A classic in psychology, Dement and Kleitman’s study provided evidence for understanding why we dream. It gave an in-depth look at the physical properties of dreams and was well-received due to the extreme amount of interest in this topic from psychologists and the public alike. Dreams are quite a hard to understand concept and the relevance of them is still disputed, yet there is something so undeniably fascinating about this human trait.
Dement and Kleitman were two researchers in the 1950s who decided to put some of their ideas about dreaming to the test using physiological measures of the brain during sleep. They were already aware of a concept known as REM (Rapid Eye Movement) sleep, within which the eyes move rapidly and it is harder than usual to be woken up. It is the heaviest stage of sleep and takes place after about 90 minutes. During those 90 minutes a gradual shift from light to heavy sleep occurs. Dement and Kleitman also knew that brainwaves could be measured using an EEG (electroencephalograph) machine, and that the patterns of brain activity differed dependant on stage of sleep. Strangely, the stage that has the closest pattern to the awake brain is REM sleep, the deepest level.
The researchers chose 7 males and 2 females to study as they slept. They would go to sleep with electrodes attached to their heads which would record their brain activity and therefore sleep stage. During the night, the participants would be woken up several times, either during REM sleep or NREM sleep (outside of REM). They would then be asked to report whether they had been dreaming, how long they had been within the dream and what the dream was about.
The results of the study showed that REM sleep was a very natural phenomenon, with it being experienced every night in all participants. The eyes were not constantly moving throughout the REM period, but in fact moved in short bursts. The average interval between REM episodes was 92 minutes. They also, perhaps most importantly, discovered that only when woken during REM sleep did participants recall dreaming, apart from a few recalled within 8 minutes of leaving REM sleep. They believed that this suggested dreams occur during REM sleep, and that after leaving REM sleep it becomes increasingly more difficult to remember the dream or its content.
Other findings were that participants were usually correct in their beliefs of how long the dreams had lasted, suggesting that dreams do occur in real time as opposed to the prior belief that dreams seemed longer when you are in them than the actual period of time dreaming. As well as this, the eye movement measured through electrodes placed around the eyes showed that where dreams involved a certain type of eye motion, looking up and down when climbing a ladder or looking from side to side while two people threw tomatoes, the same eye movement was recorded in real life. This suggests that the REM recorded as we dream could be related to our reactions to the dream itself.
There were obviously some problems with these experiments, including the difference in sleep when in such an unnatural environment, but it may be, as Dement and Kleitman believed, that ecological validity is not an issue when dealing with physiological processes such as this, since they will occur every night naturally anyway. Because of this argument and more recent research into the area, many of the ideas suggested from this study are now widely accepted, but as for the actual cause and need for dreams, there are many theories still waiting to be tested.
Image from: https://ee_ce_img.s3.amazonaws.com/cache/ce_img/media/remote/ce_img/https_ee_channel_images.s3.amazonaws.com/article-figures/8253/article-g02_400_310.jpg
0 Comment:
Be the first one to comment on this article.