1985 年 56 巻 2 号 p. 68-74
In this study, it was hypothesized that (1) both task- and performance-contingent rewards would undermine intrinsic motivation for high-interest task but enhance it for low-interest one, that (2) in the high-interest task conditions, performance-contingent rewards would undermine intrinsic motivation more than task-contingent ones, and that (3) in the low-interest task conditions, performance-contingent rewards would enhance intrinsic motivation more than task-contingent ones. Ninety female undergraduate subjects were offered task-contingent (300 yen for participating in the task for 8 min) or performance-contingent (piece rate: 15 yen for each 10 characters deciphering) rewards, or no reward, for working on a decipherment task called a cipher game of high or low interest. Results indicated that both task- and performance-contingent rewards, which did not differ from each other, undermined intrinsic motivation for high-interest task. Task-contingent rewards enhanced intrinsic motivation for low-interest task, but performance-contingent rewards did not affect it. These results were discussed in terms of a general approach to the self-perception of intrinsic motivation.