Circadian Rhythms- PEEL Sleep-Wake Cycle

POINT Make your point.

EVIDENCE

Support it with psychological

research.

EXPLAIN Explain what the research

shows or elaborate with

another example.

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These studies show that circadian rhythms persist despite isolation from natural light, which demonstrates the existence of an endogenous clock. However the research shows that external cues are important because the clock was not completely accurate and varies from day to day.

Psychologists have investigated what happens when a person is free of external cues using temporal isolation studies i.e. the biological clock is allowed to be free running and unaffected by external cues.

Michael Siffree spent long periods underground with no daylight, radio, clocks etc. He found that his sleep wake cycle generally adjusted to a 24 hr cycle (but sometimes changed dramatically to as much as 48 hrs)

His experiences showed that the free running cycle settles down to a regular rhythm which is just over 24 hrs. His case study was supported by other studies. For example, Aschoff and Wever (1976) placed participants in an underground WWII bunker in the absence of environmental and social time cues. They found that most people displayed circadian rhythms between 24 and 25 hours (though some were as long as 29 hrs)

Circadian Rhythms- PEEL Core Body Temperature

POINT Make your point.

EVIDENCE

Support it with psychological

research.

EXPLAIN Explain what the research

shows or elaborate with

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PEEL