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Sleep inspires insight


Insight denotes a mental restructuring that leads to a sudden gain of explicit knowledge allowing qualitatively changed behaviour1,2. Anecdotal reports on scientific discovery suggest that pivotal insights can be gained through sleep3. Sleep consolidates recent memories4,5,6 and, concomitantly, could allow insight by changing their representational structure. Here we show a facilitating role of sleep in a process of insight. Subjects performed a cognitive task requiring the learning of stimulus–response sequences, in which they improved gradually by increasing response speed across task blocks. However, they could also improve abruptly after gaining insight into a hidden abstract rule underlying all sequences. Initial training establishing a task representation was followed by 8 h of nocturnal sleep, nocturnal wakefulness, or daytime wakefulness. At subsequent retesting, more than twice as many subjects gained insight into the hidden rule after sleep as after wakefulness, regardless of time of day. Sleep did not enhance insight in the absence of initial training. A characteristic antecedent of sleep-related insight was revealed in a slowing of reaction times across sleep. We conclude that sleep, by restructuring new memory representations, facilitates extraction of explicit knowledge and insightful behaviour.

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  1. 1

    Köhler, W. Gestalt Psychology: An Introduction to New Concepts in Modern Psychology (Liveright, New York, 1947)

  2. 2

    Sternberg, R. J. & Davidson, J. E. The Nature of Insight (Bradford Books/MIT Press, Cambridge, MA, 1995)

  3. 3

    Mazzarello, P. What dreams may come? Nature 408, 523 (2000)

  4. 4

    Maquet, P. The role of sleep in learning and memory. Science 294, 1048–1052 (2001)

  5. 5

    Smith, C. Sleep states and memory processes. Behav. Brain Res. 69, 137–145 (1995)

  6. 6

    Buzsáki, G. Memory consolidation during sleep: a neurophysiological perspective. J. Sleep Res. 7 (Suppl. 1), 17–23 (1998)

  7. 7

    Pavlides, C. & Winson, J. Influences of hippocampal place cell firing in the awake state on the activity of these cells during subsequent sleep episodes. J. Neurosci. 9, 2907–2918 (1989)

  8. 8

    Wilson, M. A. & McNaughton, B. L. Reactivation of hippocampal ensemble memories during sleep. Science 265, 676–679 (1994)

  9. 9

    Maquet, P. et al. Experience-dependent changes in cerebral activation during human REM sleep. Nature Neurosci. 3, 831–836 (2000)

  10. 10

    Stickgold, R., Hobson, J. A., Fosse, R. & Fosse, M. Sleep, learning, and dreams: off-line memory reprocessing. Science 294, 1052–1057 (2001)

  11. 11

    Fishbein, W. Disruptive effects of rapid eye movement sleep deprivation on long-term memory. Physiol. Behav. 6, 279–282 (1971)

  12. 12

    Gais, S., Plihal, W., Wagner, U. & Born, J. Early sleep triggers memory for early visual discrimination skills. Nature Neurosci. 3, 1335–1339 (2000)

  13. 13

    Plihal, W. & Born, J. Effects of early and late nocturnal sleep on declarative and procedural memory. J. Cogn. Neurosci. 9, 534–547 (1997)

  14. 14

    Wagner, U., Gais, S. & Born, J. Emotional memory formation is enhanced across sleep intervals with high amounts of rapid eye movement sleep. Learn. Mem. 8, 112–119 (2001)

  15. 15

    McNaughton, B. L., et al. in Sleep and Brain Plasticity (eds Maquet, P., Stickgold, R. & Smith, C.) 225–246 (Oxford Press, Oxford, UK, 2003)

  16. 16

    Thurstone, L. L. & Thurstone, T. G. Factorial studies of intelligence. Psychometr. Monogr. 2, 94 (1941)

  17. 17

    Frensch, P., et al. in Attention and Implicit Learning (ed. Jiménez, L.) 335–366 (John Benjamins, Amsterdam/Philadelphia, 2002)

  18. 18

    Rose, M., Haider, H., Weiller, C. & Büchel, C. The role of medial temporal lobe structures in implicit learning: an event-related FMRI study. Neuron 36, 1221–1231 (2002)

  19. 19

    Epstein, R., Kirshnit, C. E., Lanza, R. P. & Rubin, L. C. ‘Insight’ in the pigeon: antecedents and determinants of an intelligent performance. Nature 308, 61–62 (1984)

  20. 20

    Durso, F. T., Rea, C. B. & Dayton, T. Graph-theoretic confirmation of restructuring during insight. Psychol. Sci. 5, 94–98 (1994)

  21. 21

    Jiménez, L., Méndez, C. & Cleeremans, A. Comparing direct and indirect measures of sequence learning. J. Exp. Psychol. Learn. Mem. Cogn. 22, 948–969 (1996)

  22. 22

    Cartwright, R. D. Problem solving: waking and dreaming. J. Abnorm. Psychol. 83, 451–455 (1974)

  23. 23

    Horne, J. A. Sleep loss and “divergent” thinking ability. Sleep 11, 528–536 (1988)

  24. 24

    Walker, M. P., Liston, C., Hobson, J. A. & Stickgold, R. Cognitive flexibility across the sleep-wake cycle: REM-sleep enhancement of anagram problem solving. Brain Res. Cogn. Brain Res. 14, 317–324 (2002)

  25. 25

    Fischer, S., Hallschmid, M., Elsner, A. L. & Born, J. Sleep forms memory for finger skills. Proc. Natl Acad. Sci. USA 99, 11987–11991 (2002)

  26. 26

    Clark, R. E. & Squire, L. R. Classical conditioning and brain systems: the role of awareness. Science 280, 77–81 (1998)

  27. 27

    Luo, J. & Niki, K. Function of hippocampus in “insight” of problem solving. Hippocampus 13, 316–323 (2003)

  28. 28

    McIntosh, A. R., Rajah, M. N. & Lobaugh, N. J. Functional connectivity of the medial temporal lobe relates to learning and awareness. J. Neurosci. 23, 6520–6528 (2003)

  29. 29

    McClelland, J. L., McNaughton, B. L. & O'Reilly, R. C. Why there are complementary learning systems in the hippocampus and neocortex: insights from the successes and failures of connectionist models of learning and memory. Psychol. Rev. 102, 419–457 (1995)

  30. 30

    Rechtschaffen, A. & Kales, A. A Manual of Standardized Terminology, Techniques and Scoring System for Sleep Stages of Human Subjects (NIH Publ. No. 204, Maryland, 1968)

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We thank S. Sabban, C. Benedict, M. Degirmenci, L. Hecking, A. Otterbein, and M. Rose for their assistance. This work was supported by grants from the Deutsche Forschungsgemeinschaft to J.B. and R.V.

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The authors declare that they have no competing financial interests.

Correspondence to Ullrich Wagner or Jan Born.

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Further reading

Figure 1: Task and experimental design.
Figure 2: Effects of sleep and wakefulness on the occurrence of insight.
Figure 3: Reaction time analysis.


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