Real life experiment with people on rational decision making.
Our human nature plays a big part in our lives on the decisions we make. Traders are especially haunted by our bias towards risk aversion as losses of any kind is almost automatically translated into a form of pain or threat. Being able to overcome that in one situation does not mean that you can make the right decision next time in a different situation. Hence our struggle as a trader against our human nature is a fight we have to carry on all the time.