Most people will admit that the relations between various ethnic and racial groups is a potential source of problems for a culturally diverse society such as the United States. Most rational people will also agree that prejudice plays an important role in the misunderstandings, intolerance, and even hostility that may develop and persist between such groups. If our objective is to minimize these problems, one necessary step is to address the issue of prejudice. Research has clearly established that prejudice exists and for a person expressing a prejudiced view may be unaware that it is in fact biased. An interesting experiment, which is often cited in educational textbooks, was conducted in 1973 to determine the potential effects of prejudice on the judgements of future school-teachers. The researcher made videotapes of three children speaking to an adult. The camera angle was ______ that the children's faces were not visible; however, it was obvious from the tape that the children were speaking and that they were racially different—one was white; one was African American; the third was Mexican American. A soundtrack containing exactly the same conversation in English with the same American voice was added to the tapes. Each tape was played to one of three groups of student teachers. Their task was to judge the correctness of the speech of the child they had seen on the videotape.