Dement and Kleitman Flashcards
What is the IV and DV in this study
Independent Variable (IV): Aim 1: REM or nREM sleep stage. Aim 2: waking after 5 or 15 minutes of REM sleep. Aim 3: eye-movement pattern type.
Dependent Variable (DV): Aim 1: whether the participants reported a dream, and if so, the details. Aim 2: participant’s choice of 5 or 15 mins of sleep. Aim 3: report of dream content.
Design
Experimental design: Repeated Measures Design
Psychology being investigated
- Our body follows two types of sleep: REM (rapid eye movement) sleep and nREM (non-rapid eye movement) sleep.
- nREM can be divided into 4 sleep stages.
- In REM sleep, our eyes move rapidly.
- REM sleep is known as paradoxical sleep. It resembles wakefulness as our eyes move, we often experience vivid (bizarre) thoughts in the form of dreams and our brains are active. However, it is different from wakefulness as it is difficult to wake up, we are fairly insensitive to stimuli and paralysed.
Aim
- Does dream recall differ between REM and NREM stages of sleep?
- Is there a positive correlation between estimated dream duration and REM period length?
- Are eye movements related to the dream content?
Background
Aserinsky and Kleitman found that dream recall was high when subjects were awakened during periods of rapid eye movements during sleep. These movements occurred at regular intervals in relation to changes in sleep depth as measured by the EEG. Incidental observations linked all stages of brain waves to dreaming but did not focus on dream content recall.
Sample and technique
- 7 males and 2 females
- 6 - 17 nights in the lab
- 50 - 77 times awakening
Sampling technique:Opportunity sampling.
Procedure
On each day of study participants ate normally, excluding caffeine and alcoholic drinks. They arrived at the laboratory just before their normal bedtime. They slept in a dark, quiet room and had electrodes attached beside the eyes and scalp (EEG). The wires were gathered in a single chord so the participants can move easily in bed. Participants were woken various times in the middle of the night to describe their dream if they had one. They were also not informed about the EEG pattern and their eyes moving.
Method
The study used a laboratory-based experimental method, focusing primarily on physiological measures such as brain waves and eye movements. It had repeated measures design. The independent variable was whether the participant was woken from REM or nREM sleep. The dependent variable was whether they recalled a dream or not. The dream duration and length of REM period was a correlation. For the relationship between eye movement patterns and dream content, self reports were compared.
Research method:Laboratory experiment.
Ethical issues
- Confidentiality of participants was maintained as they were identified using their initials so that dream content cannot be related to any of them.
- Protection may not have been fully provided as participants were sleeping in unnatural situation so it may have affected their sleep pattern or their ability to concentrate the next day.
- There was no way of ensuring a normal sleeping night before the study ended.
Strengths
- This is a laboratory experiment and hence has a standardised procedure and it can easily be tested for reliability
- The study has many controls and hence the researchers can be more confident in establishing a causal relationship.
Weaknesses
- Participants had to sleep in an unusual environment hence the study lacks ecological validity.
- Tasks performed by the participants aren’t task they do in their daily life and hence this study has a low mundane realism.
- This study had a small sample size and hence may not be very generalizable.
- All findings of this study are based on biological mechanisms and hence may be seen as reductionist.
- Most of the data in this study has been collected via self-reports which may not be very reliable as we do not know how truthful the participants are. This could reduce the validity of the findings.
Application to real life
Application to everyday life: The findings of this study could be used for treating or checking for sleep disorders.
Nature vs Nurture
Nature vs Nurture: REM and nREM sleep are universal and hence due to nature. However, the individual differences could have been due to environmental factors suggesting that they can affect sleeping patterns to
Results
- Participants described dreams often when woken in REM but rarely from nREM sleep.
- The waking pattern did not affect dream recall.
- Specifically, participant WD was no less accurate despite being mislead and DN was no more accurate even though he might have guessed the pattern of awakenings. This showed that practice effect was not a factor affecting the results of the experiment.
- When woken from nREM sleep, participants returned to nREM sleep and the next REM stage was not delayed.
- When woken from REM sleep, participants generally did not dream until the next REM phase.
- Participants’ responses were 88% accurate for 5-minute REM duration and 78% accurate for 15-minute REM duration.
- There was a significant positive correlation between REM duration and number of words in dream narrative. The r values varied between 0.40 and 0.71 for different participants.
- Dream narratives for very long durations were not much longer than those for 15 minutes. The participants did report that they felt as though they had been dreaming for a long time, suggesting that they couldn’t recall the early part of the dream.
- Participants could not recall the dream with such high precision.
Conclusion
Dreams probably occur only during REM sleep, which occurs regularly throughout the night. The finding that the length of an REM period and its estimation by the participants are very similar. Eye movements during REM sleep correspond to where and at what the dreamer is looking in the dream.
