How can a person be induced to do something he might not ordinarily do? What constitutes a commitment on his part of some future action? Past research indicates that compliance with a small, relatively innocuous "foot-in-the-door" request serves to increase, relative to a control group, subsequent compliance with a larger request directed toward the same goal. The present study suggests such commitment (increasing) effects may be limited to active "feet-in-the-door," predicting substitution (decreasing) effects for passive (less effortful) "foot-in-the-door" compliance. Results support only the substitution predictions and show none of the commitment effects previously demonstrated in the literature for active "foot-in-the-door" compliance. Attempts to resolve these discrepant findings generate a two-factor model, specifying both the degree of initial commitment and the active versus passive nature of the "foot-in-the-door" requests. Specifically, active "foot-in-the-door" compliance and low degrees of initial commitment seem to produce commitment effects; passive compliance and high initial commitment tend toward substitution effects. (Author)