The Study
How many participants took part in the study?
9
Where did the participants sleep during the study?
In a dark, quiet laboratory room.
What were the two sleep conditions compared in Question 1?
REM and NREM
Which sleep condition produced substantially more dream recall?
REM
Give one strength of using a laboratory setting.
It provided high control over the environment and procedure.
How many males and females were in the sample?
7 males 2 female
What happened when participants were awakened?
They were asked whether they had been dreaming and, if appropriate, were asked to describe their dream.
What was Question 2 investigating?
Whether there was a relationship between REM duration and subjective estimates of dream duration.
What did the researchers find about REM duration and dream narrative length?
There was a positive correlation: longer REM periods tended to be associated with longer dream narratives.
Give one weakness of the sample.
It was very small, with only 9 participants.
What was the overall aim of Dement & Kleitman's study?
To investigate the relationship between REM sleep and dreaming, including dream recall, dream duration and eye movements/dream content.
Why were participants not told about their EEG pattern or whether their eyes were moving?
To prevent this knowledge from influencing their responses.
What was Question 3 investigating?
Whether eye-movement patterns were related to dream content.
Give one example of an eye-movement pattern corresponding with dream content.
Vertical eye movements were associated with a participant reporting that they were climbing ladders and looking up and down.
Why could the use of participants' dream reports be considered a weakness of Dement & Kleitman's study?
Dream reports are subjective, because researchers have to rely on participants accurately remembering and describing their dreams after being awakened. This means the researchers cannot directly verify that the reported dream accurately represents what the participant actually experienced.
What three pieces of physiological information were recorded using the equipment?
Brain activity, eye movements and muscle activity — EEG, EOG and EMG.
Describe how Question 1 was investigated.
Participants were awakened during REM or NREM sleep, then asked about dream recall. The same participants experienced the different conditions.
What was changed in the procedure when participants struggled to estimate dream duration?
Participants were awakened after either 5 or 15 minutes of REM and asked to identify which duration they had been dreaming.
What percentage of REM awakenings resulted in dream recall?
79.6
Why was the use of physiological measurements a strength?
They provided objective measurements rather than relying entirely on participants' subjective reports of dreaming.
Why is Dement & Kleitman particularly appropriate as a study of the Biological Approach?
It investigates a psychological experience—dreaming—using physiological measurements of activity during sleep.
Describe the procedure used to investigate Question 3.
Researchers identified an eye-movement pattern lasting more than one minute, awakened the participant, obtained a dream report, and compared the eye-movement pattern with the reported dream content.
Explain how the three research questions required different types of investigation.
Q1 compared dream recall following REM vs NREM; Q2 examined the relationship between REM duration and dream duration; Q3 compared eye-movement patterns with dream content.
What percentage of NREM awakenings resulted in dream recall?
6.9%
Why could the laboratory setting reduce ecological validity?
Sleeping in a laboratory while connected to equipment and being repeatedly awakened may not reflect normal sleep in everyday life.