Editing Self-perception theory (section)

==Apparent disproof==
Debate ensued over whether dissonance or self-perception was the valid mechanism behind attitude change. The chief difficulty lay in finding an experiment where the two flexible theories would make distinctly different predictions. Some prominent [[Social psychology|social psychologists]] such as [[Anthony Greenwald]] thought it would be impossible to distinguish between the two theories.

In 1974, Zanna and Cooper conducted an experiment in which individuals were made to write a counter-attitudinal essay.<ref name="Zanna">Zanna, M. P., & Cooper, J. (1974). Dissonance and the pill: An attribution approach to studying the arousal properties of dissonance. Journal of Personality and Social Psychology, 29(5), 703–709. {{doi|10.1037/h0036651}}</ref> They were divided into either a low choice or a high choice condition. They were also given a [[placebo]]; they were told the placebo would induce either tension, relaxation, or exert no effect. Under low choice, all participants exhibited no attitude change, which would be predicted by both cognitive dissonance theory and self-perception theory.<ref name="Zanna" /> Under high choice, participants who were told the placebo would produce tension exhibited no attitude change, and participants who were told the placebo would produce relaxation demonstrated larger attitude change.<ref name="Zanna" />

These results are not explainable by self-perception theory, as arousal should have nothing to do with the mechanism underlying attitude change. Cognitive dissonance theory, however, was readily able to explain these results: if the participants could attribute their state of unpleasant arousal to the placebo, they would not have to alter their attitude.