The basic principles of sound investing have not changed in a couple of centuries. But neither has the most common errors made by investors.
A perfect example of how little investor misbehavior has changed can be found in a book by Thomas Gibson. Gibson wrote several books on investing and speculation. One of his more recent was published in 1923.
In it, Gibson recounts a study he did of the trading history of some 4,000 brokerage accounts over a 10 year period.
Two patterns really stood out. Far more people bought at high prices than low prices and almost every account that showed some type of plan for buying and selling not only gave up on the plan but would have made a profit had they stuck with it. Overall, losses were an overwhelming result.