The relation of eye movements during sleep to dream activity - Dement, W. and Kleitman, N. (1957)
The aim of the study was to investigate the relationship between eye movements and REM with dreaming.
There will be a significant association between REM sleep and dreaming
There will be a significant positive correlation between the estimate of the duration of dreams and the length of eye-movement
There will be a significant association between the pattern of eye movement and the context of the dream
The Participant group consisted of 9 people, with seven males and two females, although most of the information came from 5 of the participants. Data from the other four was used to back the findings of the main five.
The research method used in this study was a Lab experiment.
Hypothesis 1Participants were to report to the lab before their normal bed time, and were instructed to not drink caffeine or alcohol. They went to sleep in a dark quiet room, and an EEG machine was attached to their face and scalp (In order to gauge the depth of sleep, REM or non-REM) and eyes (To detect eye movement while sleeping). The participants never had any contact with the experimentter, and were not told if they were woken during REM or non-REM sleep. They were trained, when awoken by the bell, to describe their dream in detail, and if they either could not remember, their dream, or gave a less than satisfactory description, the dream was marked as 'No dream recall'.
The participants were woken according to a schedule, with two woken at random, one was woken three times in REM, followed by three times in non-REM and so on. One participant was woken randomly, but was told that he was only to be woken during REM sleep. Another participant was woken at the experimenter's whim.
Like before, they were told to report to the lab before their normal bed time, under the same conditions. The participants were woken either five or fifteen minutes into a REM cycle and asked to say whether they thought they had been dreaming from either five or fifteen minutes.
Under the same conditions, the participants were woken as soon as one of four patterns of eye movement had lasted at least one minute. Upon waking the participant was asked to describe in detail the content of their dream,
The four patterns that prompted an awakening were:
Mainly vertical eye movements
Mainly horizontal eye movements
Both vertical and horizontal eye movements
Very little or no eye movement
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 aREM, suggesting that the dream might have been remembered from the previous REM.
The series of awakenings which were carried out to see if the participants could accurately estimate the length of their dreams, revealed that all of the participants were able to choose the duration fairly accurately, except for one participant (DN) who could only recall the latter part of the dream, so underestimated its length.
For hypothesis 3 (Eye movement), periods of pure vertical or horizontal eye movement wer rare. During vertical eye movement, participants' dreams were associated with climbing a series of ladders, and throwing a basketball at a net. During horizontal eye movement (only occurred once) dreams were associated with people throwing tomatoes at each other.
The method was very tightly controlled (researched controlled the location, sleeping time, and participants use of stimulants such as caffeine and alcohol).
The validity is low because it was conducted in a lab setting.
Dreaming seems to occur during REM and there are REM periods throughout the night.
The study suggests that everyone dreams, even if they do not recall their dreams.
Physical eye movements in REM seem to reflect the content of the dream.
Weak ecological validity (the sleep situation was unusual and could have affected their sleep patterns. Also waking participants multiple times at nigh may have affected their ability to recall a 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).
Later studies have not supported Dement and Kleitman's findings about the relationship between eye movement and dreaming.
Does Dreaming cause REM, or does REM cause dreaming?