solution

Effect of Confederates on Compliance (Example 7) A study was done to see whether participants would ignore a sign that read, “Elevator may stick between floors. Use the stairs.” The people who used the stairs were classified as compliant, those who used the elevator as noncompliant. The study was done in a university dorm on the ground floor of a building that had three floors. There were three different situations, two of which involved a person who was secretly working with the experimenter. (This person is called a confederate.) In the first situation, there was no other person using the stairs or elevator—that is, no confederate. In the second, there was a compliant confederate (one who used the stairs). In the third, there was a noncompliant confederate (one who used the elevator). Suppose that the participants (people who arrived to use the elevator at the time the experiment was going on) were randomly assigned to the three groups. There were significant differences between groups.

a. Can we generalize widely to a large group? Why or why not?

b. Can we infer causality? Why or why not?

(Source: Lary Shaffer and Matthew R. Merrens. 2001. Research stories for introductory psychology. Allyn and Bacon. Original Source: M. S. Wogalter, et al. 1987. Effectiveness of warnings. Human Factors 29, 599–612.)