Differential responsiveness by social stimuli was demonstrated in the communicative performance of an 8-year-old autistic boy. The pragmatic behavior of the subject varied with different communicative settings (waiting vs. interaction conditions) as well as with different communicative partners (mother, stranger, clinician). Communicative intentions, relational communication, topic strategies and differential responding to adults to communicative and non-communicative utterances were analyzed. Results indicated that the adults' communicative performance was a function of their relationships with the subject (mother, stranger, clinician) as well as the different experimental conditions (waiting, interacting). The child's communicative behavior showed greater consistency in conditions with the same interlocutor than over comparable experimental settings. Conclusions were drawn on how to facilitate communicative behavior and how to enhance generalization of remedial effects to the subject's natural environment.