If a woman thinks that her husband will leave her for another woman, she will act in ways that will cause her belief to come true. She will get jealous easily and make a fuss about him being friends with other women. She will start fights whenever she suspects that he is cheating on her, or she might go through his personal things to look for evidence of cheating. Eventually, her actions will put a strain on their marriage, and her husband might leave her, causing her prediction to come true. To avoid this negative outcome she should have looked for a way to release her feelings in a healthy manner.
If a professor assumes that a certain student is not intelligent, the professor might give that student less positive attention and more negative attention, resulting in a poor performance by the student. A professor who thinks a student in his class is intelligent, may ask the student more challenging questions and praise the student more than the other students in the class. This can result in the student getting better grades than the other students in the class, but the professor has to avoid focusing too much on the student and pay attention to all the students to