Harvard Medical SchoolHarvard Medical SchoolBeth Israel Deaconess Medical CenterBeth Israel Deaconess Medical Center
Boston, MABoston, MA
Harvard Medical SchoolHarvard Medical SchoolBeth Israel Deaconess Medical CenterBeth Israel Deaconess Medical Center
Boston, MABoston, MA
Sleeping on a Problem: Where Insight is Expected Sleeping on a Problem:
Where Insight is Expected
Robert StickgoldRobert StickgoldRobert StickgoldRobert Stickgold
InsightInsight
“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 big new 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?
“Really Big?”“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"
“Really Big?”“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"
Or Not So Big?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)
Or Not So Big?Or Not So Big?
When assimilation fails (“penguins”) accommodation modifies the schemas “to fit reality”
(Piaget & Inhelder, 1969, p. 6)
So, big or small, the process of insight is probably fundamentally the same.
Sleep & InsightSleep & 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.
The processes of brain plasticity necessary for Piagetian accommodation, and hence for insight, may be most daringly activated, not during wake, but during sleep.
There are Different Kinds of Sleep
There are Different Kinds of Sleep
A Good Night’s SleepA Good Night’s Sleep
11 PM 1 AM 3 AM 5 AM 7 AM
Wake
I/REM
II
III
IV
Sleep onsetSleep onset
Stage 2 NREMStage 2 NREM
SWSSWS
REM sleepREM sleep
Sleep PhysiologySleep PhysiologyEEG
Wake
Stage 2
Stage 4
REM2 sec
EOGStage 1
Stage 2
REM
EMGWake
Stage 4
REM
Neuromodulation Varies Across the Wake-Sleep Cycle
Neuromodulation Varies Across the Wake-Sleep Cycle
Active Wake
ACh
NE5-HT
Quiet Wake
SWS REM
Ach: acetylcholine (scopolamine, belladonna)NE: norepinephrine (MAO inhibitors, cocaine)5HT: serotonin (Prozac, LSD)
Regional Activation in REM SleepRegional Activation in REM Sleep
Hippocampal-Neocortical DialogHippocampal-Neocortical DialogNeocortex
Hippocampus
There are Different Kinds of Memory
There are Different Kinds of Memory
Sleep Alters Associative Memory Systems
Sleep Alters Associative Memory Systems
• Cindi Rittenhouse• Jen Holmes• Beth Schirmer• Lauri Scott
Semantic Priming
(580 ms)thief wrong
(560 ms)right wrong
paper wrong (600 ms)
0.01 0.17 0.01
Weak
Strong
mse
c
0
10
20
30
REMNREM PM
Sleep Enhances InsightSleep Enhances InsightNumber Reduction TaskNumber Reduction Task
11 11 44 44 99 44 99 44
11 44 44 11 999911
• Ulrich Wagner• Jan Born
Wagner et al. (2004) Nature 427: 352
Development of InsightDevelopment of Insight
Wake/Night
Wake/Day
Sleep/ Night
0%
20%
40%
60%
Su
bje
cts
gai
nin
g i
nsi
gh
t
I
mp
rove
me
nt
in s
pee
d (
ms)
0
100
200
Solvers Non-solvers
SW
S
SW
S
11 11 44 44 99 44 99 44
11 99 11 44 44 11 9999
• Ina Djonlagic• Andy Rosenfeld• Mark Gluck
Sleep Calculates the Rules
Sleep Calculates the Rules
?!?
QuickTime™ and aTIFF (Uncompressed) decompressorare needed to see this picture.
QuickTime™ and aTIFF (Uncompressed) decompressorare needed to see this picture.QuickTime™ and aTIFF (Uncompressed) decompressorare needed to see this picture.
QuickTime™ and aTIFF (Uncompressed) decompressorare needed to see this picture.
Probabilistic LearningProbabilistic Learning
Card 1 Card 2 Card 3 Card 4
80% 60% 40% 20%
Practice & Sleep Enhance PerformancePractice & Sleep Enhance Performance
0
2
4
6
8
10
12
14
p = 0.01
Observation
Impro
vem
ent
(% o
f tr
ials
)
Wake
Sleep
Feedback
p = 0.06
Weather Forecasting & REM SleepWeather Forecasting & REM Sleep
15%
17%
19%
21%
23%
25%
55 65 75 85 95
Post-Training Performance (% of optimal)
REM
Sle
ep (
%)
r = 0.70p = 0.008
• Jessica Payne• Ruth Propper• Daniel Schacter
Word ListsDoor House LedgeGlass Open BreezePane Frame CurtainShade View
Sleep Enhances the Gist
Sleep Enhances the Gist
12-Hour Deterioration12-Hour Deterioration
15
0
-15
-30
-45
-60 Critical lures
Studied words
*
% C
han
ge (
rela
tive
to 2
0 m
in
Wake
Sleep
*
5
15
25
35
10 15 20 25
SWS (%)
Word
s R
eca
lled
Morning RecallMorning Recall
r = -0.47p = 0.03
60 Nap
0
10
20
30
40
50
0 10 20 30 40 50
SWS (min)
words
Morning & Nap RecallMorning & Nap Recall
r = -0.47p = 0.03
Overnight
words
SWS (min)
0
40
10
20
30
50
10040 60 80 120
r = -0.54p = 0.037
Creative IntrusionsCreative Intrusions
WordWord ListList
PlatePlate CupCup
SpoonSpoon CupCup
FuzzyFuzzy
SwirlSwirl
BloodBlood DoctorDoctor
Rough? Smooth?Rough? Smooth?
Soft? Mountain??Soft? Mountain??
0%
20%
40%
Wake
Perc
en
t of
Intr
usi
on
s
Sleep
Creative IntrusionsCreative Intrusions
New Experiences are Replayed at Sleep OnsetHypnagogic dreams
New Experiences are Replayed at Sleep OnsetHypnagogic dreams
• Erin Wamsley• Karen Emberger• Laura Babkes
Alpine Racer IIAlpine Racer II
• 14 out of 16 players (88%)14 out of 16 players (88%)• 42% of first night reports contain skiing 42% of first night reports contain skiing
imageryimagery• 3 out of 3 controls who only watched3 out of 3 controls who only watched
Alpine Racer ImagesAlpine 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)
Delayed Onset ReportingDelayed Onset Reporting
}REPORTS
Standard protocol0 2 3 4 5 6 7 81
}Math problems
REPORTS
Delayed onset0 2 3 4 5 6 7 81
Insights Without InsightInsights Without Insight
"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)
"I felt as though I was falling downhill. And I was dreaming about like instructions to a young king or something." (JAV, rpt 4)
The Biology of InsightThe 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
The Biology of InsightThe 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.
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