The Psychological Record, 1988,38, 157-174 THE LOGIC OF RESEARCH AND THE SCIENTIFIC STATUS OF THE LAW OF EFFECT WILLlAM O'DONOHUE University of Maine and Indiana University and LEONARD KRASNER Stanford University and State University of New York at Stony Brook The scientific status of the law of effect and applied research that involves the law of effect are examined through a falsificationist analysis of the logic of research and the demarcation question, that is, what should be regarded as scientific. Some logical and epis- temological problems of a nonfalsificationist, inductivist conceptuali- zation of science are reviewed. A falsificationist demarcation criter- ion is discussed as an alternative that is free of such logical and philosophical difficulties. A brief review of the history of the law of effect and criticisms of the law of effect is presented. It is concluded that the law of effect is in principle falsifiable and, hence, it is scientific. However, questions are raised regarding the extent to which the law of effect actually has been tested, given the Duhem- Quine thesis and problems with independent and valid means of identifying reinforcers. Minimally, practical questions are raised re- garding what the law of effect is and how it is to be tested. Research is, in part, a logical process. Experience, requisitely struc- tured, is obtained so that more can be known regarding the truth value of certain related beliefs, for example, scientific laws, hypotheses, and theories. This paper examines the relationship of beliefs involved in re- search-the logic of research. This issue is controversial and at the core of 20th century philosophy of science. This paper presents a falsificationist viewpoint-that a proper test of a scientific belief at least must in principle allow for the possibility of negative as well as positive evidence regarding the belief. This paper then examines applied research involving the law of effect (LOE) from this falsificationist point of view and questions the evidentiary value of this research for the LOE. Philosophers of science have seen the issue of the logic of research as providing the very definition of science (e.g., Popper, 1963). And of course, psychologists usually have claimed that psychology-or at least their favored approach to psychology-is scientific. Such diverse psychologists as Wundt, Watson, Koffka, Freud, and Skinner all claimed scientific status for their psychology: We thank Nino Cocchiarella, James Dinsmoor, Jane Fisher, Yu Houng Houng, Arthur Houts, Noretta Koertge, and Thomas Oltmanns for their helpful comments on an earlier draft of this paper. Reprint requests should be sent to William O'Oonohue, Department of Psychol- ogy, University of Maine, Orono, ME 04469.