why do we have dreams? and how come we can see thing in our dreams that we never have before and why is it sometimes

Question: why do we have dreams? and how come we can see thing in our dreams that we never have before and why is it sometimes we see things in our dreams we never have seen before but later on in life we see the thing or are in an avent that we had in our dreams which we never had before???????????????????????????????????????????????????????????? :P
- Keywords:
  dream,
  night,
  nightmare,
  sleep,
  wierd
Asked by zarakiran to Amelia, Jim, Liz, Prateek, Richard on 18 Jun 2011.
- Amelia Markey answered on 18 Jun 2011:
  
  As far as I know no-one is really sure why we dream but there are a lot of theories.
  
  The famous psychoanalyst Sigmund Freud wrote a book “The Interpretation of Dreams”. His theory was that we dream of things that we want to do or think but have “repressed” which means we hold them back in our conscious mind and then let them out when we dream. He said there are 2 bits to dreams, the actual images and the hidden meaning behind them.
  
  Another theory suggested by J. Allan Hobson and Robert McClarley in 1977 is that when we are asleep the area of the brain that is involved in emotions, sensations and memories becomes active. Your brain tries to give these signals meaning and that’s why we dream.
  
  People also think that:
  
  * our brains try to interpret external stimuli during sleep. For example, the sound of the radio may be incorporated into the content of a dream.
  
  * dreams serve to ‘clean up’ clutter from the mind, much like clean-up operations in a computer, refreshing the mind to prepare for the next day.
  
  * dreams function as a form of psychotherapy. In this theory, the dreamer is able to make connections between different thoughts and emotions in a safe environment.
- Richard Badge answered on 18 Jun 2011:
  
  What a great answer by Amelia…. The only thing I would add is that why its not clear why we have dreams, a proper sleep cycle (that often involves dreaming) is essential for health.
  
  Although there is no record of a healthy person dying of sleep deprivation, the cognitive effects of 10 days of sleep deprivation are very severe – people cannot perform very simple mental tasks and often are “microsleeping” – appearing to be awake but actually totally unresponsive to stimulation, like they are asleep. So whatever sleep and dreams are do, they are essential to keep our brains working.
  
  The feeling that we have dreamed something before and then it happens in real life is known as “deja vu” – from the French “already seen” and while when it happens we can really feel that we could predict what was going to happen next in general the apparent “memory” of having dreamed something always come along a little later than if we were really recalling something…
  
  There are lots of theories about this, but the one that seems most scientific is that the feeling is generated by our brains noticing and taking in details about somewhere or something, without us being aware of it (the divided attention or cell phone theory). When we do pay attention to it because our brain has already seen it and processed the information it labels it as “familiar” even though we haven’t (conciously) been there.
  
  The feeling of familiarity, when rationally we know we haven’t been in that place or seen that thing then needs an explanation and so our brain finds a dream image that sort of fits and then we “remember” it. So the upshot is your concious brain is confused by your subconcious brain, and comes up with a dream memory to make things fit, because this is the normal way the feeling of familiarity is generated…
  
  More good information here: http://science.howstuffworks.com/science-vs-myth/extrasensory-perceptions/deja-vu.htm
  
  P.S. Deja Vu is much more common between 15 and 25 so you guys are much more likely to have than old codgers like me!