Have you ever been insulted by someone whom you considered a friend? Initially, you are probably surprised and upset, and as you continue to think about the incident, you might become even more upset--how could that person say that to you?--and further thought might even lead to intense hatred and rage. On the other hand, has a friend ever done something especially nice for you? At first, you are pleasantly surprised. As you think more about the good deed, it may begin to seem even nicer--very few other people would have been so kind--and your attitude toward the other person may soon become extremely favorable. In both of these examples, the phenomenon of self-persuasion is occurring--thinking about some incident or issue causes your attitude to become more extreme or polarized. The attitude change that occurs is not the result of a message that originates externally but rather is the result of thoughts, ideas, and arguments that you generate yourself (see box 8.1).
In this chapter, we will first focus on research in which an attempt is made to change attitudes by having people generate their own messages on some issue. Next, parallels between the self-persuasion approach and the dissonance theory approach (discussed in chap. 5) are addressed. Finally, we discuss the importance of a person's own thoughts in inhibiting and facilitating attitude changes that result from exposure to externally originated messages. The theme of this chapter is that virtually all persuasion effects can be thought of as self-persuasion.
Janis and King ( 1954) reported one of the earliest investigations in which the effects of actively presenting arguments on an issue were compared with the effects of passively listening to arguments presented by another person. In this study, subjects participated in groups of three. In any one session, an individual subject was to present a talk on one topic and listen to the two other subjects present speeches on two different topics. The subjects were led to believe that