Harvard Medical School Beth Israel Deaconess Medical Center Boston, MA

1. Sleeping on a Problem: Where Insight is Expected Robert Stickgold Harvard Medical SchoolBeth Israel Deaconess Medical CenterBoston, MA

2. Insight “The sudden appearance in conscious awareness of a new and useful relationship among previously known information” “The sudden appearance in conscious awareness of a really bignew and useful relationship among previously known information” • Questions: • How does the nonconscious brain find these relationships? • How does it identify them as valuable? • How does it bring them into conscious awareness? • Should we only consider the “really big” ones?

3. “Really Big?” Normal science: "Curiosity demands that we ask questions, that we try to put things together and try to understand [them]... In this way we try gradually to analyze all things, to put together things which at first sight look different, with the hope that we may be able to reduce the number of ‘different things’ and thereby understand them better.” Richard Feynman (1963) "The Feynman lectures on physics"

4. “Really Big?” ”Scientific revolutions are inaugurated by a growing sense ... that an existing paradigm has ceased to function adequately in the exploration of ... nature.” Entrenchment reduces possibility of shifting Thomas Kuhn (1962) "The Structure of Scientific Revolutions"

5. Or Not So Big? Piaget proposed that children learn by constructing a model of the world built of “schemas” that explain how parts of the world work. Assimilation (like normal science) integrates new perceptual information into innate or personally developed schemas (“robins”) (Children are biased to fit data into schemas) (Piaget, 1981)

6. So, big or small, the process of insight is probably fundamentally the same. Or Not So Big? When assimilation fails (“penguins”)accommodation modifies the schemas “to fit reality” (Piaget & Inhelder, 1969, p. 6)

7. The processes of brain plasticity necessary for Piagetian accommodation, and hence for insight, may be most daringly activated, not during wake, but during sleep. Sleep & Insight Insight, then, whether related to large or small discoveries, is a special case of Piagetian accommodation in which the process occurs outside of conscious awareness. Obviously, this process of accommodation (and insight) is defined by the innate wiring and functional plasticity of the human brain.

8. There are Different Kinds of Sleep

9. REM sleep Sleep onset Stage 2 NREM SWS A Good Night’s Sleep Wake I/REM II III IV 11 PM 1 AM 3 AM 5 AM 7 AM

10. EEG Wake Stage 2 Stage 4 REM EOG Stage 1 Stage 2 REM EMG Wake Stage 4 REM 2 sec Sleep Physiology

11. Quiet SWS REM Wake Neuromodulation Varies Across the Wake-Sleep Cycle Active Wake ACh NE 5-HT Ach: acetylcholine (scopolamine, belladonna) NE: norepinephrine (MAO inhibitors, cocaine) 5HT: serotonin (Prozac, LSD)

12. Regional Activation in REM Sleep

13. Neocortex Hippocampus Hippocampal-Neocortical Dialog

14. There are Different Kinds of Memory

15. Semantic Priming paper wrong • Cindi Rittenhouse • Jen Holmes • Beth Schirmer • Lauri Scott (600 ms) wrong thief (580 ms) right wrong (560 ms) Sleep Alters Associative Memory Systems

16. Weak 30 Strong 20 msec 10 0 0.17 0.01 0.01 NREM PM REM

17. Number Reduction Task • Ulrich Wagner • Jan Born 1 1 4 4 9 4 9 4 1 9 1 4 4 1 9 Wagner et al. (2004) Nature 427: 352 Sleep Enhances Insight

18. 60% SWS 200 40% Subjects gaining insight Improvement in speed (ms) 100 20% SWS 0% 0 Wake/ Day Wake/ Night Non-solvers Solvers Development of Insight 1 1 4 4 9 4 9 4 9 1 9 1 4 4 1 9 Sleep/ Night

19. • Ina Djonlagic • Andy Rosenfeld • Mark Gluck Sleep Calculates the Rules

20. Card 1 Card 2 Card 3 Card 4 ?!? 80% 60% 40% 20% Probabilistic Learning

21. Practice & Sleep Enhance Performance p = 0.01 p = 0.06 Observation Feedback Wake Sleep 14 12 10 Improvement (% of trials) 8 6 4 2 0

22. Weather Forecasting & REM Sleep 25% 23% REM Sleep (%) 21% 19% 17% 15% 55 65 75 85 95 Post-Training Performance (% of optimal) r = 0.70 p = 0.008

23. Word Lists • Jessica Payne • Ruth Propper • Daniel Schacter Door House Ledge Glass Open Breeze Pane Frame Curtain Shade View Sleep Enhances the Gist

24. Sleep Wake * * Studied words Critical lures 12-Hour Deterioration 15 0 -15 % Change (relative to 20 min -30 -45 -60

25. 35 Words Recalled 25 15 5 10 15 20 25 SWS (%) Morning Recall r = -0.47 p = 0.03

26. Overnight Nap 50 60 r = -0.47 p = 0.03 50 40 40 words 30 words 30 20 20 10 10 0 0 0 10 20 30 40 50 120 40 80 60 100 SWS (min) SWS (min) Morning & Nap Recall r = -0.54 p = 0.037

27. Creative Intrusions

28. Creative Intrusions 40% Percent of Intrusions 20% 0% Wake Sleep

29. • Erin Wamsley • • Karen Emberger • Laura Babkes New Experiences are Replayed at Sleep OnsetHypnagogic dreams

30. Alpine Racer II • 14 out of 16 players (88%) • 42% of first night reports contain skiing imagery • 3 out of 3 controls who only watched

31. Alpine Racer Images “I keep seeing all the places where I fall- like, hit the walls. It’s kind of annoying; and then my legs fly up in the air.” (SEC) “I can sort of feel the motions of the game but more not really seeing it.” (MLC) “I envisioned myself skiing, and for a second there it felt like I was skiing backwards - something I used to attempt when I was younger.” (CMD)

32. } REPORTS Standard protocol 0 0 1 1 2 2 3 3 4 4 5 5 6 6 7 7 8 8 } REPORTS Delayed onset Math problems Delayed Onset Reporting

33. Insights Without Insight "I felt as though I was falling downhill. And I was dreaming about like instructions to a young king or something." (JAV, rpt 4) "I felt like I was sort of sliding downhill again. And, um ... there were instructions and a person and uh, I don't know." (JAV, rpt 6) "I was having a rather vivid image as though I was moving forward through some kind of a forest... I was moving forward very stiffly. Um, my entire upper body was incredibly straight ... it felt almost as if I was moving forward on a conveyor belt, and, without my legs actually moving." (MAM, rpt 8)

34. The Biology of Insight • The discovery of “insights” is aided by: • Shutting down logical (DLPFC) processing • Shutting down episodic memory replay (HC) • Enhancing error detection (ACC, MOFC) • Enhancing weak associations, and thereby … • Enhancing the recognition of accommodations that expand our understanding of the world

35. The Biology of Insight All of which occurs during REM Sleep! Thus sleep, and REM sleep in particular, may not only represent a model system for the processes involved in insight … But may actually represent a brain state which evolved, in part, to facilitate the discovery of insights.