bluuebunny/crossref_metadata_2025 huggingface dataset:
INCENTIVE THEORY: II. MODELS FOR CHOICE
Authors: Killeen Peter R.
Published: March 2006

Incentive theory is extended to account for concurrent chained schedules of reinforcement. The basic model consists of additive contributions from the primary and secondary effects of reinforcers, which serve to direct the behavior activated by reinforcement. The activation is proportional to the rate of reinforcement and interacts multiplicatively with the directive effects. The two free parameters are q, the slope of the delay of reinforcement gradient, whose value is constant across many experiments, and b, a bias parameter. The model is shown to provide an excellent description of all results from studies that have varied the terminal‐link schedules, and of many of the results from studies that have varied initial‐link schedules. The model is extended to diverse modifications of the terminal links, such as varied amount of reinforcement, varied signaling of the terminal‐link schedules, and segmentation of the terminal‐link schedules. It is demonstrated that incentive theory provides an accurate and integrated account of many of the phenomena of choice.
SENSITIVITY TO REINFORCEMENT IN CONCURRENT ARITHMETIC AND EXPONENTIAL SCHEDULES
Authors: Taylor Russell , Davison Michael
Published: March 2006

The generalized matching law states that the logarithm of the ratio of responses emitted or time spent responding in concurrent variable‐interval schedules is a linear function of the logarithm of the ratio of reinforcements obtained. The slope of this relation, sensitivity to reinforcement, varies about 1.0 but has been shown to be different when obtained in different laboratories. The present paper analyzed the results from 18 experiments on concurrent variable‐interval schedule performance and showed that response‐allocation sensitivity to reinforcement was significantly smaller when arithmetic, rather than exponential, progressions were used to produce variable‐interval schedules. There were no differences in time‐allocation sensitivity between the two methods of constructing variable‐interval schedules. Since the two laboratories have consistently used different methods for constructing variable‐interval schedules, the differences in obtained sensitivities to reinforcement are explained. The reanalysis suggests that animals may be sensitive to differences in the distribution of reinforcements in time.
A PARAMETRIC EVALUATION OF THE HEDONIC AND MOTORIC EFFECTS OF DRUGS: PIMOZIDE AND AMPHETAMINE
Authors: Heyman Gene M.
Published: March 2006

This study uses a curve‐fitting approach to evaluate the effects of drugs on reinforced responding in rats. The subjects obtained reinforcement according to a series of five different variable‐interval schedules (a five‐component multiple schedule). For each rat, pimozide, a neuroleptic, decreased response rate, and the decrease was associated with (1) a decrease in the estimated asymptotic response rate and (2) an increase in the rate of reinforcement necessary for half‐asymptotic responding. That is, pimozide decreased the proportion of responding maintained by a given rate of reinforcement. In contrast, intermediate doses of amphetamine increased response rate and increased the proportion of responding maintained by a given rate of reinforcement. It was proposed that the response rate asymptote indexes motor capacity, and the rate of reinforcement necessary for half‐asymptotic responding indexes reinforcement efficacy; accordingly, pimozide decreased motor capacity and reinforcement strength and amphetamine increased reinforcement strength.
PIGEONS' SPATIAL MEMORY: III. EFFECT OF DISTRACTORS ON DELAYED MATCHING OF KEY LOCATION
Authors: Wilkie Donald M.
Published: March 2006

The effect of distractors on pigeons' delayed matching of key location was investigated. Baseline trials began with a “ready” stimulus (brief operation of the grain feeder). Then one (randomly chosen) key from a three‐by‐three matrix was lit briefly as the sample. After a short delay (retention interval) the sample key was lit again along with one of the other eight keys. A peck at the key that had served as the sample (correct comparison) produced grain reinforcement, whereas a peck to the other key (incorrect comparison) produced only the intertrial interval. In Experiment 1, a houselight distractor, presented during either the sample, retention interval, or choice phases of the trial, had little if any effect on accuracy of matching key location. In Experiment 2, one of three types of spatial stimuli was interpolated during the retention interval, or the interval was blank as during baseline trials. The three stimuli were: the sample (correct comparison) location for that trial, the incorrect comparison location for that trial, or one of the seven unused locations for that trial. Relative to blank trials, accuracy improved slightly on sample‐interpolated trials, decreased slightly on unused location‐interpolated trials, and decreased considerably on incorrect comparison‐interpolated trials. In Experiment 3, retention intervals were blank or had one of six types of interpolation: the sample, the incorrect comparison, two presentations of the sample, two presentations of the incorrect comparison, the sample followed by the incorrect comparison, or the incorrect comparison followed by the sample. Matching accuracy remained high when one or two sample presentations occurred during the retention interval and when the incorrect comparison was followed by the sample. Matching accuracy decreased when one or two incorrect comparison presentations occurred during the retention interval or when the sample was followed by the incorrect comparison. Implications of these findings for hypotheses about how pigeons remember spatial information are discussed.
LOCAL RATES OF RESPONDING AND REINFORCEMENT DURING CONCURRENT SCHEDULES
Authors: McSweeney Frances K. , Melville Cam L. , Buck Michael A. , Whipple J. E.
Published: March 2006

The literature was searched for information about the local rates of responding and reinforcement during concurrent schedules. The local rates of reinforcement obtained from the two components of a concurrent schedule were equal when a long‐duration changeover delay was used and when many sessions were conducted, except when the two components provided different simple schedules. The local rates of responding were equal under some conditions, but they differed when one component provided a ratio and the other an interval schedule. Across schedules, local rates of reinforcement changed with changes in the schedule of reinforcement. Local rates of responding did not change with changes in changeover‐delay duration but did with changes in the changeover ratio and with changes in the programmed rates of reinforcement. The results generally conform to the Equalizing and Melioration Principles and help to clarify current statements of the Matching Law. The results also suggest that changes in the local rates of responding and reinforcement may be orderly across schedules.
FREQUENCY VERSUS MAGNITUDE OF REINFORCEMENT: NEW DATA WITH A DIFFERENT PROCEDURE
Authors: Todorov João Claudio , Hanna Elenice Seixas , Sá Maria Cristina Neves Bittencourt de
Published: March 2006

Two pigeons, with previous exposure to concurrent schedules, were submitted to 29 sessions of 8 hours each with concurrent variable‐interval variable‐interval schedules in which reinforcement parameters changed from session to session. In the first nine sessions reinforcement durations were equal in both schedules while reinforcement frequencies varied; in Sessions 10 through 18, both frequency and duration of reinforcement were varied; in Sessions 19 through 29, only reinforcement duration was varied. Results with this different procedure confirm previous findings that behavior is more sensitive to changes in reinforcement frequency than to reinforcement magnitude.
COMMENTS ON SHIMPS (1983) DOUBLE DISSOCIATION BETWEEN KNOWLEDGE AND TACIT KNOWLEDGE
Authors: Eisler Hannes
Published: March 2006

Shimp (1983) found in five pigeons “double dissociation” between the distribution of pairs of long and short reinforced interresponse times and “self‐reports,” obtained by symbolic matching to sample, concerning these interresponse times. This result can be explained by assuming that the birds used a fixed temporal interval as matching criterion, independently of which pattern of interresponse times was reinforced.
CHOICE IN A SELF‐CONTROL PARADIGM: QUANTIFICATION OF EXPERIENCE‐BASED DIFFERENCES
Authors: Logue A. W. , Rodriguez Monica L. , Peña‐Correal Telmo E. , Mauro Benjamin C.
Published: March 2006

Previous quantitative models of choice in a self‐control paradigm (choice between a larger, more‐delayed reinforcer and a smaller, less‐delayed reinforcer) have not described individual differences. Two experiments are reported that provide additional quantitative data on experience‐based differences in choice between reinforcers of varying sizes and delays. In Experiment 1, seven pigeons in a self‐control paradigm were exposed to a fading procedure that increased choices of the larger, more‐delayed reinforcer through gradually decreasing the delay to the smaller of two equally delayed reinforcers. Three control subjects, exposed to each of the small‐reinforcer delays to which the experimental subjects were exposed, but for fewer sessions, demonstrated that lengthy exposure to each of the conditions in the fading procedure may be necessary in order for the increase to occur. In Experiment 2, pigeons with and without fading‐procedure exposure chose between reinforcers of varying sizes and delays scheduled according to a concurrent variable‐interval variable‐interval schedule. In both experiments, pigeons with fading‐procedure exposure were more sensitive to variations in reinforcer size than reinforcer delay when compared with pigeons without this exposure. The data were described by the generalized matching law when the relative size of its exponents, representing subjects' relative sensitivity to reinforcer size and delay, were grouped according to subjects' experience.
CONCURRENT VARIABLE‐INTERVAL VARIABLE‐RATIO SCHEDULES CAN PROVIDE ONLY WEAK EVIDENCE FOR MATCHING
Authors: Ziriax John M. , Silberberg Alan
Published: March 2006

Herrnstein and Heyman (1979) showed that when pigeons' pecking is reinforced on concurrent variable‐interval variable‐ratio schedules, (1) their behavior ratios match the ratio of the schedules' reinforcer frequencies, and (2) there is more responding on the variable interval. Since maximizing the reinforcement rate would require responding more on the variable ratio, these results were presented as establishing the primacy of matching over maximizing. In the present report, different ratios of behavior were simulated on a computer to see how they would affect reinforcement rates on these concurrent schedules. Over a wide range of experimenter‐specified choice ratios, matching obtained — a result suggesting that changes in choice allocation produced changes in reinforcer frequencies that correspond to the matching outcome. Matching also occurred at arbitrarily selected choice ratios when reinforcement rates were algebraically determined by each schedule's reinforcement‐feedback function. Additionally, three birds were exposed to concurrent variable‐interval variable‐ratio schedules contingent on key pecking in which hopper durations were varied in some conditions to produce experimenter‐specified choice ratios. Matching generally obtained between choice ratios and reinforcer‐frequency ratios at these different choice ratios. By suggesting that reinforcer frequencies track choice on this procedure, instead of vice versa, this outcome questions whether matching‐as‐outcome was due to matching‐as‐process in the Herrnstein and Heyman study.
TEMPORAL CONTROL BY SIGNALS OF INTERVAL DURATION WITHIN VARIABLE‐INTERVAL SCHEDULES
Authors: Toal Liam , Leslie Julian C.
Published: March 2006

Rats' lever pressing produced sucrose reinforcers on a variable‐interval schedule where, in different conditions, the duration of a stimulus presented immediately after reinforcement was either correlated or uncorrected with the duration of the current interreinforcement interval. Under the baseline schedule, in which no stimulus was presented, the minimum interreinforcement interval was 8 s and the mean postreinforcement pause of each subject approximated this value. Response rates increased slowly over the first 10 to 15 s and then remained roughly constant throughout the remainder of the interval. In both the correlated and uncorrected conditions, the added stimulus resulted in the postreinforcement pauses lengthening to values in excess of the duration of the preceding stimulus. This resulted in a poststimulus pause which was, in most cases, roughly constant irrespective of the duration of the preceding stimulus, or of the reinforcement contingencies prevailing immediately after stimulus offset. Local response‐rate patterns in the uncorrelated conditions were similar to those obtained under the baseline schedule in which no stimulus was presented. However, in the correlated condition local response rates increased across the remainder of the interreinforcer interval. Further, the rate of acceleration was inversely related to the duration of the preceding stimulus. These results show that a correlation between stimulus duration and the ensuing time to reinforcement can control behavior—a type of temporal control not previously reported.
OPTIMIZATION VERSUS RESPONSE‐STRENGTH ACCOUNTS OF BEHAVIOR
Authors: Vaughan William , Miller H. L.
Published: March 2006

Pigeons were run in both single‐key and concurrent‐key experiments in which, over most of the range of response rates, an increase in response rate gave rise to a continuous decrease in reinforcement rate. In spite of the fact that a low response rate would have produced a high reinforcement rate, all birds responded at relatively high rates, thus keeping reinforcement rates substantially below the maximum possible. In the concurrent‐key experiment, in addition to responding at relatively high rates, the birds' ratios of responses approximately matched the corresponding ratios of obtained reinforcers. The results are inconsistent with most theories of optimal performance, which assume that organisms behave in ways that either maximize reinforcement value or minimize deviations from a free‐behavior point. On the other hand, the results are consistent with the assumption that reinforcement strengthens the tendency to respond.
VERBAL BEHAVIOR
Authors: Michael Jack
Published: March 2006

The recent history and current status of the area of verbal behavior are considered in terms of three major thematic lines: the operant conditioning of adult verbal behavior, learning to be an effective speaker and listener, and developments directly related to Skinner's Verbal Behavior. Other topics not directly related to the main themes are also considered: the work of Kurt Salzinger, ape‐language research, and human operant research related to rule‐governed behavior.
DELAYED SIGNAL DETECTION, DIFFERENTIAL REINFORCEMENT, AND SHORT‐TERM MEMORY IN THE PIGEON
Authors: Harnett Paul , McCarthy Dianne , Davison Michael
Published: March 2006

In two discrete‐trial delayed‐detection experiments, six pigeons were trained on dependent concurrent variable‐interval schedules. Pecking a red side key was reinforced when the brighter of two white lights (S1) had been presented on the center key, and pecking a green side key was reinforced when the duller of two white lights (S2) had been presented on the center key. Incorrect responses were red side‐key pecks following S2 presentations and green side‐key pecks following S1 presentations; these resulted in three‐second blackouts. In Experiment 1, the time between presentation of S1 or S2 on the center key and the onset of the red and green side keys was varied nonsystematically from 0.06 seconds to 19.69 seconds across experimental conditions. Stimulus discriminability decreased as the stimulus‐choice delay increased. A rectangular‐hyperbolic function better described this decrease in discriminability over time than did a negative‐exponential function. In Experiment 2, at each of three stimulus‐choice delays (0.06, 3.85, and 10.36 seconds), relative reinforcer frequency for correct responses to the red and green side keys was varied by changing the values of the dependent concurrent variable‐interval schedules. The sensitivity of choice to relative reinforcer frequency was independent of the decrease in stimulus discriminability with increasing stimulus‐choice delay.
TEMPORAL PATTERNS OF RESPONDING IN SMALL FIXED‐RATIO SCHEDULES
Authors: Crossman Edward K. , Trapp Nancy L. , Bonem Elliott J. , Bonem Marilyn K.
Published: March 2006

Pigeons were exposed to an ascending series of small fixed‐ratio schedules from fixed‐ratio 1 to 7. Two of those pigeons were later placed on a fixed‐ratio 30 schedule. The two primary dependent variables were the postreinforcement pause and the interresponse time. Changes in these variables under small fixed ratios were sometimes opposite to changes reported with large fixed ratios. For example, postreinforcement pauses decreased in length as the fixed‐ratio requirement increased from fixed‐ratio 1 to fixed‐ratio 3. Also, the interresponse times early in the small fixed‐ratio schedule were shorter than those immediately preceding reinforcement. These findings question the role of interresponse‐time reinforcement in determining temporal patterns of responding under small fixed‐ratio schedules. They also suggest that there may be a limited region in which the independent variable, fixed‐ratio size, does not operate as previously described.
PURE TIMING IN TEMPORAL DIFFERENTIATION
Authors: Zeiler Michael D.
Published: March 2006

Temporal control appears to depend on whether the critical durations are those of stimuli or those of responses. Stimulus timing (temporal discrimination) supports Weber's law, whereas response timing (temporal differentiation) indicates decreasing relative sensitivity with longer time intervals. The two types of procedure also yield different conclusions in scaling experiments designed to study the functional midpoint of two or more durations (temporal bisection procedures). In addition, the fractional‐exponent power relation between emitted and required duration usually found with animals in differentiation experiments conflicts with deductions from formal analyses. The experiment reported here derived from considering differentiation arrangements as schedules of reinforcement. When analyzed from this perspective, the procedures are tandem schedules involving a required pause followed by a response, and it is the pause alone that involves temporal control. A choice procedure separated timing from responding, and enabled observations of pause timing in isolation. Pure temporal control in differentiation consisted of linear overestimation of the standard duration, and Weber's law described sensitivity. These results indicate that the two problems, the fractional‐exponent power relations and the apparently different nature of sensitivity in differentiation and discrimination, disappear when temporal control is observed alone in differentiation.
REANALYSIS OF THE EQUATION FOR SIMPLE ACTION
Authors: Warren‐Boulton Frederick R. , Silberberg Alan , Gray Michael , Ollom Randolph
Published: March 2006

De Villiers and Herrnstein (1976) have shown that the equation for simple action, derived from the matching law, predicts change in behavioral output for some 40 experiments in which the value of a single source of reinforcement has been varied. Using only the positive‐reinforcement studies they cite that used five or more different reinforcement values, we found the high percentage of variance they report accommodated by this equation (94%) is predicated on instances of averaging rates of behavioral output before making a least‐squares fit of the equation. In our reanalysis, which minimizes rate averaging, only 78% of the data variance is accommodated. This diminished data‐variance accommodation can be improved by adding parameters that permit the equation's scaling constant to change as a function of reinforcement. Although these parameters permit acceptable levels of accommodation of data variance, they correspond to no obvious psychological processes. These findings support the view that the equation for simple action is an inadequate model for behavioral output.
VERBAL RELATIONS WITHIN INSTRUCTION: ARE THERE SUBCLASSES OF THE INTRAVERBAL?
Authors: Chase Philip N. , Johnson Kent R. , Sulzer‐Azaroff Beth
Published: March 2006

Six college undergraduates received programmed concept training on three kinds of intraverbal relations. These relations involved definition, exemplification, and example identification questions. The experimenter presented the questions, the subject answered them in writing, and the experimenter provided specific corrective consequences. After completing the training on a concept, the subject immediately received a test on the concept. The test included novel questions similar to the kind used in training (extension tasks) and question types that were not used in training but which were also considered intraverbal relations (transfer tasks). Training results indicated rapid, errorful responding on example identification tasks and slow, accurate responding on exemplification and definition tasks. Test results indicated rapid, errorful responding on example identification extension tasks; slow, accurate responding on exemplification extension tasks; and slow, errorful responding on definition extension tasks. In testing, differential responding occurred on transfer tasks as a function of the kind of intraverbal training received, and substantially lower levels of performance were obtained on transfer tasks than on extension tasks. It appears that the intraverbal can be subdivided into more specific categories of operants.
SEQUENTIAL EFFECTS IN DIMENSIONAL CONTRAST
Authors: Blough Patricia M. , Blough Donald S.
Published: March 2006

Two experiments examined pigeons' response rates during short trials signaled by stimuli closely spaced along a wavelength continuum. In Experiment 1 separate halves of the continuum were correlated with different reinforcement schedules. In Experiment 2, the middle stimulus was accompanied by a lower probability of reinforcement than were the remaining wavelengths. Both procedures resulted in dimensional contrast “shoulders,” seen as relatively enhanced or depressed response rates in the presence of stimuli between the extreme of the continuum and the border separating the positive and negative stimuli. Sequential analyses addressed possible contributions of the following interactions: (a) local contrast, seen when rate during a given schedule depends on the schedule in the just‐preceding trial; (b) modification of local contrast by the similarity of the signaling stimuli (P. Blough, 1983); and (c) schedule‐independent rate contrast, seen when rate in a given trial depends on the rate controlled by the stimulus that accompanied the just‐preceding trial (Malone & Rowe, 1981). Dimensional contrast functions were similar when isolated according to the schedule, to the similarity of the signaling stimulus, and to the response rate of the just‐preceding trial. The interactions noted above do not appear to make important contributions to this effect.
VARYING RESPONSE‐REINFORCER CONTIGUITY IN A RECYCLING CONJUNCTIVE SCHEDULE
Authors: Keenan Michael , Leslie Julian C.
Published: March 2006

Three experiments describe the effects of manipulating the frequency of response‐reinforcer contiguity in a recycling conjunctive schedule. The schedule arranged that a reinforcer was delivered after 30 s provided at least one response had occurred; otherwise the next cycle started immediately. In Experiment 1, this schedule produced the typical pause‐respond‐pause pattern, with most responses at mid‐interval; and, when a limited number of contiguities between responses and food delivery were added, the pattern became more like the monotonic scallop seen on fixed‐interval schedules. In Experiment 2, the schedule was initially presented with an additional contingency that allowed contiguity on every trial. Fixed‐interval‐like behavior occurred and tended to persist as contiguities were gradually eliminated. In Experiment 3, the recycling conjunctive schedule alternated with a condition in which a large number of contiguities occurred. The pause‐respond‐pause pattern and fixed‐interval‐like performance occurred with few or many contiguities, respectively. The results of all three experiments illustrate how contiguity interacts with a small number of other variables to determine performance on interval schedules and illuminate previous findings with fixed‐interval and fixed‐time schedules.
HUMAN OPERANT PERFORMANCE: SENSITIVITY AND PSEUDOSENSITIVITY TO CONTINGENCIES
Authors: Shimoff Eliot , Matthews Byron A. , Catania A. Charles
Published: March 2006

Undergraduates' button presses occasionally produced points exchangeable for money. Left and right buttons were initially correlated with multiple random‐ratio (RR) and random‐interval (RI) components, respectively. During interruptions of the multiple schedule, students filled out sentence‐completion guess sheets describing the schedules, and points were contingent upon the accuracy of guesses. To test for sensitivity to schedule contingencies, schedule components were repeatedly reversed between the two buttons. Pressing rates were consistently higher in ratio than in interval components even when feedback for guesses was discontinued, demonstrating sensitivity to the difference between ratio and interval contingencies. The question was whether this sensitivity was based directly on the contingencies or whether it was rule‐governed. For two students, when multiple RR RI schedules were changed to multiple RI RI schedules, rates became low in both components of the multiple RI RI schedule; however, subsequent prevention of point deliveries for the first few responses in any component produced high rates in that component. For a third student, response rates became higher in the RI component that provided the lower rate of reinforcement. In each case, performance was inconsistent with typical effects of the respective schedules with nonhuman organisms; it was therefore plausible to conclude that the apparently contingency‐governed performances were instead rule‐governed.
CHOICE BETWEEN SINGLE AND MULTIPLE DELAYED REINFORCERS
Authors: Mazur James E.
Published: March 2006

Pigeons chose between alternatives that differed in the number of reinforcers and in the delay to each reinforcer. A peck on a red key produced the same consequences on every trial within a condition, but between conditions the number of reinforcers varied from one to three and the reinforcer delays varied between 5 s and 30 s. A peck on a green key produced a delay of adjustable duration and then a single reinforcer. The green‐key delay was increased or decreased many times per session, depending on a subject's previous choices, which permitted estimation of an indifference point, or a delay at which a subject chose each alternative about equally often. The indifference points decreased systematically with more red‐key reinforcers and with shorter red‐key delays. The results did not support the suggestion of Moore (1979) that multiple delayed reinforcers have no effect on preference unless they are closely grouped. The results were well described in quantitative detail by a simple model stating that each of a series of reinforcers increases preference, but that a reinforcer's effect is inversely related to its delay. The success of this model, which considers only delay of reinforcement, suggested that the overall rate of reinforcement for each alternative had no effect on choice between those alternatives.
DELAYED TEMPORAL DISCRIMINATION IN PIGEONS: A COMPARISON OF TWO PROCEDURES
Authors: Chatlosh Diane L. , Wasserman Edward A.
Published: March 2006

A within‐subjects comparison was made of pigeons' performance on two temporal discrimination procedures that were signaled by differently colored keylight samples. During stimulus trials, a peck on the key displaying a slanted line was reinforced following short keylight samples, and a peck on the key displaying a horizontal line was reinforced following long keylight samples, regardless of the location of the stimuli on those two choice keys. During position trials, a peck on the left key was reinforced following short keylight samples and a peck on the right key was reinforced following long keylight samples, regardless of which line stimulus appeared on the correct key. Thus, on stimulus trials, the correct choice key could not be discriminated prior to the presentation of the test stimuli, whereas on position trials, the correct choice key could be discriminated during the presentation of the sample stimulus. During Phase 1, with a 0‐s delay between sample and choice stimuli, discrimination learning was faster on position trials than on stimulus trials for all 4 birds. During Phase 2, 0‐, 0.5‐, and 1.0‐s delays produced differential loss of stimulus control under the two tasks for 2 birds. Response patterns during the delay intervals provided some evidence for differential mediation of the two delayed discriminations. These between‐task differences suggest that the same processes may not mediate performance in each.
CONCURRENT ACCESS TO TWO CONCENTRATIONS OF ORALLY DELIVERED PHENCYCLIDINE: EFFECTS OF FEEDING CONDITIONS
Authors: Carroll Marilyn E.
Published: March 2006

Two experiments addressed the effects of food satiation and deprivation on oral self‐administration of two concurrently available phencyclidine concentrations. In the first experiment, 8 rhesus monkeys self‐administered either of two concentrations of phencyclidine (“PCP, angel dust”) and water under concurrent fixed‐ratio 16 schedules. One concentration was always held constant (0.25 mg/mL) while a series of other phencyclidine concentrations, ranging from 0 (water) to 1.0 mg/mL, was presented in a nonsystematic order. Initially the monkeys were tested while food satiated, and the procedure was then repeated during food deprivation. The monkeys usually selected the higher concentration within the first few minutes of the session, indicating that taste and/or other immediate postingestional effects were important factors. Contrary to a number of previous reports, there were no consistent differences across subjects in the mean number of liquid deliveries or mean drug intake (mg/kg) during food satiation and deprivation. However, for all monkeys the within‐session time course of responding during food satiation consistently differed from that during deprivation. A second experiment assessed whether the failure to find consistent differences in drug intake during food satiation and deprivation had been due to the history of concurrent access to different phencyclidine concentrations or to the extended experience with phencyclidine under food‐satiation conditions. Six additional monkeys (Group 2) were exposed to the phencyclidine self‐administration procedure (during food satiation and deprivation) for the same length of time as the monkeys in Experiment 1 (Group 1), except they received only concurrent access to phencyclidine (0.25 mg/mL) and water. Both groups then received concurrent access to phencyclidine and water during five repeated cycles of food deprivation and satiation. There were also marked individual differences in Group 2: During food satiation, 2 of the monkeys' responding increased, 1 showed no change, and 3 decreased. Examination of a number of historical variables indicated that the greater the percentage of total sessions spent during food satiation with phencyclidine available (before these experiments began), the greater the amounts of phencyclidine consumed during food satiation and the smaller the differences in phencyclidine intake when the two feeding conditions were compared.
SENSITIVITY TO REINFORCER DURATION IN A SELF‐CONTROL PROCEDURE
Authors: White K. Geoffrey , Pipe Margaret‐Ellen
Published: March 2006

In a concurrent‐chains procedure, pigeons' responses on left and right keys were followed by reinforcers of different durations at different delays following the choice responses. Three pairs of reinforcer delays were arranged in each session, and reinforcer durations were varied over conditions. In Experiment 1 reinforcer delays were unequal, and in Experiment 2 reinforcer delays were equal. In Experiment 1 preference reversal was demonstrated in that an immediate short reinforcer was chosen more frequently than a longer reinforcer delayed 6 s from the choice, whereas the longer reinforcer was chosen more frequently when delays to both reinforcers were lengthened. In both experiments, choice responding was more sensitive to variations in reinforcer duration at overall longer reinforcer delays than at overall shorter reinforcer delays, independently of whether fixed‐interval or variable‐interval schedules were arranged in the choice phase. We concluded that preference reversal results from a change in sensitivity of choice responding to ratios of reinforcer duration as the delays to both reinforcers are lengthened.
MOLAR OPTIMIZATION VERSUS DELAYED REINFORCEMENT AS EXPLANATIONS OF CHOICE BETWEEN FIXED‐RATIO AND PROGRESSIVE‐RATIO SCHEDULES
Authors: Mazur James E. , Vaughan William
Published: March 2006

In a discrete‐trials procedure, pigeons chose between a fixed‐ratio 81 schedule and a progressive‐ratio schedule by making a single peck at the key correlated with one or the other of these schedules. The response requirement on the progressive‐ratio schedule began at 1 and increased by 10 each time the progressive‐ratio schedule was chosen. Each time the fixed‐ratio schedule was chosen, the requirement on the progressive‐ratio schedule was reset to 1 response. In conditions where there was no intertrial interval, subjects chose the progressive‐ratio schedule for an average of about five consecutive trials (during which the response requirement increased to 41), and then chose the fixed‐ratio schedule. This ratio was larger than that predicted by an optimality analysis that assumes that subjects respond in a pattern that minimizes the response‐reinforcer ratio or one that assumes that subjects respond in a pattern that maximizes the overall rate of reinforcement. In conditions with a 25‐s or 50‐s intertrial interval, subjects chose the progressive‐ratio schedule for an average of about eight consecutive trials before choosing the fixed‐ratio schedule. This change in performance with the addition of an intertrial interval was also not predicted by an optimality analysis. On the other hand, the results were consistent with the theory that choice is determined by the delays to the reinforcers delivered on the present trial and on subsequent trials.
SUCCESSIVE INDEPENDENCE OF MULTIPLE‐SCHEDULE COMPONENT PERFORMANCES
Authors: McLean Anthony P.
Published: March 2006

In three experiments, pigeons' responses were reinforced on two keys in each component of a series of multiple‐schedule conditions. In each series, concurrent variable‐interval schedules were constant in one component and were varied over conditions in the other component. In the first experiment both components arranged the same, constant total number of reinforcers, in the second the two components arranged constant but different totals, and in the third experiment the total was varied in one component and remained constant in the other. Relative reinforcer rate during the varied component was manipulated over conditions in all three experiments. In all these experiments, response and time allocation in the constant component were invariant when reinforcer ratios varied in the other component, demonstrating independence of behavior allocation in a multiple‐schedule component from the relative reinforcer rate for the same alternatives in another component. In the two experiments which maintained constant reinforcer totals in components, sensitivity to reinforcement in the multiple schedules was the same as that in the concurrent schedules arranged during the varied component, with multiple‐schedule bias in the experiment in which the totals were unequal.
SELF‐CONTROL IN MALE AND FEMALE RATS
Authors: Haaren Frans van , Hest Annemieke van , Poll Nanne E. van de
Published: March 2006

Eight male and 8 female Wistar rats were exposed to a discrete‐trial procedure in which they chose between the presentation of a small (one pellet) or a large (three pellets) reinforcer. The delay to the small and large reinforcer was 6.0 s in the first condition of Experiment 1. Subjects consistently chose the large reinforcer. When the delay to the small reinforcer was decreased to 0.1 s in the next experimental condition, all subjects continued to choose the large 6.0‐s delayed reinforcer. When the contingencies correlated with the two levers were reversed in the next experimental condition, the majority of subjects (5 males and 6 females) still chose the large delayed reinforcer over the small immediately presented reinforcer. The delay to the small reinforcer was maintained at 6.0 s, but the delay to the large reinforcer was varied among 9:0, 15.0, 24.0, and 36.0 s in Experiment 2, in which 4 males and 4 females participated. Most subjects consistently chose the large increasingly delayed reinforcer, although choice for the small 6.0‐s delayed reinforcer developed in some females when the large reinforcer was delayed for 24.0 or 36.0 s. These choice patterns were not predicted from a literal application of a model that says choice should favor the alternative correlated with the higher (amount/delay) ratio.
EFFECTS OF REINFORCEMENT CONTEXT ON CHOICE
Authors: Jacob Teresa C. , Fantino Edmund
Published: March 2006

Two experiments investigated the effects of successive reinforcement contexts on choice. In the first, concurrent variable‐interval schedules of primary reinforcement operated during the initial links of concurrent chains. The rate of this reinforcement arranged by the concurrent schedules was decreased across conditions: When it was higher than the terminal‐link rate, preference for the higher frequency initial‐link schedule increased relative to baseline. (During baseline, a standard concurrent‐schedule procedure was in effect.) When the initial‐link reinforcement rate was lower than the terminal‐link rate, preference converged toward indifference. In the second experiment, a chain schedule was available on a third key while a concurrent schedule was in effect on the side keys. When the terminal link of the chain schedule was produced, the side keys became inoperative. Availability of the chain schedule did not affect choice between the concurrent schedules. These results show that only when successive reinforcement contexts are produced by choice responding do those successive contexts affect choice in concurrent schedules.
TRANSFER OF A CONDITIONAL ORDERING RESPONSE THROUGH CONDITIONAL EQUIVALENCE CLASSES
Authors: Wulfert Edelgard , Hayes Steven C.
Published: March 2006

Eight adult humans were taught conditional discriminations in a matching‐to‐sample format that led to the formation of two four‐member equivalence classes. When subjects were taught to select one comparison stimulus from each class in a set order, they then ordered all other members of the equivalence classes without explicit training. When the ordering response itself was brought under conditional control, conditional sequencing also transferred to all other members of the two equivalence classes. When the conditional discriminations in the matching‐to‐sample task were brought under higher order conditional control, the eight stimulus members were arranged into four conditional equivalence classes. Both ordering and conditional ordering transferred to all members of the four conditional equivalence classes; for some subjects this occurred without a typical test for equivalence. One hundred twenty untrained sequences emerged from eight trained sequences for all subjects. Transfer of functions through equivalence classes may contribute to a behavior‐analytic approach to semantics and generative grammar.
AN INVERSE RELATIONSHIP BETWEEN BASELINE FIXED‐INTERVAL RESPONSE RATE AND THE EFFECTS OF A TANDEM RESPONSE REQUIREMENT
Authors: Bickel Warren K. , Higgins Stephen T. , Kirby Kimberly , Johnson Lisa M.
Published: March 2006

Previous experiments examining the effects of adding a tandem fixed‐ratio response requirement on fixed‐interval schedule performance have reported inconsistent results. One variable that may account for such inconsistencies is the baseline response rate in the fixed‐interval condition. This possibility was investigated in the present study. Rats were given histories with either interresponse times greater than 11 s or fixed‐ratio 40 schedules of reinforcement, which engendered either relatively low or high rates of responding, respectively, in the subsequent fixed‐interval condition. A tandem ratio response requirement (fixed‐ratio 9) was then introduced. The effects of adding this tandem response requirement were inversely related to the baseline fixed‐interval response rates; low rates of responding in the fixed‐interval condition were markedly increased, whereas high rates of responding were relatively unaffected. This inverse relationship appears to be similar to the rate‐dependent relations observed in behavioral pharmacology. These results may provide an explanation for the inconsistent findings reported in previous studies on tandem fixed‐interval fixed‐ratio schedules and suggest that principles of behavioral pharmacology research may be applicable to the study of the effects of nonpharmacological variables on schedule‐controlled behavior.
VERTICAL JUMPING AND SIGNALED AVOIDANCE
Authors: Cándido Antonio , Maldonado Antonio , Vila Jaime
Published: March 2006

This paper reports an experiment intended to demonstrate that the vertical jumping response can be learned using a signaled‐avoidance technique. A photoelectric cell system was used to record the response. Twenty female rats, divided equally into two groups, were exposed to intertrial intervals of either 15 or 40 s. Subjects had to achieve three successive criteria of acquisition: 3, 5, and 10 consecutive avoidance responses. Results showed that both groups learned the avoidance response, requiring increasingly larger numbers of trials as the acquisition criteria increased. No significant effect of intertrial interval was observed.
THE EFFECTS OF COMPONENT DURATION ON MULTIPLE‐SCHEDULE PERFORMANCE IN CLOSED AND OPEN ECONOMIES
Authors: Fiette Michael H. La , Fantino Edmund
Published: March 2006

Pigeons responded on multiple variable‐interval variable‐interval schedules of reinforcement in an open and a closed economy. Equal duration components were increased in duration while the component rates of reinforcement were held constant, the component schedules were reversed, and component duration was decreased. In the open economy, daily sessions were limited to 1 hr, and subjects were maintained at 80% of their free‐feeding weights through supplemental feeding when necessary in their home cages. In the closed economy, subjects were housed in their experimental chambers and no deprivation regimen was enforced. Relative response rate decreased as components were lengthened in the open economy, whereas in the closed economy relative rate increased as components were lengthened. Response proportions overmatched reinforcer proportions to a greater extent at long component durations in the closed economy, but there was no systematic effect of component duration on responding in the open economy.
RESPONSE—REINFORCER DEPENDENCY LOCATION IN INTERVAL SCHEDULES OF REINFORCEMENT
Authors: Lattal Kennon A. , Freeman Timothy J. , Critchfield Thomas S.
Published: March 2006

In five experiments we studied the effects on pigeons' key pecking of the location of four or more successive response‐dependent reinforcers imbedded in a schedule arranging otherwise response‐independent reinforcers. In Experiment 1, high local response rates early in the session were extended farther into the session as the number of response‐dependent reinforcers at the beginning of the session increased. A block of four successive response‐dependent reinforcers then was scheduled at the beginning, middle, or end of the session (Experiment 2) resulting in higher local response rates at those times in the session when the response‐dependent reinforcers were arranged. When placed in random locations in successive sessions (Experiment 3), uniform local rates occurred throughout the session. In Experiments 1, 2, and 3, delivery of the remaining response‐independent reinforcers was precluded until the response‐dependent reinforcers were collected. Experiment 4 was similar to Experiments 1 and 2, except that all response‐independent reinforcers occurred irrespective of whether the response‐dependent reinforcers had been collected. This yielded results similar to those obtained in the first two experiments. In Experiment 5, responding early in the session had no consequence other than allowing access to the schedule of response‐independent food delivery. As in the first experiment, local rates generally were higher early in the session. The results indicate that the location of response‐reinforcer dependencies precisely control behavior and that such effects often are not captured by descriptions of behavior in terms of overall response rates.
REPEATED ACQUISITION OF BEHAVIORAL CHAINS: RESPONSE SEQUENCES OR CONDITIONAL DISCRIMINATIONS?
Authors: Snodgrass Samuel H. , McMillan D. E.
Published: March 2006

The purpose of this study was to determine whether pigeons learn a sequence of positional responses or a series of conditional discriminations under a repeated‐acquisition‐of‐behavioral‐chains procedure. Three pigeons were trained under a repeated‐acquisition procedure in which three different key colors served as stimuli correlated with the three steps in a chain. The order of presentation of the three stimuli was altered during the latter part of each test session after acquisition had occurred. If the pigeons had acquired a response sequence, the pattern of responding should remain the same as in the initial portion of the test session. However, if the pigeons had acquired a conditional discrimination, the response pattern should change in accordance with the changed order of the key colors. Although the results of this study do not rule out the possibility that the subjects acquired, to some degree, a response sequence, the results suggest that the behavior of pigeons under a repeated‐acquisition‐of‐behavioral‐chains procedure is controlled primarily by conditional discriminative stimuli.
THE DEVELOPMENT OF ADAPTIVE CHOICE IN A SELF‐CONTROL PARADIGM
Authors: Sonuga‐Barke Edmund J. S. , Lea Stephen E. G. , Webley Paul
Published: March 2006

Sixteen girls (ages 4, 6, 9, and 12) performed on concurrent‐chain schedules of reinforcement. The initial links were variable‐interval 10‐s schedules, and the terminal links offered a long delay (20, 30, 40, or 50 s) followed by two tokens or a short delay (10 s) followed by one token. Tokens were used to buy toys and sweets. The effect of increasing the delay to the large reward differed significantly across age groups. Whereas 6‐ and 9‐year‐olds maintained a strong preference for the larger, more delayed reward under all delay conditions, half of the 4‐year‐olds and all the 12‐year‐olds showed increasing preference for the small reward as the delay to the large reward increased. The results suggest a two‐stage account of the development of self‐control. In the first stage, behavior is increasingly controlled by reward size, as children learn how to wait for delayed rewards, and in the second phase behavior is increasingly controlled by reward rate, as children learn when it is in fact profitable to wait.