dement & kleitman sleep study

bio approach

rapid eye movement (REM)

high incidence of dream recall during these periods - is strongly associated with dreaming

non rapid eye movement (nREM)

low incidence of dream recall when awakened at other times

dement & kleitman aims

1. does dreaming occur between REM and nREM sleep

2. can participants accurately measure the time that they have been dreaming

3. do eye patterns match dream content

4. does duration of REM sleep correlate with the narrative of a reported aims

experiment type, design

natural experiment: REM and nREM sleep occurs naturally in a lab setting

repeated measure design

sampling

unknown: 9 participants, but 4 withdraw, 7 adult males, 2 females

procedure

1. participants are briefed

2. advised to eat normally, no alcohol, caffein

3. asked about normal bedtime → make it more natural

4. have their own room

5. woken up via a bell everytime they enter REM sleep, asked to recall dreaming. other participants are woken up during nREM sleep

variables & results of aim 1: does dreaming occur between REM and nREM sleep

IV: REM and nREM sleep

DV: number of dreams recalled

results:

• 152 dreams recalled, 39 no recall during REM

• 11 dreams recalled, 149 no recall during nREM

variables & results of aim 2: can participants accurately measure the time that they have been dreaming

IV: woken after 5 mins, woken up after 15 mins

DV: number of correct dream length estimations

results:

• after 5 mins of REM sleep, 45/51 awakenings had correct estimation (88%)

• after 15 mins of REM sleep, 47/60 estimations were correct (78%)

variables & results of aim 3: do eye patterns match dream content

IV: direction of eye movements

DV: part diricipants subjective report of dreaming

results:

• vertical eye movement - standing at the bottom of a tall cliff and operating a hoist

• horizontal: 2 ppl throwing tomatoes at each other

• vertical & horizontal: talking to ppl standing close to them

• little to no movement: watching sth in the distance/ staring at an object

methodology of deman & kleitman

process:

1. subject reports their usual bedtime + avoid consuming alcohol/caffein

2. researchers use EEG recording (put electrodes on subject’s head from a single cord to provide comfort)

3. EEG was run through st speed of 3 or 6mm

4. faster speed (3cm/sec) is used for detailed examination of brain waves

5. subjects are awakened to test dream recall various times in the night. the return to sleep after waking up takes less than 5 mins

quantitative & qualitative data

quantitative data: EEG recording, dream recall, dream length estimations, number of words in each dream narrative

qualitative data: participants description of their dreams

result of aim 4: does the duration of REM sleep correlate with the narrative of a reported aim

number of words used to describe a dream positively correlates with the length of the REM period

strengths

reliability:

• use quantitative data (EEG)

• participants dont drink alcohol, caffein, go to sleep at their bedtime

• operationalizing the definition of dreaming by asking participants to recall the content of their dream, turning qualitative data to number of words (description of dream)

validity:

• not telling subjects about their EEG or eye movement → prevent demand characteristic bcs they wouldnt be pressured to remember their dreams

• subjects dont drink alcohol, caffein → prevent extraneous variables

• generalizability: data across participants are consistent

weakness

validity:

• generalizability: sample size was small, w a few dropping out eventually

• lacks mundane realism

• ecological validity: controls may differ from their everyday routine (eg. they might consume caffein everyday)

• put into unnatural environment to sleep

• difficult to tell whether subjects are truthful or not, including length and content

ethical issues:

• 1 subject was told he’d be waken up when hes dreaming, but he was woken up during both REM and nREM sleep

• their normal sleep pattern may have been altered

application in real life

study shows we can identify when a person is entering REM or nREM sleep

→ help patients with sleeping problems, brain waves while sleeping

nature vs nurture

nature:

• effect of REM and nREM sleep is consistent within subjects → due to nature

• majority of dreaming takes place in REM sleep

nurture:

• environmental factors could affect sleeping patterns (eg, consuming caffein)

• could be differences between subjects (eg. some ppl is more sensitive and could have a more disturbed and uncomfortable sleep)

link to assumptions

dreaming occurs during REM sleep → similarities between ppl are bcs of biological factors