Causes of Prejudice by: VINCENT N. PARRILLO. In this article Vincent N. Parrillo tries to locate the source of prejudice itself. He does this by looking at prejudice from a psychological and sociological stand point. He explains how prejudice can have many causes such as environments, influences, and personal beliefs. Parrillo goes in great detail in explaining not only the origin of prejudice but he gives examples of prejudice by looking at history. He also quotes other studies of prejudice to better understand and overall define what prejudice is. Also in this article Parrillo defines important vocabulary that is essential to understanding prejudice. Parrillo quotes famous psychologist and sociologists to support his own claims about prejudice. He explains the other theories of psychologists and sociologists. Overall Vincent N. Parrillo comes to the conclusion that prejudice cannot be defined because it has too many external contributors to give prejudice one definition. And that prejudice as has too many causes for psychologists and sociologists to understand. He believes that prejudice has no single factor and that it is to complex to understand. Parrillo concludes that prejudice is a phenomenon that is to complex to understand and points out how sociologists today are trying to confine prejudice into certain categories.