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Dement and Kleitman (1957)

By Dr. Julia Russel, published Oct 01, 2020


Dement, W., & Kleitman, N. (1957). The relation of eye movements during sleep to dream activity: an objective method for the study of dreaming. Journal of experimental psychology, 53(5), 339.

Aim

Dement and Kleitman’s research aimed to find objective methods to demonstrate a relationship between dream content and physiological indicators of dreaming.

Specifically, they wanted to investigate:

  • Does dream recall differ between REM and nREM stages of sleep
  • Is there a positive correlation between subjective estimates of dream duration and the length of the REM period before waking?
  • Are eye movement patterns related to dream content? (c)

Procedure

Dement and Kleitman (1957) is a classic study which explored sleep and dreaming using electronic recording as well as observation and diary methods. It is summarised in the box opposite.

7 male and 2 female participants, 5 of these studied in detail.

In the day, the participant ate normally (excluding coffee and alcohol) then arrived at the laborat ory just before their normal bedtime.

The participant went to sleep with electrodes attached beside the eyes (EOG) and on the scalp (EEG), which fed to the experimenter’s room.

What is an Electroencephalograph (EEG)

The EEG is a machine which can det ect and record minute changes in voltage associated with electrical activity in nerve and muscle cells when many are active at the same time. This is recorded using macroelectrodes (larg e, flat electrodes stuck to the skin or scalp).

It produces a chart (an encephalogram) which shows how ‘brain waves’ vary, ie how the f requency and amplitude (height) of electrical output from the brain changes over time.

In addition, an EEG can be used to record the frequency of eye movement s by attaching electrodes t o the skin beside each eye. This is called an Electo - occulograph (EOG) .

Participants were woken (by a doorbell) at various times during the night, asked to describe their dream if they were having one, then returned to sleep.

    IV 1: Occurrence of Sleep Stage

  1. Participants were woken either in REM or nREM (but not told which). They confirmed whether they were having a dream and described the content into a recorder.
  2. IV 2: Duration of REM Sleep

  3. Participants were awoken after either 5 or 15 minutes in REM sleep. They chose which duration they had been woken up after. Longer REM periods were also allowed. The number of words in the dream narrative was counted (although this was affected by how expressive the par ticipant was).
  4. IV 3: Pattern of Eye Movement during REM Sleep

  5. The direction of eye movements was detected using electrodes around the eyes. Participants were woken after the persistence of a single eye - movement pattern for more than one minute and asked to report their dream. The eye - movement patterns were: mainly vertical, mainly horizontal, both vertical and horizontal, very little or no movement.

Findings
  • Uninterrupted dream stages lasted 3 - 50 minutes (mean approx 20 minutes), were typically longer later in the night and showed intermittent bu rsts of around 2 - 100 REMs.
  • The cycle length varied between participants but was consistent within individuals, eg 70 for one, 104 for another.
  • When woken in nREM participants returned to nREM, but when woken in REM they typically didn’t dream again until t he next REM phase (except sometimes in the final REM phase).
  1. Participants frequently described dreams when woken in REM but rarely did from nREM sleep (although there were some individual differences) and this differences was marked at the end of the nREM period (within 8 minutes of cessation of REM – only 6 dreams recalled in 132 awakenings). In nREM awakenings, participants tended to describe feelings but not specific dream content.
  2. Accuracy of estimation of 5 or 15 minutes’ of REM was very high ( 88% and 78% respectively). REM duration and number of words in the narrative were significantly positively correlated.
  3. Eye movement patterns were related to dream content, eg horizontal movements in a dream about throwing tomatoes, vertical ones in a dream about ladders and few movements in dreams about staring fixedly at something.
Conclusion

Dreaming is reported from REM but not nREM sleep, participants can judge the length of their dream duration and REM patterns relate to dream content.


How to reference this article:

Russel, J. (2020, Oct 01). Dement and kleitman (1957). Simply Psychology. https://www.simplypsychology.org/dement-kleitman (1957).html

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