Little research has examined factors that might weaken or strengthen commitment effects on relationship outcomes. The current research integrates attitude strength and investment model perspectives to identify uncertainty as a new moderator of commitment's predictive ability. Consistent with an attitude strength perspective, having doubt associated with commitment undermines commitment's predictive power. However, uncertainty can motivate uncertainty reduction achieved by acting in line with commitment. Therefore, uncertainty amplifies commitment effects on relationship maintenance, but only when behaviors are perceived to have implications for uncertainty. Across studies, certainty was found to moderate the link between commitment and relationship outcomes. Whether uncertainty weakened or strengthened commitment's predictive power depends on an individual's focus (implication-focused or not) when making relationship judgments.
Keywords: Attitude strength; commitment; investment model; relationship stability; uncertainty.