Further, research also suggests that people don't use the extra time to bring together the most relevant and important pieces of information. An experiment looked at people's ability to predict World Cup soccer matches and found the more time they had the more useless information they considered (e.g. which stadium) rather than critical information (e.g. teams' track records).
The conclusion from this is that conscious thinking leads to good decisions only when a limited amount of information is considered. The answer is not to think too much but leave the thinking to the unconscious part of the mind which has a far greater processing capacity.
In an experiment involving decisions about the best apartments to purchase, the people who 'slept on it' (ie. left it to the unconscious to sort out) made better decisions without exception than those who either made an immediate decision or thought consciously about it.
The moral is that you should use your conscious mind to compile all the relevant information but leave it to the unconscious mind (go on holiday, for instance) to digest it. Your instinct will then tell you what to do.
When to sleep on it
Harvard Business Review, February 2007
Review by Morice Mendoza