The Effect Of Endogenous Pacemakers And Exogenous Zeitgebers On The Sleep/wake Cycle AO3

Question 1

✅ What is a strength of animal research into the SCN’s role in the sleep/wake cycle?

Answer 1

DeCoursey et al. (2000) destroyed the SCN in chipmunks and found they were more likely to be killed by predators when released. This shows causal links between the SCN and circadian rhythm regulation, which cannot ethically be studied in humans.

Question 2

✅ How can findings on ageing improve sleep in older adults?

Answer 2

Duffy et al. (2015) showed poorer sleep in older adults may stem from circadian changes. Hood et al. (2004) found increased light exposure and activity improved insomnia, showing how environmental factors can support pacemaker function.

Question 3

❌ What does Arctic sleep research suggest about the role of exogenous zeitgebers?

Answer 3

People in the Arctic maintain normal sleep cycles despite continuous daylight. This implies internal pacemakers are dominant, and the role of light as a zeitgeber may be overstated.

Question 4

❌ Why is generalising from animal studies in circadian research problematic?

Answer 4

Despite similar brain structures (SCN, pineal gland), cognitive and environmental differences between animals and humans limit generalisation, especially for complex behaviours like sleep (e.g., DeCoursey et al.).