Further examinations of the relationship between reward contingency and intrinsic motivation

Abstract

A series of laboratory studies were conducted to examine the effect of contingent monetary reward on the occurrence of behavior presumably determined by intrinsic task motivation. A general hypothesis that contingent monetary rewards would reduce the frequency of such behaviors was derived from a postulate of cognitive evaluation theory. For all of the studies, intrinsic task motivation was operationally defined as the amount of free time a subject spent working on a task without receiving reward. Study 1 investigated the effects of reward contingency and reward magnitude upon the behavioral measure of intrinsic motivation and upon related attitudinal variables. Study 2 examined the effects of reward contingency and two individual difference variables (self-esteem and perceived locus of control) on intrinsic motivation and attitudinal measures. Although Study 2 showed no significant results, Study 1 demonstrated support for the hypothesis with the behavioral measure of intrinsic motivation, but not with the attitudinal measures. Further examination of the behavioral measure of intrinsic motivation suggested that this variable was bimodally distributed in both Studies 1 and 2. A test for normality indicated that the distributions were significantly non-normal and that parametric analyses of mean differences were inappropriate. Study 3 reported the results of nonparametric reanalyses of Studies 1 and 2 and of data previously published by Deci as supportive of the postulate under examination. Deci's data were also found to be generally bimodal. The nonparametric analyses were nonsignificant for all data sets. Theoretical implications of these results are discussed and future directions for research are suggested.