The effects of learning monologues on subsequent sleep in actors and non-actors

Objectives: Previous research from our group has found that presleep learning at a declarative task (word-pair lists) improves continuity, stability and cyclic organization of subsequent sleep. Our aims were to confirm this finding using a more ecological task (a theatrical monologue) and to investigate, by comparing a sample of normal subjects with a group of professional actors, whether the effect is modulated by learning habit (i.e., how much the individual is familiar with that kind of task). Methods: Polysomnography of a baseline sleep (BL, 9-h TIB) was compared to that of a post-training sleep (TR, same TIB but preceded by an intensive training session using a theatrical monologue), in two groups of subjects: non-actors (N = 11) and professional actors (N = 11). Results: In both groups, TR appears reorganized and re-compacted by the learning sessions, as shown, among others, by a significant decrease of WASO (P = 0.01), awakenings (P = 0.01), arousals and state transitions (P = 0.001) and by an increase of the number of complete cycles (P = 0.02), and of Total Cycle Time (P = 0.03). Concerning memory performance, number of synonyms produced was significantly higher at morning relative to immediate recall (P = 0.001). No differences were found between groups either for sleep or memory variables. Conclusions: Our results confirm pre-sleep learning’s beneficial effect on sleep quality in an ecological context. While learning habit appears not to influence memory-related sleep mechanisms, results on morning recall support the hypothesis, advanced by various authors, that sleep’s role in memory processes consists in trace “transformation” for adaptive purposes, rather than rote consolidation.