| What is a circadian rhythm? | Happens every 24 hours, so like the sleep-wake cycle |
| What regulates the sleep/wake cycle? | -Drowsy during the nighttime and alert during the day due to the effect of daylight as an external/exogenous zeitgeber
-Goverened by the internal/endogenous pacemaker called SCN, biological clock |
| How long was Siffre in the cave for? | 61 days |
| How much did Siffre's circadian rhythm extend to? | 24.5 hours, but sometimes to as much as 48 hours |
| What happened to Siffre's biological rhythem ? | it was free-running, going just beyond the usual 24 hours but he did continue to fall asleep and wake up on a regular schedule |
| What was the Aschoff and Wever study? | -Ppts 4 weeks in ww2 bunker
-All but one showed a circadian rhythem of between 24-25 hours
-Shows the natural sleep cycle is slightly longer than 24 hours but is entrained by exogenous zeitgebers |
| What was Folkard's study procedure? | Group of 12 ppts in dark cave for 3 weeks, going to be bed when the clocks said 11:45 pm and getting up at 7:45
Researrcher gradually speeded up the clock so that the 24 hours changed to 22 hours |
| What was the results of Folkard? | Only 1 ppt could adjust comfortablity to the regime, shows that the strong free running circadian rhythem cannot be easily overridden by exogenous zeigebers |
| Strength of circadian rhythm? | -Real worl application
-Bonten found that taking aspirin for heart attacks are most effective at ngith, due to the circadian rhythems corrdination with teh body's natural proccess of heart rate
-Significnat as these rise and fall during the course of hte day which has lead to chronotherapeutic, how medial treatmnet can be administed in a way that corresponds to a person's rhtyem
-Shows that research can increase the effectivness of drug treatments |
| A weakness of circadian rhythm? | -Generlisation
-Studies of the sleep wak cycle use samll groups or even 1 person like Siffre. Siffre observed that in his second study his internal clock was much slower
-Ppts might not be representative fo the wider population and this limits making meaningful generalisations.
-This meant that it is difficult to use the research data as it dissucces evertyhing as more than avarage which is meaningless |
| A strength of circadian rhythm? | -Application to shift work
-Eg: night workres engaged in shift work experience a period of reduced concentration around 6 in the morning (a circadian trough) meaning mistakes and accidents are more likely
-Research also suggests a link between shift work and poor health, with shift workers three times more likely to develop heart deseas
-Research into sleep waks cycle may hav economic implications in terms of how to best manage shift work. |
