I operate from the Helms model of oppression and prejudice, which identifies individuals as having many different aspects of social identity (groups we belong to). A person can experience discrimination / prejudice for any identity aspect in which they are a member of the non-dominant group in that aspect. Also, a person can be prejudiced against members of any non-dominant group, including their own.
The most common identity aspects that I examine in my teaching and research are those in Helms's ADDRESSING format. You can look at these aspects (below) and identify for yourself in which aspects you are a member of a dominant group or a subordinate group. Most people are surprised to see in how many aspects they are in a dominant group, because it's easier to notice when we are in a subordinate group.
___Developmental or acquired Disability
Okay. So, it turns out that prejudice seems to be somewhat of a unified construct. That is, if you are prejudiced against people who are in the subordinate group in one identity aspect, you are likely to be prejudiced against other subordinate groups as well. Altemeyer referred to people with high authoritarianism (another construct that is related to prejudice but not the same thing) as being "equal-opportunity bigots." I think this gets the point across.
So there's your background. Now here are some excerpts from my as-yet-undefended dissertation.
Prejudice-reduction measures during the college years have been examined particularly closely by prejudice researchers. Many researchers have found that exposure to diversity experiences (learning about other cultural groups, interactions with individuals from different social groups, etc.) appears to help reduce scores on various measures of prejudice. However, most studies failed to discern between voluntary diversity experiences and "structural" diversity experiences: those that are obligatory for academic or workplace situational reasons. For this reason, it was often unclear whether the kinds of diversity experiences encountered by students during college actually led to useful outcomes of prejudice reduction, or whether they simply showed who would in any case be further developing their pre-existing open-mindedness.
The present study investigated how obligatory, structural, diversity experiences during college might be related to aspects of prejudice-reduction in college students. It was implemented in hopes of finding that structural diversity experiences might help to reduce prejudice levels in individuals.
However, while there appeared to be somewhat of an effect on levels of ethnocentrism/racism, other subscales and overall prejudice did not seem to be affected by structural diversity experiences. Voluntary diversity experiences predicted both prejudice scores and authoritarianism scores, while structural diversity scores did not predict either. Rather, overall prejudice level appeared to influence the amount of voluntary contact individuals had with those in social groups other than their own.
The study also investigated whether psychological reactance appeared to play any part in modifying the relationship between diversity experiences and levels of prejudice and authoritarianism. The study furthermore investigated whether a number of other factors might also be related to prejudice and authoritarianism, such as general psychological pathology, time spent in college, level of education, and demographic characteristics. Certain demographic features predicted prejudice and authoritarianism scores, and psychological reactance was a predictor for authoritarianism scores, but it was not found to moderate the relationships between other variables.
Finally, participants' answers to open-ended questions about their experiences, attitudes, and behaviors were also examined. Themes present in handwritten short answers suggested that many participants were oblivious to their own prejudices and to their participation in a prejudiced social system.
Summary and Conclusion
The present study was implemented in hopes of finding that structural diversity experiences might help to reduce prejudice levels in individuals. However, while there appeared to be somewhat of an effect on levels of ethnocentrism/racism, other subscales and overall prejudice did not seem to be affected. Rather, overall prejudice level seemed to influence the amount of contact individuals had with those in social groups other than their own. Furthermore, themes present in handwritten short answers suggested that many participants were oblivious to their own prejudices and to their participation in a prejudiced social system. One conclusion is clear: prejudice against many groups is still quite in evidence among college students. This is clearly harmful for those occupying oppressed group status among their peers, as well as for those holding prejudices themselves, who appear to be largely ignorant of their complicity. If structural diversity experiences contribute to reduction of racial prejudice, then perhaps they can be examined and adapted for broader application in helping to reduce overall prejudice during this all-important window of developmental opportunity.
Here, additionally, is figure 1 from page 75, which graphically describes some of my findings from the qualitative portion of the study. I'm especially proud of this part.