AS Psychology

AS level PsychologyThe Core studies

The Biological Approach

What are the strengths and weaknesses of the physiological

approach?

Assumptions

• The assumptions of the physiological approach are that our biology has a significant impact on our behaviour.

• Some physiological psychologists would say that our brain and nervous system determine most of our behaviour.

• They study the brain, the nervous system, the endocrine system (hormones such as adrenaline, testosterone and oestrogen etc), heredity and disease, to determine their effects.

• In terms of the nature v nurture debate they consider nature to be most important.

Assumptions• In the past studies have often been carried out on

animals or on identical twins. • However the onset of EEG machines to measure

brainwaves and MRI scanning together with genetic engineering has recently extended our understanding of the human brain and how it works.

• The physiological approach also includes the work of evolutionary psychologists who study instinctive behaviours which are common to all animals and determine the reproduction of their species.

Evaluation of the approach…

• There are considerable strengths to the physiological approach as many tests which can be carried out such as EEG’s, MRI’s and DNA testing are highly scientific and therefore reliable.

• We all have very similar biological brains and nervous systems so data is also highly generalisable.

• However brain imaging techniques are relatively new and we cannot always be sure we are interpreting them correctly.

Evaluation of the approach…

• We may see changes in brain functions but these techniques do not tell us what is causing those changes.

• Otherwise we often have to rely on the self report method when studying the brain and so demand characteristics may be a problem.

• Studies which are carried out in laboratories or hospital settings could also be said to lack ecological validity.

Dement & Kleitman (1957)

• The relation of eye movements during sleep to dream activity…

• What can you remember so far?

Dement & Kleitman (1957) Why do we sleep?

• Theories of the function of sleep:• With a partner mind map why we sleep…

- Restoration Theory (the body repairs

damaged tissues and cells during sleep)

- Memory Consolidation Theory (Storage of new memories, linked to hippocampus)

- Evolutionary Theory (Sleep is linked to evolution, a tool used to create energy)

Why do we sleep?

• https://www.youtube.com/watch?v=LWULB9Aoopc

• REM: Rapid Eye Movement• Occupies 20-25% of total sleep,• Muscles relaxed • 90-120 minutes of a night's sleep.• Usually experience 4 or 5 periods of REM

sleep

• NREM: Non-Rapid Eye Movement, (little or no eye movement)

• Dreams do not usually take place in this stage.

• Muscles are more toned

• What is deep sleep?

• How do you measure sleep?

• What issues would you see doing this?

• EEG (Electroencephalography): A test that measures and records the electrical activity of your brain.

• EOG (Electrooculography): eye movements

• EMG: shows muscle activity

Dement & Kleitman (1957)Measuring Sleep

• Most dreaming occurs during REM sleep. • When woke in REM sleep people can say

what they were just dreaming. • The EEG pattern during REM, similar to

EEG pattern when awake.• Muscle activity is very quiet during REM

sleep. • Muscles are inactive to prevent us from

acting out our dreams. • Sleepwalkers are not in REM sleep

Sleep and Dream states

Consciousness

•Consciousness, goes on between your ears when you are awake

– DREAMING is a state of consciousness (altered state of consciousness, sleep, drugs, meditation, hypnosis)

– What did you last dream about: write it down does it make sense????

Sleep and wakefulness• Seem different but have a lot in common

– In sleep– we may ‘talk’– we may ‘walk’– we have memories– we can even plan things

– According to biographers of McCartney and the Beatles, McCartney composed the entire melody of ‘Yesterday’ in a dream one night in his room. Upon waking, he hurried to a piano and played the tune to avoid forgetting it.

Sleep and dream states

• we spend 30% of our lives asleep

• sleep is an active NOT a passive behaviour

What would happen if we didn't’t sleep?

• The evolutionary theory

• all species sleep, thus sleep MUST have a valuable function (survival of the species)

• Do animals need sleep?

• Rats deprived of sleep die after 21 days

Human sleep deprivation?

• REM sleep seems important:

• The Randy Gardner study

• volunteers who are gradually deprived of sleep

• (sleep reduced from 8 hours to 2 hours)

• pack REM sleep into the time they CAN sleep

• John Schlapobersky, consultant psychotherapist to the Medical Foundation for Victims of Torture, was himself tortured through sleep deprivation, in his case in apartheid South Africa in the 1960s.

Human sleep deprivation?

John Schlapobersky

• "I was kept without sleep for a week in all. I can remember the details of the experience, although it took place 35 years ago. After two nights without sleep, the hallucinations start, and after three nights, people are having dreams while fairly awake, which is a form of psychosis.

• "By the week's end, people lose their orientation in place and time - the people you're speaking to become people from your past; a window might become a view of the sea seen in your younger days. To deprive someone of sleep is to tamper with their equilibrium and their sanity."

John Schlapobersky

5 stages of sleep

The stages of sleep

Before sleep:

•Synchronised alpha waves

•heart rate slows, temperature falls

•muscle tension reduces

DELTA

THETAK-

Spindles

ALPHA

AWAKE

BETADELTATHETA

Beta - Emitted when we are consciously alert, or we feel agitated, tense, afraid,

Alpha - When we are in a state of physical and mental relaxation, although aware of what is happening around us.

Theta – A state of reduced consciousness.

Delta - When there is unconsciousness, deep sleep.

Brainwaves

The stages of sleep

Stage 1 sleep - alpha waves reduced

•less desynchronised brain activity

Stage 2 sleep - synchronised brain activity

•larger and slower waves

•bursts of sharp ‘spikes’

•(sleep spindles)

The stages of sleep

Stage 3 sleep - slow delta waves

•less sleep spindles

•heart and breathing rate continue to fall

Stage 4 sleep - only delta waves

•arousal threshold high (people are hard to wake up)

•4 stages of Slow Wave Sleep

Stage 5 - REM sleep

• REM sleep –

• after 90 minutes EEG shows SHIFT into fast desynchronised brain activity

• Beta Waves

• heart rate increases

• skeletal muscles relaxed (paralysis)

• Rapid Eye Movements occur (REM)

Dement and Kleitman

• Developed a rigorous and objective test of the relationship between REM sleep and dreaming

A sleep laboratory volunteer

Dement and Kleitman

Three ways to collect data:

First DV

•Dream recall during REM and NREM sleep

•they woke people up and asked them if they had dreamed

Dement and Kleitman

Three ways to collect data:

2nd DV

•Asked participants to say how long their dreams had lasted

Dement and Kleitman

Three ways to collect data:

3rd DV- patterns of eye movements were related to the reported dream content

•to test whether the movement represented specific expression of the visual dream experience

Dement and Kleitman

Third DV - the criteria

•FOUR eye movement patterns

•1 mainly vertical

•2 mainly horizontal

•3 vertical & horizontal

•4 little or none

Dement and Kleitman

• 9 participants (7 male & 2 female)

• only 5 studied intensively

• method - a lab experiment

• The procedure - Ps asked to refrain from alcohol & caffeine (control?)

• Report at bed time to sleep lab

Dement and Kleitman

• Ps go to bed in quiet room

• Electrodes stuck next to eyes to record eye movements (EOG)

• Electrodes stuck to scalp to record brain waves (EEG)

• Attached by single wire to EEG (lead wire at top of bed)

Dement and Kleitman

• Ps then awakened through the night to test their dream recall

• Participants were woken on average 5.7 times per night

• During or just after REM

• Slept on average for 6 hours

• Repeated many times

Dement and Kleitman• Woken by a bell

• Then Ps spoke into a recording device

• FIRST - they said whether they had been dreaming

• NEXT - they said what they were dreaming about (if they could)

Dement and Kleitman

• CONTROL

• No communication between experimenter and sleeper until after they told of their dream content

• In case the experimenter ‘suggested the content’

Dement and Kleitman

• CONTROL

• They were NOT told whether they had been woken in REM sleep or in NREM sleep

• Woken in BOTH REM and NREM

Dement and Kleitman

FINDINGS of 9 participants

•dream reports (DV1)

•REM SLEEP

•192 awakenings

•152 dream reports (80% could recall a dream)

• 40 no dream reports (20% could not recall a dream)

Dement and Kleitman

FINDINGS of 9 participants

•dream reports (DV1)

•NREM SLEEP

•160 awakenings

•11 dream reports (7% recalled dreams)

•149 no dream reports (93% could not recall a dream)

Dement and Kleitman

FINDINGS of 9 participants•length of dream correlated to length of REM (DV2)•How was this done??•Ps awakened randomly after 5 or 15 minutes of REM and asked to guess how long they had been dreaming •(5 or 15 minutes)

Dement and Kleitman

• FINDINGS of 9 participants• 5 minutes REM SLEEP• 45 reports were right• 6 reports were wrong• 15 minutes REM sleep• 47 reports were right• 13 reports were wrong

Dement and Kleitman

• FINDINGS of 9 participants• relationship between the type of eye movement

to CONTENT of dream• (DV3)• Ps woken when TYPE of eye movement was

regular (vertical etc)• 21 wakings - reports always looking at people

or objects near to them

Dement and Kleitman

• FINDINGS: (DV3)

• One P woken when TYPE of eye movement was regular (horizontal etc)

• Reported watching people throwing tomatoes

Dement and Kleitman

• SUMMARY & conclusions (with a partner – 5 mins!)

Dement and Kleitman

• SUMMARY & conclusions

• regularly occurring REMs every night

• lack of dream recall + light brain waves suggest NO dreaming in NREM

Evaluation points…

• What do you think?

- Methodology

- Sample

- What data was collected?

- Ecological Validity

- Validity

- Usefulness

Dement and Kleitman

• Evaluation

• REM sleep is important • the brain needs to sleep to organise itself• evidence• babies sleep longer than old people• REM is longer after complex tasks

What are the strengths and weaknesses of the method used in the study?

• Laboratory studies have high levels of control over variables but may lack ecological validity.

• The study used the EEG to measure brain activity and this allows precise measurements to be taken (its scientific and objective).

Was the sample representative?• The sample was very small indeed. • Only nine participants were studied in total and only five of

these were studied intensively. • This is a very small number of participants to generalise from. • You could argue that physiological processes are likely to be

the same in all people but this may not be the case. • It is possible that sleep patterns and in particular,

relationships between eye movements and dreaming, vary from person to person and the conclusions drawn from Dement and Kleitman’s research would be strengthened if the same relationships were established in a larger sample of people.

What type of data was collected?• The data collected in this study by mostly quantitative.

• In relation to the first two research questions, the data is simply numbers of participants who could or could not recall dreams or could or could not accurately estimate the length of their dreams.

• Quantitative data is relatively easy to collect and can be analysed statistically.

• However, it reduces complex qualitative phenomena to numbers and this often results in a lack of detail in the data.

• The data collected in relation to the third question was more qualitative as here participants were asked to describe the contents of their dreams.

• This gives us richer and more interesting data but such data is difficult to use for comparisons and is hard to analyse statistically.

Was the study ecologically valid?

• The research studied participants who went to sleep in a laboratory with electrodes stuck to their head.

• It is unlikely that this bears much relation to sleep in a normal environment! It is possible that being in such an artificial condition meant that their sleep was disturbed and if this was the case, the researchers would not have been studying normal sleep patterns.

• The participants were also woken up several times during the night and asked about their dreams.

• Again, this is unlikely to happen normally and may have had an affect on the way the participants slept.

• However, research conducted outside of the controlled conditions of the laboratory would have been unable to measure brain activity and eye movements in the ways.

Was the study useful?

• The conclusions that were reached by Dement and Kleitman have been replicated by many other researchers.

• However, there is one methodological issue that should be considered. In relation to the first research question, Dement and Kleitman conclude that dreaming takes place in REM rather then non-REM sleep.

• What they have actually demonstrated is that dreams are recalled more often from REM rather than non-REM sleep and it may be that dreaming does occur in non-REM sleep and it much harder to recall them.

• When the research was first conducted, very little was known about the relationship between eye movements and dreaming and so Dement and Kleitman’s research really did add new information to what was known about sleep.

• It is difficult, nearly fifty years later, to understand what a major breakthrough this study represented.

• The use of EEG to record brain activity whilst sleeping was also relatively new and it was not until research like this Core Study, that it became clear that dreams could be studied in an objective way.

• Dement and Kleitman’s research generated very many other studies into sleep and dreaming and there have been many useful findings.