Dement and Kleitman (1957) (Sleep and Dreams) Flashcards
Retain information about the study Dement and Kleitman (1957)
What is the general aim of the study?
To investigate the relationship between eye movements and dreaming.
What are the specific aims of the study?
- Does dream recall differ between REM and NREM stages of sleep?
- Is there a positive correlation between estimated dream duration and REM period length?
- Are eye movements related to the dream content?
What is the research hypothesis regarding REM sleep?
There will be a significant association between REM sleep and dreaming.
What is the research hypothesis regarding dream duration?
There will be a positive correlation between estimated dream duration and REM period length.
What is the research hypothesis regarding eye movement patterns?
There will be a significant association between eye movement patterns and dream content.
What does an EEG do?
EEG (electroencephalogram) traces brain waves and can measure which areas of the brain are more active. It is used in this study to measure REM/NREM sleep.
What does an EOG do?
EOG (electrooculogram) = traces eye movements during sleep.
What revealed the association between REM sleep and dreams?
Aserinsky (1955) revealed that participants who woke from REM sleep reported more vivid dreams. Just remember that previous studies suggested that REM sleep is when we dream.
What type of research method was used in the study?
A laboratory experiment.
What is the independent variable (IV) in Approach 1?
Whether they woke up from REM or NREM.
What is the dependent variable (DV) in Approach 1?
Whether they recalled a dream or not.
What correlational method was used in Approach 2?
Correlational analysis was used to cross-check estimated dream duration and word count of dream narratives.
How many participants were involved in the study?
9 participants (7 males and 2 females).
What was the sample size for the main participants?
5 main participants spent between 6 - 17 nights in the lab.
What did participants need to avoid on the day of the study?
Caffeine and alcohol.
What equipment was used to monitor participants during the study?
EOG electrodes near the eye and EEG electrodes on the scalp.
What was the purpose of waking participants with a doorbell?
For standardisation.
How did the researchers operationalize a dream?
A dream only counted if the recall was clear.
What were participants asked to do after being woken up from REM sleep?
Guess the duration they had dreamt for.
What was recorded to prevent researcher bias during dream narrative collection?
Dream narrative recorded on a tape recorder.
True or False: Participants were allowed to drink caffeine on the day of the study.
False
What percentage of dream recall occurs when woken from REM sleep?
79.6%
Waking from NREM sleep results in 7% dream recall.
Was the participants’ ability to recall their dreams affected by how soon they were woken up after REM sleep?
Yes
Waking up within 8 minutes of REM sleep results in 30% dreams recalled.
Waking after more than 8 minutes resulted in only 4% of dreams recalled.
What was the accuracy rate for estimating REM duration for 5 minutes?
88%
78% accuracy for 15 minutes.
What is the relationship between REM duration and word count in dream recall?
Positive correlation.
What types of eye movements were observed in relation to dream content?
- Vertical eye movement
- Horizontal eye movement
- Both vertical and horizontal
- Little or no movement
Do dreams occur during REM sleep or NREM sleep?
Only during REM sleep.
What does the similarity between estimated dream duration and REM period lengths indicate?
Dreams are experienced in real-time.
What is the significance of eye movements during dreams?
They correspond to where and what the dreamer is looking at.
What dream content was associated with vertical eye movements?
Standing at the bottom of a tall cliff.
What dream content was associated with horizontal eye movements?
Two people throwing tomatoes at each other.
What dream content was associated with little or no eye movement?
Watching something in the distance or staring at an object.
What are the three main conclusions of the study?
- Dreams occur during REM sleep only. Dreams reported from NREM sleep are from previous REM episodes.
- Dreams occur in real-time. Estimated dream duration and REM period length were similar, proving that dreams are not instantaneous.
- Eye movements are linked to dream content. They are not random but correspond to where and what the dreamer is looking at.
What factors increased the study’s reliability?
- Controlled lab experiment with standardized procedures.
- Doorbell ensured instant awakening, preventing memory loss of dreams.
How were demand characteristics avoided?
Participants were not told if they were in REM or NREM, preventing them from trying harder to recall dreams.
What aspects ensured validity?
- The study operationalized the definition of a dream and standardized the method of waking participants up.
- Participants had to choose between 5 or 15 minutes, reducing participant variables like guessing ability.
What types of data were collected?
- Quantitative data: Brain waves, eye movements, and REM duration (EEG & EOG).
- Qualitative data: Dream content (but this was subjective and could affect validity).
How does the sample size affect generalizability?
- Both genders were included, increasing generalizability.
- Sample size was small (9 participants), limiting generalizability.
Why does the study lack ecological validity?
- Participants avoided caffeine and alcohol, which might alter their normal dreaming patterns.
- Sleeping in a lab with electrodes may have disrupted natural sleep behavior.
How does this study relate to nature vs. nurture?
Nurture: Dream content is based on life experiences.
Nature: The ability to dream is biologically determined.
