CIRCADIAN RHYTHMS

Created by

Carys Evans

Cards (12)

What is a biological rhythm?
a change in body activity that follows a particular cycle
what is a circadian rhythm?
a biological rhythm that lasts around 24 hours
example of a circadian rhythm?
the sleep/wake cycle
what governs our circadian rhythm?
exogenous zeitgebers and endogenous pacemakers
what was Siffres procedure to test circadian rhythms?
spent 7 months a in dark cave, didn’t know what the time was the entire time
what were the results of siffres research?
his free running circadian rhythm was 25 hours
he had a regular sleep/wake cycle
what was Aschoff’s procedure?
participants spent 4 weeks in a WW2 bunker, deprived of natural light
what were the results of Aschoff’s experiment?
all but one of the participants displayed a circadian rhythm between 24 and 25 hours
What was Folkards procedure?
12 people lived in a cave for 3 weeks
agreed to go to bed at 11:45 pm and wake up at 7:45 pm
researchers secretly sped up their clock so each day was 22 hours
what were the results of Folkard’s experiment?
none of the participants could adjust to the 22 hour cycle
strengths of research
practical application to shift work - found they experience a concentration lapse around 6am so mistakes and accidents are more likely. research can have economic implications to manage worker productivity
Drug Treatments - research shows there are certain time in the day when drugs are more effective, led to guidelines on certain drugs
limitations of research
individual differences in CR research- been found ranging from 13-65 hours. Research found that people are either more active in morning or evening but Teenagers CR are 2 hours behind adults. these variations makes generalisations more difficult
Case studies and small sample sizes - often use small group, could be participant variables
confounding variables - even when deprived of natural light they still had access to artificial light which was turned off when sleeping. could alter CR