What is The aim of the Dement and Kleitman study a
Aim: The aim of the study was to investigate the relationship between eye movement and dreaming.
1 There will be a significant association between REM sleep and dreaming.
2 There will be a significant positive correlation between the estimate of the duration of the dreams and the lenght of the eye- movevment.
3 There will be a significant association between the pattern of eye movement and the context of the dream.
Procedure and method
The nine participant were seven adults males and two adults females. Five were studied intensively, while only a small amount of the data was collected on the other four just to back up the findings of the main five.
The participants were studied under controlled laboratory conditions, whereby they reported to the laboratory just before their usual bedtime. They asked to eat normally but to avoid caffeine and alcohol on the day of the study. the participants went to bed in a quiet, dark room.
An electrocephaolgraph(EEG) was used to amplify and record the signals of electordes which were attached to the participants face and scalp. To record any changes caused by eye movement.
Testing hypotheses 1
Testing Hypotheses 1: (There will be a significant association between REM sleep and dreaming)
Both during REM and N-REM sleep the participants were awakened to test their dream recall.Participant were woken by a loud dorrbell ringing close to their bed.
They were instructed (speak into a tape recoreded) to first state whether or not they had been dreaming and then, if they could repot the content of the dream.
Different participants were woken according to different schedules.
I an attempt to eliminate the possibilty of experimenter effects, the experimenter did not communicate with the particiapnt during the night.
Futhermore to help prevent bias the participants were never told, after wakening, wheteher their eyes had been moving or not.
Testing hypothesis 2 & 3
Testing hypotheesis 2: (There will be a significant positive corellation between the estimate of the duration of dreams and the length of eye-movement)The participant were also woken up either five minutes or fifteen miuntues in REM period, and asked to say whether they though they had been dreaming for five or fifteen minutes.
Testing hypothesis 3:(There will be a signifant association between the estimate of the duration of dreams and the length of eye-movement)The pariticapnts were woken up as soon as one of four patterns of eye movement had lasted for at least one minute. Once woken the participant were asked to describe in detail the content of their dream.
a) mainly vertical eye movements
b) mainly horizontal eye movemnts
c) Both vertical and horicontal eye movements.
d) Very little or no eye movement.
All the participants showed periods of REM every night during sleep. The REM EEG was characterised by a low voltage, relatively fast pattern. In between REM periods the EEG patterns were either high-voltage, slow activity or spindles with a low-voltage background, both characteristic of deeper sleep.
Results relating to hypothesis 1-The results show that REM sleep is predominantly, though not exclusively, associated with dreaming, and N-REM sleep is associated with periods of non-dreaming sleep.
Nearly all dream recall in N-REM awakenings occurred within eight minutes of an REM, suggesting that the dream might have been remembered from the previous REM
Results relating to hypithesis 2-The series of awakenings which were carried out to see if the participants could accurately estimate the length of their dreams, revealed that all the participants were able to choose the correct dream duration fairly accurately, except for one participant (DN) who could only recall the latter part of the dream and so underestimated its length.
Continuation from Hypothesis 3
Results relating to hypothesis 3-There did appear to be some relationship between the dream content and the type of eye movements.
Periods of pure vertical or horizontal eye movements were rare, but when the participant was woken up after a series of vertical eye movements they reported dreams such as:
Ø standing at the bottom of a cliff operating a hoist, and looking up at the climbers, and down at the hoist machinery.OR climbing up a series of ladders looking up and down as he climbed.
In the only instance of horizontal eye movements, the dreamer was watching two people throwing tomatoes at each other.
In order to confirm the meaningfulness of these relationships, 20 naive participants and 5 of the experimental participants were asked to observe distant and close-up activity while awake. These measurements were in all cases comparable to those occurring during dreaming
Evaluation of Procedure
Weakness: lack of ecological validity- The situation in which the participants had to sleep was unusual and could have affected their sleep patterns. Also the nature of the method of waking participants may have affected their ability to recall their dream.
Sample size- The sample size was small and only included 2 females so we could argue that the results were biased towards the dream pattern of men rather than women.(Subsequent studies have found that there are large differences between individuals in the reports of dreaming during REM)Other Studeies have not supported Dement and Kleitman's findings that there is realtionship between eye movements and what the person is dreaming about.
Strenght: The mothod is thightly controlled. For example the
researchers were able to control the location, sleeping time and the participants use of stimulants.