Transcript Restoration Theory - PsychologyResources-Y13

Restoration Theory
‘Our planet is a dangerous place, there is
ruthless competition for limited resources and
only the fittest survive. Yet all the most advanced
animals, normally alert, shrewd and watchful,
drop their defences to sleep’ (Blakemore, 1988).
Sleep occupies 1/3 of our time. What we are
interested in when we study sleep:
What function is served by sleep?
What happens when we are deprived of sleep?
Why do most animals sleep?
In order to understand the functions of
sleep, researchers have looked at the effects
of sleep deprivation...
Jouvet (1967)
•Aim: To examine the effects of REM sleep
deprivation on a domestic cat
•Method: The cat was placed on a small island
surrounded by cold water
Whenever the cat feel asleep, it would fall into the
water and instantly wake up
This was continued for 75 days
•Results: The cat became progressively more
disturbed and eventually died
Rechtschaffen et al. (1983)
Aim: to examine the effects of sleep deprivation on rats
Method: Rats were forced to remain physically active by
rotating a disc every time they started to go to sleep
Results: After 33 days, the rats
had all died
Deficits when sleep
deprived?
Dement (1960) Effects of
REM deprivation were
severe
and
included
increased aggression and
poor concentration.
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.
Example : (Horne 1988)
Randy Gardner remained awake for 264 hrs/ 11 days in 1964.
Toward the end of the 11 days he suffered from slurred speech
blurred vision and paranoia. He had less symptoms that Peter
Tripp (page 13, book) but was awake an extra 3 days.
After his deprivation Randy slept for 15 hours he slept for
longer than usual for a few nights after but soon reverted back
to his usual sleep pattern. He only recovered about 25% of the
sleep lost (80-90hrs)
If sleep were that essential, would you expect him to have
recovered more?
Extensions for Learning...
Further studies using humans:
Webb and Bonnet (1979a and b)
Dement (1965)
The Restoration Theory Of Sleep
The function of
sleep is to allow
the body to be
repaired/ restored
SWS enables
body repair. REM
sleep enables
brain recovery
(Oswald, 1980)
SWS EXPLANATIONS
•Growth Hormone
GH stimulates growth in
children and protein synthesis
in adulthood
A significant amount is released during SWS. Sassin
et al. (1969)
The decline of GH in older age is associated with the
reduction of SWS (van Cauter et al., 2000)
•Immune System: Lack of SWS has been associated
with reduced functioning of Immune system (Kreuger
et al., 1985)
Total sleep time increases during illness
REM increases during recovery from brain
injury, ECT & drug withdrawal
REM Sleep Explanations
•Brain Growth: Active/REM sleep is higher in babies
and premature babies
Is the amount of REM sleep dependent on brain
maturity at birth?
Siegel (2003):
The platypus has about
8 hrs of sleep
(Immature at birth)
Whereas dolphins have
no REM sleep and can
swim from birth
Explanations REM sleep
• Neurotransmitters
REM sleep allows for a break in
neurotransmitter release permitting neurons
to regain their sensitivity (Siegel and
Rogawski, 1988)
•Memory
Crick and Mitchison (1983) proposed that
during REM sleep unwanted memories are
discarded
Stickgold (2005): REM sleep important for
procedural memory consolidation. SWS for
semantic
Evaluation
Extrapolating from hamsters, cats and rats to
humans is always risky.
The research is not always RELIABLE and so we
might question its VALIDITY. (cf human sleep
deprivation studies and animal sleep depriavation
studies – fatal or not fatal?)
Case Studies- 'Alien Among Us' criticism
It is easy to obtain quantitative (OBJECTIVE?)
data on REM, amount of neurotransmitters etc

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,
reorganiation and repair

Increase in SWS during times of illness or injury

The main problem...
...is the lack of death among humans who are
sleep deprived!!
Task!
In pairs. One person is a radio presenter, the other,
a sleep specialist.
In your pairs, practice asking and answering
questions as if on a radio show.
Extension for Learning!
Oswald (1980) and Horne (1988) are central
to the restoration theory
Using the internet, discover how their
approaches differ slightly.
c.400-500 words
Due Date: Wed 24th Nov