1. Describe and critically evaluate the key theories aiming to explain why humans sleep.

Question 1

what are the two main theories for sleep?

Answer 1

restorative and adaptive theories of sleep

Question 2

what are the key aspects to the restorative theory

Answer 2

sleep serves as a restorative process, allowing the body and brain to repair and replenish resources depleted during wakefulness.
Oswald 1966
suggested sleep restores depleted resources of energy, removes waste from muscles and repairs cells.
sleep therefore might be an ideal time for body to remove waste and replenish levels of neurotransmitters in preparation for activity the next day. growth hormone is predominantly secreted during deep sleep, promoting tissue repair and regeneration. similarly, sleep is thought to aid in the clearance of metabolic waste products, particularly in the brain, where glymphatic system becomes more active during sleep.

Question 3

evaluate restorative theory

Answer 3

cannot fully explain complexity of sleep. theory is primarily concerned with physical restoration of body fails to account for psychological and cognitive benefits of sleep
case study on sleep deprivation found that no matter how many days of deprivation there are between 3 and 6am there was a state of extreme drowsiness followed by queasiness the next day and relatively normal function during the day

Question 4

randy gardiner- who?

Answer 4

world record holder, stayed awake for 265 hours. seemed to be no ill effects of his experience. other than slight mood changes
concentration problems
hallucinations

Question 5

are case studies limitations or strengths

Answer 5

limitation as they suggest that in effect with minor changes the body is still able to function

Question 6

other critiques

Answer 6

evidence suggests that not all types of sleep are involved in physical restoration which challenges notion that sleep serves only a restorative function
prolonged periods of sleep deprivation do not seem to produce long-lasting physiological or behavioural disturbance and beyond 48h of sleep deprivation the effects remain constant
missed sleep doesn’t seem to need to be regained.

Question 7

what is the adaptive theory

Answer 7

idea that sleep serves an adaptive function. examples being protection from accidents, predation and energy conservation
species at risk of predation sleep the least.

Question 8

restorative vs adaptive theory

Answer 8

fact that most animals sleep must suggest that it serves a physiological function. some species have evolved complex mechanisms to help them sleep.

Question 9

critiques adaptive theory

Answer 9

discovering the true evolutionary functions of sleep ie the reason sleep adds to fitness of an organism would explain why we sleep explains why animals would hide during the night but not sleep

Question 10

critique

Answer 10

we need sleep every day, never have an opportunity to adapt to darkness. adapting to darkness could compromise our ability to survive during the day. in this theory we hide from dangers of darkness including inability to see predators. so therefor we hide from the danger of adapting to darkness.

Question 11

sleep serving immune function?

Answer 11

aids for recuperation from disease states, sleep loss is associated with a reduction in subsequent immunisation induced antibody-titers. studies describe changes in sleep over course of infectious diseases, an association was shown between robust sleep responses to infectious challenge and lowered morbidity and mortality. correlation suggests sleep does help with bodily function of recuperation from infectious disease. EVOLUTIONARY VALUE

Question 12

Sleep restores brain energy stores

Answer 12

studies in humans show that brain glucose consumption is approx twice as high during waking as during slow wave sleep. brain metabolic rate is higher during REM sleep than during waking. sleep doesn’t reverse wake-dependent depletion of glycogen but instead may free energetic resources for reactions other than those facilitate local production and use of glycogen

Question 13

circadian rhythm theory

Answer 13

sleep driven by body internal circadian clock, 24 hour cycle that regulates physiological processes

Question 14

evidence for circadian. rhythm theory

Answer 14

in absence of external cues- for example light and clocks the body maintains consistence sleep-wake cycle. disruptions such as jet lag can significantly impact sleep quality and daytime functioning

Question 15

critique- circadian rhythm theory

Answer 15

doesnt explain specific functions of sleep beyond its association with the circadian rhythm doesn’t account for individual variations in sleep patterns and needs

Question 16

evaluation- no single theory

Answer 16

its likely no single theory will explain functions of sleep. may serve multiple purposes with each stage playing distinctive roles.

Question 17

evaluation- interplay of factors

Answer 17

need for sleep influenced by multiple factors including evolutionary pressures, energy conservation, restorative processes and regulation of circadian rhythms.

Question 18

evidence- ongoing research

Answer 18

research using advanced tech is shedding new light on mechanisms underlying sleep and its vital role in human health and well-being