Increasing speech intensity of chronic patients ("mumblers") bu shaping techniques.

The present experiment sought to increase the volume of speech in three adult male institutionalized patients. The method consisted of shaping modeled responses. Reinforcement was contingent upon the vocalization surpassing the threshold on an electronic volume indicator, which could be set at various levels of sensitivity. Results indicated that the volume of speech was increased in all three cases, as a function of manipulation of reinforcement contingencies. Follow-up data indicated that the long term maintenance of the acquired behavior was dependent on the ward environment.