
may not be necessary. Some people apparently act out of a more abstract knowledge
that their action is morally right.
indexauthorsWaters, V. V.Altruism seems to motivate cooperation in social dilemmas,
even when strangers are involved. For example, Hershey, Asch, Thumasathit,
Meszaros, and Waters (1994) studied subjects’ willingness to be vaccinated against
a (hypothetical) flulike illness. For some vaccines, vaccination is a cooperative act,
because the vaccine prevents the recipient from passing the disease on to others. This
is called “herd immunity.” (If most animals in a herd are vaccinated, probably none
will get the disease.) Other vaccines prevent the symptoms of the disease but do not
prevent the vaccinated person from being infected in a way that passes the disease
to others. In this case, vaccination does not help others. Subjects were given several
hypothetical cases of each type of vaccination. The cases of each type varied in the
percentage of others who had decided to get the vaccine (88%, 64%, or 36%). If subjects
were interested in helping others, the effect of herd immunity on willingness to
vaccinate would be greatest when the fewest other people are vaccinated, because
the benefit to others would be greatest here. This result was found.
Outside of the laboratory, it is clear that people often cooperate when they need
not sacrifice much, even when those who benefit are strangers. People leave tips
for waiters even when they are traveling and have nothing to gain in terms of better
service next time. Dawes and Thaler (1988) provide another telling example: “In the