Dement & Kleitman Sleep Study

AICE Psychology study

What is the first assumption of the biological approach?

Behavior, cognitions, emotions, can be explained by the working of the brain and the effect of hormones, genetics, and evolution.

What is the second main assumption of the biological approach?

Similarities and differences between individuals can be understood in terms of the biological factors and their interaction with other factors.

What is the psychology being investigated?

• Using observations and interviews

• 9 ppts total, 5 studied intensively

• opportunity sample

• repeated measures

Explain the background to the study

• There is a connection between REM and dreaming

• Physiological approach - dreams are random firings we put meaning to

  • D&K noticed REM connected with dreaming

What are the aims of the study

• Does dream recall correlate to REM?

• Is there a correlation between REM duration and estimates of dream length?

  • Is REM connected to content in dreams?

What was the sampling method and what were the characteristics?

• sleep lap

• EEG machine to measure brain activity

• 9 adults: 7m 2f

• 5 studied intensively

  • 4 used for minimal data as confirmation

Describe the procedure of the study (excluding each hypothesis)

• ppts report to lab before bedtime

• asked to eat normally but avoid caffeine/alcohol on day of study

• 2 electrodes near eye to record muscle activity

• 2-3 others record brain activity

  • EEG used

What was the procedure for hypothesis 1?

• ppts woken at various times to test dream recall

• bell woke ppts - they then recorded dream recall on tape

• this avoided experimenter effects

• 2 ppt woken at random

• 1 ppt woken at whim of experimenter

• 1 ppt woken 3 times in REM and 3 times in nREM

  • 1 ppt was random but told they were only woken during REM

Describe the procedure for hypothesis 2

• woken either 5 or 15 minutes after entering REM

• Asked to estimate duration - given the option of 5 or 15 min

  • were then asked to relate dream content

Describe the procedure for hypothesis 3

• ppts woken up 1 minutes after 1 of 4 patterns of eye movement occured

• A. Mainly vertical

• B. Mainly horizontal

• C. Both

• D. little/none

• ppts tell what they dreamt about

• D&K analyzed data to detail patterns between the eve movement

  • total of 351 awakenings over 61 nights

What were the ethical issues of the study?

Negative - No mention of informed consent or the right to withdraw

Positive - no significant harm or stress to ppts; used initials as identification

What were the results of the study

• REM never occured at the start of the cycle

• all showed period of REM 

  • categorized by low voltage/fast pattern EEG

• Avg. of REM was once every 92 min

  • REM lasted between 2-50 min and increased over time

What were the results for hypothesis 1

• subjects were able to give a relatively coherent & detailed description of the dream

• REM sleep is where dreaming occurred the most

• Dreaming occurs more in REM than nREM

What were the results for hypothesis 2

• subjects could estimate time correctly

What were the results for hypothesis 3

• eye movement correlates to dream content

• vertical: being on a mountain looking down or climbing up a ladder

• Horizontal: watching two people throw tomatoes at each other

• both: looking or interacting with objects up close

• none: looking at something far away or stationary

What were the conclusions of the study

• cannot definitively say dreaming only occurred in REM

  • dreams occur in real time

What were the strengths and weaknesses of the study

Strengths:

• well controlled lab experiment

• breakthrough in dream research

• seem to have correlations in each hypothese

Weaknesses:

• small sample size

• correlation does not equal causation

Discuss the generalizability of the study

Poor generalizability

Only 5 people studied intensively

small sample which does not represent a large population

Discuss the reliability of the study

good reliability

Heavily standardized procedure allowed for easy replicability and high levels of control

Discuss applicability of the study

Can use EEG to determine if someone has a sleep disorder

Discuss validity of the study

Mixed validity

There was low ecological validity as it was a lab experiment. However, it was high in mundane realism as people sleep everyday. There were also issues with self reports due to social desireability.

How does the study support both nurture and nature

Nature: Everyone sleeps, dreams, and goes through REM and nREM

Nurture: Individuals have differences such as sleeping no matter what or needing certain conditions

How does the study support both individual and situational factors

Individual: some participants may have issues with sleep and struggle no matter what or have memory issues

Situational: participants are in a weird environment which can cause weird dreams