sleep and dreams

Question 1

The role of the brain in sleep

Answer 1

 The SCN detects light from the optic nerve.
When sunlight decreases, it sends a signal
to the pineal gland
 This releases the hormone melatonin which
makes us feel sleepy. Melatonin levels peak
in the middle of night and fall back down
towards daytime.
 Adenosine builds up in the brain during the
day and makes us feel tired, and gets
replaced during sleep

Question 2

Non-Rem sleep stage 1

Answer 2

• Relaxed wakefulness, drifting off.
• Brain waves = theta
• Easy to awaken. Muscle jerking can
  occur.

Question 3

Circadian Rhythms

Answer 3

 Circadian rhythms are like a ‘body clock’
that all species have. It’s a cycle of
physiological and biological processes that
fluctuate on a roughly 24-hour timetable.

Question 4

Non rem sleep stage 2

Answer 4

• Heart rate slows and body temp
  decreases.
• Brain waves = sleep spindles and k-
  complexes.
• Block out external stimuli and possible
  memory consolidation. Harder to wake.

Question 5

Non rem sleep stage 3/4

Answer 5

• Deep sleep.
• Brain waves = delta
• People hard to wake up
• Parasomnias occur

Question 6

Rem sleep

Answer 6

 Eyes move under eyelids
 Irregular breathing and higher blood pressure
 Temporary sleep paralysis
 Dreams
 Brain waves = Alpha and Beta.

Question 7

Oswald’s (1966) Restoration theory of sleep
explain

Answer 7

Oswald (1966) states that all animals sleep
because it allows the body to carry out
essential repair tasks.
Sleep appears to be universal among complex
animals (even fruit flies). We know it must
fulfil an essential purpose
Possible restoration functions that the body
might need to do during sleep include:

o Repair cells
o Removal of waste chemicals in
the muscles
o Restore resources of energy
 In particular, this theory suggests that
NREM sleep is important for restoring
physiological functions (body) REM
sleep is important for restoring mental
functions (brain)
 Sleep is the perfect time for the body
to make these restorations, because it
is inactive so resources are not being
used up and new injuries are not being
made.

Question 8

Oswald’s (1966) Restoration theory of sleep evaluate strengths

Answer 8

 Restoration is a key explanation of why all
mammals sleep and is better able to explain the
loss of consciousness compared to alternative
ideas.
 Supported by lots of research evidence, including
Rechtschaffen’s (1989) rat study; Savard’s (2003)
insomnia and immune system study, Shapiro’s
(1981) ultramarathon runner study.
 Further supported by findings that many of the
major restorative functions in the body like muscle
growth, tissue repair, protein synthesis, and
growth hormone release occur mostly, or in some
cases only, during sleep.

Question 9

Oswald’s (1966) Restoration theory of sleep evaluate weaknesses

Answer 9

• Most of the evidence in this area comes from
  correlational studies, so doesn’t show cause and
  effect.
• Sleep probably has multiple functions, and it could
  be that the different stages of sleep serve
  completely different functions. Therefore, it is
  probably over-simplistic to suggest that sleep is
  just about restoration but this may well be one of
  the main functions of non-REM sleep.

Question 10

Oswald’s (1966) Restoration theory of sleep
analyse

Answer 10

Link – to STUDIES like Rechstaffen et al (1989) (Rats), Savard et al (2003) (immune cells), Shapiro et al (1981)
(ultramarathon runners), Peter Tripp. Make sure to CLEARLY link to why it is supporting restoration theory.
Implications – Injuries will not heal as well if there is lack of sleep – if we are ill it is important we get
adequate sleep. Can be applied to medically induced comas to help brain-damaged patients – people put to
sleep in order to let their brain repair and restore. Athletes – need more sleep to reduce injury risk and
improve performance
Compare – Reorganisational theory – both argue sleep is vital to function properly. The reorganisational
theory argues sleep is essential to reorganise information and improve memory rather than physical aspects
of restoring. The restoration theory also argues that the brain’s neurotransmitters are replenished for the
brain to function properly but also takes into account bodily repairs.
Psychodynamic theory – Argues dreams have hidden, deeper meanings but restoration argues dreams are
meaningless. Restoration uses objective evidence whereas psychodynamic uses case studies.

Question 11

Dement, W. and Kleitman, N. (1957)

Answer 11

Aim – investigate the relationships between
sleep stages and dreaming. To investigate the
relationship between eye movements and
dream content. To investigate the function of
REM sleep.
Method – sleep lab study, 7 females and 2
males, hooked up to PSG. Asked to avoid
caffeine and alcohol. Asked to sleep in lab and
were woken up several times by researchers
and asked if they had been dreaming, what
about and how long for.
Results – 80% of the time participants said
they were dreaming in REM and 9% of the
time said they were dreaming during nREM.
Also eye movements were linked to dream
content e.g. tomato dream.

Question 12

Dement, W. and Kleitman, N. (1957) evaluate strengths

Answer 12

 Sleep lab – could control EVs making sure people
weren’t woken unless they were meant to be (e.g.
noise)​
 Eliminated demand characteristics using single
blind design- blind to knowledge (participants
didn’t know whatstage they were in so could not
have faked results)​

Question 13

Dement, W. and Kleitman, N. (1957) evaluate weaknesses

Answer 13

 Small sample - only 9​ (cannot generalise)
 Sample all adults - no children (whosleep for
longer) follow the same patternin terms of
dreaming?​
 Gender imbalance in sample
 Artificial setting - in a lab and woken upfrequently
(low ecological validity)

Question 14

Dement, W. and Kleitman, N. (1957) analyse

Answer 14

Link - To the restoration theory as they both agree that REM and N-REM sleep are distinct sleep phases and
offer separate functions. The findings support the idea that REM sleep is when our brains are more active,
as participants reported dreaming during this stage.
Implication - If a person experiences brain injury, we can understand the parts of the brain operating when
we are dreaming to see if they are impacted. Can help those suffering from sleep disorders – medication
can be used to alter sleeping patterns by targeting REM sleep (as this is when you dream according to this
study).
Compare –
Roffwarg et al (1962) – agrees with D&K as found eye movement in REM is similar to dream content.
Goodenough (1959) – contrasts with D&K as study found people had high (53%) amount of recall of dreams
in NREM
Faulkes (1962) – found 54% recall rate of dreams in NREM – contrasts with D&K.
Siclari et al (2017) – found evidence people have dreams in both REM & NREM – contrasts with D&K.

Question 15

How sleep facilitates information processing

Answer 15

The cognitive approach explains sleep very
much in terms of the computer analogy – that
sleep is a way to facilitate information
processing.
 The cognitive approach focuses on the role of
sleep in memory and thinking.
 According to this viewpoint, the mind is a
processor of information and sleep largely
exists in order to facilitate the processing.
 During sleep, the mind can ‘clean up files’,
strengthening the links between memories
 The cognitive approach also explains dreams
as being related to the brain working through
information (such as schemas, memories,
emotions, etc.) during sleep

Question 16

Crick and Mitchison’s Reorganisational Theory

Answer 16

 ‘We dream in order to forget’
 Main function of dreams is reorganisation in
order to improve memory storage.
 Learning can be undone during REM sleep.
 Dreams are side effect of decluttering
 Cortex overloaded during the day, and during
REM unwanted memories are deleted to
make space
 Adaptive memories and parasitic memories.

Question 17

Crick and Mitchison’s Reorganisational Theory evaluate strengths

Answer 17

 A strength of the reorganisational theory is that it
gives a clear theory about why REM sleep
specifically could be important. By making
memory more efficient, Crick and Mitchison
(1983) argue that better use is made of the
available space in the brain.
 Good explanation for why we sometimes cannot
remember our dreams

Question 18

Crick and Mitchison’s Reorganisational Theory evaluate weaknesses

Answer 18

 Major weakness of this theory is that it lacks
research support on human participants. We
cannot apply evidence on dolphins and echidnas
to humans.
 Does not explain why dreams often have a
narrative (i.e. a story) – our dreams appear to
make sense the majority of the time, which does
not fit well with the idea that dreams are a
results of a random decluttering process.
 Numerous studies have shown that rather than
destroying memories, sleep is beneficial to
memory (e.g. Mednick, 2003). We now also know
humans have effectively unlimited long term
memory capacity, so there would be no need to
‘prune’ and delete.

Question 19

Crick and Mitchison’s Reorganisational Theory analyse

Answer 19

Link – Echidna and dolphin species have larger brains than expected for body = due to lack of REM sleep so
pruning useless memories doesn’t occur.
Implication - This theory suggests that during times of learning (e.g. childhood/teens) sleep is most important to
that adaptive memories are saved and parasitic memories are deleted to free up space.
Should avoid alcohol at night and get sufficient physical activity to ensure we get enough REM sleep so our
memories can be organised
Compare - This can be compared to the restoration theory as they both argue sleep is important for optimum
functioning of the brain. Agree REM particularly important for the mind. Agree dreams are meaningless.
Restoration uses empirical evidence, reorganisational does not.
Psychoanalytic Theory – says dreams are controlled by the id and are for wish fulfilment. This contrasts to the
reorganisational theory which argues dreams are random. Both theories uses non-objective methods to back up
their ideas.

Question 20

Czeisler’s (1990) study into night shift workers

Answer 20

 Aim - This study aimed to find if a routine
that included light exposure would help
night shift workers adapt to daytime
sleeping.
 Method – 8 men aged 22-29, no medical,
mental health or sleep disorders. No
medication, no alcohol or caffeine – urine
checked. Men came to research lab at
night to do ‘shifts’ doing cognitive tasks
and reported on mood and alertness. Two
groups – experimental exposed to very
bright light (12,000 lumen) and slept in
blacked out conditions. The control group
exposed to normal light (150 lumens) and
slept in normal conditions.
 Results – Experimental group slept on
average 2 hours more than control (7.7
compared to 5.7). Also, their alertness and
performance improved during shifts.
 Biological measures showed that the
experimental group’s circadian rhythms
moved forward 9 hours.

Question 21

Czeisler’s (1990) study into night shift workers evaluate strengths

Answer 21

 Workers still travelled to work as normal so
exposed to normal daylight on commute
home so replicates real life.
 Differences between groups were significant
so unlikely to happen by chance.
 Lab experiment – so good control over EV’s
(e.g. drug tested) so sleep wasn’t disrupted.

Question 22

Czeisler’s (1990) study into night shift workers weaknesses

Answer 22

 Very small sample of men – cannot generalise
to wider population
 Only men in sample – no gender balance
 Several EV’s were still not controlled (e.g.
breakfast, how long they actually tried to
sleep at home)
 They were not actually working over night –
low ecological validity.

Question 23

Czeisler’s (1990) study into night shift workers analyse

Answer 23

Link – This study links to the idea that sleep facilitates cognitive processes. The experimental group did
better in performance therefore it can be suggested that their increase in sleep helped them to do so.
Reorganisational theory - experimental group slept for longer so experienced more time in REM sleep which
allowed for reverse learning to take place. Led to improved cognitive function and higher reported levels of
alertness as they were able to declutter brains during REM sleep
Biological approach as it backs up idea that light controls our sleep. Experimental groups’ circadian rhythms
shifted and they slept better, showing that the light/darkness routine led to the SCN changing sleep cycle.
Implication - Show why so many night shift workers suffer from lack of sleep – the control group who tried
to sleep during the day in normal conditions did not sleep well.
Suggest that a strict light exposure routine might help shift workers sleep better, since the experimental
group slept for 2 hours more on average.
The results show it would be beneficial for employers to think about this, since their staff would probably be
more alert as a result. Employers (like factories) could install bright lights for night shift workers and
encourage them to use black out blinds during the day.
Compare – Boivin et al (1996) – artificial light helped biological rhythms adjust to suit environment
Leppamaki et al (2003) – exposture to bright light during night shift allowed for better adaptation to shift
work
Campbell (1995) – bright light exposure wasn’t effective – middle age ppts did not adapt therefore
CONTRASTS results

Question 24

Psychodynamic Approach

Answer 24

 Freud argues the purpose of sleep is in order to
dream.
 We dream for ‘wish fulfilment’. Dreams are
representations of the unconscious mind (ID) and
pleasure motivated. Dreams are about our desires
not happening in real life.
 Dreams consist of manifest and latent content. This
is because our unconscious wishes are so
unacceptable that they are hidden in dreams and are
presented in a way to protect our mind from being
disturbed.

Question 25

Psychodynamic Approach evaluate strengths

Answer 25

• Large influence in terms of popular understanding
  (most people believe it!)
• Study of stroke patients did reveal they lost the
  capacity to dream if their higher forebrain was
  damaged (the part associated with desire). This is
  evidence for link between dreaming and ‘wishes’

Question 26

Psychodynamic Approach evaluate weaknesses

Answer 26

 Psychoanalysts do not even agree amongst
themselves how to analyse dreams (e.g.
Freud and Jung)
 Majority of evidence is from case studies
therefore hard to generalise.
 Freud’s wish fulfilment suggests dreams show
what we desire – how does this explain
nightmares?

Question 27

Psychodynamic Approach analyse

Answer 27

Link – Little Hans (1909). Study of stroke patients did reveal they lost the capacity to dream if their higher forebrain
was damaged (the part associated with desire). This is evidence for link between dreaming and desires or wishes.
Brain scans also showed that the parts of the brain responsible for self-control (pre-frontal cortex) are not active
during REM sleep. The pre-frontal cortex is where Freud would expect to find the superego, which therefore supports
his idea that the id is dominant when dreaming.
Implication – This has led to the popular belief that dreams mean something and dream dictionaries have been
produced to help people try and uncover their unconscious wishes. People can still visit dream analysts to help them
uncover what their dreams really mean.
Compare – Restoration Theory – argues sleep is only for restorative functions and has nothing to do with our
unconscious desires being presented and is all about replenishing brain resources and body repairs. Psychodynamic is
more holistic than restoration – more reductionist.
Reorganisational theory – Dreams are side effect of decluttering process rather than having hidden meanings. Both
use non-objective measures for backing up their ideas (case studies & dolphins/echidnas).

Question 28

Impact of drugs on sleep

Answer 28

Expand
 Recreational and prescription drugs can affect sleep
 Stimulant drugs have the effect of making people more
alert or more awake.
 They can not only reduce sleep quantity but also quality
of sleep.
Examples:
 Caffeine – stimulant drug present in coffee, tea,
chocolate. Keeps people alert and makes it hard for them
to sleep.
 Cocaine increases wakefulness and suppresses REM sleep
and withdrawal often results in sleep disturbance and
unpleasant dreams.
 Cannabis – ease of getting to sleep but withdrawal leads
to increased difficult sleep and strange dreams.
 Alcohol – depressant of the CNS and can make you feel
sleepy. Changes proportion of NREM and REM sleep.
Quality compromised as increased wakening.
 Prescription drugs – can interfere with sleep patterns e.g
anti. Depressant drug tamazepam can cause sleepiness.

Evidence:
 Drake et al (2013) - caffeine consumed up to 6 hours
before sleep may have disruptive effects on sleep
 Pollak (2003) - higher caffeine intake was associated with
shorter nocturnal sleep duration, increased sleep
disruption and increased daytime sleep
 Orbeta et al (2006) - reports of feeling tired in the
morning and having difficulty sleeping was experienced
more commonly in those adolescents that had a high
intake of caffeine.

Question 29

Impact of light on sleep

Answer 29

Expand
 Zeitgebers refer to environmental signals
that affect ourcircadian rhythms and make
our brain think that it is timeto sleep or
wake up – the most obvious one for
sleepbeinglight. The SCN is triggered
when there is a lack of light which releases
melatonin that makes us sleepy. If light is
there we will be kept awake.
Examples
 Using your phone/ipad before bed may
lead to you having a restless night’s sleep
Evidence
 Hysing et al (2015) did a correlational
study with 10,000 teenagers in Norway
and found that bedtime use of electronics
was related to shorter sleep duration and
longer sleep onset latency (how long it
takes to fall asleep)
 Figueiro (2014) - Exposed participants to
pulsing blue light through closed eyelids
and found this suppressed melatonin
production. This suggests blue light pulses
could be used to delay circadian cycles.