That's one way to train the brain, surely, but the type of training I'm referring to involves getting to a baser level of perception which allows the individual to shirk subconscious assumptions before allowing them to dominate what one's first impression of something would be. The story of the monk with the sweaty palms illustrates this well. Said monk came into contact with a powerful political figure and, unwittingly, found himself sweating due to the association of high status that accompanied said figure. Part of his training in becoming a teacher involved recognizing the sameness in all human beings, but he obviously was still struggling with this. Thus, due to social stereotyping and subliminal conditioning, we come to assumptions based on what we believe in others to be power, status, ect.. When one can bypass this filter and see things without shaping them to a personal standard and become simply a passive observer, one can begin to perceive realistically. Of course, it will always help to be able to associate certain things with subconscious reactions, such as in dangerous situations, but its always good to find yourself past the red tape without having to do much cutting. Meditation is something that would be helpful in shaping ones mind in this direction. Once these borderlines are broken down, you can get to the root of things easier, and by doing so think more critically, and hopefully become more empathetic.