Decreasing junk food consumption: A comparison of self-perception theory and reinforcement theory

A behavior reduction procedure based on self-perception theory was developed, and its efficacy was compared to that of a common behavior modification intervention based on traditional reinforcement theory. Following a baseline phase, university students were monetarily reinforced for increasing (in the self-perception condition) or decreasing (in the behavior modification condition) their consumption of junk food. Subsequently, the magnitude of reinforcement was reduced and, finally, the reinforcement contingency was withdrawn. The intervention based on reinforcement theory produced the predicted decrease in junk food consumption while the intervention was in effect, and the postreinforcement intake of subjects in that condition remained below baseline. However, despite an increase in junk food consumption during the intervention phase in the self-perception condition, the hypothesized overjustification effect was not produced. While the results did not support self-perception theory, the data were consistent with an alternative account of the overjustification effect proposed by Williams (1980).This research was partially supported by National Science Foundation Grant SPI8026324 to John F. Kremer and Robert G. Bringle.