There are many theories about the functions of sleep. For example, there is a theory that the major function of sleep is to conserve our energy. Another suggestion is that as the hunger mechanism is suppressed during sleep, we sleep in order to conserve food supplies. That means that sleep is a protective mechanism developed early in man's revolution. Another argument is that we are the weakest in the time of darkness, sleep renders us less likely to be selected as a tasty meal by nocturnal animals. In psychological points of view, it stated that our learning processes are largely inactivated during sleep, this gives the brain a chance to reorganize and store more efficiently the information gathered during the day. Apart from that, there is still a common believe that sleep is to help the body to recuperate physically.
Let us look at these theories in details:
The Neuro-physiological Model of Dreaming
In the Neuro-physiological model of dreaming, it suggests that during REM sleep the brain stem spontaneously generates signals which stimulate sensory channels in the brain much as input from the senses stimulates them in waking life. The brain elaborates these signals into visual and auditory images, a kind of sensory mimicry which tricks the sleeper into believing he is having real experiences - in other words which tricks him into experiencing dreams. Since in sleep we are deprived of regularising and stabilising information from outside our heads against which we can test our dream events, we accept these events as real no matter how outrageous they may be. And outrageous they certainly are, since the signals generated in sleep by the brain stem are random and confused, unlike the ordered events presented to us by the waking world.
| The physiological model also suggests that, since the production of serotonin and noradrenaline is reduced during sleep, the brain processes information in a more confused way, and we thus lose in dreams our sense of self-awareness and of critical judgement. However this model fails to tell us why dreams contain such a strong narrative content. |
 Debate |
The Learning/ Remembering Model
This Model can be explained by a situation. Do you ever have an experience that you will have an exam tomorrow and you study overnight? After the examination, do you have the feeling that you can recall most of the things you have learned the night before? This experience bring up the Learning/Remembering Model. The function of sleep is to rearrange all the things you have learnt in daytime. Therefore, if you don't have enough sleep, your learning and remembering ability will be much weakened. Therefore, you should get enough sleep each day in order for your well-being.
The Forgetting Model
Everyday there are many things that are useful and many things that are useless that we have encountered. This model suggests that the function of sleep is to remove the unwanted things in our brain. This model seems to be acceptable. Our dreams are often difficult to remember. If we follow the hypothesis of this model, we are harming ourselves by try to recall the content of our dreams(useless materials).
1.Sleep by J. Allan Hobson
2. Teach Yourself to Dream by David Fontana
| "I have never taken any exercise except sleeping and resting." |
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Mark Twain
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Sleep
