The modification and generalization of voice loudness in a fifteen-year-old retarded girl.

A fifteen-year-old severely disturbed girl was treated for aphonia. Because of the extent of her withdrawal, the subject was conditioned in a laboratory setting and received tokens for speaking loudly enough to operate a voice-operated relay. Conditioning at first consisted of saying 100 monosyllabic words, with the possibility of reinforcement on each word. Later, the subject was required to say a polysyllabic word, and finally, five or six words per token. The subject was shaped to speak with normal loudness in the laboratory, and generalization to a reading situation in the laboratory was measured and observed to occur, at first for a few minutes, and later for a longer period. Generalization to a reading situation in the classroom did not occur, but the subject's voice loudness also increased in the classroom when several new reinforcement contingencies were put into effect there.