Dement and Kleitman SLICE Flashcards
Summary
Aim: Dement and Kleitman's study had 3 separate aims. Does dream recall correlate to REM? Is there a
correlation between REM duration and estimates of dream length? Are rapid eye movements connected
to the content of dreams?
Method: In their study, they used nine adults (seven male, two female) who came to a sleep laboratory
for a polysomnography. The participants had been told to avoid alcohol and caffeine during the day. The
participants slept in the sleep laboratory and were woken several times during the night by the
researchers. They were asked if they had been dreaming, and if so what their dream had been about and
how long it had lasted.
Results: Dement and Kleitman found that participants were much more likely to say that they had been
dreaming if woken during REM sleep, doing so on almost 80% of wakings, compared to around 9% if
woken during non-REM sleep. They also said that their dreams had been shorter if they were woken five
minutes after the start of the REM phase, compared to being woken 15 minutes after it started.
In terms of eye movements, these did appear to link to what the dream had been about. A participant
who had been making left to right movements of the eyes reported a dream about people throwing
tomatoes at each other, for example. After each waking, participants generally got back to sleep inside
five minutes.
Links
REM/ NON-REM - Dreaming might not occur in NREM sleep because the alpha, theta and delta
waves are not appropriate for dreams. Whereas, in REM sleep our brain is just as active when we
are awake.
Role of the brain (Cerebral cortex, thalamus and amygdala) - 3 areas of the brain are only active
during REM.
Restoration theory - Dreams may occur as a result of neurotransmitters being replenished.
Reorganisational theory – Dreams may occur as a result of memories being strengthened or reverse
learned.
Implications
These results could help in the creation of sleep disorder interventions.
Comparisons
Czeisler (1990) - Czeisler was a field study so more externally valid and D & K was a lab study so
more internally valid.
Peter Tripp (1959) - Hallucinations may have been a result of P.Tripp entering REM sleep when
he was awake.
Evaluation
– Strengths:
Ground breaking research
Lab, unnatural location – Low external validity
Lab, controlled conditions – High internal validity
Lab, easily replicated – High reliability
Weaknesses:
Ethical issues – waking participants during the night
Sample size – low external validity
Self-reporting – low internal validity
