Waking performance decrements following minimal sleep disruption: The effects of habituation during sleep

The present research was concerned with whether the occurrence of habituation to auditory stimuli during sleep might attenuate the disruptive effects these stimuli can have on waking performance. Human subjects were exposed on different nights to either 0, 6, or 24 presentations of a 15-sec burst of filtered auditory noise, and their morning waking performance was measured by a reaction-time task previously shown to be sensitive to minimal sleep disturbances. The results indicated that on nights when 24 stimuli were presented, the subjects’ average arousal response was significantly less as compared to the nights when only 6 stimuli were presented, thus demonstrating the occurrence of habituation. However, the decreased average arousal when 24 stimuli occurred was not associated with superior morning performance. On the contrary, the subjects performed significantly better following the nights when only 6 stimuli occurred even though the average arousal associated with the stimulus presentations was significantly greater. The data thus suggest that the relation between sleep disruption and waking performance is a function of not only the arousal produced by the individual stimulus occurrences but also, and perhaps more importantly, the number of stimuli occurring during the night.