Effects of a cognitive intrusion manipulation on the sleep-onset latency of good sleepers

Thirty-eight female good sleepers were instructed to go to sleep as quickly as possible in a daytime nap session under one of three instructional sets designed to manipulate the likelihood of cognitive intrusions. Subjects informed that they would be required to present a speech after their sleep period and told the topic of the speech required significantly longer to fall asleep and obtained less sleep than subjects in two control conditions. Analysis of heart rate and skin conductance measures failed to support the mediational role of autonomic activity in retarding sleep-onset.