Two main theories:
1. Restoration theories
2. Ecological theories
http://www.psychology4a.com/biological_rhythms.htm
Functions of Sleep – Restoration
Theory
BATs
A01 Describe the restoration approach to the
functions of sleep
A02/3 Analyse and evaluate research on the
restoration approach to functions of sleep
A02/3 Consider evidence for memory
consolidation during sleep
Synoptic points – case studies, sleep deprivation
studies - validity
Why do we sleep?
Jot down 3 reasons why you think we
need to sleep
The function of
sleep is to allow
the body to be
repaired/ restored
Van Cauter et al 2000
– decline of Growth
hormone in old age
associated with
reduced SWS
Did you know?
..Growth
Hormone is
secreted during
SWS
Hartmann (1973) said that REM sleep is a time for making
neurotransmitters to compensate for the amount used during the
day.
Stern and Morgane (1974) also thought that that REM sleep
allows the brain to restore levels of neurotransmitters to
'factory settings'.
Oswald (1980) claimed that NREM sleep restored the
body and REM sleep restored the brain, through
protein synthesis and that Slow Wave Sleep (SWS)
helped the body restore itself.
Horne (1988) distinguished between core (SWS & REM) sleep
and optional (stages 1 to 3) sleep
Restoration theories
Oswald
(1966)
“Every stage of
sleep is essential
for restoration!”
A. SWS1-4 are all needed:
for repair/restoration of
the body
B. REM is essential: for
repair/restoration of the
brain
“No! Only
SWS4 and REM
are essential for
restoration!”
Horne
(1988)
1. ‘Core sleep’ = SWS4 + REM:
essential for repair/restoration
of the brain
2. ‘Optional sleep’ = SWS1-3: not
needed at all for
repair/restoration
Restoration of the body happens
when we are awake and relaxed
http://www.psychology4a.com/biological_rhythms.htm
The main predictions of Restoration
Theory are:

Deficits in functioning when sleep deprived

'Rebound' effects following sleep deprivation


Increase in REM sleep during brain growth,
reorganisation and repair
Increase in SWS during times of illness or injury
Evidence for restoration
theories
Total Sleep Deprivation
Studies
Partial Sleep Deprivation
Studies (REM deprivation)
1. Everson (rats)
1. Jouvet (cats)
2. Michel Corke (case study
– fatal familial insomnia)
2. Dement (human REM
deprivation)
3. Peter Tripp (case study –
DJ – awake 8 days/nights)
http://www.psychology4a.com/biological_rhythms.htm
Dement (1960) Effects of REM
deprivation were severe and
included increased aggression
and poor concentration.
Deficits when sleep
deprived?
Randy Gardner, a 17 year old
student, stayed awake for 11
days (260) in 1965 and effects
included disorganised speech,
blurred vision, and a small
degree of paranoia.
DJ Peter Tripp - 1959
Stayed awake for
201 hrs in a
‘wakeathon’. After 3
days abusive, 5
days began to
hallucinate (spiders
in shoes).
Rebound effects?
Dement (1960)
PPs deprived of REM sleep
seemed to have a need to catch
up Attempts to enter REM sleep
doubled from an average of 12
to 26 times by the seventh
night.
When allowed to sleep normally
the participants spent much
longer than normal in REM
sleep, as did Randy Gardner.
Rebound
Generally, people catch up on sleep following
deprivation
Not all lost sleep is reclaimed
Only some sleep is necessary
‘Rebound’ suggests that sleep is a
necessary function
psychlotron.org.uk
About 70% of lost SWS and about 50% of lost REM
typically recovered
Microsleep
When participants, being monitored, have been
sleep deprived for over 72 hours they had short
periods of MICROSLEEP while apparently
awake.
Williams et al 1959 - EEG recordings show that
microsleep is the same as sleep
Which of these effects
could be attributed to
A) lack of restoration
of the brain?
A) lack of restoration
of the body?
http://www.psychology4a.com/biological_rhythms.htm
Increase in REM sleep during brain
growth, reorganisation and repair?
24 hour period
5yrs
REM
NREM
Age
• Reduction in
sleep over
lifespan
• Highest in
infants; highest
REM in early
years
• Some changes in
adolescence
psychlotron.org.uk
Growth & reorganisation
Total sleep time increases during illness
REM increases during recovery from brain
injury, ECT & drug withdrawal
REM sleep and memory
Crick and Mitchison (1983) –
During REM sleep unwanted memories are
disposed of – thus making more important
memories easier to access.
Stickgold, (2005)
REM may be important to consolidate procedural
memory (e.g.driving a car)
SWS important for consolidation of semantic
memory (knowledge and meaning) and episodic
memory (events)
Over to you …
• Read p12-13 and the ‘Restoration Theories of
sleep’ worksheet.
• Do the ‘What you need to do’ activity
• Give one methodological criticism of each study.
Evaluation
The FACE VALIDITY of this theory is high – it
makes sense.
 It is easy to obtain quantitative (OBJECTIVE?)
data on REM, amount of neurotransmitters etc
X Extrapolating from hamsters, cats and rats to
humans is always risky.
X The research is not always RELIABLE and so
we might question its VALIDITY. ( human sleep
deprivation studies and animal sleep deprivation
studies – fatal or not fatal?)
X Case Studies- 'Alien Among Us' criticism

The main problem...
...is the lack of death among humans who are
sleep deprived!!
Rechtschaffen et
al 1983 – rats
died after being
kept wake on a
moving disc for
33 days.
Stress more
likely the cause!
Homewor
k–q4
p13
Plenary
Do question 3 p13 – try this method …
Draw round your hands
On one hand write the arguments that support
Restoration Theory
On the other hand write the arguments against the
Restoration theory
For
Against