Dement and Kleitman (sleep and dreams)
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Title: The Relation of Eye Movements During Sleep To Dream Activity: An Objective
Method for the Study of Dreaming
Year: 1957
Psychology being investigated:
Our body follows two types of sleep: REM (rapid eye movement) sleep and nREM (nonrapid eye movement) sleep.
nREM can be divided into 4 sleep stages.
In REM sleep, our eyes move rapidly under the lids.
Aserinsky and Klietman’s (1955) study: observed periods of rapid, conjugate eye
movements during sleep and found a high incidence of dream recall in awakening
participants during these periods and a low incidence when awakened at other times.
REM sleep is known as paradoxical sleep. It resembles wakefulness as our eyes move,
we often experience vivid (bizarre) thoughts in the form of dreams and our brains are
active. However, it is different from wakefulness as it is difficult to wake up, we are fairly
insensitive to stimuli and paralyzed.
Background
Sleep and dreaming are clearly hard to investigate because the participant is
necessarily asleep and so cannot communicate with the researcher. Even when awake,
only self-report data can be obtained about dream content, which alone may be invalid
as it is subjective.
The electro-encephalograph (EEG) monitors the electrical activity of the brain.
The electrooculogram (EOG) allowed the electrical recording of eye-movement patterns,
their presence or absence, their size and direction (vertical or horizontal).
The EEG detects and records tiny electrical charges associated with nerve and muscle
activity.
In REM sleep, EEG is relatively low voltage/amplitude and high frequency.
In nREM sleep, EEG has either high voltage/amplitude and slow (low frequency) waves
or frequent ‘sleep spindles’ which are short-lived high voltage, high-frequency waves.
Aims
Overall aim: To investigate dreaming objectively by looking for the relationship between
eye movements in sleep and the dreamer’s recall.
Specific aims:
To test whether dream recall differs between REM and nREM sleep.
To investigate whether there is a positive correlation between subjective estimates of
dream duration and the length of REM period.
To test whether eye-movement patterns are related to dream content. (Whether these
patterns represent the visual experience of dream content or whether they are simply
random movements arising from the activation of the CNS)
Procedure
Research Method: Laboratory Experiment, Observations, interviews and correlation
Experimental design: Repeated Measures Design
Three approaches were used to test the three specific aims. (scroll below to find the
three aims)
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Sample: seven adult males and two adult females. Five of them were studied intensively
while the data gathered from the other four were minimal with the intent of confirming
the results.
Sampling technique: Opportunity sampling
Participants studied in detail spent between 6-17 nights with 50-77 awakenings. The
four others spent only one or two nights with 4-10 awakenings.
Participants were identified by their initials to maintain confidentiality.
Participants reported to the lab a little before their usual bedtime.
They were instructed to eat normally but to abstain from alcoholic or caffeine-containing
beverages on the day of the experiment.
Participants were fitted with electrodes on their scalps and around their eyes.
Once they were in bed in a quiet, dark room, the wires were gathered into a “ponytail” to
allow freedom of movement.
The EEG ran continuously to monitor the participants sleep stages and to inform the
researchers when they should be woken up.
Participants were woken by a doorbell that was loud enough to rouse them from any
sleep stage.
The doorbell rung at various times during the night and the participants indicated
whether they had been dreaming and described their dream into a voice recorder.
Analysis of dream narrative: This was only considered a dream if there was a coherent,
fairly detailed description of the content. Vague, fragmentary impressions were not
scored as dreams.
METHOD
Aim
1
DESIGN
Participants were woken either
from REM or nREM sleep, but
were not told which stage they
were in.
Natural experiment in a laboratory setting
They confirmed whether they
were having a dream and if so,
reported the content into a
recorder.
IV: REM or nREM sleep stage
DV: whether the participants reported a
dream, and if so, the details
Aim
2
Participants were woken following
5 or 15 minutes of REM sleep.
The data was used in both experimental
and correlational designs.
They were asked if they thought
they had been dreaming for 5 or
15 minutes.
Experimental analysis: IV - waking after 5
or 15 minutes of REM sleep. DV participant’s choice
Their dream narrative was
recorder and the number of words
were counted.
Correlational analysis: two variables were
the participant’s time estimate and number
of words in the dream narrative
Aim
3
METHOD
DESIGN
Participants were woken after
exhibiting a single eye-movement
pattern for longer than a minute.
Natural experiment in a laboratory setting.
This was measures using
electrodes and an EOG.
IV: eye-movement pattern type (mainly
horizontal, mainly vertical, vertical &
horizontal, little or none) This could not be
manipulated.
The dream content was recorded.
DV: report of dream content