Dement & Kleitman Flashcards
REM sleep
Rapid Eye Movement sleep, when the body is paralysed, but the eyes move. This happens at the end of each sleep cycle.
N-REM sleep
Non-Rapid Eye Movement sleep, which happens during stages 1-3 of each sleep cycle (NREM is after REM)
EEGs
Measures the amplitude and frequency of electrical activity in brain.
- during REM, EEG displays rapid, low voltage brain waves, similar to wakeful brain activity
- during NREM, EEG shows slow, high voltage brain waves
EOGs
Can measure eye movement during sleep.
- used to determine whether someone is in REM sleep or not
- because the show rapid eye movements during REM, but none during NREM
What are some previous research before they carried out this study? (sleep cycle, recall)
Aserinsky & Kleitman: (1955)
Found higher incidence of dream recall when PPs were woken up during REM sleep than in other periods of sleep
Dement & Kleitman (1955)
Also previously found that REM sleep seems to happen at regular intervals in relation to sleep cycles, as shown using EEGs
Why did they want to carry out this research?
THEREFORE based on previous research, D & K wanted to do ‘rigorous’ testing of the relationship between eye movements and dreaming
What was the sample used?
7 adult males, 2 adult females
How many participants were studied intensively? And what about the ones that were not?
5 studies intensively
4 minimal, with the main intent of confirming the results on the first five
What were the three aims of the study? Just vaguely describe.
Aim 1: dream recall
Aim 2: estimation of duration
Aim 3: eye movements
Now describe the three aims of the study!
H1. To investigate whether dream recall differs between REM and NREM
H2. To investigate the relationships between the PPs subjective estimate of dream duration/content and the actual length of eye movement periods before awakening
H3. To investigate whether the pattern of the eye movements will be related to the dream content
Describe the method for H1, IV and DV
Natural experiment - repeated measure
IV: whether they are REM or NREM
DV: whether pps dreamt, and content
Describe the method for H2, correlation and experiment
Correlation
variable 1: duration of REM period
variable 2: no. of words used in pps description of dream content
only did with 5 pps that were studied in detail
Experiment - repeated measure
IV: waking pps after 5 or 15 mins
DV: pp estimates 5 or 15 mins
only did with 5 pps that were studied in detail
Describe the method for H3, IV and DV
Natural experiment
IV: regular vertical/horizontal eye movement
DV: dream content
Describe the results for HI (statistic results)
REM dream recall: 152
NREM dream recall: 11
Describe the results for HI (4 points)
- High incidence of dream recall for REM sleep, LOW incidence for NREM
- Waking patterns did not affect recall
- recall of dreams during NREM sleep more common when PP woken just after REM sleep
- Pps sometimes reported experiencing emotions when woken from NREM sleep e.g. anxiety
Describe the results for H2 (correlation)
For all pps there was a significant positive correlation between no. of words used to describe dreams, and the duration of REM sleep
Narratives of 152 dreams recorded, but 26 not used for correlation due to poor recording
Describe the results for H2 (experiment)
Most pps were highly accurate in estimations
individual difference - one pp had difficulties - frequently underestimated the length of longer dreams because he only remembered the end of dreams.
Describe the results for H3
hard to identify periods of purely horizontal or vertical, mixed eye movements is more common
3 periods vertical movement = looking up at climbers
1 period horizontal = people throwing tomatoes
10 periods little/no movement = staring at something
21 periods of mixed = looking at nearby objects
***Awake eye movements studied by D&K when focusing on distant/near objects showed similar patterns
What did they control before the pps arrive?
- eat normally
- no caffeine
- no alcohol
How did they wake pps up? And how did they make sure this would wake up everyone?
Ringing of an ordinary door-bell, placed near the bed, sufficiently loud to ensure immediate awakening in all levels of sleep.
What was the role of experimenter? When would they have conversation with the participants?
E occasionally entered the room to further question them on some particular point of the dream,only enter and question after pps have committed that they are dreaming
no communication between pps and E in any instance.
How did they make sure the pps are actually dreaming? What is considered to be negative?
relate a coherent, fairly detailed description of dream content)
Any vague, fragmentary impressions of content, were considered negative
How did they record pps recall of their dreams?
After awakening, pps speak into a recording device near the bed, when finished speaking
What was the total awakening, average night awakening, and average sleeping time?
total awakening = 351
average night awakening = 5.7
average sleeping time = 6hrs (4h20m-7h50m)
Which period of sleep was the pps awakened? And were they told about this?
Waken up either during REM or varying period during NREM - they were not told which period they were in when awakened
Did they have a standardised procedure, if not, give examples.
No standardised procedure - some pps were awaken according to the whim of E, some were chosen 3 REM awakenings and 3 NREM awakenings.
What are the three conclusions from the study?
when does dreaming occur, does it happen in an instant?, eye movements and its meaning
- Dreams mostly occur during REM sleep, which occurs regularly throughout each night.
- —- Perhaps earlier research that did not find evidence of nightly dreaming did not record continuously, or didn’t catch small eye movements - Dreams happen in ‘real time’ (in periods)- not in an instant, which was previously thought
- Eye movements in REM sleep correspond to where and at what the dreamer is looking. Therefore eye movements are not ‘random events’ caused by activation of nervous system during sleep, but directly related to dream imagery
Describe the experimental design used in this study
Repeated measure, all pps were woken after both 5 and 15 minutes
One advantage of this experimental design used
Pps may have differed in duration-guessing ability, which will produce spurious differences between conditions in an independent group design
Describe what researchers are able to learn about sleep from an EEG.
The stage of sleep a person is in, so that it can be seen how long they are dreaming for, from their brain waves
The EEG electrodes were gathered into a single cord at the top of the participant’s head. Explain why this was done.
Allow free movement, sleep more normally, increases ecological validity
To what extent are these findings likely to be typical of the normal sleep times for
these participants?
- Not typical because lab conditions probably made them sleep less
- Not typical because being woken up means less opportunity to sleep
Evidence that helped D&K to conclude relationship between dreaming and rapid eye movement
- EEG (quantitative)
- dream content (qualititive)
Evaluate the study in terms of the use of Quantitative data
- no. of words used to describe their dream
- allows analysis of data so make comparisons between variables
- also correlated against actual dream length
- so can come to conclusions about significance of results and whether hypotheses can be accepted
Evaluate the study in terms of the use of Qualitative data
- dream content description
- detailed info about what people dreamt about, lead to deeper understanding of link between dream content and eye movement.
Useful application to real life
- treat sleep disorders
- suffer poor sleep due to excessive dream
- intervention could target the REM period of sleep
- reduce dreaming or improve dream length and content
- the study also have educational value
Describe the apparatus used
EEG wires from head to EEG machine
Wires collected together in a pony tail
EEG measures amplitude and frequency of waves for activities in brain, whether REM or NREM sleep
EOG measures eye movement, how many movements and what direction
Describe one of the dream
Driving a car and staring at the road ahead, just before awakening, saw a man standing on the side of road and hailed him as he drove past.
Dream content related to mixed eye movement
Talking to a group of people
What was displayed on EEG about eye movement, how many movements, how does activity occurred?
Activity occurred in bursts of 1 or 2, up to 50 or 100 movements.
A single movement is accomplished by 1-2s followed by fixational pulse.
