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Sleep

Circadian Rhythm – 24 hour, Key rhythms regulated – Sleep wake cycle

-          Siffre, nature nurture debate, Folkhard isolated from external cues showed natural rhythm, Luce and Segal, arctic regular rhythm – Aschoff and Wever, WW2 bunker showed natural rhythm.

-          Czeisler – managed to fluctuate rhythms between 22-28 hour rhythms using light

-          Consider individual differences

-          Sleep Labs, talk about flaws

-          Studies supporting SCN – Green and Gillette, Recording electrodes picked up rhythmic bursts of activity on 24 hour cycle

-          IDA –nature nurture

Ultradian rhythm – 90M – eating, sleeping etc – REM paralysis

-          Friedman and fisher found eating cycle

-          Bollani observed babies and found their cycle

-           Loomis found showed cycle in sleep. EEG – found sleep deepened wave increased

-          Dement and Klietman support rhythm by inspecting 9 participants. 2 kinds of sleep found. 79% of dreams in REM.

-          Sleep labs, talk about flaws – ARTIFICIAL ENVIRONMENT

-          Danish children only sleep for an average of 9.5 hours per day compared to the 12 hours found in conflicting research

-          Lifespan changes effect ultradian rhythms. REM sleep duration changes through life

-          Science- falsifiable, replicable and empiricism, scientific credibility

Infradian rhythm – Menstrual cycle and SAD. Light as zeitgebers

Individual differences

-          SAD research – Foster – disrupted melatonin release linked to SAD, biological but affected by light

-          Terman, 30M of intense light reduces symptoms.

-          William – 8/10 people found light therapy effective. 

-          Menstrual cycle –

-          Russell – pheromones collected sweat from one woman, found cycles linked to p’s

-          Timmerman – Light months of the year conception increased, nurture

-          Rhynberg- 3 months in cave with dim light, menstrual cycle 25 days, nurture- took a year to return to normal length, role of nurture

-          Gender – not applicable to males, lacks population validity, can’t say role of Infradian rhythms can be applied to males

Endogenous pacemakers and exogenous zeitgebers –CIRCADIAN RHYTHM

Ecological approach to sleep – doesn't consider restoration - flawed

-          Webb, energy conservation theory  - sleep to conserve energy 

-          Young - asleep for as long as you can get away with’ was the best way of surviving

-          Zepelin found that smaller animals sleep for longer durations compared to larger animals, and as smaller animals need to conserve more energy

-          Meddis – Predator avoidance sleep helps keep animal’s safe, predator avoidance. Larger animals sleep less than small ones

-          – LARGE CONTRADICTION- sleep evolved to keep animals safe but prey sleepless to remain vigilant – lacks falsifiability

-          sleep when they can’t hunt and to avoid hunted

Restoration approach to sleep

Oswald – REM causes brain recovery and without it there’s brain malfunctions – Restoration theory

SWS- body recovery – all studies on non human animals

Sharipo studied a group…