Psychology, Department of


Date of this Version



Published in MOTIVATIONAL FACTORS IN THE ETIOLOGY OF DRUG ABUSE: VOLUME 50 OF THE NEBRASKA SYMPOSIUM ON MOTIVATION, ed. Richard Dienstbier, Rick A. Bevins, and Michael T. Bardo. Lincoln, NE: University of Nebraska Press, 2004.


The aim of scientific explanation is to characterize the important antecedents of observable (or at least objectively confirmable) events. Explanations of behavior in terms of motivational states are appeals to unobservable, internal events for interpretations of behavior that is variable under apparently constant external stimulus conditions (see, e.g., Brown, 1953; Hinde, 1960). To be identified as the cause of a behavior, the unobservable event or condition must preexist the behavioral event to be explained. A behavior cannot be explained by its consequences, though it may be explained as a consequence of similar events in the animal's history. Scientific explanation involves the sequential identification of what comes first and what follows. To understand correctly what comes first and what follows is to achieve the primary goal of science.