(b) dement & kleitman Flashcards
psychology investigated
sleep, dreaming, ultradian rhythms
dreams
sequence of images, emotions, thoughts passing through a sleeping person’s mind
EOG
electrical recording of eye-movement patterns
2 electrodes near eye
EEG
monitors the electrical activity of the brain associated with nerve and muscle activity
nREM sleep stages (4)
Awake, Stage 1, Stage 2, Stage 3&4
nREM - stage 1 (lasts 1-7 minutes)
- slower breathing and heart rate
- hypnagogic (falling/floating) sensations or hallucinations
- easily awakened
nREM - stage 2 (approx. 20 minutes)
- decrease in breathing, heart rate, body temperature
- helps you process simple and complex motor skills
- not easily awakened
nREM - stage 3&4
- deep sleep, extremely relaxed
- heart rate, respiration, body temp, blood flow to brain - reduced
- growth hormone secreted
- for body maintenance & restoration
- disorientation & confusion on waking
ultradian rhythms
biological rhythms which repeay more frequently than once a day
do u sleep in nREM or REM sleep stages
REM
REM sleep
- vivid dreams occur
- breathing rate increases
- muscles are completely paralysed (aka, paradoxical sleep)
general aim
to investigate dreaming in an objective way by looking for the relationship between eye movements in sleep and the dreamers recall
aim 1 (dream recall)
to investigate if dream recall between REM and nREM sleep is different
aim 2 (dream length & REM length)
to investigate if dream length estimates and length of REM period correlate positively
aim 3 ( eye patterns & dream content)
to investigate if eye movement patterns are related to dream content
participants
7 males, 2 females (5 studied intensly)
how were the participants recruited
opportunity sample (all american, from chicago)
how long was the study
6-17 nights - (with 50-77 awakenings)
for the 5 studied intensely,
1-2 nights - (with 4-10 awakenings)
instructions given to ppts/the sample
- avoid caffeine and alcohol
- eat normally
- you will sleep in a dark, quiet room
- woken at random intervals by doorbell
- ppts were asked to report on dreams
electrodes - how many? where are they placed?
EOG - 2/3 near the eye
- tracks horizontal/vertical
eye movements
EEG - 2/3 on scalp
record brain waves
equipment - how were they woken up
by doorbell
- placed near bed, loud enough
how were the DV’s operationalised?
recording device to minimise contact with the ppt
Procedure 1 (dream recall)
IV: stage of sleep - REM or nREM
DV: dream content recall - dream or no dream
woken up at random intervals
Procedure 2 (dream length & REM length) - INITIAL METHODOLOGY
initially, ppt were woken up at random intervals and asked to estimate dream legth to the nearest minute
proved to be too hard.
Procedure 2 (dream length & REM length) - IMPROVED METHODOLOGY
ppt were woken following either 5 or 15 minutes (randomly)
ppt then guessed if they were sleeping for 5 or 15 minutes
dream narrative was later recorded & number of words counted
IV: length of REM - 5 or 15 minutes
DV: % of correct estimates of 5 or 15 minutes
Procedure 3 (eye movement patterns) - INITIAL METHODOLOGY
ppt asked to report every eye-movement in order
proved to be too hard.
Procedure 3 (eye movement patterns) - IMPROVED METHODOLOGY
ppts woken up after 1 of the 4 eye movement patterns were done
(mainly vertical, mainly horizontal, vertical and horizontal, very little/no movement) - measured using electrodes and EOG
recall what dream content was
Results about REM sleep
All ppts showed REM sleep every night in a regular pattern.
Varied between ppts
Average length 20 mins – increases with sleep duration.
When woken in nREM sleep, participants fell back into the same
sleep stage as before woken
REM eye movements are not continuous 1-2 movements in a burst.
Huge variation in eye movement across REM sleep, but brain
wave pattern remains stable.
Results 1 (dream recall)
ppts described dreams often when woke from REM (DN- 152/191) but
rarely when woken from nREM sleep (DN- 11/160)
Results 2 (dream length and REM length)
Responses 88% accurate for 5-min REM duration
Responses 78% accurate for 15-min REM duration
Significant positive correlation between length of dream and no. of words in dream narrative (+0.4- +0.71)
DN differed from other ppts.
Equally likely to get 15min estimate right or wrong.
Estimation of 5min correct 80% of the time.
Often underestimated dream length
Results 3 (eye movement patterns)
Pure vertical or pure horizontal movements were very rare.
- 3 participants had pure vertical eye movements corresponding to narratives
of vertical eye movements (eg. climbing a series of ladders) - 1 participant had horizontal movements (eg. watching people throw tomatoes)
2 participants had a large eye movement to the left (eg. driving and a man on the left hailed his car as he drove past)
21 awakenings of mixed eye movements (talking to ppl)
10 very little or no eye movement (staring at fixed objects)
conclusions
Dreams probably occur only in REM sleep Dream most likely persists from earlier period of REM > best recalled within 8 mins.
Length of dream estimations correlate with REM sleep duration
suggesting dreams are experienced in real time
Eye movements in REM sleep correspond to where and at what the
dreamer is looking at in their dream.
REM eye movements are linked to dream content
ethical issues
PROS:
- confidentiality maintained
- no lasting permanent damage is caused
CONS:
- ppts were sleeping in unnatural settings and woken up throughout the night
- this may have affected them the following day
