Aroused dissonance in 80 female swimmers who used a campus pool by making them feel hypocritical about their showering habits. A 2 * 2 factorial design manipulated Ss' mindfulness that they had sometimes wasted water while showering and then varied whether they made a public commitment urging other people to take shorter showers. The hypocrisy condition (in which Ss made the public commitment after being reminded of their past behavior) was expected to be dissonance-arousing, thereby motivating Ss to increase their efforts to conserve water. Compared with controls, Ss in the hypocrisy condition took significantly shorter showers. Ss who were merely reminded that they had wasted water, or who only made the public commitment, did not take shorter showers than control Ss.