Evoked Sleep-Talking

Abstract

Evidence for modifications of verbal behavior without awareness when awake, increased spontaneous sleep-speech by posthypnotic suggestion, and discriminative motor responses during sleep suggested the possibility of induced/conditioned sleep-talking. Three students with no history of sleep disturbance or talking were trained for a total of 8 nights with avoidance-escape conditioning to sleep talk. The administration of light and tone stimuli followed schedules based on sleep stage and time (continuous, variable and fixed interval), with Ss at first naive and later informed. Reinforcements of vocalization through reductions or elimination of stimuli were adjusted to maximize responding without awakening S. Responses varied from groans, sighs, and unintelligible mumbling to coherent speech with and without affective tone, related and unrelated to the experiment, and rich or stereotyped. Latency and frequency of sleep responses over successive nights may depend on the interaction of stimuli intensity levels with type of sleeper (light/deep). Avoidance vocalizations, behavioral and transient EEG awakening significantly decreased from Stage 1 through 4. Conditioning techniques may be feasible in the development of sleep-talking skills.