Science Questions

I was wondering why it was so difficult for us to remember our dreams when we wake up in the morning? Paula Ogilvie, Johannesburg, SA

Professor Mark Blagrove, Professor of Psychology at Swansea University:

People differ on whether or not they can remember their dreams.  Some people have a great deal of interest in their dreams, have very vivid dreams or their level of anxiety or sleep quality results in people remembering dreams at different amounts each month, say.  In general, for all of us dreams are very easily forgotten once we wake up if we don’t consolidate them or in other words if we don’t transfer them from short-term to long term memory immediately upon waking. 

There’s a few theories of why that happens to all of us.  One possibility is that our brain neuro-chemicals during sleep are very different from during wake time and so they don’t allow us to consolidate memory.  The other thing that’s quite possible is that we don’t pay attention to our dreams or are unable to do so during sleep.  We are unable to remember what occurs to us during sleep.  Even people with sleep apnoea who wake up during the night don’t know that that happens to them.

Similarly when we have a dream we’re not consolidating it as it occurs.  Indeed, if you have people having a long REM sleep period and you wake them up once the REM sleep period gets over about 20 minutes you don’t find that dreams increase in length very much.  It’s as if during the dream we forget what was happening.  The same happens immediately we wake up.  The dream just disappears.

July 2008