Expectancy Disconfirmation and Attitude Change

Abstract

An experiment was conducted testing the hypothesis that sources delivering unexpected communications (long-haired males arguing against marijuana usage and seminarians arguing in its favor) would be more persuasive than communicators of expected messages (promarijuana hippies and antimarijuana seminarians). Greater attitude change for unexpected sources was found only when the message was antimarijuana. Unexpected communicators also were rated as more sincere and honest than expected sources. Possible reasons for the failure of the expectancy effect to hold for promarijuana communications were suggested, and the results were discussed in terms of a variety of social-psychological theories.

Expectancy-Violation, Similarity, and Unexpected Similarity as Sources of Credibility and Persuasiveness

“…This is shown by the finding that only Ss in the liberal-communicator condition had significantly less permissive attitude scores than the control Ss, Furthermore, the liberal communicator was viewed more positively than his neutral and conservative counterparts: as more fair and better qualified, less dogmatic according to the more authoritarian Ss, and as providing more valuable information according to the more rebellious Ss. Thus, the present data support previous findings by Dutton (6), Koeske and Crano (10), McPeek and Edwards (20), and Walster, Aronson, and Abrahams (26) in emphasizing the importance of expectancy-violation as a determinant of communicators' credibility and persuasiveness.…”

“…In an applied context, it seems worth noting that both this study and that of McPeek and Edwards (20) show that an unexpected source is' particularly effective in arguing against illicit drug use. This suggests that the use of predictable sources for dissuasive messages about drugs is suboptimal.…”

“…The present study provided a situation in which several previously demonstrated effects conflicted: enhancement of a communicator's effectiveness by similarity to his audience (2,3,5,27); enhanced persuasiveness of a communicator through his advocacy of an unexpected position (6,10,20,26), and increased attractiveness and credibility of a communicator who agrees unexpectedly with his audience, plus decreased attractiveness and credibility of a communicator who disagrees unexpectedly with his audience (9,24). While the results of this study were not unequivocal, they did suggest that enhancement of a communicator's credibility by his advocacy of an unexpected position is the dominant process.…”

“…Other research suggests that communicators are especially effective when advocating positions which are, for them, unexpected: e. g., an apparent hippie opposing the use of marijuana (6,10,20,26). The common explanation for such findings is that people who take unexpected positions are perceived as particularly credible, and the cited studies seem to support this interpretation.…”

On reluctant testimony

“…McPeek and Edwards (1975) used two messages (favoring and opposing marijuana) and three source conditions (a hippie, a religious seminarian, and an unseen/ unidentified source). They found no difference for source in the pro-marijuana message.…”