Why does developing the ability to understand what another person is going through decrease prejudice?

By developing the ability to understand what another person is going through, you develop what is known as empathy. Researchers in the field of emotion usually define it as the capacity of perceiving other individual's emotions and trying to think about what that person has in his/her mind or what he/she is feeling. In this way, we reduce prejudice, and we learn to put ourselves in the place of the other.