One theory of the nature of why we sleep is that it is essential for health reasons, and sleep deprivation can seriously endanger our lives. Jouvet deprived cats from sleep (by placing them on a water lily above water; when they fell asleep the fell in the water) and found that the felines behaved ‘abnormally’; one died 26 days constant deprivation. Killgore found that sleep deprivation in humans can lead to great latency in decision making.
This could have serious implications for certain professions; nurses, for example, who work alternating day/night shifts, could take a long time in administering certain drugs which could endanger patients’ life; or, drivers, who drive during the night and often refuse to take breaks, are endangering themselves and others on the road by doing so. These studies suggest that sleep deprivation should certainly be avoided whenever possible – but it could be argued that parts of Jouvet’s research were superfluous.
You don’t need to be a psychologist to work out that prolonged sleep deprivation can cause lasting suffering and the death in his study could certainly have been avoided if common sense was used – i. e. how much did our understanding of sleep improve after the death of that cat? Certainly, even without that study we could’ve guesses with reasonable reliability that elongated periods without sleep can lead to both psychological and physiological illness.
Radio DJ Peter Tripp once stayed awake for over 200 hours and was reported to have suffered hallucinations and paranoia. This, with the research I have mentioned previously, evaluates that prolonged time without sleep is not to be recommended and that for well-being a constant and regular sleep cycle is urged. Another theory of sleep, linked with health reasons, is that it has restorative purposes.
Studies show that when we are awakened from sleep can lead to how we feel when we are awakened: disruption during slow wave sleep (SWS) leads to one feeling tired; disruption during rapid-eye movement sleep (REM) leads to one feeling anxious/irritable – ostensibly, this means that if we are allowed enough SWS sleep we will be physically restored and if we are allowed enough REM sleep we will be mentally and psychologically restored and ‘fit.
‘ However, there are serious limitations to any research studying dreams as there is always a myriad of apparatus involved which could interfere with dreaming patterns and thus give any findings low ecological validity. Our cognitions can also be affected by lack of sleep; Turner has found that memory capability is reduced after four days of continuous deprivation. This evidence could be useful in a variety of real life situations.
Students, for example, will often ‘cram’ the night before an exam in order to fathom as much as possible; actually, this may be counter-productive, as memory is reduced with prolonged periods of being awake. More research would have to be done, however, in order for us to understand how sleep deprivation affects our other cognitions (i. e. comprehension; puzzle solving) and with a variety of ages in a variety of conditions (possibly including real-life, natural experiments with students doing real examinations.)
A final theory of sleep is evolutionary theory; we have adapted to sleep because of evolution. Animals, it has been argued, have adapted to spend darkness asleep; reasons are twofold; firstly, sight is reduced in the dark and it would be harder to hunt/forage for food/resources; secondly, this allows them, if they are prey, to seek safety and reduced light makes it harder for predators to find them. It is more difficult when we link it to humans, however.
Nowadays, the majority of the human population has artificial light which enables them to see even without the assistance of sunlight – the idea, then, that we as a species sleep less than we did in the past is supported with evidence which suggests that we sleep on average 500 less hours per year than we used to; sleep hasn’t got the ‘protective’ element that it used to with the invent of houses for protection; and, wider reaching, the urbanising of humanisation has removed us from natural predators, meaning we no longer need to be ‘on guard’ and prolonged periods of sleep have become exorbitant.
Also, the evolutionary theory doesn’t really explain the phenomenon of dreaming – what is its purpose? Have we ever dreamt or has this also been created with the advent of sleep. Plenty more research needs to be done if we are to accurately say that there is a concrete link with the idea that we have ‘evolved’ to dream, and it isn’t just a naturally occurring process (i. e. perhaps by studying ancient literature; any references? ), or possibly even looking at sleeping patterns in ‘new’ species of animal to see if there are any present.