Roger T. Kelleher, rightly known as one of the foremost contributors to behavioral pharmacology, also made many important contributions to the experimental analysis of behavior. He participated significantly in the development of the discipline, through both his research and his editorial contributions to this journal. This article summarizes his…

Daily administration of cocaine often results in the development of tolerance to its effects on responding maintained by fixed-ratio schedules. Such effects have been observed to be greater when the ratio value is small, whereas less or no tolerance has been observed at large ratio values. Similar schedule-parameter-dependent tolerance, however,…

The article discusses two important influences of B. F. Skinner, and later workers in the behavior-analytic tradition, on the study of animal timing. The first influence is methodological, and is traced from the invention of schedules imposing temporal constraints or periodicities on animals in "The Behavior of Organisms," through the rate…

The goal of the present study was to explore the emergence of verbal behavior resulting from the joint control of two antecedent stimuli that are presented together for the first time. Conditional discriminations were used for teaching and for probing. Four stimuli PI, P2, 0 1 , and 02 were samples and four stimuli Al, A2, BI, and B2 were the…

Behavioral contrast can be defined as an inverse relationship between the conditions of reinforcement in one setting and the rate of responding in another setting. Behavioral contrast is a phenomenon that is reliably demonstrated in pigeons and rats and in the context of multiple experimental preparations with these animals. However, little…

The author argues that the field of behavior intervention has two subject matters that are distinct in several ways. Each is derived from, and contributes to, the foundation science and epistemology associated with behavior selection. The differences that the author wants to describe occurred to him as he sought to identify which of two Spanish…

When behavior suggests that the value of a reinforcer depends inversely on the value of the events that precede or follow it, the behavior has been described as a "contrast" effect. Three major forms of contrast have been studied: "incentive contrast," in which a downward (or upward) shift in the magnitude of reinforcement produces a relatively…

Mice from replicate lines, selectively bred based on high daily wheel-running rates, run more total revolutions and at higher average speeds than do mice from nonselected control lines. Based on this difference it was assumed that selected mice would find the opportunity to run in a wheel a more efficacious consequence. To assess this assumption…

Using verbal material, this study explored the effect of the temporal interval of feedback as it interacted with two other variables: (1) method of presenting learning material (inductive or deductive), and (2) activity of the learner during the delay interval (activity relevant or irrelevant to the material). The major objective was to compare…

Following Walter Nord (1969), the present article contains a predictive model of individual behavior based on both operant conditioning and management literatures. The behavior of an organizational member is seen as a function of the reinforcement contingencies applied by various groups in his environment and of his cognitive assessment of such…

Recent studies have demonstrated that external rewards can affect intrinsic motivation to perform an activity. Money tends to decrease intrinsic motivation, whereas positive verbal reinforcements tend to increase intrinsic motivation. This paper presents evidence that negative feedback and threats of punishment also decrease intrinsic motivation.…

The authors believe that the future of psychology lies in a unification of enhancement and reinforcement, not in the wasted energy of continued conflict. (Author)