ABSTRACT
Psychological experiments are usually carried out as follows: when the subject is brought into the laboratory, he is carefully introduced to the task he is to perform. He receives a set of instructions, written or oral or both, and then a series of practice tasks and examples. The experimenter answers any questions he may raise about points he does not understand. Only after the subject has completed these steps and the experimenter is satisfied that the subject understands the task, does the actual “experiment” begin.
