Dr. Winstell is interested in studying prejudice, and devises a study in which Caucasian participants are led to believe that they are chatting electronically with an African-American participant. In reality, the participants are responding to another Caucasian participant, and she discloses this information to all participants at the end of the study. Dr. Winstell has used in her study.

Dr. Winstell has used parody participant in her study.

Explanation:

Dr. Winstell is very much aware that, for her study to be successful, she needs to be able to create the impression that what the participants was told is what is actually being done.

This is the reason why he adopted the parody (fake) participants inorder to create the impression that, the participants in the experiment are actually chatting with the African-American as they were initally told.