Warren Buffett has mentioned in several interviews that he doesn’t think intelligence much above average is required to be a good investor and may actually be a hinderance. Investing, like high-level poker, is about having a sound strategy and sticking to it. Eventually if you play enough hands you should end up on top. Most people can’t do this because emotions get in the way.
It is why investing in an S&P 500 Index fund and not touching it tends to out perform even professional investors. It is a sound strategy and eliminates human judgement. If you are thinking about getting into investing start with small amounts and learn the hard lessons. Panic selling and buying is a very hard emotion to overcome.