Passage 1 The human mind is wonderful and powerful, but it's far from perfect. There are several common judgment errors that it's prone to make. In the field of psychology these are known as cognitive biases, or fallacies in reasoning. They happen to everyone regardless of age, sex, education or intelligence. Negative self-fulfilling prophecies. A self-fulfilling prophecy is a prediction that motivates a person to take actions that cause the prediction to come true. A negative self-fulfilling prophecy often tears relationships apart and causes people to fail at their goals. Beginner's optimism . Beginner's optimism is the human tendency to underestimate the time required to complete an unfamiliar task. It occurs due to a lack of planning and research on the part of someone who is excited about doing something they have never done before. In other words, when we get assigned a new task that we are anxious to get started on, instead of delaying the start time to accurately evaluate the level of difficulty and resources required, we simply guess and begin. Thus, our expectation of the workload is based on raw optimism instead of past experience and reliable data. And it all backfires on us a little later when we find ourselves knee-deep in work we were unprepared for. Rebelling simply to prove personal freedom . Although more common in children, this thinking fallacy can affect people of any age. It's basically a person's urge to do something they have been told not to do, for fear that their freedom of choice is being taken away from them. This person may not even want to do whatever they are doing to rebel; however, the simple fact that they are not supposed to do it motivates them to do so anyway. The tactic of reverse psychology is a commonly used method of exploiting this thinking fallacy in others. Trying to diminish losses by continuing to pursue a previous failure. Sometimes called the sunk cost fallacy, it is a thinking fault that motivates us to continue to support a previously unsuccessful endeavor. We justify our decision to continue investing in this failed endeavor based on our cumulative prior investment, despite new evidence suggesting that the cost, starting today, of continuing to pursue it outweighs the expected benefit. The logical thing to do would be for us to cut our losses and change our course of action. However, due to the sunk costs we have already invested, we feel committed to the endeavor, so we invest even more time, money and energy into it, hoping that our additional investment will reverse the outcome. But it never will.