Attribution of Causality and the Overjustification Effect

Using false physiological feedback to influence attribu tions of intrinsic or extrinsic motivation, it was found that the overjustification effect is mediated by one's self-perceived motiva tion. Contingent reward significantly decreased intrinsic interest, which was defined as the number of trials on the target activity during a free choice period. This overjustification effect was significantly decreased when individuals were given an intrinsic interpretation of their behavior, while individuals given an extrin sic interpretation for their behavior showed a non-significant augmentation of the overjustification effect.