Dement and kleitman


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Dement and kleitman

  1. 1. AS level Psychology The Core studies The Biological Approach
  2. 2. 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?
  3. 3. 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
  4. 4. 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)
  5. 5. 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
  6. 6. Sleep and dream states• National Initiatives – UfI – NGFL• Sector Developments – Connectivity – Local initiatives – Inclusivity and widening participation
  7. 7. The brain and its states...• Waking EEGs -• Desynchronised brain waves• not all chanting together• brain waves while awake
  8. 8. The stages of sleep• Before sleep• just as we fall asleep• synchronised alpha waves• heart rate slows, temperature falls• muscle tension reduces
  9. 9. 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)
  10. 10. 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
  11. 11. 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)
  12. 12. 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
  13. 13. The brain and its states...• EEG recording of brain activity
  14. 14. 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)
  15. 15. 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
  16. 16. Do we only DREAM in REM sleep?• How can we find out?• Plan a research project!
  17. 17. Dement and Kleitman• Developed a rigorous and objective test of the relationship between REM sleep and dreaming
  18. 18. A sleep laboratory volunteer
  19. 19. 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
  20. 20. Dement and Kleitman• Three ways to collect data• 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
  21. 21. 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
  22. 22. Dement and Kleitman• Third DV - the criteria• FOUR eye movement patterns• 1 mainly vertical• 2 mainly horizontal• 3 vertical & horizontal• 4 little or none
  23. 23. 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
  24. 24. 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
  25. 25. 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)
  26. 26. 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
  27. 27. 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)
  28. 28. 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’
  29. 29. 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
  30. 30. Dement and Kleitman• FINDINGS of 9 participants• dream reports (DV1)• REM SLEEP• 192 awakenings• 152 dream reports• 39 no dream reports
  31. 31. Dement and Kleitman• FINDINGS of 9 participants• dream reports (DV1)• NREM SLEEP• 160 awakenings• 11 dream reports• 149 no dream reports
  32. 32. Dement and Kleitman• FINDINGS of 9 participants• dream reports (DV1)• HIGH incidence of dream recall after REM• LOW incidence of dream recall after NREM
  33. 33. 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)
  34. 34. 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
  35. 35. Dement and Kleitman• FINDINGS of 9 participants• length of dream correlated to length of REM (DV2)• all Ps guessed accurately except one P who could only remember the ends of dreams
  36. 36. 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
  37. 37. Dement and Kleitman• FINDINGS: (DV3)• One P woken when TYPE of eye movement was regular (horizontal etc)• Reported watching people throwing tomatoes
  38. 38. 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
  39. 39. 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
  40. 40. 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?
  41. 41. Dement and Kleitman - QUESTIONS• 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?
  42. 42. Dement and Kleitman - QUESTIONS• 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?
  43. 43. Dement and Kleitman• You must read this study up• Read a chapter on Sleep research
  44. 44. Dement and Kleitman• Try recalling your own dreams• Keep a dream diary• Do you dream more after you have been studying hard?