Want higher returns? Don't take Prozac: James Saft

(James Saft is a Reuters columnist. The opinions expressed are his own)

By James Saft

LONDON (Reuters) - It's no fun at parties, but when it comes to investing being depressed just might help.

Fund managers, like so many of us, consistently think they are smarter than they are and that their ideas are of an unusually high quality. And to keep thinking these reassuring thoughts, they ignore evidence that contradicts their beliefs while paying rapt attention to data or news that confirms their own biases.

But not the depressed, whom multiple research studies have shown to have a more accurate and realistic view of their own abilities and insights, according to James Montier, a strategist at Societe Generale who specializes in behavioral finance, the study of how emotion and thinking patterns influence economics and investment.

"The depressed tend to be less optimistic," said Montier,. "And they certainly would be less prone to the chronic optimism that characterizes pretty much all of the market participants we come across."

Montier thinks that human beings have been hard-wired by evolution to have an optimistic or bullish outlook on things. While that is very useful when you need to leave the cave and hunt saber tooth tigers and the summit of your ambition is to make it to age 20 and pass your genes along, it leaves investors today with some in-built problems in analyzing company or economic prospects.

"All behavioral biases have some evolutionary reasons for existing and it's very tough to overcome those deep-rooted impulses," he said.

A survey of over 500 professional fund managers showed that 74 percent rate themselves as above average at their jobs, according to Montier, a figure that a glance at the performance tables on mutual funds will show to be, well, wildly optimistic. And investors don't just overrate themselves, they think their holdings and the stocks they cover are great too.