Dement and Kleitman Flashcards
Aim
- 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?
Research Method
Lab
Sample
7 males and 2 females were 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 nights in the lab. Approximately 50 - 77 times awakening. 4 spent only 1 - 2 nights. 4 - 10 times awakening. Participants were identified by their initials.
Approach 1
natural experiment; repeated measures design; IV - whether they woke up from REM or NREM; DV - whether they recalled a dream or not.
Procedure 1
They were woken up at various times to test their 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, and if they did, then they recorded it. Dream only counted if the recall was clear.
Result 1
Awakenings from REM produced a dream recall of 79.6%, and from NREM produced a dream recall of 7%.
Waking participants under 8 minutes of completing their REM period resulted in 5/17 dreams being recalled. However, waking participants after 8 minutes resulted in only 6/132 dreams being recalled.
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’ estimate dream duration and the word count of their respective dream narrative.
Procedure 2
Participants were woken up after either 5 or 15 minutes into their REM sleep. Participants guessed the duration they had dreamt for. The number of words in the dream narrative was counted after the participants reported their dream.
Result 2
The estimation of REM duration was accurate and very high. 88% for 5 mins; 78% for 15 minutes.
There was a positive correlation between REM duration and words in the recall. The narratives of 152 dreams were collected, but 26 were omitted due to poor recording thus, there were 126.
Approach 3
natural experiment; repeated measures design; IV - eye movement patterns; DV - dream content.
Procedure 3
Participants’ eye movement direction was detected with the EOG. Participants were woken up and they reported their dream.
Result 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.
Overall results
- 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 longer later in the night. Bursts of 2 - 100 rapid eye movements.
- Those woken in NREM returned to NREM. Those woken in REM went to NREM (but sometimes went to REM to complete the final phase).
Conclusions
- Dreams occur during 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 dream, hence, it explains that they are not random events.
Strengths
- High reliability
- High internal validity
