Attribution of causality and the overjustification effect

Abstract. 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. A number of investigators have recently become interested in the effects of tangible reinforcers on intrinsic motivation (e.g. Deci, 1971; Lepper, Greene & Nisbett, 1973). In general, they have found that individuals who are given tangible reinforcers (e.g. money, Good Player Awards) for engaging in initially interesting activities (e.g