Biopsychology - circadian rhythms

Question 1

circadian rhythm

Answer 1

cycle that is around a day long

Question 2

exogenous zeitgebers

Answer 2

external changes that influence rhythms

Question 3

endogenous pacemakers

Answer 3

internal biological clock

Question 4

examples of circadian rhymths

Answer 4

sleep/wake cycle, hormone release, body temperature

Question 5

when is body temperature highest and lowest

Answer 5

highest at 6pm around 38 degrees, lowest at 4am around 36

Question 6

what affect does body temperature have on cognitive functioning

Answer 6

higher body temp = higher info processing and recall

Question 7

evidence for link between body temp and cognitive functions

Answer 7

Folkard - child read a story, optimum time for recall is at 3pm, not 9am
Gupta - 7pm had better IQ results than 9am and 2pm

Question 8

suprachiasmatic nucleus (SCN)

Answer 8

provides internal body clock, located above optic chasm which is responsible for the detection of light

Question 9

animal studies that show internal body clock through SCN

Answer 9

removed SCN from chipmunks brains meaning they had no internal body clock. they quickly died as they were going out at wrong times and predators were killing them easier.

Question 10

evidence of circadian rhythms

Answer 10

• Siffre - cave studies (1962 and 1972), 2 months in the alps and 6 months in Texas, no natural light or sound, sleep/wake cycle = 25 hours for most but individual differences, some had 48-hour cycle
• Folkard et al, 12 pts in cave for 3 weeks, specific wakeup and sleep times, reduced cycle to 22 hours, only 1 could do this without discomfort
• Aschoff and Weaver (1976), pts in WW2 bunker for 2 weeks, sleep wake cycle = 25 hours, proof of internal clock

Question 11

strengths of research into circadian rhythms

Answer 11

+ provides understanding of adverse consequences when disrupted. night shifts - more mistakes at 6am (Boivin et al). shift workers 3x more likely to develop heart disease. real world applications to best manage productivity in workers
+ used to improve medical treatments. chronotherepeutics can correspond with biological rhythms. aspirin most effective at night, timing matters to reduce heart attacks (Bonten)

Question 12

limitations of research into circadian rhythms

Answer 12

• correlational methods used. Solomon - high divorce rates in night shift workers = missing out on important family events/strain of deprived sleep rather than desynchronisation of sleep/wake cycle. it might not be biological factors creating adverse affects
• generalisations difficult to make, small sample sizes. Czeisler et al - individual differences sleep/wake cycle between 13-65 hours.