Dement and Kleitman Flashcards
What was the aim of this study?
general: to investigate the relationship between eye movements and dreaming
specific:
1. does dream recall differ between REM and NREM stages of sleep?
2. is there a positive correlation between estimate dream duration and REM period length
3. are eye movements related to the dream content
what was the research hypothesis of this study?
- there will be a significant association between REM sleep and dreaming
- there will be a positive correlation between the estimate of dream duration and REM period length
- there will be a significant association between eye movement patterns and dream content
what was the background of this study?
Psychometrics used in the study
1. EEG: traces cyclical changes that occur in brain activity during sleep. electrodes are placed around the skull to analyse brain waves
- EOG: traces eye movements during sleep. uses electrodes placed around the eye region
REM —> rapid eye movement is when dreaming occurs
NREM —> non rapid eye movement
a student of Kleitman revealed that participants woken from REM sleep were more likely to report a vivid, visual dream than participants that woke up from NREM. they also showed that we have several sleep stages alternating between REM and NREM
what was the research method in this test?
Laboratory experiment, but different methods to test each aim
what was the research design of this study?
Approach 1. Natural experiment: repeated measures design
IV: whether they woke up from REM or NREM
DV: whether they recalled a dream or not
Approach 2: true experiment using correlational study
Repeated measures design
IV: waking participants after 5 or 15 minutes into REM sleep
DV: participants guess on dream duration (5 or 15 minutes) correlational analysis used to cross check participants time estimate and the number of words in the dream narrative
approach 3. natural experiment, repeated measures design
IV: eye movement patters
DV: dream content
what was the sample of this study?
7 males and 2 females recruited through opportunity sampling. 5 studied in detail and 4 used to confirm the results of the first 5
5 main participants spent between 6-17 night in the lab. approximately 50-77 times awakening
4 spent only 1-2 nights. 4-10 times awakening
participants were identified by their initials
what was the procedure of this study?
participants reported to the lab before ther personal bedtime. they ate their normal diet but were asked to avoid caffeine and alcohol on the day of the study. they left in a dark quiet room. they had 2 EOG electrodes near their eye and 2/3 electrodes to the scalp which were of EEG. a doorbell for standardisation had been used to wake participants up at random from REM of NREM. all participants were woken up when an eye movement pattern lasted for at least a minute. everyone returned to sleep in less than 5 minutes
procedure 1. they were woken up at various times to test dream recall (during REM and NREM) dream narrative recorded on a tape recorder (to prevent researcher bias) they were asked if they had a dream or not. if they did, then they recorded it. dream only counted if the recall was clear
procedure 2. participants were woken up after either 5 or 15 minutes into REM sleep. participants guessed the duration they dreamt for number of words in dream narrative was counted after the participants reported their dream
procedure 3. eye movement direction was detected with an EOG. participants reported their dream.
what were the results of this test?
all subjects showed REM every night. REM patterns varied per individual but each individual had a regular REM pattern
92 minutes was the average time gap between different dreams. the range was 70-104 minutes
the average REM length was 20 minutes and the range was 3-50 minutes. it was later longer in the minute. bursts of 2-100 rapid eye movements
those woken in NREM returned to NREM. whose woken in REM went to REM
Results 1: awakening from REM produced dream recall of 79.6% and from NREM produced dream recall of 7%
after completing REM, but waking participants under 8 mins, 5/17 dreams were recalled, but waking participants after, 6/132 dreams were recalled
results 2: the accurate estimation of REM duration was very high: 88% for 5 minutes, 78% for 15 minutes. there was a positive correlation between REM duration and words in the recall. narrative of 152 dreams was collected, but 26 were omitted due to poor recording thus, there were 126
results 3: vertical eye movement: standing at the bottom of a tall cliff and operating a hoist
Horizontal: 2 people throwing tomatoes at each other
Vertical and horizontal: talking to people standing close to them
little or no movement: watching something in the distance or staring at an object
what were the conclusions of this study?
dreams occur REM sleep only. dreams reported from NREM sleep are from previous REM episodes
estimated dream duration and REM period lengths are very similar, thus it shows that dreams are not instantaneous events but rather experienced in real time
eye movements correspond to where, and what the dreamer is looking at in the dreamer is looking at in the dream, so it explains that they are not random events
what were the strengths and weaknesses?
reliability is high as it was a lab experiment with many controls. for example, the doorbell made people instantly woke up so that dreams wouldn’t be forgotten by slow woken people
demand characteristics were avoided as participants were not told whether they were in REM or not as otherwise, they would try recalling harder
exhibits validity as the details recorder focused on dreaming, dream definition was operationalised, and asking participants to choose between 5 or 25 minutes helped reduce participants variables such as the ability to guess
quantitative data such as brain waves, eye movement patterns, and REM sleep duration was collected through the EEG and EOG
qualitative Dara such as the dream content was collected but its subjective and can affect the validity since the narrative length is not only dependant on the REM phase length but also on age participants expressiveness
both genders were included, thus there’s generalisability. however, the sample size is too small, hence, it limits generalisability
deception of participant WD sign woken up in the wrong sleep stage can cause distress as they’d try recalling dreams harder
lacks ecological validity as people used to drinking alcohol or caffeine may experience atypical dreams. sleeping in a lab connected to electrodes would be unusual, and this may tamper with sleeping behaviour
