Dement & Kleitman (1957)
Core Study
Physiological approach
The relation of eye movements during
sleep to dream activity: An objective
method for the study of dreaming.
Recap quiz of Social approach
1) In the core study by Milgram,
participants were;
A)
B)
C)
D)
50 Males aged 20 – 50.
40 Males aged 20 – 50.
40 Males aged 30 – 60.
40 Males and Females aged 20 – 50.
2) Which of the following was not a
prod used by the experimenter?
A) The experiment requires that you continue.
B) Please continue.
C) I will take the responsibility for what happens
here today.
D) It is absolutely essential that you continue.
3) Milgram’s results showed
A) 100% of participants shocked the learner up
to 300V.
B) 65% of participants shocked the leaner up to
450V.
C) Participants showed a variety of nervous
physiological reactions to the task.
D) All of the above.
4) If a person supresses their values
and no longer feels responsible, this is
know as being;
A)
B)
C)
D)
In an agentic state
In an autonomous state
Cognitively dissonant
Collectivist
5) What was not an independent
variable in Piliavin et al’s experiment?
A)
B)
C)
D)
Type of victim (lame or drunk)
Race of victim
Group size
Gender of victim
6) Results for Piliavin et al showed
A)
B)
C)
D)
Males were more helpful than females
A slight tendency for same race helping
No evidence for diffusion of responsibility
All of the above
7) What is the term used to describe
people looking to others to define a
situation if it is ambiguous?
A)
B)
C)
D)
Bystander apathy
Diffusion of responsibility
Pluralistic ignorance
Model intervention
8) Reicher & Haslam conducted a
study which is an example of a
A)
B)
C)
D)
Naturalistic observation
Laboratory experiment
Experimental case study
Field experiment
9) Which of the following was not an
independent variable for R & H?
A)
B)
C)
D)
Permeability
Legitimacy
Cognitive alternatives
Group identification
10) Reicher & Haslam found the
situation to have an effect on
A)
B)
C)
D)
Social identification of guards and prisoners
Group self-efficacy of guards and prisoners
Depression levels of guards and prisoners
All of the above
Dement & Kleitman (1957)
Core Study
Physiological approach
The relation of eye movements during
sleep to dream activity: An objective
method for the study of dreaming.
Learning Objectives
• Be familiar with the context of study into sleep
and dreaming by understanding stages of
sleep and REM.
• Be able to identify the three hypotheses for
the study.
• Be able to outline the research procedure and
the results of the study.
• Be able to discuss the relationship between
REM and dreaming.
Differences between social and
physiological psychology
SOCIAL ASSUMPTION
Social context is extremely influential in shaping behaviour.
Our behaviour is influenced by the imagined or implied
presence of others.
PHYSIOLOGICAL ASSUMPTION
Behaviour and experience can be explained by
physiological changes i.e. our biology.
Investigates the brain, nervous system and other biological
factors e.g. hormones.
Is sleep important?
Is sleep important?
We spend 1/3 of our lives asleep.
Average person will spend 25
years of their life asleep.
What happens if we don’t sleep?
•
•
•
•
•
•
•
Logic and reasoning affected
Difficulty concentrating
Memory problems
Depression and anxiety
General paranoia
Hallucinations
Increased risk of various medical
conditions e.g. heart disease,
diabetes, obesity.
Sleep is an active NOT a
passive behaviour.
Examples of sleep deprivation
Peter Tripp 1959
200 hour wakeathon on American radio.
Began to hallucinate, saw spiders in his shoes,
thought one of the scientist there to look after
him was an undertaker coming to bury him.
Randy Gardner 1960s
Set out to break world record for longest time
spent awake (11 days)
Effects = contracted problems with his eyesight,
speech and memory problems, started to
hallucinate towards end of experiment.
Why do we sleep?
Why do we sleep?
Evolutionary theories – All animals sleep so it
must have some valuable function (survival of
the species), energy conservation, predator
avoidance.
Restoration theories – Repair and restore the
brain (e.g. growth hormones released) and body
(e.g. repair muscle tissue).
Brain processing and memory consolidation
theories – People need sleep to process
information acquired during the day, transform
information into long-term memory etc.
Why do we dream?
Why do we dream?
PYSCHOANALYSIS - FREUD
Dreaming is the ‘royal road to the
unconscious’.
We dream to fulfil wishes.
Dreams are symbolic, repressed
fantasies.
COGNITIVE – INFORMATION PROCESSING
THEORIES
As our brain is dealing with the multitude of
information and memories that we experienced
during the day, our brain creates images and a
narrative to manage this activity.
PHYSIOLOGICAL - ACTIVATION SYNTHESIS MODEL
During REM sleep, circuits in the brain become activated which causes certain areas
of our brain associated with emotions and memories to become active.
The brain interprets this internal activity and attempts to find a meaning which
results in dreaming.
How can we objectively measure
sleep?
1) ElectroEncephaloGram (EEG) – Records brain
activity/waves
2) ElectroOculoGram (EOG) – Records eye
activity
3) ElectroMyoGram (EMG) – Records muscle
activity
Electroencephalogram (EEG)
Electro (electric)
En Cephalo (in the head)
Gram (drawing)
• The EEG machine uses recording
electrodes (stuck to the skin or
scalp) to detect the simultaneous
activity of groups of neurons in the
brain.
• It produces a chart (an
encephalogram) which shows how
‘brain waves’ vary i.e. how the
frequency and amplitude (height)
of electrical output from the brain
changes over time.
• These charts show that we go
through several cycles of sleep a
night.
Electrooculogram (EOG)
Electro (electric)
Oculo (relating to the eyes)
Gram (drawing)
The EOG machine uses
electrodes placed on the
skin on either side of the
eye to record frequency of
eye movements.
Records eye activity.
The sleep cycle
Read P 33 and P35 in your booklet AND the
sleep stages handout
Use the information to complete the sleep cycle
worksheet
NREM OR SWS
Non Rapid Eye Movement or Slow Wave Sleep
STAGE 1
Theta waves
Lowered heart rate, muscle tension and body
temperature.
Can be easily awoken in this stage.
STAGE 2
Slower and larger EEG waves and sleep
spindles (bursts of high frequency waves)
which last for about 1 second.
A person can still easily be awoken.
STAGE 3
Delta waves, large and slow.
People in stage 3 do not easily respond to
external stimuli and can be difficult to wake
up.
STAGE 4
Delta waves, deepest of all 4 stages.
Metabolic activity low and people are very
difficult to wake up.
EEG OF NREM SLEEP CYCLES
What happens next?
REM (RAPID EYE MOVEMENT)
REM sleep occurs roughly every 90
minutes and is associated with
various physiological changes in the
body
1)
2)
3)
4)
Eyes begin to dart back and
forth under the eyelids.
Heart rate increases.
Skeletal muscles relax
(paralysis).
Brain waves are fast –
resembling the awake stage.
After REM has finished (approx 15
minutes), the sleep cycle starts
again.
https://www.youtube.com/watch?v=H0DJzFDOgzg – REM video
The sleep process
• When asleep you descend
through the stages but after
reaching STAGE 4 you ascend
to STAGE 3 and to STAGE 2.
• From STAGE 2 you ascend
through stage 1 to REM.
• REM lasts approximately 15
minutes and then you return
to STAGE 2.
• This cycle is repeated
throughout the night but with
each cycle the amount of deep
sleep shortens and the amount
of REM sleep lengthens.
• Each cycle lasts approximately
90 mins.
How would you draw this?
Research context
Previous research had demonstrated:
• The cyclic change in depth of sleep, as
measured by EEG.
• A relationship between REM and dreaming
(Aserinsky & Kleitman, 1955).
Sleep and dreaming
https://www.youtube.com/watch?v=GidiLjnbNG
c
Featuring Kleitman
The Core Study – Dement & Kleitman
(1957)
Group 1: Aim, hypotheses, variables (Ivs and
Dvs)
Group 2: Methodology, participants, materials
Group 3: General procedure
Group 4: Procedure for hypotheses 1, 2 and 3.
The Core Study – Dement & Kleitman
(1957)
WHAT DID THEY WANT TO FIND OUT?
AIM
To see if the physiological aspects of REM
sleep relate to participants’ experiences of
dreaming.
I.e. to determine the relationship between
eye movements and dreaming.
Three questions, three hypotheses
1) Will people be more likely to report dreams if they are
awoken during periods of REM than during periods of NREM
sleep?
There will be a significant association between REM and
reported dreaming.
2) Can people accurately estimate duration of dreaming?
There will be a significant positive correlation between
estimates of dream length (subjective) and measurement of
REM sleep (objective).
3) Is the direction of eye movement during REM sleep related
to dream content?
There will be a significant association between the pattern of
eye movement and reported content of the dream.
Correlations briefly
A correlation = an association (extent to which two variables
are related).
Positive correlation – as one variable increases, the other
increases.
E.g. as temperature increases, so do sales of ice creams.
Negative correlation – as one variable increases, the other
decreases
E.g. as alcohol consumption increases, inhibitions decrease.
No correlation – no connection between the two variables
E.g. number of people who own a cactus in Bradford and
number of people who have a bath mat in Leeds.
Variables
Whether woken in REM
sleep or NREM sleep
Whether dream is recalled
Whether woken after 5
minutes or 15 minutes
of REM sleep
Estimate of length of
dreaming
Movement of eyes
Content of dream
Methodology and participants
Laboratory experiment involving the collection of
data through observation (of objective measures)
and self-report measures (participants spoke into a
tape recorder).
Participants
7 adult males and 2 adult females.
5 were studied intensively, 4 to confirm these
results (only tested on 1 or 2 nights).
Materials
• Setting – a sleep laboratory with
specialised equipment to
objectively measure sleep.
• Electrodes attached near the
eyes to measure eye movement
(EOG) and to the scalp to
measure brain wave activity i.e.
depth of sleep (EEG).
• Doorbell used to wake
participants.
• Tape recorder to record
recollections of what they had
been dreaming about.
What was the procedure?
Procedure
• Participants reported to sleep laboratory just
before their usual bedtime (had been told to eat
normally but avoid alcohol and caffeine on the
day of the experiment).
• Electrodes were attached around eyes to
measure electrical activity and therefore eye
movement (EOG).
• Electrodes were attached to scalp to record brain
waves (EEG) to measure depth of sleep.
• Participants went to sleep in a darkened room.
Procedure continued
• At various times the participants were awoken by a
doorbell.
• On waking the participants immediately spoke into the
tape recorder to report A) if they had been dreaming
or not and B) to describe the content of their dream
(they were only classed as dreaming if they could give a
detailed description).
• An experimenter listening outside the door and
occasionally entered to further question the
participant on some particular point of their dream.
• Participants were not told whether their eyes had been
moving.
Procedure for hypothesis 1
Procedure for hypothesis 2
Procedure for hypothesis 3
Hypothesis 1 Procedure
Participants were awoken in one of four ways:-
1) 2 participants were woken according to a
random numbers table.
2) 1 participant was woken at the whim of the
experimenter.
3) 1 participant was woken during 3 REM periods
and 3 NREM periods.
4) 1 participant was woken randomly (but had
been told he would only be woken during REM
sleep).
Hypothesis 2 Procedure
Participants were woken either 5 or 15 minutes
after REM sleep began and were asked to
estimate the length of their dream by choosing
between the two (5 or 15 minutes).
Participants were asked to relate the content of
their dream and the length of the narrative was
correlated with the duration of REM sleep
before they were awoken.
Hypothesis 3 Procedure
Participants were woken as soon as 1 of 4 patterns
of eye movement had occurred for a minute and
were asked what they had just been dreaming
about.
Patterns were:
1) Mainly vertical
2) Mainly horizontal
3) Both vertical and horizontal
4) Very little/no eye movement.
GENERAL RESULTS FOR REM SLEEP
RESULTS FOR HYPOTHESIS 1
RESULTS FOR HYPOTHESIS 2
RESULTS FOR HYPOTHESIS 3
General results for REM sleep
 All participants showed periods of REM every night that they slept
in the laboratory (shown through EEG readings).
 Total number of awakenings (for all 9 participants) was 351 times
over 61 nights, averaging 5.7 per participant per night.
 Average occurrence of REM was one period every 92 minutes for
the whole group with variations between 70 and 104 minutes.
 The lengths of REM was between 3 minutes and 50 minutes and
they tended to increase in length as the night progressed.
Results Hypothesis 1
Does dream recall correlate with periods of REM
sleep?
• Participants were much more likely
to recall dreams in REM sleep than
NREM sleep.
Total awakenings = 191 Total awakenings = 160
Therefore – there is a correlation
between dreaming and REM so we
accept HYPOTHESIS 1
200
150
• When no dream recall was recorded
in REM this tended to be in the
earlier periods of the night.
• NREM dreams were usually within 8
minutes of REM sleep (poss recalling
dreams from previous REM sleep?)
Recall
100
No Recall
50
0
REM
NREM
Results Hypothesis 2
Is there a correlation between the estimate of
dream length and time spent in REM?
Woken after 5 mins Woken after 15 mins
(REM)
(REM)
Correct Incorrect Correct Incorrect
45
6
47
50
40
30
20
10
0
13
Correct
Participants were mostly accurate in
their estimation of dream length.
There was a significant correlation
between the length of dreams
(number of words in dream report)
and the amount of time spent in
REM.
Therefore – there is a significant
correlation between estimates of
dream length and time spent in REM
so we accept HYPOTHESIS 2
Incorrect
5 minutes
15
minutes
One participant was responsible for a
large proportion of incorrect
estimates.
Results Hypothesis 3
Will the direction the eyes are moving in be
related to the content of the dream?
Type of eye movement
Number of times
Examples of Dream content
Vertical
3
Looking up at a cliff
Climbing a ladder
Throwing basketballs at a net.
Horizontal
1
Watching two people throw
tomatoes at each other.
Vertical and horizontal
21
Talking to a group of people
Looking for something.
Non/very little
10
Driving a car and staring at the
road
Staring at an object.
Eye movements appeared to be related to dream content, indicating that the eyes were moving as if
seeing what the participants were dreaming about.
Therefore there is a correlation between eye movement and dream content so we accept HYPOTHESIS
3
Conclusion
Hypothesis 1?
Dreams are related to REM sleep.
Hypothesis 2?
People do dream in real-time.
Hypothesis 3?
Eye movements are closely related to dream
content.
Discussion
• EEG showed participants were at their lightest
level of sleep during REM periods.
• Participants awoken during NREM occasionally
reported feelings of emotional states rather than
narrative dreams i.e. anxiety, pleasantness
• Eye movements related to dream content
indicated that the eyes were moving as it seeing
what the participant was dreaming about.
• Objective measurement of dreaming may be
achieved by recording REMS whilst people sleep.
Discussion continued
HOWEVER
• Babies in the womb - have periods of REM yet they
must be unable to recall objects and events as they
have no experience of them.
• Individual differences - Later studies showed that not
everyone follows this pattern so it is likely that
significant individual differences exist between people
in respect to dreaming.
• Cause and effect - A significant relationship was found
between REM and dreaming but it cannot be
confirmed that one causes the other or if they just
coincide by chance.
Learning Objectives
• Be familiar with the context of study into sleep
and dreaming by understanding stages of
sleep and REM.
• Be able to identify the three hypotheses for
the study.
• Be able to outline the research procedure and
the results of the study.
• Be able to discuss the relationship between
REM and dreaming.