What are the three types of prejudice?

"We are doing it at school. There are heaps!! There's Racism, Sexism, Ageism and prejudice based on wealth, disability, sexuality lifestyle etc.."

Although the above is informative, I believe the question has to do with the study done by Allport and Kramer.

If that is the case the three Levels of prejudice are cognitive, emotional and action orientation.

From:Psychology of race and ethnic relations; by Lisa Harrison and Hugh Villalta.