bluuebunny/crossref_metadata_2025 huggingface dataset:
THE VALUE OF EVERYDAY EXAMPLES IN THE TEACHING OF LEARNING: A COMMENT PROMPTED BY MACHADO AND SILVA (1998)
Authors: Baldwin John D. , Baldwin Janice I.
Published: March 2006

Why are so few psychology students and professors interested in the study of learning? Part of the answer lies in the techniques we use for teaching behavioral psychology and communicating its relevance to numerous aspects of life. We add to this journal's discussion of the teaching of learning by explaining the importance of using examples drawn from everyday life: Numerous familiar examples provide powerful pedagogical tools for showing the importance of learning theory and helping students learn behavior principles. This approach does not exclude using other strategies and techniques in our quest to communicate the value of learning theory and teach our behavioral science in meaningful and thought‐provoking ways.
SIMILAR CONSUMPTION AND RESPONDING ACROSS SINGLE AND MULTIPLE SOURCES OF DRUG
Authors: Bickel Warren K. , Madden Gregory J.
Published: March 2006

Two experiments were conducted to assess whether total response output and total consumption would be similar when drugs are available from single and multiple sources of reinforcement, as predicted by behavioral economics. In Experiment 1, cigarette‐deprived smokers were exposed to a concurrent‐chains schedule in which equal fixed‐ratio schedules served as the initial links, and different reinforcer magnitudes (i.e., number of cigarette puffs) were arranged across alternatives. After the session, obtained unit price was calculated and imposed in the next session when a different number of puffs was available according to a single fixed‐ratio schedule. Thus, the unit price at which cigarette puffs could be earned was yoked within subjects across the single and concurrent‐chains schedules. When plotted as a function of unit price, similar consumption and response rates were usually obtained across these schedules. Experiment 2 addressed a weakness of Experiment 1, namely, that responding was allocated exclusively to the larger reinforcer magnitude in concurrent‐chains conditions, and therefore this schedule may have functioned as a single schedule. In Experiment 2, subjects were instructed to alternate responding between the two alternative schedules. Instructions produced approximately equal response allocation between the two alternatives. Again, similar consumption and response rates were observed across the single and instructed concurrent‐chains schedules. These findings are discussed in the context of direct effects and behavioral economics perspectives of drug self‐administration.
THORNDIKE'S LEGACY: LEARNING, SELECTION, AND THE LAW OF EFFECT
Authors: Catania A. Charles
Published: March 2006

This introduction to a symposium on the centennial of Edward L. Thorndike's 1898 monograph on animal intelligence briefly considers the origins of his law of effect and the influence of Darwin's selectionism. It also provides the background for an unfinished book review by William W. Cumming of a biography of Thorndike. The review places in historical context Thorndike's position both on psychology as a science of behavior and on the vocabulary of that science.
PAVLOV AND SKINNER: TWO LIVES IN SCIENCE (AN INTRODUCTION TO B. F. SKINNER'S “SOME RESPONSES TO THE STIMULUS ‘PAVLOV’”)
Authors: Catania A. Charles , Laties Victor G.
Published: March 2006

The sesquicentennial of Ivan Petrovich Pavlov's birth in September 1999 is being celebrated in Russia by a special issue of the Russian Journal of Physiology (the former I. M. Sechenov Physiological Journal, founded by Pavlov in 1917). The following article and the address by Skinner that it introduces are scheduled to appear in Russian translation in that special issue. Skinner's “Some Responses to the Stimulus ‘Pavlov’” was his presidential address to the Pavlovian Society of North America in 1966. The following article provides the context for Skinner's address by describing some ways in which Pavlov's research influenced Skinner's contributions.
SUPPORT FOR A THEORY OF MEMORY FOR EVENT DURATION MUST DISTINGUISH BETWEEN TEST‐TRIAL AMBIGUITY AND ACTUAL MEMORY LOSS
Authors: Zentall Thomas R.
Published: March 2006

Staddon and Higa's (1999) trace‐strength theory of timing and memory for event duration can account for pigeons' bias to “choose short” when retention intervals are introduced and to “choose long” when, following training with a fixed retention interval, retention intervals are shortened. However, it does not account for the failure of pigeons to choose short when the intertrial interval is distinct from the retention interval. That finding suggests that stimulus generalization (or ambiguity) between the intertrial interval and the retention interval may result in an effect that has been attributed to memory loss. Such artifacts must be eliminated before a theory of memory for event duration can be adequately tested.
THE CHOOSE‐SHORT EFFECT AND TRACE MODELS OF TIMING
Authors: Staddon J. E. R. , Higa Jennifer J.
Published: March 2006

The tuned‐trace multiple‐time‐scale (MTS) theory of timing can account both for the puzzling choose‐short effect in time‐discrimination experiments and for the complementary choose‐long effect. But it cannot easily explain why the choose‐short effect seems to disappear when the intertrial and recall intervals are signaled by different stimuli. Do differential stimuli actually abolish the effect, or merely improve memory? If the latter, there are ways in which an expanded MTS theory might explain differential‐context effects in terms of reduced interference. If the former, there are observational and experimental ways to determine whether differential context favors prospective encoding or some other nontemporal discrimination.
CLASS‐CONSISTENT DIFFERENTIAL REINFORCEMENT AND STIMULUS CLASS FORMATION IN PIGEONS
Authors: Meehan Edward F.
Published: March 2006

Match‐to‐sample training clusters of A1 (sample): B1/B2 (comparisons), A2: B2/B1, B1: A1/A2, B2: A2/A1, B1: C1/C2, B2: C2/C1, C1: B1/B2, and C2: B2/B1 were presented to pigeons with class‐consistent differential reinforcement using two dissimilar types of food reinforcers. Distinctive class‐consistent response patterns occurred to the samples during the fixed‐ratio 5 sample observing response requirement. Subsequent tests, modeled from the equivalence class paradigm demonstrated the emergence (80% class consistent) of the transitive‐like A‐C and C‐A relations for 4 and 2 of 12 pigeons, respectively, and a strong trend (over 70%) for 7 and 6 others, respectively; the emergence of the reflexive‐like identity relation when the nonidentical comparison was from the other class; and the disruption of the trained within‐class relation with the addition of a reflexive comparison. After directional training of C1: D1/D2 and C2: D2/D1, tests indicated no emergence of the symmetric‐like D‐C relation or the composite D‐B and D‐A relations, but the B‐D and A‐D transitive‐like relation occurred with some pigeons. Off‐baseline training with class‐consistent differential reinforcement contingent on responding to the D stimuli alone produced distinctive responding and, in turn, a trend to D‐C symmetric‐like control in 4 of 12 pigeons, as well as a shift toward class‐consistent control on D‐B and D‐A test trials. Class‐consistent differential reinforcement that produced distinctive sample behavior promoted stimulus control relations like those that circumscribe equivalence class formation. Respondent—operant interactions permit an analysis of the possible enrollment of stimulus values of distinctive responding to the discriminative stimuli forming the stimulus classes via processes corresponding to naming in humans.
USE OF NUMBER BY CROWS: INVESTIGATION BY MATCHING AND ODDITY LEARNING
Authors: Smirnova A. A. , Lazareva O. F. , Zorina Z. A.
Published: March 2006

Hooded crows were trained in two‐alternative simultaneous matching and oddity tasks with stimulus sets of three different categories: color (black and white), shape (Arabic Numerals 1 and 2, which were used as visual shapes only), and number of elements (arrays of one and two items). These three sets were used for training successively and repeatedly; the stimulus set was changed to the next one after the criterion (80% correct or better over 30 consecutive trials) was reached with the previous one. Training was continued until the criterion could be reached within the first 30 to 50 trials for each of the three training sets. During partial transfer tests, familiar stimuli (numerals and arrays in the range from 1 to 2) were paired with novel ones (numerals and arrays in the range from 3 to 4). At the final stage of testing only novel stimuli were presented (numerals and arrays in the range from 5 to 8). Four of 6 birds were able to transfer in these tests, and their performance was significantly above chance. Moreover, performance of the birds on the array stimuli did not differ from their performance on the color or shape stimuli. They were capable of recognizing the number of elements in arrays and comparing the stimuli by this attribute. It was concluded that crows were able to apply the matching (or oddity) concept to stimuli of numerical category.
ACQUISITION OF ARBITRARY CONDITIONAL DISCRIMINATIONS BY YOUNG NORMALLY DEVELOPING CHILDREN
Authors: Pilgrim Carol , Jackson Jan , Galizio Mark
Published: March 2006

Three experiments investigated conditions designed to facilitate acquisition of arbitrary conditional discriminations in 3‐ to 6‐year‐old normally developing children. In Experiment 1, 6 subjects failed to master the arbitrary match‐to‐sample task under conditions of differential reinforcement alone, but 7 subjects did so when instructions or instructions and sample naming were added. In Experiment 2, sample naming introduced in a blocked‐trial arrangement resulted in acquisition, but only when the sample name was a nonsense syllable provided by the experimenter (5 of 7 subjects) and not when the sample name was generated by the subject (0 of 5 subjects). Experiment 3 demonstrated the effectiveness of a training sequence involving thematically related stimuli as an intermediate step facilitating the transition from identity to novel arbitrary relations. The difficulties in mastering arbitrary conditional discriminations shown here imply that further analyses with young children will be particularly important in efforts to investigate the development of theoretically important stimulus relations.
THE SPATIAL DISTRIBUTION OF BEHAVIOR UNDER VARYING FREQUENCIES OF TEMPORALLY SCHEDULED WATER DELIVERY
Authors: Ribes‐Iñesta Emilio , Torres Carlos
Published: March 2006

Two studies evaluated the effects of response‐independent water deliveries on the location (on the floor of the experimental chamber) and position (height) of rats' behavior. In both experiments, fixed‐time schedules delivered water in two dispensers that were located at opposite ends of the chamber. In Experiment 1, the two schedules provided complementary frequencies of water deliveries while the overall number of deliveries stayed constant. In Experiment 2, one of the schedules delivered water twice as frequently as the other; this proportion was kept constant while the overall density of water deliveries changed systematically. In both experiments, a single position (height) of behavior was dominant. Also, the percentage of time allocated to each dispenser was roughly proportional to the percentage of water deliveries associated with the dispensers. These data and additional considerations support the importance of examining the spatial properties and patterning of behavior.
EFFECTS OF COMPOUNDING DRUG‐RELATED STIMULI: ESCALATION OF HEROIN SELF‐ADMINISTRATION
Authors: Panlilio Leigh V. , Weiss Stanley J. , Schindler Charles W.
Published: March 2006

Previous experiments have demonstrated that presenting independently established discriminative stimuli in compound can substantially increase operant responding maintained by food reinforcement or shock avoidance. Recently, this phenomenon was also shown to occur with cocaine self‐administration. The present study further assessed the generality of these stimulus‐compounding effects by systematically replicating them with heroin self‐administration. Rats' nose‐poke responses produced intravenous heroin (0.025 mg/kg per infusion) on a variable‐ratio schedule when either a tone or a light was present. In the absence of these stimuli, responding was not reinforced. Once discriminative control by the tone and light had been established, the stimuli were presented in compound under extinction (with heroin discontinued) or maintenance conditions (with heroin available during test‐stimulus presentations). In extinction, the tone—light compound increased responding approximately threefold compared to tone or light alone. Under maintenance conditions, compounding increased heroin intake approximately twofold. These effects closely matched those obtained earlier with cocaine. This consistency across pharmacological classes and across drug and nondrug reinforcers further confirms that (a) self‐administered drugs support conditioning and learning in a manner similar to that supported by other reinforcers; and (b) multiple drug‐related cues interact in lawful and predictable ways to affect drug seeking and consumption.
VARYING WHEEL‐RUNNING REINFORCER DURATION WITHIN A SESSION: EFFECT ON THE REVOLUTION—POSTREINFORCEMENT PAUSE RELATION
Authors: Belke Terry W.
Published: March 2006

Previous investigations of wheel‐running reinforcement that manipulated reinforcer duration across conditions showed a strong relation between wheel‐running rate and average postreinforcement pause (PRP) duration. To determine if the basis of this relation across conditions was a local effect of fatigue or satiation, the correlation between revolutions run and the duration of the immediately following PRP was investigated under conditions in which reinforcer duration was either constant or variable within a session. Seven male Wistar rats pressed a lever on a fixed‐interval 60‐s reinforcement schedule with the opportunity to run for 60 s as the reinforcing consequence. In the constant‐duration condition, the duration of the reinforcer was always 60 s. In the variable‐duration condition, the duration of the reinforcer varied between 2 and 240 s with a mean of 60 s. Mean correlations between revolutions run and the next PRP duration for constant, variable, and constant conditions were –.07, .20, and –.07, respectively. Although the positive correlation in the variable‐duration condition is consistent with an effect of momentary fatigue or satiation, little of the variance in PRP duration appears to be attributable to these factors.
FALSIFICATION OF MATCHING THEORY'S ACCOUNT OF SINGLE‐ALTERNATIVE RESPONDING: HERRNSTEIN'S K VARIES WITH SUCROSE CONCENTRATION
Authors: Dallery Jesse , McDowell J. J. , Lancaster Juliana S.
Published: March 2006

Eight rats pressed levers for varying concentrations of sucrose in water under eight variable‐interval schedules that specified a wide range of reinforcement rate. Herrnstein's (1970) hyperbolic equation described the relation between reinforcement and responding well. Although the y asymptote, k, of the hyperbola appeared roughly constant over conditions that approximated conditions used by Heyman and Monaghan (1994), k varied when lower concentration solutions were included. Advances in matching theory that reflect asymmetries between response alternatives and insensitive responding were incorporated into Herrnstein's equation. After fitting the modified equation to the data, Herrnstein's k also increased. The results suggest that variation in k can be detected under a sufficiently wide range of reinforcer magnitudes, and they also suggest that matching theory's account of response strength is false. The results support qualitative predictions made by linear system theory.
REINFORCER CONTROL AND HUMAN SIGNAL‐DETECTION PERFORMANCE
Authors: Johnstone Victoria , Alsop Brent
Published: March 2006

Eight humans participated in a two‐choice signal‐detection task in which stimulus disparity was varied over four levels. Two procedures arranged asymmetrical numbers of reinforcers received for correct left‐ and right‐key responses (the reinforcer ratio). The controlled procedure ensured that the obtained reinforcer ratio remained constant over changes in stimulus disparity, irrespective of subjects' performances. In the uncontrolled procedure, the asymmetrical reinforcer ratio could covary with subjects' performances. The receiver operating charateristic (ROC) patterns obtained from the controlled procedure approximated isobias functions predicted by criterion location measures of bias. The uncontrolled procedure produced variable ROC patterns that were somewhat like the isobias predictions made by likelihood ratio measures of bias; however, the obtained reinforcer ratio became more extreme as discriminability decreased. The obtained pattern of bias was directly related to the obtained reinforcer ratio. This research indicates that criterion location measures seem to be preferable indices of response bias.
PROGRESSIVE‐RATIO SCHEDULES: EFFECTS OF LATER SCHEDULE REQUIREMENTS ON EARLIER PERFORMANCES
Authors: Baron Alan , Derenne Adam
Published: March 2006

Four rats were studied with variants of a progressive‐ratio schedule with a step size of 6 in which different terminal components followed completion of the 20th ratio: (a) a reversal of the progression, (b) a fixed‐ratio 6 schedule, or (c) extinction. Responding in the progressive‐ratio components of these schedules was compared to performances under conventional progressive‐ratio baselines. Under baseline conditions, postreinforcement pauses increased exponentially as a function of increasing ratio size, whereas running rates showed modest declines. The procedure of linking the progressive‐ratio schedule to the reversed progression or to the fixed‐ratio component resulted in decreased pausing. Linking the progressive‐ratio schedule to the extinction component had the opposite effect, that of producing weakened progressive‐ratio performances as evidenced by increased pausing. Subjects whose responses were reinforced on half of the ratios also showed exponential increases; however, pauses were substantially shorter following ratios on which the reinforcer was omitted. The results suggested that progressive‐ratio pausing reflects the influence of remote as well as local contingencies.
CHOICE IN A VARIABLE ENVIRONMENT: EVERY REINFORCER COUNTS
Authors: Davison Michael , Baum William M.
Published: March 2006

Six pigeons were trained in sessions composed of seven components, each arranged with a different concurrent‐schedule reinforcer ratio. These components occurred in an irregular order with equal frequency, separated by 10‐s blackouts. No signals differentiated the different reinforcer ratios. Conditions lasted 50 sessions, and data were collected from the last 35 sessions. In Part 1, the arranged overall reinforcer rate was 2.22 reinforcers per minute. Over conditions, number of reinforcers per component was varied from 4 to 12. In Part 2, the overall reinforcer rate was six per minute, with both 4 and 12 reinforcers per component. Within components, log response‐allocation ratios adjusted rapidly as more reinforcers were delivered in the component, and the slope of the choice relation (sensitivity) leveled off at moderately high levels after only about eight reinforcers. When the carryover from previous components was taken into account, the number of reinforcers in the components appeared to have no systematic effect on the speed at which behavior changed after a component started. Consequently, sensitivity values at each reinforcer delivery were superimposable. However, adjustment to changing reinforcer ratios was faster, and reached greater sensitivity values, when overall reinforcer rate was higher. Within a component, each successive reinforcer from the same alternative (“confirming”) had a smaller effect than the one before, but single reinforcers from the other alternative (“disconfirming”) always had a large effect. Choice in the prior component carried over into the next component, and its effects could be discerned even after five or six reinforcers into the next component. A local model of performance change as a function of both reinforcement and nonreinforcement is suggested.
EQUIVALENCE RELATIONS AND THE REINFORCEMENT CONTINGENCY
Authors: Sidman Murray
Published: March 2006

Where do equivalence relations come from? One possible answer is that they arise directly from the reinforcement contingency. That is to say, a reinforcement contingency produces two types of outcome: (a) 2‐, 3‐, 4‐, 5‐, or n‐term units of analysis that are known, respectively, as operant reinforcement, simple discrimination, conditional discrimination, second‐order conditional discrimination, and so on; and (b) equivalence relations that consist of ordered pairs of all positive elements that participate in the contingency. This conception of the origin of equivalence relations leads to a number of new and verifiable ways of conceptualizing equivalence relations and, more generally, the stimulus control of operant behavior. The theory is also capable of experimental disproof.
SYNTHESIZING CONCURRENT INTERVAL PERFORMANCES
Authors: MacDonall James S.
Published: March 2006

Concurrent schedules may be viewed as consisting of two pairs of stay and switch schedules, each pair associated with one of the alternatives. A stay schedule arranges reinforcers for staying and responding at one alternative, whereas the associated switch schedule arranges reinforcers for switching to the other alternative. In standard concurrent schedules, the stay schedule at each alternative is equivalent to the switch schedule at the other alternative. MacDonall (1999) exposed rats to one pair of stay and switch variable‐ratio schedules and varied the response requirements across conditions. Combining results from symmetric pairs produced composite performances that were described by the generalized matching law. This outcome was noteworthy because the data were obtained from performances at two alternatives with contingencies that were functionally unrelated to each other. This result suggests that concurrent performances may consist of two unrelated performances that alternate as behavior moves between alternatives. The purpose of the present experiment was to extend those results to interval schedules. Rats were exposed to pairs of random‐interval schedules, and across conditions their mean intervals were varied. When data from appropriately paired conditions were combined, the composite performances were consistent with the generalized matching law. In addition, the results supported two models of concurrent performances that were based on local variables at an alternative (behavior, and stay and switch reinforcers): a modified version of the contingency discrimination model (Davison & Jenkins, 1985) and the local model (MacDonall, 1999).
INTERACTION OF PROCEDURAL FACTORS IN HUMAN PERFORMANCE ON YOKED SCHEDULES
Authors: Raia Christopher P. , Shillingford Stephen W. , Miller Harold L. , Baier Phillip S.
Published: March 2006

The differential effects of reinforcement contingencies and contextual variables on human performance were investigated in two experiments. In Experiment 1, adult human subjects operated a joystick in a video game in which the destruction of targets was arranged according to a yoked variable‐ratio variable‐interval schedule of reinforcement. Three variables were examined across 12 conditions: verbal instructions, shaping, and the use of a consummatory response following reinforcement (i.e., depositing a coin into a bank). Behavior was most responsive to the reinforcement contingencies when the consummatory response was available, responding was established by shaping, and subjects received minimal verbal instructions about their task. The responsiveness of variable‐interval subjects' behavior varied more than that of variable‐ratio subjects when these contextual factors were altered. Experiment 2 examined resistance to instructional control under the same yoked‐schedules design. Conditions varied in terms of the validity of instructions. Performance on variable‐ratio schedules was more resistant to instructional control than that on variable‐interval schedules.
DRUG DISCRIMINATION: STIMULUS CONTROL DURING REPEATED TESTING IN EXTINCTION
Authors: Zarcone Troy J. , Ator Nancy A.
Published: March 2006

Rats were trained, under a two‐lever drug‐discrimination procedure, to respond differentially depending upon whether lorazepam (1.0 mg/kg) or no injection had been administered before the session. Responses on the appropriate lever produced a food pellet under a modified fixed‐ratio (FR) 10 schedule, in which the 10 responses had to be emitted consecutively. In reinforcement tests, completing an FR 10 on either lever produced a pellet. In extinction tests, stimulus changes paired with reinforcement occurred but no pellet was delivered. Training sessions were conducted between test sessions. Each of four extinction phases consisted of six tests preceded by one stimulus (e.g., lorazepam). Repeated exposures to extinction reduced response rates for all rats, but stimulus control, as inferred from either percentage of total responses or percentage of total FR 10s on the drug‐appropriate lever, remained high. The percentage of total FR 10s measure was less subject to skewing under low‐rate conditions than was the percentage of total responses measure and provided an evaluation of stimulus control in terms of meeting the consecutive response contingency. These results demonstrate a level of independence between response rate and stimulus control in drug discrimination, which has positive implications for the validity of interpreting discriminative effects of novel test conditions in well‐trained animals, even when overall response rates are low.
EFFECT OF DRUGS ON RESPONSE‐DURATION DIFFERENTIATION VII: RESPONSE‐FORCE REQUIREMENTS
Authors: McClure G. Y. H. , Hardwick W. C. , McMillan D. E.
Published: March 2006

Rats were trained to press a lever for at least 1 s but for less than 1.3 s. The force required to press the lever was then increased or decreased by 10, 15, or 20 g. Increases in the force requirements for lever pressing decreased timing accuracy, but decreases in the force requirement had the opposite effect. Accuracy decreases at increasing force requirements were characterized by an increase in the relative frequency of responses that were too short to meet the reinforcement criterion. In contrast, increases in accuracy when the force requirements were decreased were characterized by increases in response durations that met the reinforcement criterion and decreases in the relative frequency of responses that were too short to produce the reinforcer. Phencyclidine (PCP) and methamphetamine produced dose‐dependent decreases in accuracy that were associated primarily with increases in the relative frequency of short response durations, although methamphetamine also produced increases in long response durations at some doses. When the effects of PCP were determined with the force requirement increased by 10 g or decreased by 15 g, the cumulative response‐duration distribution shifted toward even shorter response durations. When the effects of methamphetamine were determined with the force requirement on the lever increased by 10 g, the cumulative frequency distribution was shifted toward shorter response durations to about the same extent as it had been before force requirements increased; however, when the force required to press the lever was decreased by 15 g, these shifts toward shorter response durations almost completely disappeared. These results show that increases and decreases in the force requirements for lever pressing have different effects on the accuracy of temporal response differentiation.
EXPERIMENTAL ANALYSIS OF HUMAN VOCAL BEHAVIOR: APPLICATIONS OF SPEECH‐RECOGNITION TECHNOLOGY
Authors: Wirth Oliver , Chase Philip N. , Munson Kevin J.
Published: March 2006

Recent developments in speech recognition make it feasible to apply the technology to study vocal behavior. The present study illustrates the use of this technology to establish functional stimulus classes. Eight students were taught to say nonsense words in the presence of arbitrarily assigned sets of symbols consistent with three three‐member experimenter‐defined stimulus classes. Computer‐controlled speech‐recognition software was used to record, analyze, and differentially reinforce vocal responses. When the stimulus classes were established, students were taught to say a new nonsense word in the presence of one member of each stimulus class. Transfer of function was tested subsequently to determine if the novel stimulus names transferred to the remaining stimulus class members. Most subjects required two iterations of the training and testing procedures before transfer occurred. The data illustrate the usefulness of recording vocal behavior during stimulus control procedures and demonstrate the use of speech‐recognition technology. The paper also describes the current state of speech‐recognition technology and suggests several other areas of research that might benefit from using vocal behavior as its primary datum.
GENERALIZATION OF DELAYED MATCHING TO SAMPLE FOLLOWING TRAINING AT DIFFERENT DELAYS
Authors: Sargisson Rebecca J. , White K. Geoffrey
Published: March 2006

Four groups of pigeons were trained to perform a delayed matching‐to‐sample task with a single delay of 0, 2, 4, or 6 s from the outset of training. The longer the training delay, the more sessions were required for all birds to reach the same level of response accuracy. Following initial training, five test sessions that included nonreinforced trials with delay intervals of 0, 2, 4, 6, 8, and 10 s were interspersed between training sessions. Unlike typical forgetting functions in which accuracy decreases monotonically with increasing delay, the forgetting functions from test sessions resembled generalization gradients with the peak of the functions occurring at the training delay. Following additional training for all birds with a 0‐s delay, forgetting functions decreased monotonically with increasing delay. The results suggested that remembering can be trained at a specific delay interval, and generalizes to similar delay intervals. Generalization along the temporal dimension of delay may contribute to typical forgetting functions in which accuracy decreases from 0‐s delay.
THE PRINCIPAL COMPONENTS OF RESPONSE STRENGTH
Authors: Killeen Peter R. , Hall Scott S.
Published: March 2006

As Skinner (1938) described it, response strength is the “state of the reflex with respect to all its static properties” (p. 15), which include response rate, latency, probability, and persistence. The relations of those measures to one another was analyzed by probabilistically reinforcing, satiating, and extinguishing pigeons' key pecking in a trials paradigm. Reinforcement was scheduled according to variable‐interval, variable‐ratio, and fixed‐interval contingencies. Principal components analysis permitted description in terms of a single latent variable, strength, and this was validated with confirmatory factor analyses. Overall response rate was an excellent predictor of this state variable.
EFFECTS OF SIGNALED VERSUS UNSIGNALED DELAY OF REINFORCEMENT ON CHOICE
Authors: McDevitt Margaret A. , Williams Ben A.
Published: March 2006

Pigeons chose between 5‐s and 15‐s delay‐of‐reinforcement alternatives. The first key peck to satisfy the choice schedule began a delay timer, and food was delivered at the end of the interval. Key pecks during the delay interval were measured, but had no scheduled effect. In Experiment 1, signal conditions and choice schedules were varied across conditions. During unsignaled conditions, no stimulus change signaled the beginning of a delay interval. During differential and nondifferential signal conditions, offset of the choice stimuli and onset of a delay stimulus signaled the beginning of a delay interval. During differential signal conditions, different stimuli were correlated with the 5‐s and 15‐s delays, whereas the same stimulus appeared during both delay durations during nondifferential signal conditions. Pigeons showed similar, extreme levels of preference for the 5‐s delay alternative during unsignaled and differentially signaled conditions. Preference levels were reliably lower with nondifferential signals. Experiment 2 assessed preference with two pairs of unsignaled delays in which the ratio of delays was held constant but the absolute duration was increased fourfold. No effect of absolute duration was found. The results highlight the importance of delayed primary reinforcement effects and challenge models of choice that focus solely on conditioned reinforcement.
SENSITIVITY TO RELATIVE REINFORCER RATE IN CONCURRENT SCHEDULES: INDEPENDENCE FROM RELATIVE AND ABSOLUTE REINFORCER DURATION
Authors: McLean Anthony P. , Blampied Neville M.
Published: March 2006

Twelve pigeons responded on two keys under concurrent variable‐interval (VI) schedules. Over several series of conditions, relative and absolute magnitudes of reinforcement were varied. Within each series, relative rate of reinforcement was varied and sensitivity of behavior ratios to reinforcer‐rate ratios was assessed. When responding at both alternatives was maintained by equal‐sized small reinforcers, sensitivity to variation in reinforcer‐rate ratios was the same as when large reinforcers were used. This result was observed when the overall rate of reinforcement was constant over conditions, and also in another series of concurrent schedules in which one schedule was kept constant at VI 120 s. Similarly, reinforcer magnitude did not affect the rate at which response allocation approached asymptote within a condition. When reinforcer magnitudes differed between the two responses and reinforcer‐rate ratios were varied, sensitivity of behavior allocation was unaffected although response bias favored the schedule that arranged the larger reinforcers. Analysis of absolute response rates on the two keys showed that this invariance of response‐ratio sensitivity to reinforcement occurred despite changes in reinforcement interaction that were observed in absolute response rates on the constant VI 120‐s schedule. Response rate on the constant VI 120‐s schedule was inversely related to reinforcer rate on the varied key, and the strength of this relation depended on the relative magnitude of reinforcers arranged on the varied key. Independence of sensitivity to reinforcer‐rate ratios from relative and absolute reinforcer magnitude is consistent with the relativity and independence assumptions of the matching law.
THE GENERALIZED MATCHING LAW DESCRIBES CHOICE ON CONCURRENT VARIABLE‐INTERVAL SCHEDULES OF WHEEL‐RUNNING REINFORCEMENT
Authors: Belke Terry W. , Belliveau Julie
Published: March 2006

Six male Wistar rats were exposed to concurrent variable‐interval schedules of wheel‐running reinforcement. The reinforcer associated with each alternative was the opportunity to run for 15 s, and the duration of the changeover delay was 1 s. Results suggested that time allocation was more sensitive to relative reinforcement rate than was response allocation. For time allocation, the mean slopes and intercepts were 0.82 and 0.008, respectively. In contrast, for response allocation, mean slopes and intercepts were 0.60 and 0.03, respectively. Correction for low response rates and high rates of changing over, however, increased slopes for response allocation to about equal those for time allocation. The results of the present study suggest that the two‐operant form of the matching law can be extended to wheel‐running reinforcement. The effects of a low overall response rate, a short changeover delay, and long postreinforcement pausing on the assessment of matching in the present study are discussed.
STIMULI INEVITABLY GENERATED BY BEHAVIOR THAT AVOIDS ELECTRIC SHOCK ARE INHERENTLY REINFORCING
Authors: Dinsmoor James A.
Published: March 2006

A molecular analysis based on the termination of stimuli that are positively correlated with shock and the production of stimuli that are negatively correlated with shock provides a parsimonious account for both traditional discrete‐trial avoidance behavior and the data derived from more recent free‐operant procedures. The necessary stimuli are provided by the intrinsic feedback generated by the subject's behavior, in addition to those presented by the experimenter. Moreover, all data compatible with the molar principle of shock‐frequency reduction as reinforcement are also compatible with a delay‐of‐shock gradient, but some data compatible with the delay gradient are not compatible with frequency reduction. The delay gradient corresponds to functions relating magnitude of behavioral effect to the time between conditional and unconditional stimuli, the time between conditioned and primary reinforcers, and the time between responses and positive reinforcers.
SAFE PERIODS BOTH EXPLAIN AND NEED EXPLAINING
Authors: Sidman Murray
Published: March 2006

Dinsmoor's (2001) stress on the response‐produced safe period as a reinforcer for avoidance behavior is a positive contribution, even though several questions about such safe periods remain to be answered.
BEYOND THE MOLAR—MOLECULAR DISTINCTION: WE NEED MULTISCALED ANALYSES
Authors: Hineline Philip N.
Published: March 2006

Dinsmoor's (2001) adherence to molecular analyses may require him to assert that molar and molecular principles are mutually exclusive, but to instead analyze the phenomena of avoidance as inherently multiscaled is to follow a well‐established practice in the natural sciences. Besides the issue of scale, two‐factor theory, which Dinsmoor advocates, has little to say about some important and longstanding results in experiments that qualify as avoidance.
TWO‐FACTOR THEORY HAS STRONG EMPIRICAL EVIDENCE OF VALIDITY
Authors: Williams Ben A.
Published: March 2006

Traditional two‐factor theory is supported by parallels in the clinical literature. Theoretical problems with two‐factor theory are obviated by the role of safety signals, which serve as positive conditioned reinforcers and retard the extinction of conditioned fear.
STILL NO EVIDENCE FOR TEMPORALLY EXTENDED SHOCK‐FREQUENCY REDUCTION AS A REINFORCER
Authors: Dinsmoor James A.
Published: March 2006

There is no consensus and very little overlap in the criticisms of my target article. Because the primary consequences of avoidance behavior are by definition alterations in the distribution of shocks in time, any theory about the reinforcement of such behavior necessarily must begin with that dimension. However, the safety‐signal version of two‐process theory calls on positively and negatively correlated stimuli, including the responses themselves serving as stimuli, to transmit the effects of those alterations to the relevant behavior. Meanwhile, the Herrnstein—Hineline single‐process theory hypothesizes an additional source of reinforcement: a direct effect of reduction in the density of shock over some extended period of time. I can find no data that selectively support that hypothesis.
THE LONG‐TERM EFFECT OF HIGH‐AND LOW‐RATE RESPONDING HISTORIES ON FIXED‐INTERVAL RESPONDING IN RATS
Authors: Cole Mark R.
Published: March 2006

Ten rats were given extended lever‐press training on a fixed‐interval (FI) 30‐s food reinforcement schedule from the outset or following exposure to one or two previous reinforcement schedules. For 4 rats the previous schedule was either fixed‐ratio 20, which generated high response rates, or differential‐reinforcement‐of‐low‐rate 20 s, which produced low response rates. For 4 additional rats the extended training on FI 30 s was preceded by experience with two schedules: fixed‐ratio 20 followed by differential‐reinforcement‐of‐low‐rate 20 s; or the same two schedules in the reverse order. Fixed‐interval response rates were initially affected by the immediately preceding schedule, but after 80 to 100 sessions, all traces of prior schedule history had disappeared. The results also showed no long‐term effect of schedule history on the interfood‐interval patterns of responding on the FI 30‐s schedule. These results support one of the most central tenets of the experimental analysis of behavior: control by the immediate consequences of behavior.
RELATIONS AMONG EQUIVALENCE, NAMING, AND CONFLICTING BASELINE CONTROL
Authors: Carr D. , Blackman D. E.
Published: March 2006

Three studies were conducted with different groups of 6 students each to explore the effects of training class‐inconsistent relations and naming on demonstrations of emergent arbitrary stimulus relations. In all studies, two three‐member equivalence classes of Greek symbols (A1B1C1 and A2B2C2) emerged as a result of training in conditional discriminations. Two new symbols were introduced (X and Y), and additional conditional discriminations were trained, whereby X was designated as the positive discriminative stimulus (S+) and Y was designated as the negative discriminative stimulus (S‐) for A1 and B2. Conversely, Y was designated as the S+ and X as the S‐ for B1 and A2. This introduced conflicting sources of control within and between classes. In Study 1, subjects were not provided with names for the stimuli. In Study 2, the experimenter provided common names for the stimuli within each class. In Study 3, the subjects were required to use the common names during conditional discrimination training and test‐trial blocks. In all experiments, equivalence responding with respect to the original classes was disrupted for some subjects subsequent to learning the new relations. Furthermore, in Studies 2 and 3, there were frequent examples of non‐correspondence between observed (listener or speaker) naming patterns and derived relations. These results support the view that demonstrations of equivalence are subject to control from a variety of sources rather than being fundamentally dependent on naming.
EQUIVALENCE CLASSIFICATION BY CALIFORNIA SEA LIONS USING CLASS‐SPECIFIC REINFORCERS
Authors: Kastak Colleen Reichmuth , Schusterman Ronald J. , Kastak David
Published: March 2006

The ability to group dissimilar stimuli into categories on the basis of common stimulus relations (stimulus equivalence) or common functional relations (functional equivalence) has been convincingly demonstrated in verbally competent subjects. However, there are investigations with verbally limited humans and with nonhuman animals that suggest that the formation and use of classification schemes based on equivalence does not depend on linguistic skills. The present investigation documented the ability of two California sea lions to classify stimuli into functional classes using a simple discrimination reversal procedure. Following the formation of functional classes in this context, the second experiment showed transfer of the relations that emerged between class members to a matching‐to‐sample procedure. The third experiment demonstrated that the functional classes could be expanded through traditionally defined equivalence relations. In these three experiments, appropriate within‐class responding produced class‐specific food reinforcers. Experiment 3 addressed the role of these reinforcers in equivalence classification and showed that the class‐specific reinforcers were sufficient to relate new stimuli to the functional classes. These findings show that sea lions can form equivalence classes in simple and conditional discrimination procedures, and that class‐specific reinforcers can become equivalence class members.
TOLERANCE TO THE EFFECTS OF COCAINE ON PERFORMANCE UNDER BEHAVIOR‐CORRELATED REINFORCEMENT MAGNITUDE
Authors: Miller Michelle L. , Brodkorb G. Wade , Branch Marc N.
Published: March 2006

Four pigeons responded under a fixed‐interval 8‐min schedule of food delivery in which the amount of food delivered at the end of each interval depended on performance during the interval (i.e., a correlated schedule). Specifically, duration of access to grain was contingent upon the number of responses made during the first 4 min of the interval. This differential outcome did not affect response rates or patterning relative to performance under a simple fixed‐interval 8‐min schedule. Behavior under the correlated schedule was then investigated under doses of cocaine ranging from 0.3 to 10.0 mg/kg. A bitonic dose—response function was obtained for response rates and the time with head in the food hopper, whereas dose‐dependent decreases were observed in the mathematical index of curvature (Fry, Kelleher, & Cook, 1960). The dose that produced the greatest increase in the head‐in‐hopper time was then administered prior to each session. Following repeated administration of cocaine, disruptions in response patterning were attenuated for all 4 pigeons; tolerance was also observed to the rate‐increasing effects and increased head‐in‐hopper time for 2 pigeons after chronic cocaine administration. Tolerance therefore developed despite the fact that the initial effect of cocaine was to increase the amount of food obtained.
AREA UNDER THE CURVE AS A MEASURE OF DISCOUNTING
Authors: Myerson Joel , Green Leonard , Warusawitharana Missaka
Published: March 2006

We describe a novel approach to the measurement of discounting based on calculating the area under the empirical discounting function. This approach avoids some of the problems associated with measures based on estimates of the parameters of theoretical discounting functions. The area measure may be easily calculated for both individual and group data collected using any of a variety of current delay and probability discounting procedures. The present approach is not intended as a substitute for theoretical discounting models. It is useful, however, to have a simple, univariate measure of discounting that is not tied to any specific theoretical framework.
HABITUATION CONTRIBUTES TO WITHIN‐SESSION CHANGES IN FREE WHEEL RUNNING
Authors: Aoyama Kenjiro , McSweeney Frances K.
Published: March 2006

Three experiments tested the hypothesis that habituation contributes to the regulation of wheel running. Rats ran in a wheel for 30‐min sessions. Experiment 1 demonstrated spontaneous recovery. Rats ran more and the within‐session decreases in running were smaller after 2 days of wheel deprivation than after 1 day. Experiment 2 demonstrated dishabituation. Running rate increased immediately after the termination of a brief extra event (application of the brake or flashing of the houselight). Experiment 3 demonstrated stimulus specificity. Rats completed the second half of the session in either the same wheel as the first half, or a different wheel. Second‐half running was faster in the latter case. Within‐session patterns of running were well described by equations that describe data from the habituation, motivation, and operant literatures. These results suggest that habituation contributes to the regulation of running. In fact, habituation provides a better explanation for the termination of wheel running than fatigue, the variable to which this termination is usually attributed. Overall, the present findings are consistent with the proposition that habituation and sensitization contribute to the regulation of several forms of motivated behavior.