Biopsychology - Circadian rhythms

Question 1

what are biological rhythms

Answer 1

• patterns of changes in body activity
• influenced by endogenous pacemakers and exogenous zeitgebers

Question 2

what are circadian rhythms

Answer 2

• 24 hour cycle
• sleep/wake cycle

Question 3

what is the sleep wake cycle

Answer 3

• governed by the superchiasmatic nucleus above the optic chiasm which provides information from the eye about light (EP)
• EZ (light) can reset the clock

Question 4

what was Siffre’s cave study

Answer 4

• spent several periods underground to study the effect of his own biological rhythms
• derived exposure to natural light and sound but access to adequate food / drink
• spent two months in the cave
• found it was 25 hours not 24

Question 5

what is the supporting evidence

Answer 5

Aschcoff and Wever (1976)
- group of pps spent 4 weeks in a WW2 bunker deprived of natural light
- all but 1 pps had a circadian rhythm between 24-25 and others 29 hours

Question 6

what are the strengths of circadian rhythms

Answer 6

Shift work
- provides understanding of consequences of shift work
- relationships between shift work and poor health
- reduced concentration

Medical treatment
- coordinate body’s processes such as heart rate and digestion
- chronotherapeutics - medical treatments can be administered in a way that corresponds to someone’s biological rhythm
- Aspirin for heart attacks is most effective at night as heart attacks likely to occur in the morning

Question 7

what are the limitations of circadian rhythms

Answer 7

Individual differences
- studies are based on small samples or individuals
- sleep /wake cycles vary from each person
- some have a natural preference of being going to bed early or late