how did these sterotypes come about??

[DrPhil]

ProBlack, doing a keyword search for "colorism" on the search engine turns up pages of threads on this topic. Skim through those old threads because we're tired of discussing such matters.

It actually is sad that someone who just did a senior thesis can't figure out the answer to this question himself. Stereotypes exist because some people fit the stereotype and the stereotype represents some kind of ideal and ranking system. Apply that to all of your questions.