Dement and Kleitman

AIMS

• To investigate if dream recall differs between REM and nREM stages of Sleep

• To investigate if there was a positive correlation between estimates of dream duration and length of REM sleep

• To investigate if eye movement of were related to dream content.

Psychology being investigated

• Rapid Eye movement/ REM sleep is a phase of sleep where a person is paralysed; Their eyes flicker and they can breathe but all other muscles are paralysed'

• Non rapid eye movement/ nREM sleep are the other stages of sleep and they differ in brain activity

• Dreaming is a subjective experience of imagery while we are asleep.

• Electroencephalograms (EEGs) measure brain wacve activity; they are used to measure the amplitude and frequency of brain waves

RESEARCH METHOD IV1: SLEEP STAGE OF AWAKENING

IV1: Sleep stage of awakening:

1. PS were woken either in REM or nREM sleep (but not told which). they confirmed whether they were having a dream and described the content in a recorder.

IV: timing of awakening (REM or nREM)

DV: Whether a dream was reported

DV: report of dream narration content

RESEARCH MEHTOD IV 2: DURATION OF REM SLEEP

1. participants were awoken randomly after either 5 or 15 minutes of REM sleep. initially, participants were asked to estimate the length of time in REM sleep to the nearest minute. in the revised procedure participants procedure ps were gievn a fixed choice and aksed if they were dreaming for 5 or 15 minutes.

2. The number of words in the dream narrative was counted (although this was affected by how expressive the participant was)

IV: randomly woken after 5 or 15 minutes

DV: dream duration:

• estimate which duration (5 or 15 minutes) they had been dreaming

• the number of words in the dream narrative was counted as a measure of dream length.

RESEARCH MEHTOD IV 3: PATTERN OF EYE MOVEMENT DURING REM SLEEP

1. direction of eye movements was detected using electrods around the eyes (EOG)

2. The eye movement patterns were: mainly vertical, mainly horizontal, both vertical and horizontal, and very little or no movement.

3. Participants were woken after the persisitence of a single eye moevemnet pattern for more than 1 minute and asked to report their dream.

IV: eye movement pattern (not manipulated by the researcher → natural experiment)

DV: content of the dream.

SAMPLE

• 9 adult participants, were predominantly male (7 males and 2 females)

• the 5 main ps were studied intensively: spending between 6 and 17 nights in the laboratory

• the other 4 were used to confirm the results of the main participants: spending only 1-2 nights in the lab

• all ps were identified by their initials in the study

Procedure:

1. Durng the day, the ps were asked to eat normally, avoid alcohol and coffee. And then arrived at the lab just before their usual bed time

2. Then they went to bed in a quiet, dark room

3. The participant went to sleep with 2+ electrodes attached beside the eyes(EOG) and on the scalp (EEG) which were fed to the experimenters’ room.

4. The EEG wires became a single cord/ponytail (to stop entanglement)

5. After the elctrodes had ben fitted, the participants had to go off to sleep

6. They were then awoken form diff REM and nREM of sleep throughout the night by the doorbell sound (placed near the bed) or they were randomly woken 5 or 15 mins after REM began

7. Participants were asked if they dreamed or not

8. If they had, they were asked to “please describe the dream that you have just experienced” into a recording device near the bed.

9. Then, they would go to sleep again.

10. Sometimes the experimenter would enter the room and ask them more questions clarify some aspect of the participant’s dream

11. They were given the fixed choice and aksed if they were dreaming for 5 or 15 mins.

Strength: Objective quantitative data

Researchers calculated the percentages of dream recall by ps following awakenings from REM or nREM stages of sleep. Similarly they calculated the percentages of accuracy of their dream duration estimates when awoken from their 5-min or 15-min sleep.

→ this help researchers objectively compare in which stage of sleep participants reported a greater recall of dreams.

→ Liekwise, they objectively compared when their accuracy of dream duration estimates between the two durations of awaskenings was better, without any bias. This increases the internal validity of findings

strength: reliability - high level of standardisation

all the ps were fitted with the same quipment, including electrodes near their eyes and scalp, with the wires tided tgt behind their head. They all slept in a bed in a quiet dark room, were woken by the same doorbell sound and were required to narrate their dream into a tape recorder. They were also asjed to aeat normally, and avoid alcohol and coffee. Ensuring such consistent procedure meant that the study could be replicated to test whether the association between dreaming and REM sleep was reliable.

→ prevent their normal parrtern of sleep being disrupted in the lab

→ these and other controls ensured that any dream-related activity of participants could be attributed only to the stages of sleep they were in and not to uncontrolled variables like the influence of coffee or alcohol, etc, that created disruption in sleep.

Strength replicable

• standardised procedure: used a clear and well-defined methodology including the use of EOG to record eye moveemnts; a structured protocol specifying the duration REM sleep before awakening participants and collecting dream reports; and all ps were in a quiet dark room —> make it easire for other researchers to replicate the study and test for reliability

Objective measure: the use of EOG provides an objective measure of eye movements during sleep, which is leass prone to subjective interpretation or bias compared to self-reported measures alone. —> this objectivity enhances the reliability of the findings and makes it easier for other researhcers to.

A strength is that an EEG was used in this study, which gave an objective measure of the sleep stage a participant was in. The frequency and amplitude of brain waves for both REM and non-REM can be quantified, allowing little room for subjective interpretation by the researchers. This increased the validity of the data, as the researchers could be confident of the sleep stage in which a person was being woken

Strength: Avoiding investigator effects

A strength of this study is that the researchers ensured nobody else was present when the

participants recalled their dreams. This was to avoid the possibility of the experimenter

influencing a person’s dream narrative through prompting or expectation. Although an

experimenter did enter the room occasionally to question the participant further about their

dream content, this was after the participant had given their full recording. This made the

research more valid and the dream reports free from experimenter effects.

Weakness: Low generalisability

• the sample only included 9 people, and only 5 of them were studied intensively → very small number of participants to generalize from

• There was no diversity in age, ethnicity and sex

• it is possible that sleeping patterns such as the duration or frequency of the stages of sleep they experience could be different frm that experienced by the rest of the population

• —> individuals have different sleeping patterns, given that the ps mostly have their dreams in REM sleep but we cant not generalise to other people with other different sleeping patterns → low generalisation

Weakness: low ecological validity

• the research studies ps who went to sleep in a lab which electrodes stiuck to their heads → it is unliekly that this bears much relation to sleep in normal environement

• being in such artificial condition meant that their sleep was disturbed → is this was the case, the researchers would not have been studying thier normal sleep patterns

• ps were also woken up several times during the night and asked about their dreams → unlikely to happen normally and may have had an effect on the way the ps slept

Weakness: small naumber of observation for each eye movement pattern

the study reported only 3 instnaces of vertical eye movements, 1 instnace of horizontal and 21 instnaces of mixed moevements, and 10 instnaces of little or no movement.

→ this small sample size for each pattern limits the generalizability of the findings

→ increase the possibility that observed correlations between eye movemnts and dream content could be due to chance or individual differences

→ large smaple will provide more robust and reliable results

Application to everyday life

• EEG can detect rem and non rem sleep stages → helpful in diagnosing sleep-related problems → can be used to develop appropriate treatments for sleep disorders

• identify abnormalities in the sleep cycle

Nature vs Nurture

• support Nature as all ps reported a significantly greater number of dreams during rem sleep than non rem sleep, indication that dreaming during REM sleep is an innate biological mechanism, emphasizing the role of physiological processes (REM sleep, eye movements)

• regularly occuring periods of REM were observed in all ps on every night of sleep, indicating that this ultraradian rhyhm is universal for all humans and is biologically determined.

• the fact that people had such diverse dreams with differing contnt demonstrates the role or nurture in dream and sleep, as our diff life experiences will impact what we dream about.

Individual and situational explanations

The study considers both individual differences (e.g., variation in dream recall ability) and situational factors (e.g., time of night, duration of REM sleep).

It suggests that dream experiences are influenced by both individual physiology and the specific sleep situation.