Ultradian Rhythms AO3

Question 1

✅ What evidence supports qualitatively different sleep stages, including REM sleep?

Answer 1

Dement & Kleitman (1957) found that REM sleep correlates with dreaming and vivid brain activity. Participants woken during REM could accurately recall dreams—supporting the idea of distinct ultradian stages.

Question 2

✅ What did Albers et al. (1981) show about ultradian and circadian rhythms?

Answer 2

Lesions to the SCN in primates disrupted circadian, but not ultradian rhythms, suggesting they are controlled by separate biological mechanisms.

Question 3

❌ Why are lab studies of sleep potentially low in ecological validity?

Answer 3

Although labs control extraneous variables, sleeping with equipment in unfamiliar environments can lead to unnatural sleep patterns.

Question 4

❌ What did Tucker et al. (2007) find about individual differences in sleep?

Answer 4

Even under controlled conditions, participants showed consistent biological differences, especially in deep sleep. This questions the generalizability of sleep studies