Biological rhythms - Circadian rhythms

Question 1

Circadian rhythms

Answer 1

Biological rhythms that run in a 24 hour cycle e.g sleep wake cycle and core body temp
Sleep/wake cycle is controlled by a biological clock (endogenous pacemaker) but it is also influenced by external cues (exogenous zeitgebers) e.g light

Question 2

Sleep/wake cycle

Answer 2

• Exogenous zeitgeber = daylight
• Endogenous pacemaker = suprachiasmatic nucleus (SCN)
• Daylight can reset the SCN

Question 3

Siffre’s cave study

Answer 3

• Spent several amount of time underground to study his own biological clock
• Deprived of daylight and sound
• Came out after 2 months but he thought he’d only been in there for a month
• His biological rhythm settled to around 25 hours

Question 4

Other research - Aschoff and Wever

Answer 4

• Sent p’s to spend 4 weeks in a WWII bunker deprived of daylight
• All but 1 p’s biological rhythm changed to between 24 and 25 hours

Question 5

Biological rhythms - evaluation - strength

Answer 5

• Shift work
• Provides an understanding of consequences that occur when they are disrupted
• e.g night shift workers experience a period of reduced concentration around 6am - means mistakes and accidents are more likely
• means research into sleep/wake cycles have real world value

Question 6

Biological rhythms - evaluation - limitation

Answer 6

• Difficult to generalise
• Study by Aschoff and Wever are based on a very small sample - seems sleep/wake cycles may vary widely from person to person
• Means it’s difficult to use the research to discuss anything more than averages