The target paper by Barba (2012) raises issues that were the focus of the author's first two publications on operant variability. The author will describe the main findings in those papers and then discuss Barba's specific arguments. Barba has argued against the operant nature of variability. (Contains 2 figures.)

Some researchers claim that variability is an operant dimension of behavior. The present paper reviews the concept of operant behavior and emphasizes that differentiation is the behavioral process that demonstrates an operant relation. Differentiation is conceived as change in the overlap between two probability distributions: the distribution of…

Barba's (2012) article deftly weaves three main themes in one argument about operant variability. From general theoretical considerations on operant behavior (Catania, 1973), Barba derives methodological guidelines about response differentiation and applies them to the study of operant variability. In the process, he uncovers unnoticed features of…

The following article by Barba (2012a) addresses Neuringer's proposal that variability is an operant dimension of behavior, that is, that variability can be reinforced, extinguished, and brought under stimulus control, just like any other response property. Barba confines his argument to methodological considerations: He points out that the…

In his article, the author claimed that studies of operant variability that use a lag-"n" or threshold procedure and measure the obtained variability through the change in U value fail to provide direct evidence that variability is an operant dimension of behavior. To do so, he adopted Catania's (1973) concept of the operant, which takes the…

Barba's (2012) paper is a serious and thoughtful analysis of a vexing problem in behavior analysis: Just what should count as an operant class and how do people know? The slippery issue of a "generalized operant" or functional response class illustrates one aspect of this problem, and "variation" or "novelty" as an operant appears to fall into…

Serving as Rachlin's teaching assistant for his graduate course on animal learning in 1973 determined the direction of the author's career, which has been to build computer models and robots based mostly on the equations from that course and related ones. These artificial beings behave and learn very much like animals, and creating them forces a…

A series of experiments on operant variability by Neuringer and colleagues (e.g., Neuringer, 1986, 2002; Page & Neuringer, 1985) have been repeatedly cited as showing that behavioral variability can be reinforced by making reinforcement contingent on it. They showed that the degree of variability in pigeons' eight-peck sequences, as measured by U…

The experimental analysis of behavior (EAB) is in trouble. Financial support for basic operant-conditioning research is difficult to obtain; teaching and research positions in colleges and universities are few; and bright undergraduates join other fields for graduate study. One reason for the difficulty is that EAB basic research does not focus…

This paper describes and analyzes B. F. Skinner's coauthoring practices. After identifying his 35 coauthored publications and 27 coauthors, we analyze his coauthored works by their form (e.g., journal articles) and kind (e.g., empirical); identify the journals in which he published and their type (e.g., data-type); describe his overall and local…

Following from an earlier analysis by B. F. Skinner, the present article suggests that the verbal processes in science may usefully be viewed as following a three-stage progression. This progression starts with (a) identification of basic data, then moves to (b) description of relations among those data, and ultimately concludes with (c) the…

The topic of stimulus control is too broad and complex to be traceable here. It would probably take a two-semester course to cover just the highlights of that field's evolution. The more restricted topic of equivalence relations has itself become so broad that even an introductory summary requires more time than we have available. An examination…

Despite the central status of avoidance in explaining the etiology and maintenance of anxiety disorders, surprisingly little behavioral research has been conducted on human avoidance. In the present paper, first we provide a brief review of the empirical literature on avoidance. Next, we describe the implications of research on derived relational…

When neural events are analyzed as stimuli and responses, functional relations among them and among overt stimuli and responses can be unveiled. The integration of neuroscience and the experimental analysis of behavior is beginning to provide empirical evidence of involvement of neural events in the three-term contingency relating discriminative…

This article reviews evidence from basic and translational research with pigeons and humans suggesting that the persistence of operant behavior depends on the contingency between stimuli and reinforcers, and considers some implications for clinical interventions. (Contains 4 figures.)