Dement and Kleitman (sleep and dreams)

Aim #1 (dream recall)

To investigate whether dream recall is more common in REM than in NREM sleep.

Aim #2 (duration)

To investigate whether participants can accurately estimate the duration of their dreams.

Aim #3 (dream content)

To investigate whether eye movements (vertical/horizontal) correspond with dream content.

Aim #4

To investigate whether there is a correlation between the duration of a REM sleep episode and the number of words (the narrative) used to describe any dreams experienced.

Experimental Type

Laboratory Experiment

Experimental Design

Repeated Measures

Data collection techniques

• Self-reports

• Interviews

Independent variables - whether the participants were woken

• During REM or NREM sleep (as shown by the EEG)

• Following 5 or 15 minutes of REM sleep

• Following REM sleep with mainly vertical, mainly horizontal, mixed or limited eye movements.

Dependent variables

• Whether a dream was reported or not (quantitative) — dream has to be described in detail to be counted

• perceived duration of dream (5 or 15 minutes)

• Verbal description of dream/content (qualitative date); number of words used (quantitative)

Sample

• Seven men and two women (five studied in depth, four to confirm results)

• From Chicago, USA

• Sampling technique: Not Stated
  
  Two participants withdrew after Night One and Two others others withdrew after Night Two.

Procedure (participants slept..)

• in a quiet, dark room at the University of Chicago

• with electrodes placed near the eyes and on the scalp:
  -wires were tied together to stop them from becoming tangled

• The EEG machine was in an adjoining room.

Procedure (participants were woken..)

• several times each night

• to self-report all the DVS using a bedside recording device.

Procedure (the researchers..)

• chose when to wake the participants using the EEG and a timer.

• Listened to the self-reports from the adjoining room.

• occasionally entered the sleep room to interview the participant about their dream.

Controls

• Participants all:
  - Abstained from alcohol and caffeine throughout the duration of the study
  - Reported to the laboratory at their normal bedtime.
  - Always recorded their dream recalls into the tape recorder.
  - Ate as normal.
  

• The same doorbell was used for all awakenings

• The positioning and number of electrodes was standardized (2-3 near the eyes and on the scalp)

Results (general)

REM sleep never occurred immediately after sleep onset.

All participants had regular REM sleep periods throughout the night:

» one REM period every 92 minutes (range 70-104 minutes)

» average REM sleep duration of 20 minutes (range 3-50 minutes)

» longer REM sleep periods later in the night.

Results (sleep stage when woken/frequency of dream reports)

• REM: 80

• NREM: 7%

Results (Accuracy of dream duration estimates)

5 Minutes: 88%
15 minutes: 78%

Dream content (mainly vertical)

Looking up and down while:

• standing at the bottom of a cliff and hoisting things up and down.

• climbing a series of ladders while looking up and down.

• dribbling and shooting basketballs into a net.

Dream content (mainly horizontal)

• Watching two people throwing tomatoes at each other

Dream content (mixed)

• Talking in a group of people

• Searching for something

• Fighting with someone

Dream (limited eye movement)

• Driving a car and staring at the road ahead.

Conclusions

• Dreams are more likely to be reported in REM than NREM sleep.

• Dreams are experienced in real time - dream length and REM sleep duration match.

• Eye movements in sleep are not random; they match dream content.

• The subjective experience of dreaming can be measured objectively using EEG to identify REM sleep.

Apparatus

• Quiet Room at the Lab

• Bed

• The EEG machine with Electrodes

• Door Bell.

• Tape Recorder

Research Methods

• Self-reports

• Observations

  • Controlled

  • Non-participant

  • Overt

Data Collected

Quantitative and Qualitative.

Quantitative Data

• Instances of Dream Recall

• Dream Length Estimates

• Number of Words In Each reported Dream Narrative

Qualitative Data

• Descriptions of the Dreams (recorded by a tape recorder after waking up)