Teachers gave the selected children more attention because（）

A. they were not as clever as the other children
B. they were told to teach them in a different way
C. they expected them to learn faster
D. they did not want to challenge them

In this experiment, Robert Rosenthal and Lenore Jacobson studied the way that innocent subjects might be affected by another person’s expectations. First, they gave an intelce test to the entire student body at an unnamed primary school in the San Francisco area. Then, they selected students at random(随便) and told their teachers that the students’ tests had shown that they were about to experience a period of rapid learning. Teachers did not change their methods or materials for teaching the selected students, but, at the end of the year, when the test was administered (实施) again, first and second graders who had been selected had, in fact, gained twice as many IQ points as the other children. The experimenters concluded that they had performed better because they had been given more attention. Teachers had challenged them and had given them more positive reinforcement because they had expected more from them.