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Abstract We describe novel computer algorithms for rapid, sometimes virtually instantaneous generation of trial sequences needed to instrument many behavioral research procedures. Implemented on typical desktop or laptop computers, the algorithms impose constraints to forestall development of undesired stimulus control by position, recent trial outcomes, and other variables that could impede simple and conditional discrimination learning. They yield trial‐by‐trial lists of sequences that can serve (1) as inputs to procedure control software or (2) in generating templates for constructing sessions for implementation by hand or machine.

Abstract Four rats responded on concurrent variable‐interval schedules that delivered token stimuli (stimulus lights arranged vertically above each of two side levers). During exchange periods, each token could be exchanged for one food pellet by responding on a center lever, with one response required for each pellet delivery. In different conditions, the exchange requirements (number of tokens that had to be earned before they could be exchanged for food) varied between one and four for the two response levers. The experiments were closely patterned after research with pigeons by Mazur and Biondi ( ), and the results from the rats in the present experiment were similar. Response percentages on the two levers changed as each additional token was earned, and these patterns indicated that choice was controlled by both the time to the exchange periods and the number of food pellets that were delivered in the exchange period. In some conditions, the exchange requirement was three tokens for each lever, but the token lights were not turned on as they were earned for one of the two keys. The rats showed a slight preference for the lever without the token lights, which may indicate that the token lights were not serving as conditioned reinforcers (a result also found by Mazur and Biondi with pigeons). Overall, these results suggest that, in this choice procedure, the token stimuli served primarily as discriminative stimuli that signaled the temporal proximity and quantity of the primary reinforcer, food.

A half‐century of research in behavioral pharmacology leaves little doubt that behavior–environment contingencies can determine the behavioral effects of drugs. Unfortunately, a coherent behavior‐analytic framework within which to characterize the myriad ways in which contingencies interact with drugs, and to predict effects of a given drug under a given set of conditions, still has not developed. Some behavioral pharmacologists have suggested the concept of behavioral mechanisms of drug action as a foundation for such a framework. The notion of behavioral mechanisms, however, does not seem to have been fully embraced by behavioral pharmacologists. It is suggested here that one reason for this is that the concept itself has not been sufficiently clarified (i.e., stimulus control over use of the phrase is not sufficiently precise). Furthermore, early behavioral pharmacologists may not have possessed an adequate set of analytic tools to develop a viable framework based upon behavior mechanisms. In the first part of this paper, the notion of behavioral mechanisms of drug action is explored, and the sort of data that might provide evidence of a behavioral mechanism is considered. In the second part, it is suggested that the increased availability of quantitative models in behavior analysis may help provide the tools needed for elucidating behavioral mechanisms of drug action. Some examples of how these models have been, and could be used are provided.

The therapeutic workplace is an employment‐based abstinence reinforcement intervention for unemployed drug users where trainees receive on‐the‐job employment skills training in a classroom setting. The study is an extension of prior therapeutic workplace research, which suggested that trainees frequently violated noise standards. Participants received real‐time graphed feedback of noise levels and had the opportunity to earn monetary group reinforcement for maintaining a low number of noise violations. Results suggested that feedback and monetary reinforcement reduced the number of noise violations.

Although treatments for elopement (leaving an assigned area or a caregiver without permission) and dropping (falling to the floor) have been reported in the literature, there are no studies that have examined the concurrent treatment of these behaviors. The current investigation reports on the emergence and treatment of dropping during the treatment of elopement.

Abstract The present experiment investigated the effects of reinforcer magnitude on resistance to disruption of remembering and response rates. Pigeons were exposed to a variable‐interval (VI), delayed‐matching‐to‐sample (DMTS) procedure with two components (rich and lean, distinguished by differing discriminative stimuli and hopper presentation duration). Completion of a VI 20 s schedule resulted in DMTS trials. In a DMTS trial, a choice of one of two comparison stimuli resulted in food if the choice matched the color of the previously presented sample stimulus. Separable aspects of the forgetting functions (initial discrimination and rate of forgetting) were examined by determining accuracy across a range of delays. Response rates and accuracy were higher in the rich relative to the lean component during baseline, and were more persistent during disruptors (extinction and prefeeding). During DMTS trials, extinction decreased initial discrimination more in the lean than the rich component, but had no systematic effect on rate of forgetting. During prefeeding, the rate of forgetting increased more in the lean than the rich component, but initial discrimination was not systematically affected. These results show persistence of response rates and remembering are positively related to reinforcer magnitude. The type of disruptor also influences the way in which remembering is disrupted.

El estudio de las relaciones de similitud física (RSF) y las relaciones arbitrarias resulta de interés ya que permite evaluar la capacidad de formación y discriminación de nuevas relaciones entre estímulos cuando está disponible un criterio de respuesta potencialmente más arraigado, como el de similitud física. El propósito del presente estudio fue investigar los efectos de la competencia de respuesta entre las relaciones derivadas de relaciones (RDR) y las RSF. Se consideraron como indicadores de respuesta el número de respuestas por las RDR y los tiempos de respuesta. Participaron del estudio 158 sujetos adultos. Los resultados demostraron que, cuando los participantes formaron RDR consistentemente, la presencia de competencia no generó dificultad para seleccionar respuestas por RDR. Los participantes que respondieron inconsistentemente a las RDR, sí presentaron efectos de competencia en ambos indicadores de respuesta. Se pone de manifiesto la conveniencia de utilizar los tiempos de respuesta además de la cantidad de respuestas por la RDR, como una medida más fina del control de estímulos y de estudiar tanto el desempeño de los participantes que responden consistentemente a todas las relaciones derivadas como el de aquellos que sólo exhiben consistencia en el establecimiento de clases de equivalencia de estímulos. Debe atenderse tanto a las relaciones que son estrictamente arbitrarias, como también a las RSF en tanto se sabe que la tendencia a considerar estas relaciones estaría también en la base del formación del razonamiento analógico.

Clinical theories often appeal to general cognitive styles in explaining psychopathology, but without describing in detail how the patterns are formed. In the present investigation, two experiments were conducted to examine how individuals respond to ambiguous relational networks. In both experiments, the participants learned two 3‐stimulus networks (A1 LESS THAN B1, A1 GREATER THAN C1 and A2 GREATER THAN B2, C2 LESS THAN A2). Participants were presented with test trials to examine if they classified the combinatorial relations (B1 ↔ C1 and B2 ↔ C2) as SAME or DIFFERENT and as GREATER THAN or LESS THAN. Although the B–C combinatorial relation in Network 1 is derivable in a readily coherent way (B1 GREATER THAN C1 and thus also B1 DIFFERENT C1), in Network 2 the combinatorial relation is ambiguous. When participants were required to specify the Network 2 B–C relation as either SAME or DIFFERENT, those who chose DIFFERENT, also consistently chose B2 as either GREATER THAN or LESS THAN C2. Conversely, those who classified the B–C relation as SAME were inconsistent within themselves in choosing B2 as GREATER THAN or LESS THAN C2. In Experiment 2, nonarbitrary multiple exemplar pretraining was used to bias SAME versus DIFFERENT as a response for ambiguous combinatorial relations. In accord with the pattern seen in Experiment 1, those biased toward DIFFERENT consistently chose a comparative relation between B2 and C2 while those biased toward SAME were inconsistent in their comparative choices. The findings provide support for the importance of history and coherence in establishing patterns of responding to ambiguous relational networks, providing a beginning behavioral model of cognitive styles and errors.

Responding by exclusion is to select a correct alternative by rejecting other potential alternatives. Studies describe this ability in some mammals and birds. However, this type of performance has not been reported in rodents. The aim of this study was to verify the occurrence of responding by exclusion in Wistar rats after a baseline of simple simultaneous visual discrimination. Six male Wistar learned nose‐poking tunnels displaying visual stimuli (projected geometric shapes) in an operant chamber. After establishing the simultaneous discrimination baseline, three probe sessions were conducted. In each session, there was a novelty‐control probe (a new stimulus was presented together with a stimulus trained as the S + ) and an exclusion probe (a second new stimulus was presented simultaneously with a stimulus trained as the S ‐ ). Only one rat responded to the new stimulus in one of the three novelty probe trials. Four rats responded to the three new stimuli and one responded to the new stimulus in two of the three exclusion probes. One subject responded to the S ‐ in all the exclusion probes. Five of the six subjects were therefore able to choose the new stimulus, rejecting stimuli trained as the S ‐ . This is the first experimental evidence for performance by exclusion in rats.

Responding by exclusion, one of the most robust phenomena in Experimental Psychology, describes a particular form of responding observed in symbolic, matching‐to‐sample tasks. Given two comparison stimuli, one experimentally defined and one experimentally undefined, the participant prefers the undefined comparison following an undefined sample. The goal of the present study was to determine whether responding by exclusion could be obtained using samples that varied along a single dimension. Using a double temporal bisection task, 10 university students learned to choose visual comparisons (colored circles) based on the duration of a tone. In tests of exclusion, sample stimuli with new durations were followed by comparison sets that included one previously trained, defined comparison (colored circle) and one previously untrained, undefined comparison (geometric shape). Participants preferred the defined comparisons following the defined samples and the undefined comparisons following the undefined samples, the choice pattern typical of responding by exclusion. The use of samples varying along a single dimension allows us to study the interaction between stimulus generalization gradients and exclusion in the control of conditional responding.