The Nature and Function of Sleep

OCR

GCSE

The study of sleep encompasses the biological mechanisms regulating sleep-wake cycles (circadian rhythms) and the psychological and physiological functions of sleep states. Candidates must analyze the interplay between endogenous pacemakers (e.g., Suprachiasmatic Nucleus) and exogenous zeitgebers (e.g., light). Critical evaluation of evolutionary and restoration theories is essential, supported by empirical evidence from isolation studies and neurophysiological research.

Objectives

Exam Tips

Pitfalls

Key Terms

Mark Points

What You Need to Demonstrate

Key skills and knowledge for this topic

Credit accurate identification of the SCN (Suprachiasmatic Nucleus) as the primary endogenous pacemaker detecting light levels.
Award marks for explicitly linking REM sleep to brain restoration/memory consolidation and NREM sleep to physical repair/growth hormone release in Oswald's theory.
Candidates must explain the mechanism of 'reverse learning' or 'parasitic memory' removal in Crick & Mitchison's Reorganisation Theory.
Responses must demonstrate understanding of the pineal gland's role in secreting melatonin to induce sleep onset.

Example Examiner Feedback

Real feedback patterns examiners use when marking

"You have described the theory well; now evaluate it by discussing a limitation, such as the lack of human evidence for reverse learning."
"Be precise: specify whether the restoration is physiological (NREM) or psychological (REM)."
"Link the scenario explicitly to the theory—how does the character's lack of REM sleep specifically explain their memory loss?"
"Differentiate clearly between the biological clock (endogenous) and environmental cues (exogenous)."

Marking Points

Key points examiners look for in your answers

Credit accurate identification of the SCN (Suprachiasmatic Nucleus) as the primary endogenous pacemaker detecting light levels.
Award marks for explicitly linking REM sleep to brain restoration/memory consolidation and NREM sleep to physical repair/growth hormone release in Oswald's theory.
Candidates must explain the mechanism of 'reverse learning' or 'parasitic memory' removal in Crick & Mitchison's Reorganisation Theory.
Responses must demonstrate understanding of the pineal gland's role in secreting melatonin to induce sleep onset.

Examiner Tips

Expert advice for maximising your marks

💡When evaluating theories, use specific counter-evidence, such as the survival benefits of sleep in different species (e.g., dolphins sleeping with one hemisphere awake).
💡In scenario questions (AO2), explicitly name the sleep disorder or mechanism affecting the person before explaining the theory.
💡Allocate 15 minutes for the 13-mark extended response; ensure a balance of AO1 (Description) and AO3 (Evaluation).
💡Use the term 'exogenous zeitgeber' rather than just 'external cues' to demonstrate specialist vocabulary.

Common Mistakes

Pitfalls to avoid in your exam answers

Confusing the functions of the SCN (detection) with the pineal gland (secretion).
Failing to distinguish between the specific restorative functions of REM (brain) and NREM (body) when discussing Oswald.
Describing the sleep cycle as purely circadian without acknowledging the ultradian nature (90-minute cycles) of sleep stages.

Key Terminology

Essential terms to know

Likely Command Words

How questions on this topic are typically asked

Identify

Describe

Explain

Discuss

Evaluate

Calculate

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