Night brings counsel?

It is quite okay to question how exactly this late 16th century saying holds up: how exactly does a good night’s sleep contribute to our decision-making, other than helping us to delay it? There are, of course, good reasons for not rushing into a decision if you don’t have to, but there is also an increasing amount of research that suggests that sleep itself, not just the passage of time, can move our thinking forward, in at least two ways.

The first concerns formal problem-solving. For example, in an experiment, subjects were given a number of tasks, such a logic puzzles which require you to work out what comes next in the sequence. They were then tested again, later the same day. Those who slept in the interval regularly performed better than those who didn’t. Functional MRI scans suggest that the reason for this is that the brain ‘rehearses’ in sleep precisely those brain patterns involved in problems that have been occupying us while awake.

Another way sleep changes thought, however, is of more questionable value. Most memories fade with time, whether we sleep or not. But there is one exception: our memories of emotionally evocative people, places or events actually seem to improve after a night’s sleep.

Whether this is a help or hindrance depends. If your feelings about something are an important factor in what decision you should make, then it may indeed help for less affecting factors to slip from your mind and the more affecting ones to move centre-stage. But on many occasions, such rejigging might cloud your judgment. Sleep might help you forget some important, but emotionally neutral factors and focus more on less important, perhaps changeable, factors with negative emotional connotations. For instance, the repaintable walls of a house which remind you of a much hated place may cloud out the many advantages of a prospective new home.

“Sleeping on it”, then, probably doe shed new light on a problem, but that does not mean we should always take the advice the night brings.


(Adapted from Julian Baggini’s ‘Should You Judge This Book by Its Cover?’)


~ by irwin on February 26, 2012.

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