Stereotypes
One of the most common causes of racism is stereotypes. Through television, through radio, through the internet, through music, through books, and the like, the potential for stereo types to build are a definite possibility. When a person, especially one that is very young, is exposed to stereotypes of a specific group for the first time, then that person will assume all are that way. Likewise, when a source is constantly displaying negative things about a particular race, then that will affect the overall opinions as well.
Unfamiliarity
Another very common, and probably the most common cause of racism is unfamiliarity. People fear what they do not know or understand. If someone hasn't grown up around a particular race before, then there is more of a chance the person can be racist toward that particular group. Not all the time, but when the person has already been fed negative stereotypes, and does not have the actual real life experiences with at least one within the particular group, then the chances of racism are increased. This is why it is important for children to be around other races at a young age: to ensure they get their minds used and adapted to being around them, and also to help counterbalance any false stereotypes they may encounter in the future.
Selfishness
Selfishness is another obvious cause of racism. Humans are sometimes very selfish creatures caring only about their own at the expense of others. If individuals aren't taught how to respect others, then the potential for the person to become racist is increased as well. This is why you will find that most caring individuals aren't racist. Neither are they sexist or anything else.
Include with selfishness that of economic strife. Rarely explored in USA racism is the idea that African Americans were an underclass to serve as slaves. The Civil War changed all that, but, the culture still lived. Some would say that hierarchy is still alive today. Sometimes, those Black Folks don't know there place.
Environmental Factors
The lastly and probably the most surprising cause of racism is environmental causes. We are all made different biologically and genetically. Our physical environment can affect our biology and therefore, in many cases, affect our minds. This does not mean freewill and choice are not options, but that an individual's potential for racism could possibly be increased through certain environmental factors unknown to man. By default, racism is nonexistent. However, things such as improper health maintenance, excess chemicals, head injuries, or other factors may help contribute to it. This should not be used as an excuse that racism has to persist, but more of a better chance to cure racism by enhancing biological health and medical technology, rather than thinking it can only be done by other means.
