Effects of loss of sleep on retrieval from semantic memory at two different times of day

Abstract

This study is concerned with the effects of loss of sleep on retrieval from long-term semantic memory as assessed at two different times of day. Sixteen subjects performed a semantic classification task in the morning (08.00) and at midday following a night's sleep and the loss of one night's sleep. Classsification latencies were significantly slower, and the time taken to retrieve low- relative to high-dominance category members significantly increased following loss of sleep. In addition, classification latencies were significantly faster, and the low- relative to high-dominance retrieval time significantly decreased at midday compared to in the morning. It is suggested that the effects of loss of sleep and time of day may be mediated by arousal: the effects of loss of sleep due to a state of chronic low arousal and the effects of time of day due to a rise in an underlying circadian arousal rhythm.