Why do I insist that it is right to judge a book by its cover?

What causes us to have this psychological tendency of judging people by their appearances? In fact, this is a psychological instinct of human beings, which we call the first cause effect in psychology. It means that people will leave a deep impression when they come into contact with something or someone for the first time. In the process of social cognition, the information that individuals first input through the "first impression" has an impact on their later cognition of the object. The first impression has the strongest effect and lasts for a long time, which is stronger than the information obtained later on the overall impression of things.