Mind over matter
"Investors are human beings. There is a part of all of us that says 'I don't want to lose money'. If we do, we are prepared to take a risk to play catch up," Graham says. "There is a point when people stop seeing their investments as real money, and that is where it can become dangerous."
He points out that similar problems affect fund managers. "At times it can seem they are no more prone to being rational than an average investor," he says. "They are also overconfident in selling and buying in volatile markets."
So what should investors do? Having a diversified portfolio is important. It would be a very rare set of events if every investment went down at the same rate at the same time.
"A knowing investor would have their attitude to loss measured in a risk profile and build their portfolio accordingly," says Graham. "They will then have to take the return in line with their attitude. Most investors want a portfolio that will make them the most money but then are shocked when the markets turn volatile. You can't swing from being positive when markets are up to negative when they are down."
Investors need to divorce themselves from what is happening in the market, which Graham accepts isn't easy to do.
"You should say 'I'm going to dictate what happens to my money in the next 10 years or so' as opposed to worrying about the present. Don't look at market prices every day," advises Graham. "Find out what you can tolerate and operate accordingly. It takes discipline to let the head rule the heart but you'll have fewer sleepless nights."