h2g2 The Hitchhiker's Guide to the Galaxy: Earth Edition

>>Many neuroscientists remain convinced that our dreams are meaningless. To avoid 'overload' they are just a way of clearing the day's unwanted data from our 'cluttered' memory banks.

This is not quite up to speed with current neuroscience.

The memory-bank clearing hypothesis was mooted by the psychologist and computer scientist, Chris Evans, (http://www.answers.com/topic/christopher-evans) some time in the 70's. This was in the days when big computers did, indeed need to be (as it were) swept out overnight, and he reasoned that something similar might be happening in the brain. But there is little experimental evidence to suggest that dreaming - or sleep as a whole - plays a role in memory encoding.

The contemporary view is even less interesting. Neuroscientists suggest that during sleep, the brain undergoes burts of activity (some corresponding to REM slep - but other types of activity in different portions of sleep). These seem to serve no other purpose than to keep the brain ticking over. Keeping the synapses oiled, if you will.

So how does this yield the technicolor movies in our heads? Well - humans have evolved to derive order out of sensory chaos. As evidenced by optical illusions, we're quite capable of seeing things which aren't there. It is suggested that our dreams result from the relevant parts of the brain trying to rationalise a bunch of random activity into some sort of coherent (if frequently bizarre) narrative. The raw materials for the narrative will tend to be familiar chunks of perception and memory - which is why our dreams frequently seem to allude to well-worn memories (eg the house where I grew up is often in mine) or our concerns of the day. The same sort of thing happens in waking life. If stone-age humans heard a rustling, they might automatically 'perceive' a sabre-toothed tiger. That would be a very important thing to be able to perceive. We might simply perceive someone eating a bag of crisps or maybe shuffling papers or...who cares.

One upshot of this is that it is very difficult to see dreams as Freud's 'Royal Road to the Unconscious'. Why should dreaming life be any more a key to our main concerns than waking life?

Good article! The researcher should coose her/himself a 'proper' user name and join in the various community conversations.

Editorial Note: This conversation has been moved from 'Dreams' to 'Dreams'.