Ultradian Rhythms

Question 1

What are Ultradian rhythms?

Answer 1

Cyclical patterns within biological systems that last less than 24 hours (eg. Sleep stages)

Question 2

Sleep stages

Answer 2

5 distinct stages of sleep, lasting approximately 90 mins each, altering between REM and NREM. Cycle starts at light sleep and brain waves become slower, progressing to deep sleep then REM where brain activity speed up and dreaming occurs

Question 3

Dement & Kleitman (1957)

Answer 3

Monitored sleep in 9 adults for 6-17 nights, recording brain activity on an EEG. P’s recalled more dreams with higher detail when awoken from REM sleep than NREM. REM activity in sleep was highly correlated with dreaming and brain activity raised according to how vivid dreams were

Question 4

Strength of Ultradian rhythms

Answer 4

• Understanding of age-related changes (eg. Slow wave sleep which is crucial for growth hormones decreases with age. Treatments allowing mitigation of health issues)

Question 5

Limitations of Ultradian rhythms

Answer 5

• Lacks ecological validity (eg. Sleep in lab wired to EEG lacks mundane realism plus small sample size)
• Individual differences (eg. Tucker found large variations in duration of each sleep stage, especially 3 and 4 which are crucial for restoration)