Dement and kleitman

AS level PsychologyThe Core studiesThe Biological Approach

Sleep and Dream states

• Consciousness

• What is consciousness?

– Consciousness is what goes on between your ears when you are awake?

– DREAMING is a state of consciousness

– Altered states of consciousness

– Sleep, drugs, meditation, hypnosis?

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

– Sleep patterns vary - average = 7/8 hours per night

Sleep

• Disruption of sleep leads to fatigue

• What goes on in the brain of a sleeper?

• Brain activity can be recorded by an EEG (ElectroEncephaloGram)

Sleep and dream states

• Every 24 hours we sleep

• we spend 30% of our lives asleep

• sleep is an active NOT a passive behaviour

• Dement and Kleitman (1950s)

• the five stages of sleep

Sleep and dream states

• National Initiatives

– UfI

– NGFL

• Sector Developments

– Connectivity

– Local initiatives

– Inclusivity and widening participation

The brain and its states...

• Waking EEGs -

• Desynchronised brain waves

• not all chanting together

• brain waves while awake

The stages of sleep

• Before sleep

• just as we fall asleep

• synchronised alpha waves

• heart rate slows, temperature falls

• muscle tension reduces

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

• all synchronised slow wave activity

REM sleep

• REM sleep - after about 90 minutes EEG shows SHIFT into fast desynchronised brain activity

• heart rate increases

• skeletal muscles relaxed (paralysis)

• Rapid Eye Movements occur (REM)

REM sleep

• REM sleep - 15 minutes in REM sleep then back through stage 2 3 and 4

• this cycle repeats every 90 minutes

• 5 or 6 cycles per night

• towards morning more REM sleep

• we dream in REM sleep, thus dream more in early morning

The brain and its states...

• EEG recording of brain activity

What is sleep FOR?

• 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

• Jouvet - cats & the flower pot technique

• (these animals may have died of stress)

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

Do we only DREAM in REM sleep?

• How can we find out?

• Plan a research project!

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


• 2nd DV

• Subjective estimate of the duration of dreams CORRELATED to the duration of REM before awakened

• they asked people to say how long their dreams had lasted

Dement and Kleitman


• 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

• Have we all got that?

• 3 ways to collect the data (DVs)

• self report of dreaming

• self report of length of dream - correlated to length of EEG REM

• correlation of eye movement to reported dream content

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

• 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

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

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

Dement and Kleitman

• Now - Ps awakened through the night to test their dream recall

• 21 awakenings in first 2 hrs of sleep

• 29 awakenings in 2nd 2 hrs of sleep

• 28 awakenings in 3rd 2 hrs of sleep

• 22 awakenings in 4th 2 hrs of sleep

Dement and Kleitman

• They were woken by a bell placed next to the bed

• when woken the Ps spoke into a recording device near the bed

• 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

• 39 no dream reports

Dement and Kleitman



• NREM SLEEP

• 160 awakenings

• 11 dream reports

• 149 no dream reports

Dement and Kleitman



• HIGH incidence of dream recall after REM

• LOW incidence of dream recall after NREM

Dement and Kleitman


• 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


• 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


• length of dream correlated to length of REM (DV2)

• all Ps guessed accurately except one P who could only remember the ends of dreams

Dement and Kleitman


• 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

• regularly occurring REMs every night

• ALL Ps recalled dreaming in REM

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

• Objective measurement of dreaming MAY be achieved by recording REMS while people sleep

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

Dement and Kleitman - QUESTIONS

• Does it matter that only 2 Ps were female?

• Why were Ps asked to refrain from alcohol / caffeine?

• Why was it important that the Ps did not know whether they were in REM or NREM?

• Does the size of the sample matter?


• Why might the sleep patterns be different when the Ps sleep in their own beds?

• Why might some of the Ps have recalled dreams when they were woken in NREM

• To whom can we generalise the findings?

• Was the study ethical?


• What was the IV?

• What were the three DVs?

• What is the MAIN disadvantage of correlational analysis?

• Have D & K established that dreaming ONLY occurs in REM sleep?

Dement and Kleitman

• You must read this study up

• Read a chapter on Sleep research

Dement and Kleitman

• Try recalling your own dreams

• Keep a dream diary

• Do you dream more after you have been studying hard?

Dement and kleitman

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