By the end of his long life, B. F. Skinner (1904-1990) had become one of the most influential and best known of psychologists (Gilgen, 1982; Heyduke & Fenigstein, 1984). An important feature of the approach to the study of behavior that he championed, behavior analysis, is the intensive study of individual subjects over time. This approach, which is characterized by the use of within-subject experimental designs, repeated and direct measures of behavior, and graphic analysis of data, stands in marked contrast to the research methods favored by many nonbehavioral psychologists. Skinner...