Dement and Klietman (Sleep and Dreams)

Question 1

Aim

Answer 1

1- Does dream recall differ between REM and NREM stages of sleep?
2- Is there a positive correlation between estimated dream duration and REM period length?
3- Are eye movements related to the dream content?

Question 2

Research Hypothesis

Answer 2

1- There will be a significant association between REM sleep and dreaming.
2- There will be a positive correlation between estimated dream duration and REM period length.
3- There will be a significant association between eye movement patterns and dream content.

Question 3

Psychometrics used in the study

Answer 3

✦ EEG (electroencephalogram) = traces cyclical changes that occur in brain activity during sleep. Electrodes are placed around the skull to analyse brain waves.
✦ EOG (electrooculogram) = traces eye movements during sleep. Uses electrodes placed around the eye region.

Question 4

Research Method

Answer 4

✦ A laboratory experiment, but different methods to test each aim.

Question 5

Research Design (Approach 1)

Question 6

Research Design (Approach 2)

Question 7

Research Design (Approach 3)

Question 8

Sample

Answer 8

✦ 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.

Question 9

Procedure for the study

Answer 9

✦ Participants reported to the lab before their personal bedtime.
✦ They ate their normal diet but were asked to avoid caffeine (alertness) and alcohol (drowsiness) on the day of the study.
✦ They slept in a dark, quiet room.
✦ They had 2 EOG electrodes near their eye and 2/3 EEG electrodes to the scalp.
✦ A doorbell (for standardisation) had been used to wake participants up at random from REM or 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.

Question 10

Procedure 1

Answer 10

✦ 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.

Question 11

Procedure 2

Answer 11

✦ 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.

Question 12

Procedure 3

Answer 12

✦ Participants’ eye movement direction was detected with the EOG.
✦ Participants were woken up and they reported their dream.

Question 13

Results

Answer 13

✦ 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).

Question 14

Results 1

Answer 14

✦ 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.

Question 15

Results 2

Answer 15

✦ 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.

Question 16

Results 3

Answer 16

✦ Vertical eye movement - - standing at the bottom of a tall cliff and operating a hoist.
- Climbing a ladder, looking up and down.
- Throwing a basketball.
✦ 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.

Question 17

Conclusion

Answer 17

1- Dreams occur during REM sleep only. Dreams reported from NREM sleep are from previous REM episodes.
2- 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.
3- Eye movements correspond to where, and what the dreamer is looking at in the dream, hence, it explains that they are not random events.

Question 18

Strengths: Level of control

Answer 18

Level of control:
✦ One method used was the laboratory experiment. In this part of the study it was therefore possible to control extraneous variables.
✦ If some participants, or participants in different stages of sleep, had woken more slowly they may have forgotten more of their dream, This was avoided by using a loud doorbell that woke them instantly, from any sleep stage.

Question 19

Strengths (Validity)

Answer 19

Validity:
✦ At the beginning of the study, participants were asked to estimate how long they had been dreaming and although they were roughly (and occasionally exactly) accurate, this task was too difficult, so the method was changed.
✦ The task was limited to a choice between 5 and 15 minutes. This also helped to raise validity as it reduced participant variables such as differences in the ability to recall dreams.

Question 20

Strengths (Standardisation)

Answer 20

✦ The consistent placing of the electrodes ensured that recordings taken from each participant would provide the same information.
✦ The reliability of the findings is supported by the similarity of the results to those of previous studies.
✦ As there may be differences in the dreaming of men and women, or between the way they report their dreams, it was useful in terms of generalisability that there were both genders in the sample.