Zusammenfassung der Ressource
Physiological Psychology -
Dement & Kleitman (1957)
- Aim
- To determine the relationship
between eye-movement and
dreaming during sleep.
- D&K wanted to answer 3 questions
- 1) Will people be more likely to report
dreams during REM sleep or non-REM sleep?
- 2) Can people accurately estimate the length of their dreams?
- 3) Is the direction of eye movement related to dream context?
- Participant/Sample
- 9 participants
- 7 males and 2 females.
- 5 were studied in depth and minimal amount of data was collected for the
other four, hoping that the four would confirm the findings of the first five.
- Sample -
Unknown
- Prodecure/Method
- Laboratory Experiment
- Participants reported to the sleep laboratories just before their normal bedtime.
Anmerkungen:
- The sleep laboratory would be a dark quiet room.
- Participants had been asked to avoid drinking caffine and alcohol but otherwise eat and drink normally.
- Electrodes were attached near the eyes to measure eye-movement, and the scalp to determine
the depth of sleep. The electrodes were attached to an EEG machine running all night.
- Throughout the night participants would be woken up by a doorbell sound and would speak
to the taperecorder near the bed, stating if they could recall their dream, and if so, its contents.
- They were also meant to state how long they believe they had been dreaming, 5 minutes of fifteen.
- Findings/Results
- 1) Participants were much more likely to
recall dreams when they were woken during
the REM sleep, than non-REM sleep.
- 2) Participants were accurate in their
estimation of dream length (on average).
- 3) Eye movement seemed to be related to dream content.
- Background
- Sleep consists of a number of
stages that can be shown by
distinctive patterns produced
during electroencephalography.
- Stage 1 - Lowered heart rate, muscle tension and body
temperature. EEG shows brain activity with alpha waves
that have 8-12 cycles per second (hertz). People cannot
be easily woken from this stage.
- Stage 2 - Slower and larger EEG waves with
sleep spindles. Bursts of high frequency
waves (12-16 heartz) lasting for 1 second.
People can be woken up relatively easiliy.
- Stage 3 - Sleep delta waves are seen as large slow
waves of 1-3 heartz. People do not easiliy respond
to external stimuli and are quite difficult to wake up.
- Stage 4 - Delta waves are around 1 hertz and is the deepest of the four
stages of sleep. Metabolic rate is low and people are hard to wake up.
Anmerkungen:
- However, significant noises such as a baby crying will wake them up.
- REM Sleep - Appears around 30 minutes after Stage 4 and occurs for around 30 minutes
before the cycle re-starts. EEG shows disyncronised pattern. Metabolic activity
increases, as does heart rate, but the body is still more or less paralysed and is the
hardest stage to wake from. Shows a similar pattern as if the subject was awake.
- Conclusion
- People do recall dreams better during REM. When people recall
dreams during non-REM sleep it is most likely that they are just
remembering the dream they had had in their last period of REM sleep.
- People can estimate the length of their dreams quite accurately.
- Eye movement seems to be related to a dreams content.
- Usefulness
- Made it apparent that brain activity can be monitored
during sleep accurately by an EEG machine.
- Gave an objective way
to measure dreams.
- Weaknesses
- Validity
Anmerkungen:
- It could be argued that dream recall was being tested rather than actual dreams. People might dream during non-REM sleep but are only able to recall it during REM sleep.
- Representivity
Anmerkungen:
- 9 participants were used in the study and only 5 of them were studied in detail.
- Low Ecological
Validity
Anmerkungen:
- The sleeping lab was an already alien enviroment to the paticipants, added to the fact they had electrodes attached to their heads whilst sleeping, the conditions in this study had a very low ecological validity.
- The participants were woken up constantly through the night with no specific timings to record theirs dreams and dream time estimations which was unlikely to happen in their every day sleeping lives.
- Caffine and alcohol were not to be consumed on the day of the study. Caffine could mean tea to coffee and redbull to coca cola. Drinks with caffine may have played a substantial part in a participants everyday life (their main fluid of consumption). In not being allowed to drink this they may not have drunk as much fluids as normal which could effect how they felt throughout the day and in turn how they slept which could have altered the results.
- Strengths
- Promotes
Anmerkungen:
- Promotes furthur research into sleep and dreaming.
- Quantitative Data
Anmerkungen:
- Easy to collect and statistically analyse.
- Both quantitaive and qualitiative data was collected.
- High Controls
Anmerkungen:
- High controls over the variables within the laboratory experiment.
- This made it easier to draw conclusions from the results.
- And reduced the chance of confunding variables.
- Scientific Evidence
Anmerkungen:
- The EEG scan made it possible to know when to wake up a participant using the stages as a guide giving the study a scientific background which is seen as credible.
- Validity
Anmerkungen:
- The equiptment used was precise and measured what was needed to be measured.
- Reductionist
- Dement & Kleitman reduced a complex
phenomenom (dreaming) to a simple
physiological measure. This could be
seen as oversimplifying the matter.
- However, it allowed research into this
area to be conducted in a scientific
manner and the relationship between
eye movement and dreaming to be
established.