ultradian rhythms

Question 1

what is an ultradian rhythm

Answer 1

a type of biological rhythms with a frequency of more than one cycle in 24 hours, such as the stages of sleep which span approx 90 mins

Question 2

outline stages 1 and 2 of the sleep cycle

Answer 2

known as light sleep where a person can be easily woken. brain wave patterns start to slow down

Question 3

outline stages 3 and 4 of the sleep cycle

Answer 3

deep sleep of slow wave sleep. it is difficult to wake someone at this point, and brain waves are even slower that in stages 1 and 2

Question 4

outline stage 5 of the sleep cycle

Answer 4

REM sleep. the body is paralysed yet brain activity speeds up significantly in a manner that resembles the awake brain. REM = rapid eye movement to denote the fast jerky activity of the eyes under the eyelids. researchers suggest that the REM activity is highly correlated with the experience of dreaming

Question 5

outline dement and kleitmans study

Answer 5

• used 7 adult males and 2 females who were asked to report to the laboratory at bedtime where they were connected to an EEG which took measurements throughout their time asleep. ppts were asked not to drink caffeine the day before
• found that all ppts has periods of REM every night. and found that high incidences of dream recall when ppts were awakened during REM periods of sleep and if awakened during other stages few reported dreaming
• concluded that sleep follow a typical pattern through the night

Question 6

what is a limitation of dement and kleitman (sample)

Answer 6

9 people, only 2 were female. low population validity meaning that their conclusion that sleep follows a typical pattern throughout the night may be invalid since their sample may be unrepresentative of a wider population and may not apply to the sleep cycle of others. however there is also no evidence that this is in fact the case, and its reasonable to argue that a small sample size isn’t enough to discount the findings.

Question 7

what is a strength of dement and kleitman ( objective)

Answer 7

EEG’s provide highly empirical data, and objective evidence to show that sleep follows a typical pattern throughout the night, which is a strength a these findings provide verifiable evidence for ultradian rhythms

Question 8

what is a strength of ultradian rhythms (research)

Answer 8

supported by dement and kleitman

Question 9

evaluate sleep stages ( biologically determined )

Answer 9

there is evidence to suggest sleep patterns may be biologically determined, for example tucker found large differences between individuals sleep patterns which were consistent over 11 nights in a controlled sleep lab. individuals also responded very differently to 36 hour periods of sleep deprivation. suggests sleep is at least partially determined by genes