Those who don't believe in trading psychology are the same with those who think they can trade without Stop Loss (SL), it doesn't matter how a trader's winning rate is. It's just a matter of time before they got burnt. Back to psychology in trading, whether one is a fundamental or technical trader doesn't matter. Every trader needs to master their psychology to be able to profit from the market. Otherwise, they will be messed up by the market once they get hit by loss and they will lose confidence of the little they even know. Nothing messes a trader up like loss of confidence in their trading strategy or plan. Risk Management/Money Management is benched on trading psychology. It's an important aspect of trading.