bluuebunny/crossref_metadata_2025 huggingface dataset:
EFFECTS OF REINFORCER DURATION ON RESPONDING IN TWO‐LINK CHAINED INTERVAL SCHEDULES
Authors: Lendenmann Karl W. , Myers David L. , Fantino Edmund
Published: March 2006

Each of five pigeons was exposed to two or more durations of access to mixed grains on two‐link, chained, interval schedules in which both links were identical fixed‐interval or variable‐interval schedules. Response rates were an increasing function of reinforcer duration for both initial and terminal links. For both types of interval schedules, initial‐link response rates were more sensitive to reinforcer duration than were terminal‐link response rates. The present results, together with prior ones, suggest that chaining and choice procedures are each sufficient for demonstrating substantial sensitivity of responding to changes in reinforcer duration.
INTRACTABLE PROPERTIES OF RESPONDING UNDER A FIXED‐INTERVAL SCHEDULE
Authors: Gentry G. David , Mark M. Jackson
Published: March 2006

The behavior engendered by the fixed‐interval schedule is characterized by its variability within and across intervals. The present experiment was designed to assess further the magnitude of interval‐to‐interval dynamics and to explore conditions which might enhance control by response number for subsequent output. Pigeons were exposed to three experimental manipulations after responding had stabilized under a fixed‐interval five‐minute schedule. First, a discrete five‐stimulus counter was added so that the key color changed after a fixed number of responses. Then additional grain presentations were made at the end of the interval so that high response output was differentially reinforced in the presence of the counter stimuli. Finally, the counter stimuli were presented as an irregular clock (i.e., independently of responding), but the durations were yoked to performance under the counter condition. The data show that response number can exert influence from one interval to the next, but this source of control is weak and not influenced by the experimental manipulations. Results from the clock arrangement indicate that behavior is controlled largely by the stimulus conditions prevailing at the time of interval onset.
HUMAN FIXED‐INTERVAL PERFORMANCE WITH CONCURRENTLY PROGRAMMED SCHEDULES: A PARAMETRIC ANALYSIS
Authors: Poppen Roger
Published: March 2006

Young adults pressed a lever for points, exchangeable for money, programmed on concurrent schedules in which one component was a fixed‐interval and the other component either a fixed‐ratio (Experiment 1) or a differential‐reinforcement‐of‐low‐rate (Experiment 2). Two general patterns of fixed‐interval responding, postreinforcement pause or constant rate, occurred in both experiments as a function of the parameter values of each component. Also patterns of interaction between the component schedules developed, in which responding or point delivery on one component appeared to be discriminative for responding on the other component. Once a pattern of responding was established, it tended to persist when the parameter values of the schedule were changed. On many schedules, subjects with an experimental history responded differently than did naive subjects, although certain schedule values were resistant to the history effects. The role of verbal strategies in mediating history effects was discussed.
STIMULUS CONTROL OF THE PIGEON'S ABILITY TO PECK A MOVING TARGET
Authors: Pisacreta Richard
Published: March 2006

Two pigeons were trained to peck whichever of eight keys displayed a white field (SD). The other seven keys displayed a white “X” on a black background (SΔ). Each peck to SD produced three‐second access to grain, a three‐second intertrial interval (ITI), and the next trial. Pecks to SΔ produced a three‐second timeout (TO) and the same trial. During later sessions the key displaying SD changed every t seconds (t=3, 2, 1, .5, and .25 sec), requiring the birds to track the position of the SD. Pecks on a ninth key increased t. Several sessions employed novel stimuli to ascertain the controlling stimulus dimensions. Both birds made few errors acquiring the original discrimination. During the tracking sessions, both birds made few errors when t=.5 sec. Only one reliably lengthened t. Data from sessions with novel stimuli indicate that color and form were important aspects of SD and SΔ respectively; movement contributed to the final performance.
ON THE ANALYSIS OF STUDIES OF CHOICE
Authors: Mullins Eamonn , Agunwamba Christian C. , Donohoe Anthony J.
Published: March 2006

In a review of 103 sets of data from 23 different studies of choice, Baum (1979) concluded that whereas undermatching was most commonly observed for responses, the time measure generally conformed to the matching relation. A reexamination of the evidence presented by Baum concludes that undermatching is the most commonly observed finding for both measures. Use of the coefficient of determination by both Baum (1979) and de Villiers (1977) for assessing when matching occurs is criticized on statistical grounds. An alternative to the loss‐in‐predictability criterion used by Baum (1979) is proposed. This alternative statistic has a simple operational meaning and is related to the usual F‐ratio test. It can therefore be used as a formal test of the hypothesis that matching occurs. Baum (1979) also suggests that slope values of between .90 and 1.11 can be considered good approximations to matching. It is argued that the establishment of a fixed interval as a criterion for determining when matching occurs, is inappropriate. A confidence interval based on the data from any given experiment is suggested as a more useful method of assessment.
INTERVAL AND RATIO REINFORCEMENT OF A COMPLEX SEQUENTIAL OPERANT IN PIGEONS
Authors: Schwartz Barry
Published: March 2006

Pigeons were required to produce exactly four pecks on each of two keys in any order for reinforcement. Correct response sequences were reinforced on either fixed‐interval two‐minute or fixed‐ratio four schedules, with each correct sequence treated as a single response. Each pigeon developed a particular dominant sequence that accounted for more than 80% of all sequences. Sequence stereotypy was relatively unaffected by the temporal properties of the fixed‐interval and fixed‐ratio schedules. Response time (time from the first response in each sequence to the last) was also relatively unaffected by the temporal properties of the schedules. In contrast, response latency (time from end of one sequence to the beginning of the next) was markedly affected by the schedules. Latencies were long early in the interreinforcement interval and got shorter as the interreinforcement interval progressed. These data suggest that stereotyped response sequences become functional behavioral units, resistant to disruption or alteration by reinforcement variables that ordinarily influence the temporal spacing of individual responses.
INDEPENDENCE OF STIMULUS DISCRIMINABILITY FROM ABSOLUTE RATE OF REINFORCEMENT IN A SIGNAL‐DETECTION PROCEDURE
Authors: McCarthy Dianne , Davison Michael
Published: March 2006

Three experiments are reported in which two pigeons were trained to detect differences in stimulus duration under varying levels of absolute rate of reinforcement. Two red stimuli, differing in duration, were arranged probabilistically on the center key of a three‐key chamber. On completion of the center‐key duration, the center‐keylight was extinguished and the two side keys were illuminated white. Correct responses were left‐key pecks following the shorter duration and right‐key pecks following the longer duration. In Experiment 1, relative rate of reinforcement for correct responses was held constant and absolute rate of reinforcement was varied in seven conditions from continuous reinforcement to a variable‐interval 90‐second schedule. In Experiment 2, relative rate of reinforcement was manipulated across three different absolute rates of reinforcement (continuous reinforcement, variable‐interval 15‐second, and variable‐interval 45‐second). Stimulus discriminability was unaffected by changes in absolute or relative rates of reinforcement. Experiment 3 showed that discriminability was also unaffected by arranging the same consequences (three‐second blackout) for unreinforced correct responses and errors.
PIGEONS' SPATIAL MEMORY: FACTORS AFFECTING DELAYED MATCHING OF KEY LOCATION
Authors: Wilkie Donald M. , Summers Russell J.
Published: March 2006

The delayed‐matching‐to‐sample procedure was modified to study pigeons' spatial memory. Nine pecking keys, arranged as a three‐by‐three matrix, served as the spatial cues. Trials began with a brief “ready” stimulus (dimming of the houselight). Then a randomly chosen key was lit briefly as a sample. After a short delay 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 produced grain reinforcement, whereas a peck to the other key produced only the intertrial interval. After delayed matching of key location was learned, the effects of sample and delay duration, number of keys illuminated as sample and comparisons, and organization of three‐key samples were studied. Matching accuracy decreased as sample duration decreased, delay increased, the number of locations serving as samples increased, the number and proximity of comparisons increased, and when the three‐key samples were “discontinuous” rather than “lines.”
ACQUISITION AND MAINTENANCE OF POSTSHOCK RESPONSE PATTERN IN NONDISCRIMINATED AVOIDANCE WITH RATS
Authors: Shimai Satoshi , Imada Hiroshi
Published: March 2006

Five experimentally naive albino rats were placed under a nondiscriminated lever‐press avoidance schedule in which the delay to the next shock for responses after a shock was longer than the delay for responses after a response. Four rats acquired the postshock response pattern and maintained it for a prolonged period. The results revealed that postshock responding was under operant control and was not purely shock‐elicited. It was suggested that the two kinds of response‐shock interval, i.e. the shock‐response‐shock interval and the response‐response‐shock interval, could and should be independently controlled in nondiscriminated avoidance schedules.
DELAYED CHOICE RESPONDING BY PIGEONS WHEN THE CORRECT RESPONSE IS NOT PREDICTABLE FROM THE SAMPLE STIMULUS
Authors: Smith James Phillip , Attwood Julia C. , Niedorowski Laura
Published: March 2006

Food‐deprived pigeons were presented with a row of four response keys situated above a grain hopper aperture. At the start of a trial, three of four keys were randomly selected and illuminated white for six seconds. After a variable blackout period, one of the three previously white keys and the previously dark key were illuminated green, and the remaining white keys were reilluminated as before. A response to the green key that was previously white was reinforced with three‐seconds access to grain; a response to any other key resulted in a three‐second blackout and the start of a new trial. Five of six subjects responded to the correct green key more often than chance at an interstimulus interval of 1.5 seconds, and they displayed maximal performance at different intertrial interval values ranging from 15 to 60 seconds. Choice accuracy decreased for all but one subject as the interstimulus interval was increased. For the range of interstimulus interval durations employed, decrements in choice accuracy were qualitatively similar to, but lower than those typically obtained from, delayed‐matching‐to‐sample or delayed‐pair comparison procedures.
REINFORCEMENT CONTINGENCIES AND SIGNAL DETECTION
Authors: Nevin John A. , Jenkins Peter , Whittaker Stephen , Yarensky Peter
Published: March 2006

Pigeons were trained to discriminate temporal stimuli in a discrete‐trial signal‐detection procedure. Pecks to one side key were reinforced intermittently after exposure to one duration, and pecks to the other side key were reinforced intermittently after exposure to a different duration. In Experiment I, the allocation of reinforcers was varied systematically for correct responses and for errors, using a procedure that controlled the obtained numbers of reinforcers. When reinforcers were allocated symmetrically, the level of discrimination decreased as the proportion of reinforcers for errors increased. When reinforcers were allocated asymmetrically, the decrease in discrimination was less systematic. Bias toward one or the other side key roughly matched the ratio of reinforcers obtained by pecks at those keys, independent of the level of discrimination. In Experiment II, the overall rate of reinforcement for correct responses was varied both within and between experimental conditions. The level of discrimination was positively related to the overall rate of reinforcement. The discrimination data of both experiments were interpreted in relation to the contingencies of reinforcement and nonreinforcement, characterized by the average difference in reinforcement probability for correct responses and errors.
PREFERENCE IN CONCURRENT VARIABLE‐INTERVAL FIXED‐RATIO SCHEDULES
Authors: Davison Michael
Published: March 2006

Five pigeons were trained on concurrent variable‐interval fixed‐ratio schedules in three experiments. Experiment 1 used two variable‐interval schedules and one fixed‐ratio schedule, and the ratio requirement was varied. Using the generalized matching law, sensitivity to reinforcement was close to 1.0, but performance was biased toward the variable‐interval schedule with the lower reinforcement rate. In Experiment 2, which used one variable‐interval and one fixed‐ratio schedule, the interval schedule was varied. All birds showed sensitivities to reinforcement of less than 1.0 and of less than the values obtained in Experiment 1. The performance was also biased toward the fixed‐ratio schedule. Because the generalized matching law could not account for the differences in the data from Experiments 1 and 2, an extension of this law was suggested and successfully tested in Experiment 3. The proposed dual‐sensitivity model was also shown to clarify some previously reported results.
MATCHING, MAXIMIZING, AND THE BEHAVIORAL UNIT: CONCURRENT REINFORCEMENT OF RESPONSE SEQUENCES
Authors: Fetterman J. Gregor , Stubbs D. Alan
Published: March 2006

Pigeons pecked two keys in a probability matching situation in which four two‐peck sequences were intermittently reinforced: left‐left, left‐right, right‐left, and right‐right. In Phase 1, relative reinforcement rate was varied with respect to the first response of a sequence: reinforcers were differentially assigned for left‐left and left‐right sequences as opposed to right‐left and right‐right sequences. The second response of reinforced sequences occurred equally on the left and right keys across conditions. In Phase II, relative reinforcement rate was varied for sequences that involved an alternation as opposed to those that did not. The relative outputs of the different sequences matched the relative reinforcement rates for the different sequences in both phases. Relative response rates for key pecks did not always match relative reinforcement rates. The intertrial interval separating responses was varied in both phases; increases in the intertrial interval affected the relative frequency of different sequences. The results demonstrate that response sequences acted as functional units influencing choice and thus support a structural account of choice. At the same time, the matching of relative sequence proportion and relative reinforcement rate supports a matching account.
DETERMINANTS OF PIGEONS' WAITING TIME: EFFECTS OF INTERREINFORCEMENT INTERVAL AND FOOD DELAY
Authors: Manabe Kazuchika
Published: March 2006

Four pigeons performed on three types of schedules at short (i.e., 10, 30, or 60 s) interreinforcement intervals: (a) a delay‐dependent schedule where interreinforcement interval was held constant (i.e., increases in waiting time decreased food delay), (b) an interreinforcement‐interval‐dependent schedule where food delay was held constant (i.e., increases in waiting time increased interreinforcement interval), and (c) a both‐dependent schedule where increases in waiting time produced increases in interreinforcement interval but decreases in food delay. Waiting times were typically longer under the delay‐dependent schedules than under the interreinforcement‐interval‐dependent schedules. Those under both‐dependent schedules for 1 subject were intermediate between those under the other two schedule types, whereas for the other subjects waiting times under the both‐dependent procedure were similar either to those under the delay‐dependent schedule or to those under the interreinforcement‐interval‐dependent schedule, depending both on the subject and the interreinforcement interval. These results indicate that neither the interreinforcement interval nor food delay is the primary variable controlling waiting time, but rather that the two interact in a complex manner to determine waiting times.
RISKY CHOICE AS A FUNCTION OF AMOUNT AND VARIANCE IN FOOD SUPPLY
Authors: Hastjarjo Thomas , Silberberg Alan , Hursh Steven R.
Published: March 2006

In Experiment 1, 4 rats earned their daily food ration by choosing on a trials basis between a “risky” and a “riskless” lever. The risky lever produced either 15 45‐mg food pellets or no pellets, and on average provided five pellets per choice. The riskless lever always produced three pellets. Across conditions, the number of trials per session was varied. Body weight and choice of the risky lever decreased as the number of trials per session decreased, even though body weight could only be defended by increased choice of the risky lever. In Experiment 2, trials per session were fixed, but the number of pellets delivered by the risky and riskless levers was either at the same level as in Experiment 1 or tripled from those levels. Now choice of the risky lever was inversely related to the size of reinforcement and to body weight. The results of these experiments show that risk aversion covaries with the amount of food available in a session and the daily variance in the amount of food earned.
TIMEOUT FROM CONCURRENT SCHEDULES
Authors: Dunn Roger
Published: March 2006

Response‐contingent timeouts of equal duration and frequency were added to both alternatives of unequal concurrent schedules of reinforcement. For each of 4 pigeons in Experiment 1, relative response rates generally became less extreme as the frequency of timeout increased. In Experiment 2, relative response rates consistently approached indifference as the duration of timeout was increased. Variation in time allocation was less consistent in both experiments. Absolute response rates did not vary with the timeout contingency in either experiment. In a third experiment, neither measure of choice varied systematically when the duration of a postreinforcement blackout was varied. In contrast to the present results, preference has been shown to vary directly with the parameters of shock delivery in related procedures. The pattern of results in the first two experiments follows that obtained with other manipulations of the overall rate of reinforcement in concurrent schedules. The results of the third experiment suggest that an intertrial interval following reinforcement is not a critical feature of the overall rate of reinforcement.
CHOICE WITH UNCERTAIN OUTCOMES: CONDITIONED REINFORCEMENT EFFECTS
Authors: Dunn Roger , Spetch Marcia L.
Published: March 2006

Pigeons responded on concurrent chains with equal initial‐ and terminal‐link durations. In all conditions, the terminal links of one chain ended reliably in reinforcement; the terminal links on the alternative chain ended in either food or blackout. In Experiment 1, the terminal‐link stimuli were correlated with (signaled) the outcome, and the durations of the initial and terminal links were varied across conditions. Preference did not vary systematically across conditions. In Experiment 2, terminal‐link durations were varied under different stimulus conditions. The initial links were variable‐interval 80‐s schedules. Preference for the reliable alternative was generally higher in unsignaled than in signaled conditions. Preference increased with terminal‐link durations only in the unsignaled conditions. There were no consistent differences between conditions with and without a common signal for reinforcement on the two chains. In the first series of conditions in Experiment 3, a single response was required in the initial links, and the stimulus conditions during 50‐s terminal links were varied. Preference for the reliable outcome approached 1.0 in unsignaled conditions and was considerably lower (below .50 for 3 of 5 subjects) in signaled conditions. In a final series of signaled conditions with relatively long terminal links, preference varied with duration of the initial links. The results extend previous findings and are discussed in terms of the delay reduction signaled by terminal‐link stimuli.
TEMPORAL DIFFERENTIATION OF RESPONSE DURATION IN CHILDREN OF DIFFERENT AGES: DEVELOPMENTAL CHANGES IN RELATIONS BETWEEN VERBAL AND NONVERBAL BEHAVIOR
Authors: Pouthas V. , Droit S. , Jacquet A.‐Y. , Wearden J. H.
Published: March 2006

Children aged 4.5, 7, or 11 years received an experimental session in which a contingency was placed on button‐press duration. Each discrete trial was followed by a brief verbal probe asking a question about the contingency requirement. Other groups of children received an identical task followed by a postexperimental interview. Level of adaptation to the duration contingency tended to increase with age in subjects receiving posttrial verbal probes, but not for those who were interviewed. Eleven‐year‐olds in the verbal probe condition showed a strong correlation between accurate temporal differentiation and number of verbalizations relating to response duration or timing. The younger subjects, with one exception, showed no association between timing‐related verbalizations (which were almost totally absent) and response duration differentiation. This developmental difference occurred even though the younger subjects verbalized after almost every trial. The results suggest that although 11‐year‐old children apparently produce rule‐governed behavior under verbal control as adults do, the behavior of younger children may be controlled directly by reinforcement contingencies even when their verbal repertoires are highly developed.
OPERANT HOARDING: A NEW PARADIGM FOR THE STUDY OF SELF‐CONTROL
Authors: Cole Mark R.
Published: March 2006

In the first of four experiments, rats were exposed to a modified multiple continuous reinforcement‐extinction schedule during 15‐min daily sessions. In one condition (saves condition) with the cuelight on, a single lever press produced a food pellet, briefly extinguished the cuelight, and started a clock. Saves (additional lever presses with interresponse times less than 1 s) produced an additional food pellet, briefly extinguished the cuelight, and restarted the interresponse time clock. The cuelight was extinguished 1 s after the last lever press and remained off during a 10‐s period of extinction, during which no food pellets were delivered. In the other condition (savings account condition), the contingencies were the same except that the cuelight was extinguished and was not reilluminated after the initial lever press, and the delivery of all food pellets in the reinforcement component was delayed until the onset of extinction. In both conditions, rats made saves, but mean saves (total saves divided by the number of reinforcement components) were slightly reduced in the savings account condition. In Experiment 2, using six equally spaced 15‐min sessions per day on alternate days, saves were either followed immediately with food and brief cuelight offset (saves condition) or were not reinforced at all. Mean saves were much greater when saves were reinforced. In Experiment 3, during 5‐min daily sessions, saves earned a single pellet (savings account condition) or a number of pellets equal to the ordinal number of the lever press (interest condition). Rats made fewer mean saves, with little change in the food rate, when saves earned interest. In Experiment 4, the rats earned all their food in the operant situation during 24 daily 5‐min sessions, these separated by 55‐min intersession intervals during which no food was available; otherwise, the conditions were the same as in Experiment 3. In Experiment 4, the shift to interest for saves led to an increase in mean daily mean saves (total daily mean saves divided by the number of daily sessions) as well as to an increase in the number of food pellets delivered in each session. The results are discussed in terms of self‐control and behavioral economics.
VERBAL SELF‐REPORTS OF DELAYED MATCHING TO SAMPLE BY HUMANS
Authors: Critchfield ThomasS. , Perone Michael
Published: March 2006

Undergraduates participated in two experiments to develop methods for the experimental analysis of self‐reports about behavior. The target behavior was the choice response in a delayed‐matching‐to‐sample task in which monetary reinforcement was contingent upon both speed and accuracy of the choice. In Experiment 1, the temporal portion of the contingency was manipulated within each session, and the presence and absence of feedback about reinforcement was manipulated across sessions. As the time limits became stricter, target response speeds increased, but accuracy and reinforcement rates decreased. When feedback was withheld, further reductions in speed and reinforcement occurred, but only at the strictest time limit. Thus, the procedures were successful in producing systematic variation in the speed, accuracy, and reinforcement of the target behavior. Experiment 2 was designed to assess the influence of these characteristics on self‐reports. In self‐report conditions, each target response was followed by a computer‐generated query: “Did you earn points?” The subject reported by pressing “Yes” or “No” buttons, with the sole consequence of advancing the session. In some cases, feedback about reinforcement of the target response followed the reports; in other cases it was withheld. Self‐reports were less accurate when the target responses occurred under greater time pressure. When feedback was withheld, the speed of the target response influenced reports, in that the probability of a “Yes” report increased directly with the speed of accurate target responses. In addition, imposing the self‐report procedure disrupted target performance by reducing response speeds at the strictest time limit. These results allow investigation of issues in both behavioral and cognitive psychology. More important, the overall order in the data suggests promise for the experimental analysis of self‐reports by human subjects.
THE EFFECTS OF NODALITY ON THE FORMATION OF EQUIVALENCE CLASSES
Authors: Fields Lanny , Adams Barbara J. , Verhave Thom , Newman Sandra
Published: March 2006

A four‐member equivalence class (A → B → C → D) can be formed by training AB, BC, and CD. The nodal stimuli, B and C, mediate all of the derivative (transitive and equivalence) relations in the class. The derivative relations AC, CA, BD, and DB are separated by one node, whereas AD and DA are separated by two nodes. How do the number of nodes that separate the stimuli in a derivative relation influence the induction of stimulus control exerted by that relation? Seven college students learned two four‐member classes made up of nonsense syllables. After training, all derivative relations were presented repeatedly without informative feedback. Stimulus control exerted by each derivative relation was assessed concurrently. For the 7 subjects, control exerted by the derivative relations increased gradually with repeated presentations. With 6 of the 7 subjects, the one‐node relations exerted more control than the two‐node relations during the process. However, the disparity between the one‐ and two‐node relations decreased with repeated presentations. Eventually, all derivative relations exerted complete control. The control exerted by derivative relations during induction was inversely related to the number of nodes separating the terms in the derivative relations. These results demonstrate that nodal distance is a determinant of the relatedness of stimuli in equivalence classes. The findings are discussed in terms of remote association, semantic memory networks, and the study of transitive inference.
ALTERNATIVE REINFORCEMENT INCREASES RESISTANCE TO CHANGE: PAVLOVIAN OR OPERANT CONTINGENCIES?
Authors: Nevin John A. , Tota Mary E. , Torquato Richard D. , Shull Richard L.
Published: March 2006

Two multiple‐schedule experiments with pigeons examined the effect of adding food reinforcement from an alternative source on the resistance of the reinforced response (target response) to the decremental effects of satiation and extinction. In Experiment 1, key pecks were reinforced by food in two components according to variable‐interval schedules and, in some conditions, food was delivered according to variable‐time schedules in one of the components. The rate of key pecking in a component was negatively related to the proportion of reinforcers from the alternative (variable‐time) source. Resistance to satiation and extinction, in contrast, was positively related to the overall rate of reinforcement in the component. Experiment 2 was conceptually similar except that the alternative reinforcers were contingent on a specific concurrent response. Again, the rate of the target response varied as a function of its relative reinforcement, but its resistance to satiation and extinction varied directly with the overall rate of reinforcement in the component stimulus regardless of its relative reinforcement. Together the results of the two experiments suggest that the relative reinforcement of a response (the operant contingency) determines its rate, whereas the stimulus‐reinforcement contingency (a Pavlovian contingency) determines its resistance to change.
CONDITIONED REINFORCEMENT VERSUS TIME TO REINFORCEMENT IN CHAIN SCHEDULES
Authors: Williams Ben A. , Royalty Paul
Published: March 2006

Pigeons were trained on three‐component chain schedules in which the initial component was either a fixed‐interval or variable‐interval schedule. The middle and terminal components were varied among fixed‐interval fixed‐interval, variable‐interval variable‐interval, and an interdependent variable‐interval variable‐interval schedule in which the sum of the durations of the two variable‐interval components was always equal to the sum of the fixed‐interval fixed‐interval components. At issue was whether the response rate in the initial component was controlled by its time to primary reinforcement or by the temporal parameters of the stimulus correlated with the middle terminal link. The fixed‐interval initial‐link schedule maintained much lower response rates than the variable‐interval initial‐link schedule regardless of the schedules in the middle and terminal links. Nevertheless, the intervening schedules played some role: With fixed‐interval schedules in the initial links, response rates were consistently highest with independent variable‐interval schedules in the middle and terminal links and intermediate with the interdependent variable‐interval schedules; these initial‐link differences were predicted by the response rates in the middle link of the chain. With variable‐interval schedules in the initial links, response rates were lowest with the fixed‐interval fixed‐interval schedules following the initial link and were not systematically different for the two types of variable‐interval variable‐interval schedules. The results suggest that time to reinforcement itself accounts for little if any variance in initial‐link responding.
ABSENCE OF ANTICIPATORY CONTRAST IN RATS TRAINED ON MULTIPLE SCHEDULES
Authors: Williams Ben A.
Published: March 2006

Rats were trained on three‐ and four‐component multiple schedules in which two of the components were correlated with identical reinforcement schedules that remained unchanged throughout training. These target components differed in terms of whether their respective following schedules were either higher or lower in value. Unlike corresponding experiments previously reported with pigeons, higher response rates occurred in the target component followed by a higher valued schedule than in the target component followed by the lower valued schedule. Overall contrast effects occurred independently of these sequential effects, but were inconsistent across subjects. The results suggest that the effects of a following schedule of reinforcement are opposite for pigeons and rats, and that one reason previous studies have often failed to show contrast effects with rats is that the effects of the following schedule in rats are in competition with contrast dynamics.
CHOICE BEHAVIOR IN TRANSITION: DEVELOPMENT OF PREFERENCE FOR THE HIGHER PROBABILITY OF REINFORCEMENT
Authors: Bailey John T. , Mazur James E.
Published: March 2006

Ten acquisition curves were obtained from each of 4 pigeons in a two‐choice discrete‐trial procedure. In each of these 10 conditions, the two response keys initially had equal probabilities of reinforcement, and subjects' choice responses were about equally divided between the two keys. Then the reinforcement probabilities were changed so that one key had a higher probability of reinforcement (the left key in half of the conditions and the right key in the other half), and in nearly every case the subjects developed a preference for this key. The rate of acquisition of preference for this key was faster when the ratio of the two reinforcement probabilities was higher. For instance, acquisition of preference was faster in conditions with reinforcement probabilities of .12 and .02 than in conditions with reinforcement probabilities of .40 and .30, even though the pairs of probabilities differed by .10 in both cases. These results were used to evaluate the predictions of some theories of transitional behavior in choice situations. A trial‐by‐trial analysis of individual responses and reinforcers suggested that reinforcement had both short‐term and long‐term effects on choice. The short‐term effect was an increased probability of returning to the same key on the one or two trials following a reinforcer. The long‐term effect was a gradual increase in the proportion of responses on the key with the higher probability of reinforcement, an increase that usually continued for several hundred trials.
SERIAL CONDITIONING AS A FUNCTION OF STIMULUS, RESPONSE, AND TEMPORAL DEPENDENCIES
Authors: Palya William L. , Bevins Rick A.
Published: March 2006

Six experiments were used to examine the effects of explicit response, stimulus, and temporal dependencies on responding in an interfood interval. The first two experiments demonstrated that 10‐segment 60‐s interfood clocks controlled similar distributions of key pecking in pigeons regardless of whether response‐reinforcement contiguity was required, allowed, or precluded. The third and fourth experiments found that in the absence of an explicit response‐reinforcement dependency, systematic explicit stimuli in an interfood interval were sufficient to establish and maintain the characteristic distribution of key pecking and that an interval without an explicit clock failed to establish or maintain key pecking. The last two experiments demonstrated that the interfood interval need not be of fixed length, and that a simple correlation of stimuli with increments from either a minimum to a maximum imminency or probability of food presentation controlled behavior in a similar manner. Successively higher rates generally occurred to successively later stimuli in the upper half of the range.
EFFECTS OF d‐AMPHETAMINE, DIAZEPAM, AND PENTOBARBITAL ON THE SCHEDULE‐CONTROLLED PECKING AND LOCOMOTOR ACTIVITY OF PIGEONS
Authors: Bordi Fabio , Matthews T. James
Published: March 2006

Pigeons were trained on a variant of the autoshaping procedure devised by Matthews and Lerer (1987) in which a keylight stimulus ramp of increasing brightness signaled the passing of a 30‐s interfood interval. This procedure generates two distinct behavioral components: key pecking and locomotor activity. The effects of three psychoactive drugs on these behavior classes were measured. d‐Amphetamine had negligible effects on both types of behavior, whereas diazepam and pentobarbital increased key pecking and decreased activity in a dose‐dependent fashion. In Experiment 2, the possibility that drug effects were suppressed by excessively strong stimulus control exerted in Experiment 1 was tested by decreasing the discriminability of the stimulus ramp. The direction of the effects of diazepam and pentobarbital was the same as in Experiment 1 but the magnitude of the effects tended to be larger. The effects of d‐amphetamine, however, remained quite small, suggesting that, under these conditions, locomotor activity and key pecking are less sensitive to d‐amphetamine. In Experiments 3 and 4, key pecking was eliminated by removing the keylight. Reinforcers were presented at fixed intervals in Experiment 3 and at variable intervals in Experiment 4. The drug effects on activity observed in Experiments 1 and 2 disappeared in both Experiments 3 and 4. The results suggest that diazepam and pentobarbital affect activity indirectly by increasing key‐pecking behavior, which, in turn, competitively decreases activity.
EFFECTS OF ETHANOL ON REINFORCED VARIATIONS AND REPETITIONS BY RATS UNDER A MULTIPLE SCHEDULE
Authors: Cohen Lorenzo , Neuringer Allen , Rhodes Dell
Published: March 2006

Response sequences emitted by five Long‐Evans rats were reinforced under a two‐component multiple schedule. In the REPEAT component, food pellets were contingent upon completion of a left‐left‐right‐right (LLRR) sequence on two levers. In the VARY component, pellets were contingent upon variable sequences (i.e., a sequence was reinforced only if it differed from each of the previous five sequences). The rats learned to emit LLRR sequences in the REPEAT component and variable sequences in VARY. Intraperitoneal injections of ethanol (1.25, 1.75, and 2.25 g/kg) significantly increased sequence variability in REPEAT, thereby lowering reinforcement probability, but had little effect on sequence variability in the VARY component. These results extend previous findings that alcohol impairs the performance of reinforced repetitions but not of reinforced variations in response sequences.
VARIABLE‐INTERVAL SCHEDULE PERFORMANCE IN OPEN AND CLOSED ECONOMIES
Authors: Hall Genae A. , Lattal Kennon A.
Published: March 2006

In two experiments, pigeons obtained food according to variable‐interval schedules. In the first experiment, equivalent variable‐interval schedules with average interreinforcer intervals ranging between 10 and 80 s in different conditions were studied in both open and closed economies. Response rates increased as reinforcement frequency decreased in the closed economy. By contrast, in the open economy response rates decreased for 1 bird and were variable for the other as reinforcement frequency decreased. The second experiment showed that the differences in the functions between responding and reinforcement frequency in the two types of economies were not due to changes in deprivation level. These results suggest that open and closed economies yield different behavioral effects. This conclusion is supported further by a reconsideration of previous findings that appear counter to the conclusion.
THE MOMENTUM OF HUMAN BEHAVIOR IN A NATURAL SETTING
Authors: Mace F. Charles , Lalli Joseph S. , Shea Michael C. , Lalli Elizabeth Pinter , West Barbara J. , Roberts Maura , Nevin John A.
Published: March 2006

Adults with mental retardation in a group home received popcorn or coffee reinforcers for sorting plastic dinnerware. In Part 1 of the experiment, reinforcers were dispensed according to a variable‐interval 60‐s schedule for sorting dinnerware of one color and according to a variable‐interval 240‐s schedule for sorting dinnerware of a different color in successive components of a multiple schedule. Sorting rates were similar in baseline, but when a video program was shown concurrently, sorting of dinnerware was more resistant to distraction when correlated with a higher rate of reinforcement. In Part 2 of the experiment, popcorn or coffee reinforcers were contingent upon sorting both colors of dinnerware according to variable‐interval 60‐s schedules, but additional reinforcers were given independently of sorting according to a variable‐time 30‐s schedule during one dinnerware‐color component. Baseline sorting rate was lower but resistance to distraction by the video program was greater in the component with additional variable‐time reinforcers. These results demonstrate that resistance to distraction depends on the rate of reinforcers obtained in the presence of component stimuli but is independent of baseline response rates and response‐reinforcer contingencies. Moreover, these results are similar to those obtained in laboratory studies with pigeons, demonstrating that the determination of resistance to change by stimulus‐reinforcer relations is not confined to controlled laboratory settings or unique to the pigeon.
RECOGNITION MEMORY IN OLDER ADULTS: ADJUSTMENT TO CHANGING CONTINGENCIES
Authors: Baron Alan , Surdy Theodore M.
Published: March 2006

Four older and 4 younger men were given extended exposure to a continuous‐recognition memory procedure. Experimental variables included the type of stimulus (alphanumeric strings, words, or sentences), the intervals separating repeated items, gains and losses for correct and incorrect recognitions, and the extent of practice with the memory task. Signal detection analyses indicated that the older men generally were less accurate (sensitivity), particularly when the stimuli were strings, but that age differences decreased with practice. Under conditions in which the payoff matrix was neutral, the older and younger men showed equivalent rates of hits and false alarms (bias). Alteration of the matrix to require more liberal or more conservative patterns of recognition responding led to corresponding changes for men of both ages. Adjustments by the older men, however, were not as close to the bias values called for by the new matrices.
RELATIONS BETWEEN BASELINE CONTINGENCIES AND EQUIVALENCE PROBE PERFORMANCES
Authors: Pilgrim Carol , Galizio Mark
Published: March 2006

Following the emergence of two three‐member equivalence classes (A1B1C1 and A2B2C2), 5 college students were exposed to one or more changes in the reinforcement contingencies controlling baseline conditional discriminations. AC relations were either reversed (i.e., C2 was reinforced and C1 punished when A1 was the sample; C1 was reinforced and C2 punished when A2 was the sample) or arranged randomly (i.e., C2 and C1 were reinforced and punished equally often in the presence of A1 and A2). In a third condition, the original AB and AC relations were reversed. Results showed that although baseline conditional discrimination performances were under the control of reinforcement contingencies, and performances on symmetry trials varied with baseline responding for 3 of 4 subjects when contingencies were reversed, performances on transitivity probes remained consistent with the initial equivalence class. These inconsistencies between probe and baseline performances were striking because conditional discriminations are thought to be the determinants of equivalence class performance. Similarly, the contrast between performances on symmetry and transitivity probes was of theoretical interest because equivalence classes are defined by congruent patterns of responding on probe trials.
TACTING AND MANDING IN CORRESPONDENCE TRAINING: EFFECTS OF CHILD SELECTION OF VERBALIZATION
Authors: Baer Ruth A. , Detrich Ronnie
Published: March 2006

We investigated correspondence between verbal and nonverbal behavior in preschool children in a play setting. Four children (4 years old) participated in a multiple baseline across subjects design. Children were asked what toy(s) they were going to play with during an immediately upcoming play period. When no contingencies were placed on either verbal or nonverbal behavior, children showed high rates of correspondence. When children were required to verbalize about a toy from a restricted range of infrequently used toys, but no contingencies were placed on correspondence, low rates of correspondence were observed. High rates of correspondence were noted when reinforcement was contingent on it. Results are discussed in terms of tacting and manding.
THE EFFECTS OF VERBAL PERFORMANCE DESCRIPTIONS ON NONVERBAL OPERANT RESPONDING
Authors: Torgrud Laine J. , Holborn Stephen W.
Published: March 2006

The effect of reinforced verbal descriptions on key‐pressing rate was studied in the context of reinforcement for pressing on schedules opposed to the verbal description and schedules delivering a constant or randomly chosen point value regardless of pressing rate (nondifferential schedules). Undergraduates' key presses produced points exchangeable for lottery tickets on alternating schedules. Subjects experienced one of four manipulations. In Experiment 1, after schedule control had been demonstrated using a “medium rate” schedule for each of two response keys, subjects were awarded maximum points for choosing one of five verbal descriptions of “the best way to earn points” for each key. Subjects experienced either (a) maximum points for verbal descriptions of “press very fast” for one key and “press very slowly” for the other, with the schedule gradually moved from medium to oppose this description, or (b) maximum schedule points for a very fast rate on one key and very slow rate on the other, with the maximum points for verbal descriptions gradually moved to oppose the schedule. Key‐pressing rates conformed to the active schedule, not to the verbal performance description. In Experiment 2 subjects received maximum points for verbal descriptions of “press very fast” for one key and “press very slowly” for the other while the same nondifferential schedule was operative for both keys. Correspondence of pressing rate to verbal description was either complete, transient, or absent. The precise discriminative control of the schedules employed may account for less verbal response‐rate control in the present versus past research. Possible differences between computer‐ and experimenter‐generated verbal behavior are discussed.
THREE‐TERM CONTINGENCY PATTERNS IN MOTHER‐CHILD VERBAL INTERACTIONS DURING FIRST‐LANGUAGE ACQUISITION
Authors: Moerk Ernst L.
Published: March 2006

Selections from a large longitudinal data set of verbal interactions between a mother and her child are presented. Two sets of three‐term contingency sequences that seemed to reflect maternal rewards and corrections were noted. Both the antecedents as well as the immediate consequences of maternal interventions are presented to explore training and learning processes. The observed frequencies of three‐step sequences are compared to those expected based upon Markov‐chain logic to substantiate the patterning of the interactions. Behavioral conceptualizations of the learning process are supported by these analyses, although their sufficiency is questioned. It is suggested that maternal rewards and corrections should be integrated with perceptual, cognitive, and social learning conceptualizations in a skill‐learning approach to explain the complexity of language transmission and acquisition processes.