David Morgan

Single-participant research design: Bringing science to managed care.

The ongoing transition to managed health care continues to have repercussions for health care providers, perhaps the most important of which is an emphasis on accountability for demonstrating the usefulness of clinical interventions. This requirement places a premium on intervention research and highlights the historically strained relationship between psychological research and professional practice. In the midst of this challenge, researchers have increasingly criticized the logic and practice of traditional null hypothesis significance testing. This article describes the history, epistemology, and advantages of single-participant research designs for behavioral scientists and professionals in clinical settings. Although its lack of correspondence with the Fisherian tradition has precluded widespread adoption, the single-participant alternative features a design power and flexibility well suited to both basic science and applied research.

Extinction-Induced Response Variability in Humans

Two experiments evaluated changes in response topography during extinction in human subjects. In Experiment 1, subjects fulfilled a sequence of DRL schedule parameters, responding on a computer keyboard to accumulate points on the monitor. Following the last DRL condition, an extinction condition was programmed during which points could no longer be accumulated. Response/reinforcer ratios increased consistently with each change in schedule parameter and interresponse time (IRT) distributions during extinction showed increased variability relative to preextinction baseline responding. In Experiment 2, subjects responded on a single DRL schedule value prior to being placed on extinction. Results paralleled those of Experiment 1, indicating greater response variability during extinction than during the DRL phase. The results are discussed within the context of a selectionist perspective on operant behavior, with extinction being identified as one ontogenic source of behavioral variability.

Variation and selection: The evolutionary analogy and the convergence of cognitive and behavioral psychology.

The empirical and theoretical work of both operant and cognitive researchers has increasingly appealed to evolutionary concepts. In particular, both traditional operant studies of extinction-induced behavior and cognitive investigations of creativity and problem solving converge on the fundamental evolutionary principles of variation and selection. These contemporary developments and their implications for the alleged preparadigmatic status of psychology are discussed.

SCHEDULES OF REINFORCEMENT AT 50: A RETROSPECTIVE APPRECIATION

Published just over a half century ago, Schedules of Reinforcement (Sor) (Fer- ster & Skinner, 1957) marked the seminal empirical contribution of the book’s second author and ushered in an era of research on behavior-environment relationships. This article traces the origins of both the methods and the data presented in Sor, and its legacy within experimental psychology. The operant methodology outlined in Sor revolutionized the study of behavior pharmacology and early investigations of choice behavior. More recently, schedules have been used to examine microeconomic behavior, gambling, memory, and contingency detection and causal reasoning in infants, children, and adults. Implications of schedules research for the psychology curriculum are also discussed.

Using Single-Case Design and Personalized Behavior Change Projects to Teach Research Methods:

Students in research methods courses, especially those taught in an intense format, might be hard pressed to actually conduct research studies due to logistics and time constraints. I describe the use of single-case research design and a personalized behavior project as an alternative research project for students in an undergraduate psychology methods course. Students were able to complete the project, including the collection, analysis, and interpretation of data, within the confines of an intensive, 6-week course.

SELECTIONIST THOUGHT AND METHODOLOGICAL ORTHODOXY IN PSYCHOLOGICAL SCIENCE

Selectionist theory in psychology conceptualizes behavior as a dynamic phenomenon subject to a variation and selection process similar to that characterizing biological evolution. Though not formally recognized as a dominant psychological metatheory, selectionist thought can be identified in the writings of many of the discipline’s eminent scholars. Although selectionism may possess considerable promise as a unifying theory, its widespread acceptance has likely been impeded by the large sample, null hypothesis testing research deSigns associated with the Fisherian tradition.