Transcript Dement & kleitman (1957) rem sleep and dreaming Core study

DEMENT & KLEITMAN (1957)
REM SLEEP AND DREAMING
CORE STUDY
Physiological Approach
STARTER TASK:
• I’m going to put you into 3 groups
• In your group you have 12 minutes to complete the quiz
Fill in your worksheet as we go along!
Core study: Dement & Kleitman (1957)
They wanted to test 3 hypotheses:
Background:
Dement & Kleitman wanted to find a rigorous way of
measuring sleep and dreaming.
How could you measure objectively if someone was
dreaming or not?
Aim:
To see if the
physiological aspects
of REM sleep (i.e.
movement of the
eyes) related to the
subjects experience of
dreaming.
1. There is a significant association
between REM and reported
dreaming.
2. There is a significant positive
correlation between the estimate of
time spent dreaming and the
measurement of REM sleep.
Subjects:
7 adult males, 2
adult females (5
studied intensively, 4
used to confirm the
findings)
3. There is a relationship between
the pattern of eye movement and the
reported content of the dream.
General procedure:
• The 9 subjects were tested individually
• Asked to report to the lab at their usual bed time
• Told to avoid alcohol and caffeine
• WHY?
• Electrodes were applied to the subjects’ head and faces
• They slept in a quiet, dark lab
• A doorbell was used to wake the subjects
WHY DO YOU THINK THEY USED A DOORBELL?
Hypothesis 1
Method and design:
• The purpose was to compare dream recall in REM and NREM sleep
• Dement and Kleitman measured whether the subject was in REM or
NRM sleep using an EEG and whether or not the subjects reported
that they had been dreaming when they were woken
Procedure:
• At various times during the night PPs were woken up with doorbell.
• They had been instructed to record immediately into a tape recorder
whether or not they had been dreaming.
• No contact with experimenter before dream reports, in order to
avoid...WHAT?
Hypothesis 2:
Method and design:
• Quantitative data was collected for a correlational analysis
Procedure:
• Participants were woken up either FIVE MINUTES or FIFTEEN
MINUTES into a REM period
• Asked to estimate whether they had been dreaming for five or
fifteen minutes
• Length of dream estimate was correlated with the length of time
in REM sleep
Hypothesis 3:
Method and design:
• Qualitative data was gathered regarding the content of subjects’
dreams
• This was compared with observations of the way the subjects’ eyes
were moving
Procedure:
• Participants were woken when one of four patterns of eye
movement had lasted for at least a minute
1. Vertical eye
movements
2.Horizontal eye
movements
3. Both vertical and horizontal
eye movements
4.No eye
movement
• Participants were asked to describe the content of their dream
General results:
• All subjects experienced REM sleep
• REM never occurred at beginning of
sleep cycle
• Mean duration of REM 20 minutes
• Average occurrence of REM was one
period every 92 mins
10 MINUTE TASK
YOU HAVE 10 MINUTES TO WRITE 3-5 QS ON
THE PROCEDURE OF THIS STUDY
Please keep these safely in your folder or iPad
for next lesson.
Results for hypothesis 1:
RAPID EYE MOVEMENT
Total
NON RAPID EYE
MOVEMENT
Dream
recall
No dream
recall
Dream
recall
No dream
recall
152
39
11
149
More dreams were reported in REM sleep than NREM sleep – this gives support to the
suggestion that dreaming occurs during REM sleep.
Results for hypothesis 2:
Total
Estimates after 5 minutes REM
Estimates after 15 minutes REM
Right
Wrong
Right
Wrong
45
6
47
13
There was a significant relationship between subjects’ estimate of dream length and
the amount of time spent in REM sleep.
There were more wrong estimates when subjects had been in REM sleep for 15
minutes, suggesting that the longer the subject had been asleep, the less accurate their
dream estimates.
Results for hypothesis 3
The results suggested that eye movement was related to dream content.
Type of eye movement
Example of dream content
Vertical
Climbing ladders
Looking up a cliff
Horizontal
Watching people throw tomatoes at each
other
Vertical & horizontal
Talking to groups of people, looking for
something
Little or no movement
Staring at an object
Driving and staring at road ahead
Conclusions:
• Dement and Kleitman concluded that there is a strong connection
between REM sleep and dreaming
• HOWEVER from their findings, it is not certain that dreaming did not
take place during other stages of sleep
• D&K suggest this may be because if woken in a stage of sleep soon
after REM stage, they may still remember their dream, so think they
were dreaming at the time of being woken
• Overall they concluded that the measurement of REM during sleep can
be used as an objective measure of dreaming
• This enables further research to be carried out in the field of
dreaming e.g. factors that affect dreaming such as stress or drugs
ESQs and PEER MARKING - Sec A
A
B
In Dement and Kleitman:
Describe one way in which the study lacked
Ecological validity. (2)
In Dement and Kleitman:
Identify two controls used in this study. (2)
Explain why it is appropriate for this study to
lack EV. (2)
Explain why one of these controls was used.
(2)
In Dement and Kleitman:
Identify two features of the sample used in
this study. (2)
In Dement and Kleitman:
Explain what an EEG measures. (2)
Outline one weakness of this sample. (2)
Describe one limitation of using an EEG to
investigate dreaming. (2)
A June 2010
A Jan 2012
B – Jan 2011
B – Jan 2011
B – June 2011
B – June 2011
Homework
• Complete the Section B Qs on Dement and Kleitman
• Due next lesson