An interaction between receiver ability to decode vocalic cues and speaker vocalic patterns in obtaining compliance was investigated in this study. Expectancy theory was offered as an explanation for this interaction. Because changes in vocalic patterns can violate expectations, receivers make consistent interpretations of these vocalic cues, and evaluations of these interpretations may be affected by decoder predispositions toward communication that, in turn, produce differential perceptions of source reward. Respondents were interviewed by trained encoders who used neutral, pleasant, and hostile vocal patterns. Compliance was assessed by asking for a donation of time to communication research. Follow-up surveys measured perceived relational messages, interviewer credibility, vocal pleasantness, and the degree to which the vocalic pattern was expected. The predicted disordinal interaction between decoding ability and voice condition was found. Decoding ability did not correlate with predispositions, nullifying source reward as a factor in the evaluation of vocalic violations. It was suggested that preferences for vocalic patterns influenced evaluations: Good decoders may have preferred affiliative cues and thus complied more with pleasant voices, whereas poor decoders may have preferred assertive patterns and complied more with hostile voices.