The answer to this question depends on the belief system of psychology that is being used to interpret it. In learning theory, such as that posed by Dollard and Miller, the answer to this question is that emotions, both positive and negative towards one ‘s own race, would be learned through reinforcement of social messages. Simply, if you grew up in an environment that positively reinforced pride and self respect of your race the response to that reinforcement would be a strong and healthy racial identity. On the other hand, if the experience of racial identity was based in negativity and self doubt, the profile would be the opposite. (Even XXXXX XXXXX the famous behaviorist stated that he could make a child feel and do anything as long as he had control over the reinforcements contained in the environment.)
Social psychologists feel that cognitive-dissonance may play a large part of negative racial evaluation, even self hatred of one’s own race. In this case, cognitive dissonance is created if self pride and worth of one’s race is thought, but the actions of prejudice and external influence force you to act differently. For example: You are proud of your heritage, but others who have power force you to act in a demeaning role because of your race. The two things, your positive thought and your demeaning conduct cause cognitive dissonance…thus causing you to alter your positive thought for a negative one.
Psychoanalysis also contributes a thought to discussion as well. A defense mechanism, reaction-formation, where you show the opposite of what you feel, may be involved. If you feel proud of your racial heritage, but feel that you should not through cultural messages contained by your Super-Ego, your reaction would be to show the opposite of what you felt; shame and embarrassment, instead of pride.
Another reason is a belief based on reaction formation. Those who perceive another race as suffering or otherwise repressed, may feel guilt based on being a person of the majority race or dominate race in the culture. They in turn become prejudiced against their own race in a effort to show that they are caring and sympathetic, when what really happens is that in an effort to deny their prejudice against the minority group, they emphasize it against their own race.
I hope this has helped you,