I read an interesting article on the weekend (think it was SMH).
An experiment was performed on both rats and humans.
Two lights - a red and a green one. The contestant had to guess which light was going to light next (the rats were given mild electric shock or some food).
The trick was, that the red one lit up 80% of the time.
So humble rodent worked out that he/she may as well just keep pressing the red one - and was rewarded 80% of the time.
The highly sophisticated humans on the other hand (inventors of the digital watch and other modern marvels) kept trying to guess which one was going to be next and so ended up scoring 65% correct.
The moral (from the article) - you cannot really predict which way the market is going to go, so you should be more of a patient hold and wait investor.