Why Do We Dream, And What Affects What We Dream About ?

Chris - why do we think dreaming is so important and why do we have problems remembering our dreams?

Mark - We are not sure yet why we dream or what it does. You're more likely to dream during rapid eye movement sleep or REM sleep, which is when your brain waves look like you're awake but your body is flat out. We know that when you wake people up from REM sleep, people are able to solve anagrams and puzzles quickly. REM sleep is also associated with memory, so it could be that you're laying down memories in REM sleep as well, which is what our brain is doing. What your dreams are doing during REM sleep, we don't know, it could be they're telling us what our brain is doing during REM sleep or it could be a lot of chaos. It's not quite that chaotic - samples of people's dreams have shown they are related to their lives and the dreams are sensible and have a purpose. In the case of remembering them though, there are parts of the frontal lobe which switch off during REM sleep, and these bits are related to laying down memory and critical thinking, so it may be that we're just not paying attention while we're dreaming. The other possibility is that our brain chemistry just won't allow us to remember our dreams or possibly we have evolved to not be able to remember our dreams, because we may spend too much time in the day thinking about the meaning of our dreams!

Chris - and what about nightmares ?

Mark - There is a worldwide search going on at the moment to find out why some people have more nightmares than others. If people are stressed or live through stressfull experiences like earthquakes and things like that they do have more nightmares than others. On the whole if you look at how stressed, anxious or depressed people are the relationship between that and the number of nightmares they have is really quite small. So it looks like we are almost designed to have some bad dreams even if our lives are actually quite okay.