Rotter's (1966) "control of reinforcement" construct is a dimension of belief or expectancy about the locus of reinforcing consequences for behavior. A generalized disposition is represented which ascribes reinforcement contingencies to either "external" (and, hence, uncontrollable) factors or to "internal" sources in which case the individual perceives himself as the effective determinant of reinforcing events. In this study, the "control of reinforcement" dimension was used to generate differential predictions about subjects' responsiveness to subtle social influence and experimenter effectiveness in producing change in verbal behavior. As predicted, "external" control Ss, selectively reinforced in a sentence construction task, evidenced significantly greater performance gains then "internal" Ss. Other differences are also reported. All differences are interpreted as being due to the internal's resistiveness to subtle forms of influence. Consideration of the control of reinforcement dimension as an important determinant of responsiveness to social influence in certain situations is emphasized. (Author/TL)