BIOLOGICAL RHYTHMS - ULTRDIAN

Question 1

Ultradian rhythms

Answer 1

• biological rhythms that occur more than once every 24 hours

Question 2

stages of ultrian rhytms

Answer 2

1) Starting to fall asleep; easily woken up
2) Heart rate slows, body temp drops
3/4) we fall into deep sleep; brain activity and blood pressure drops; difficult to wake up
5) REM; eyes move around rapidly; brain is active Each cycle last around 90 minutes

Question 3

one strength of research into UR is that there is supporting research.

Answer 3

• For example, Dement and
  Kleitman monitored sleep patterns of adults in a lab using EEG while controlling the effects of caffeine and alcohol as extraneous variables.
• It was found that distinct periods of REM sleep were recorded where participants were able to recall their dreams after being woken up from REM sleep.
• This demonstrates the key principles of the sleep wake cycle where dreaming is associated with REM sleep.
• Furthermore, the use of standardised procedures means many replications have confirmed findings.
• This increases the validity of the theory

Question 4

One limitation of research into UR is that supporting research often lacks external validity.

Answer 4

• For example, investigating sleep wake cycles in laboratories means participants are likely to show demand characteristics as they are aware they are being observed, and so may act differently.
• Also, being observed in highly controlled environments could affect their sleeping patterns as it may be more difficult to sleep- the amount of REM sleep may be different at home.
• This is a disadvantage as behaviour observed may be unrepresentative of real life, which decreases ecological validity