Biological Rhythms: Ultradian Rhythms

Question 1

what are ultradian rhythms?

Answer 1

• type of biological rhythm with a frequency of more than once cycle in 24 hours

Question 2

what is an example of ultradian rhythms?

Answer 2

• stages of sleep

Question 3

what did psychologists do to identify the stage of sleep?

Answer 3

• used EEGs to identify 5 distinct stages of sleep that altogether span approximately 90 minutes

Question 4

what are stages 1 and 2 of the sleep cycle?

Answer 4

• this is ‘light sleep’ where a person is easily woken
• beginning of sleep , brainwave patterns start to become slower and more rhythmic (alpha waves move onto deeper theta waves)
• occasional bursts of activity are referred to as ‘sleep spindles’
• if woken the sleeper may not realise how long they had been asleep or even that they had been sleeping

Question 5

what are stages 3 and 4 of the sleep cycle?

Answer 5

• this is ‘deep sleep’ or slow wave sleep (SWS)
• involves delta waves which are slower and have a greater amplitude than theta waves
• difficult to wake someone during this state

Question 6

what is stage 5 of the sleep cycle called?

Answer 6

• REM sleep

Question 7

what is stage 5 of the sleep cycle?

Answer 7

• body is paralysed and there is fast, jerky activity of the eyes under the eyelids = rapid eye movement
• brain activity speeds back up to theta waves and resembles the awake brain
• dreaming is most likely to occur during this stage

Question 8

what are the evaluation points of ultradian rhythms?

Answer 8

+ improved understanding
- individual differences
+ control over EVs in lab studies