More and more investors are turning their back on the age-old advice that when it comes to trading on the stock market, they should call in the experts.

For reasons that have as much to do with basic human nature as anything else, thousands of people have jumped into the "day trading" game, which typically involves rapid-fire transactions - sometimes totalling hundreds in a single day - predominantly through the Internet. These traders are a small minority, but we know that many other investors have caught a less virulent form of the trading bug over the last few years. The Net stock mania has crystallised this phenomenon, though it probably would have happened even without the Net stocks.

Most of these investors, however, are not hyperactive - certainly not by day traders' standards. So is it wrong for you to be trying your hand at trading as well? "Most people who try to trade will fail miserably at it," those ubiquitous Wall Street "experts" will argue. Fair enough. But some percentage of people do trade well.

But how can the small trader know something about a stock that Wall Street pros do not? The wealth of market information available to average investors today makes that a more realistic prospect than ever before. However, one analyst has pinpointed one essential trait that drives many individuals who join the trading game. "The average trader is naturally a chronic bull," he said. "It is human nature to prefer optimism to pessimism."