restoration theories
This theory of sleep believes that the purpose of sleep is to restore body functions and allow the body to rest and recover after the exertions of the day. During sleep, growth hormones are released and is important in the role of the metabolism of proteins.
Oswald (1980) claimed that there are high levels of brain activity in REM sleep are characteristics of brain recovery, and that the increase in hormone activity symbolises body recovery and restoration. REM sleep is essential for brain repair.
Horne (1988) argues that only stage 4 and REM sleep are critical for normal brain functioning. This is supported by sleep deprivation studies which show that after deprivation, recovery is concentrated in stages 4 and REM sleep. Horne argues stage 4 and REM sleep is 'core sleep' with stages 1-3 being optional.
Evaluation
Oswald (1980) claimed that there are high levels of brain activity in REM sleep are characteristics of brain recovery, and that the increase in hormone activity symbolises body recovery and restoration. REM sleep is essential for brain repair.
Horne (1988) argues that only stage 4 and REM sleep are critical for normal brain functioning. This is supported by sleep deprivation studies which show that after deprivation, recovery is concentrated in stages 4 and REM sleep. Horne argues stage 4 and REM sleep is 'core sleep' with stages 1-3 being optional.
Evaluation
- Research only weakly supports - for example, someone who has done alot of physical exercise may fall asleep quicker, but not necessarily for longer.
- Sleep deprivation does not appear to interfere with the ability to do physical exercise.
- However, sleep deprivation in rats does appear to interfere with the immune system. Animals - sleep may be the only time for tissue restoration, however humans can recover in a state of quiet wakefullness.
EVOLUTIONARY THEORIES
Despite the universality of sleep, there are major differences in lengths of animals sleep, and the proportion of 'optional' and 'core' sleep.
Meddis (1979) argued that sleep evolved to keep animals safe from predators at times when their normal activities were impossible. Thus, diurnal and nocturnal animals have evolved to be active at different parts of the 24 hour cycle.
Webb (1982) supported the view that sleep helps to conserve energy but also thought that it allowed animals to become inconspicuous and avoid predators.
An animals ecological niche effects its sleep cycle. Air breathing acqautic animals such dolphins regularly need to come up for air, making prolonged sleep impossible. Thus, dolphins sleep for sometimes only seconds at a time, repeatedly for the whole day.
Smaller animals have higher metabolic rates - using up energy quicker, because of this small animals will sleep more often and for longer periods.
Meddis (1979) argued that sleep evolved to keep animals safe from predators at times when their normal activities were impossible. Thus, diurnal and nocturnal animals have evolved to be active at different parts of the 24 hour cycle.
Webb (1982) supported the view that sleep helps to conserve energy but also thought that it allowed animals to become inconspicuous and avoid predators.
An animals ecological niche effects its sleep cycle. Air breathing acqautic animals such dolphins regularly need to come up for air, making prolonged sleep impossible. Thus, dolphins sleep for sometimes only seconds at a time, repeatedly for the whole day.
Smaller animals have higher metabolic rates - using up energy quicker, because of this small animals will sleep more often and for longer periods.
TEACHING POINTS
Good example essay on restoration theory -
https://simplypsych.wordpress.com/2014/02/14/outline-and-evaluate-restoration-explanations-of-the-functions-of-sleep-416-marks/
youtube video - good description of both theories
https://www.youtube.com/watch?v=mUuHNidBdho
https://simplypsych.wordpress.com/2014/02/14/outline-and-evaluate-restoration-explanations-of-the-functions-of-sleep-416-marks/
youtube video - good description of both theories
https://www.youtube.com/watch?v=mUuHNidBdho
