Quote from Ticketwatcher:
Psychology is important in trading, but I am not sure it is the psychology found in academic courses. I have taken quite a few psychology courses, but the kind of pychology useful in trading is the kind where you can read human nature. The human nature of yourself as well as the human nature of the market which tends to have a collective mind of its own. Western civilization has studied pyschology indirectly over the ages through literature. There is certainly a lot of psychology to be learned from reading the likes of Twain, Shakespeare, Dostoevsky, and the Old Testament. Much can be learned from some of the master pychologists of our popular culture who are coaches such as Pat Riley and Bill Parcells. In years past, it was always reputed that there was no better reader of people than the professional bartender. I think a lot of traders apply the psychology learned from varied life experiences as well. If there is such a thing as a trading light bulb, don't expect it to be turned on by taking a psychology course.
Regarding a mob psychology, there is not a better source than Gustave Le Bon.