ABSTRACT
Since the time of Galileo, scientists have employed the laboratory experiment as a method of understanding natural phenomena. This chapter focuses on some of the qualities peculiar to psychological experiments. The experimental situation is one which takes place within the context of an explicit agreement of the subject to participate in a special form of social interaction known as "taking part in an experiment". The demand characteristics perceived in any particular experiment will vary with the sophistication, intelligence, and previous experience of each experimental subject. It becomes an empirical issue to study under what circumstances, in what kind of experimental contexts, and with what kind of subject populations, demand characteristics become significant in determining the behavior of subjects in experimental situations. The most obvious technique for determining what demand characteristics are perceived is the use of post-experimental inquiry. In this regard, it is well to point out that considerable self-discipline is necessary for the experimenter to obtain a valid inquiry.
