ultradian rhythms Flashcards
What are ultradian rhythms
Cycles that last less than 24hours, such as the cycle of sleep stages that occur throughout the night
How long does a sleep cycle last
90 minutes
how many sleep stages are there
5
what are the sleep stages
Stage 1:(NREM) Light sleep, muscle activity slows down, alpha waves
Stage 2:(NREM) Breathing pattern and heart rate slows, slight decrease in body temp, alpha waves
Stage 3:(NREM) Deep sleep begins, brain begins to generate slow delta waves
Stage 4:(NREM) Very deep sleep, rhytmic breathing, limited mucle activity, brain produces delta waves
Stage 5:(REM) Rapid eye movement, brainwaves speed up and dreaming occurs, muscles relax and heart rate increases, breathing is rapid and shallow
Research into ultradian
Dement & Kleitman (1957) made the link between REM sleep and dreams
-sample of five participants
-participants were taken to a sleep lab
-told not to drink alcohol or caffeine before the experiment
-An EEG machine was used to track their brainwaves during sleep
-They were woken at specific intervals during their sleep and asked if they were dreaming and if so, what was the dream about
The findings showed a positive correlation between REM sleep and dreaming
The nature of the dreams was matched by their eye movements e.g.
vertical eye movements occurred with dreams of climbing ladders, watching climbers, and throwing basketballs in the air
horizontal eye movements occurred with dreams of watching people throw tomatoes at each other
AO3: ultradian rhythms
str: Kleitmans study
str: study replicated
Ultradian rhythms str: Kleitmans study
Dement & Kleitman conducted a well-controlled study
Extra care taken to eliminate possible confounding variables of alcohol or caffeine intake before the study
This means that their research is high in reliability
Ultradian rhythms str: Kleitmans study replicated
Subsequent replications of their sleep study have supported Dement & Kleitman’s findings
This gives good validity to the idea that REM sleep is associated strongly with dreaming
A sample of five participants means that the findings are difficult to generalise
This means that the findings lack external validity
A larger sample would also increase the robustness of the data
Dement & Kleitman carried out their research in the 1950s which means that it may lack temporal validity
The use of digital technology such as smartphones, which did not exist at the time of the research, may interfere with people’s ultradian rhythms
This means that new research should be conducted to investigate the extent to which REM and dreaming are linked
