Theories Of Sleep

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Theories Of Sleep

Restoration Theory

Sleep is used to restore the brain and body from demands placed upon it during the day.

happens through stage 3+4+REM sleep (core sleep)

Stages 1+2 are elastic sleep.

Sleep deprivation, growth, exercise put on extra strains so more sleep is needed after these activities.

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Supporting + refuting evidence

Rechshaffen's Rat's- deprived of sleep = die. this is animals thought so.....

Peter Tripp - stayed awake for 200 hours. began to hallucinate without sleep it can't restore itself.

Green - High proportion of infants spend high proportion of sleep in REM. During 1st weeks alot of growing. more energy given = more sleep after, detailed case study + scientific weight

Randy Gardner - stayed awake for over 200 hours, no long lasting effects

Horne + Minard - exhausted participants. fell asleep quickly but didn't sleep longer. Don't need more sleep for more Strains WAS OBSERVATIONAL THOUGH!

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Ecological Theory Of Sleep

Sleep can be adaptive for mammals

sleep has suvival benefits so it changes from species to species

some micro sleep + some sleep unbroken

has survival benefits as conserves valuable energy

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Hibernation Theory (Webb)

It reduces energy demands at a time of year when they are hard to fulfill.

foraging animals = high metabolic rate = more energy used

Zepelin + Rechtshaffen - correlated body size + total sleep time in 53 species. negative correlation. High metabolic rate sleeps longer as suggested.

Only conserve 5-10% more energy

dolphins use 1 hemisphere at a time, must be another satisfied function as not conserving

sloths - low metabolic rate - 20hours sleep (outlier)

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Predator Avoidance

Time spent asleep relates to exposure to predators.

lions -> hunt-> infrequent-> not at risk-> lots of sleep

Deer-> grazing-> often-> at rick-> little sleep

so patterns of sleep do reflect relative survival benefits

Allison + ciahetti - correlated total sleepwith typical amount of danger. strong negative correlation more risk - less sleep, less risk - more sleep. patterns have evolved to reduce risk of predatation

if sleep is purely for protection, most risk shouldn't sleep.

rabbits+moles sleep the same but predatation risk varies.

being asleep may make you less conspicuous so should be the other way around

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General Commentry On Ecological Theories

Explains the variation of sleep patterns

if these are true + sleep just "kills time" or keeps us safe, why did peter tripp react so badly to sleep deprivation.

Are humans and animals different?

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