bluuebunny/crossref_metadata_2025 huggingface dataset:
RUNNING AND RESPONDING REINFORCED BY THE OPPORTUNITY TO RUN: EFFECT OF REINFORCER DURATION
Authors: Belke Terry W.
Published: March 2006

The present study investigated the effect of reinforcer duration on running and on responding reinforced by the opportunity to run. Eleven male Wistar rats responded on levers for the opportunity to run in a running wheel. Opportunities to run were programmed to occur on a tandem fixed‐ratio 1 variable‐interval 30‐s reinforcement schedule. Reinforcer duration varied across conditions from 30 to 120 s. As reinforcer duration increased, the rates of running and lever pressing declined, and latency to lever press increased. The increase in latency to respond was consistent with findings that unconditioned inhibitory aftereffects of reinforcement increase with reinforcer magnitude. The decrease in local lever‐pressing rates, however, was inconsistent with the view that response strength increases with the duration of the reinforcer. Response rate varied inversely, not directly, with reinforcer duration. Furthermore, within‐session data challenge satiation, fatigue, and response deprivation as determinants of the observed changes in running and responding. In sum, the results point to the need for further research with nonappetitive forms of reinforcement.
USING THE SIMULTANEOUS PROTOCOL TO STUDY EQUIVALENCE CLASS FORMATION: THE FACILITATING EFFECTS OF NODAL NUMBER AND SIZE OF PREVIOUSLY ESTABLISHED EQUIVALENCE CLASSES
Authors: Fields Lanny , Reeve Kenneth F. , Rosen Devorah , Varelas Antonios , Adams Barbara J. , Belanich James , Hobbie Sharon A.
Published: March 2006

The emergence of equivalence classes in college students is unlikely when all baseline relations are trained concurrently and all probes for emergent relations are then introduced concurrently (the simultaneous protocol). This experiment showed how the number of nodes and the size of previously established equivalence classes enhanced the emergence of new equivalence classes under the simultaneous protocol. First, one‐node three‐, five‐, or seven‐member classes or three‐node five‐ or seven‐member classes were established with college students. A sixth group received no pretraining. Then, the simultaneous protocol was used to establish new three‐node five‐member equivalence classes with all students. The speed and variability with which the baseline relations were established in the simultaneous protocol were inverse functions of number of nodes in the previously established classes, but not of their size. The percentage of subjects who showed the emergence of new equivalence classes under the simultaneous protocol was a direct function of number of nodes and size of pretrained classes. The additional time spent for pretraining greatly reduced the total training time needed to produce individuals who showed the emergence of classes under the simultaneous protocol. The total time saved was a direct function of number of nodes and number of stimuli in the pretrained classes.
ON THE RELATION BETWEEN PREFERENCE AND RESISTANCE TO CHANGE
Authors: Grace Randolph C. , Nevin John A.
Published: March 2006

Nevin (1979) noted that preference in concurrent chains and resistance to change in multiple schedules were correlated, in that both measures were affected similarly by variations in parameters of reinforcement such as rate, immediacy, and magnitude. To investigate the relationship between preference and resistance to change directly, we used a within‐session procedure that arranged concurrent chains in one half of the session and a multiple schedule in the other half. The same variable‐interval schedules served as terminal links in concurrent chains and as the components of the multiple schedule, and were signaled by the same stimuli. After performances had stabilized, responding in the multiple schedule was disrupted by delivering response‐independent reinforcement during the blackout periods between components. Both preference in concurrent chains and relative resistance to change of multiple‐schedule responding were well described as power functions of relative reinforcement rate, as predicted by current quantitative models (Grace, 1994; Nevin, 1992b). In addition, unsystematic variation in preference and resistance to change was positively correlated, which suggests that preference and resistance to change are independent measures of a single construct. That construct could be described as the learning that occurs regarding the prevailing conditions of reinforcement in a distinctive stimulus situation.
OPEN VERSUS CLOSED ECONOMIES: PERFORMANCE OF DOMESTIC HENS UNDER FIXED‐RATIO SCHEDULES
Authors: Foster T. Mary , Blackman Katharine A. , Temple William
Published: March 2006

Domestic hens responded under fixed‐ratio schedules of food (wheat) reinforcement under several experimental conditions. Part 1 (open economy) investigated performance on fixed‐ratio schedules over both multisession steady‐state conditions and daily changes of the schedule, with hens maintained at 80% of free‐feeding weights by extraexperimental feeding. In Parts 2 and 3 (closed economy and short sessions) sessions were 40 min long, and the hens' weights were allowed to vary (Part 2) or sessions were conducted only when the hens were at approximately 80% of free‐feeding weights (Part 3). In Part 4 (closed economy and long sessions) sessions were 24 hr long and the fixed‐ratio requirement was changed either daily or after 7 consecutive days. In general, the daily changes of fixed‐ratio requirement in the open economy and short‐session closed economy gave much the same result as the steady‐state open‐economy sessions. Overall response and reinforcer rates decreased with increasing fixed‐ratio requirement (except at the shortest fixed ratios). Running response rates decreased, and postreinforcement pauses generally increased. In contrast, overall response rates in the long‐session closed economy generally increased with the fixed‐ratio requirement. Session length is suggested as a cause of the differences between the short‐ and long‐session closed‐economy results.
BEHAVIOR OF RATS UNDER FIXED CONSECUTIVE NUMBER SCHEDULES: EFFECTS OF DRUGS OF ABUSE
Authors: Snodgrass Samuel H. , Hardin Janet L. , McMillan D. E.
Published: March 2006

Four rats responded under a simple fixed consecutive number schedule in which eight or more consecutive responses on the run lever, followed by a single response on the reinforcement lever, produced the food reinforcer. Under this simple schedule, dose—response curves were determined for diazepam, morphine, pentobarbital, and phencyclidine. The rats were then trained to respond under a multiple fixed consecutive number schedule in which a discriminative stimulus signaled when the response requirement on the run lever had been completed in one of the two fixed consecutive number component schedules. Under control conditions, the percentage of reinforced runs under the multiple‐schedule component with the discriminative stimulus added was much higher than the percentage of reinforced runs under the multiple‐schedule component without the discriminative stimulus. All of the drugs decreased the percentage of reinforced runs under each of the fixed consecutive number schedules by increasing the conditional probability of short run lengths. This effect was most consistently produced by morphine. The drugs produced few differences in responding between the multiple fixed consecutive number components. Responding under the simple fixed consecutive number schedule, however, was affected at lower doses of the drugs than was responding under the same fixed consecutive number schedule when it was a component of the multiple schedule. This result may be due to the difference in schedule context or, perhaps, to the order of the experiments.
VARIETIES OF CONTRAST: A REVIEW OF INCENTIVE RELATIVITY BY CHARLES F. FLAHERTY
Authors: Williams Ben A.
Published: March 2006

The phenomenon of contrast has been studied from two quite separate perspectives, one derived from the classic studies of incentive contrast such as Crespi (1942) and the other from the study of behavioral contrast within behavior analysis. This book reviews both of these types of contrast effects and finds both differences and similarities between them. Still at issue is the validity of the interpretation of contrast that assumes that the value of some target level of reward is modified in inverse relation to the level of reward from other sources in the same context. This concept works well for the classic studies of incentive contrast, but is challenged by the emerging importance of anticipatory contrast and the finding in both of the separate research traditions that anticipatory contrast is inversely related to other measures of reinforcement value.
INCONGRUOUS STIMULUS PAIRING AND CONDITIONAL DISCRIMINATION TRAINING: EFFECTS ON RELATIONAL RESPONDING
Authors: Roche Bryan , Barnes Dermot , Smeets Paul M.
Published: March 2006

In Experiment 1, 5 subjects were exposed to a stimulus‐pairing procedure in which two nonsense syllables, identified by a letter‐number code as A1 and C2, each predicted the onset of a sexual film clip, and the nonsense syllables A2 and C1 each predicted the onset of a nonsexual film clip. Subjects were then exposed to a matching‐to‐sample test in which the nonsense syllables A1 and A2 were presented as sample stimuli and C1 and C2 were presented as comparison stimuli and vice versa (i.e., C stimuli as samples and A stimuli as comparisons). All subjects matched A1 with C2 and A2 with C1. Subjects were then trained on the conditional discriminations A1‐B1, A2‐B2, B1‐C1, B2‐C2, after which the matching‐to‐sample test was again administered. All subjects continued to match A1 with C2 and A2 with C1 in accordance with the earlier stimulus‐pairing contingencies. An additional 5 subjects were exposed first to conditional discrimination training and testing before being exposed to the incongruous stimulus pairing and matching‐to‐sample testing. Under these conditions, 4 of the 5 subjects always matched A1 with C1 and A2 with C2. Experiment 2 replicated Experiment 1, except that a matching‐to‐sample test was not administered following the initial training procedure. Under these conditions, matching‐to‐sample test performances were controlled by the contingencies that had immediately preceded the test. Experiment 3 indicated that initial matching‐to‐sample test performances were unlikely to change, even after repeated exposure to incongruous training and testing. Experiment 4 demonstrated that pretraining with unrelated stimulus sets increased the sensitivity of matching‐to‐sample test performances to incongruous contingencies when they were similar in format to those arranged during pretraining. These data may have implications for a behavior‐analytic interpretation of attitude formation and change.
SCHEDULE INTERACTIONS INVOLVING PUNISHMENT WITH PIGEONS AND HUMANS
Authors: Crosbie John , Williams April Michele , Lattal Kennon A. , Anderson Michelle M. , Brown Suzanne M.
Published: March 2006

The principal aim of the present experiments was to assess whether punishment increased or decreased the rate of unpunished behavior (contrast and induction, respectively) for which reinforcement rate was held constant, with physical and nonphysical punishers (electric shock and response cost), pigeon and human subjects, signaled and unsignaled components (multiple and mixed schedules), and the presence or absence of a blackout period between components. Across the three experiments there were 20 punishment conditions. Induction was found in nine of those, less consistent response‐rate reduction was found in three, contrast was found in four, and in four there was no change in responding from conditions without punishment. Contrast occurred consistently only with multiple schedules during the first exposure to electric‐shock punishment. Induction and no change, however, were found with every combination of the independent variables studied. Four conclusions regarding the interactions between punished and unpunished responding emerged from the present results: (a) Both contrast and induction occurred with the reinforcement rate held constant and a blackout between components, (b) induction was more common than contrast, (c) contrast occurred only in the presence of a stimulus different from that correlated with the punisher, and (d) contrast diminished with prolonged exposure to punishment. None of the current theoretical accounts of punishment contrast can explain the present results.
PIGEONS' PREFERENCE FOR FREE CHOICE: NUMBER OF KEYS VERSUS KEY AREA
Authors: Cerutti Daniel , Catania A. Charles
Published: March 2006

In concurrent‐chains schedules, pigeons prefer terminal links that provide two keys correlated with reinforcers (free choice) over those that provide only one key (forced choice), terminal‐link reinforcement rates being equal. With same‐size keys, free choice provides a larger area available for pecking. Preferences were examined using terminal links that differed in key number only (one or two) or key size only (small and medium or medium and large), or that equated the area of the two free‐choice keys with that of the forced‐choice key. Medium (standard) keys were typically preferred to small keys, but indifference was typically obtained between medium and large keys. The size preference usually overrode free‐choice preference with one medium key pitted against two small keys, but free‐choice preference was reliably observed with one large key pitted against two medium keys. In other words, preferences were a joint function of key number and key area, implying that free‐choice preference is not reducible to preference for larger key areas. Free‐choice preference requires separate keys rather than larger areas; the relevant behavioral units are the discriminated operants correlated with each terminal‐link key rather than classes defined by topographical features such as area or perimeter.
SEXUAL REINFORCEMENT IN THE FEMALE RAT
Authors: Matthews T. James , Grigore Mihaela , Tang Liana , Doat Mimi , Kow Lee‐Ming , Pfaff Donald W.
Published: March 2006

Sexual reinforcement in the female rat was studied in a preparation that allowed continuous operant responding for access to a male rat leading to intromission. Experiment 1 used a high operant level nose‐poke response to test the possible reinforcing effects of some components of access to a male. A simple tone stimulus used as a conditioned reinforcer and two odor stimuli, target male bedding and emulsified preputial gland, were tested. None of these contingent events altered responding above or below operant level. Access to the male, which was always accompanied by intromission, immediately increased response rate when it was made contingent upon the nose‐poke response. Performance on fixed‐ratio schedules was erratic, and response rate was low in comparison to typical food‐reinforced responding. An interresponse‐time analysis indicated, however, that some effect of the ratio contingency may have been present. In Experiment 2, several modifications of the procedure were tested with the objective of creating a more tractable preparation for behavior analysis. Response type and the hormone delivery method were changed, and 2 target males were used instead of 1. The latter tripled the average number of reinforcers earned in a single session. Differences between sexual and other reinforcers are discussed in terms of procedural, quantitative, and motivational aspects of the sexual reinforcement procedure.
TRADE‐OFFS IN CHOICE BETWEEN RISK AND DELAY DEPEND ON MONETARY AMOUNTS
Authors: Christensen Joyce , Parker Scott , Silberberg Alan , Hursh Steven
Published: March 2006

In Experiments 1 and 2, 25 and 48 college students made binary choices between hypothetical money amounts. In Part A, choices were between small amounts available with certainty and larger amounts ($10 to $10,000) available with risk. Choices in Part B were between immediate small amounts and delayed larger amounts. As money amount grew, risk aversion and delay aversion both changed but in opposite ways: Risk aversion grew but delay aversion shrank. Part C of Experiment 1 pitted risky amounts against delayed amounts, and its results were consistent with those of Parts A and B. Equivalences of particular risks and delays depended on the particular monetary amounts to which they attached. In Experiment 3, 20 college students made binary choices between money amounts, knowing that they would actually receive some of the selections they made. In Part A, choices were between certain small amounts and risky larger amounts ($1 and $10). Choice problems in Part B were between immediate small amounts and delayed receipt of $1 or $10. The results were like those of Experiment 1, though weaker. These results argue against models of choice that posit an equivalence of risk and delay that is independent of monetary amount.
RESPONSE ACQUISITION WITH DELAYED REINFORCEMENT: A COMPARISON OF TWO‐LEVER PROCEDURES
Authors: Sutphin Glen , Byrne Tom , Poling Alan
Published: March 2006

Groups of 8 experimentally naive rats were exposed during 8‐hr sessions to resetting delay procedures in which responses on one lever (the reinforcement lever) produced water after a delay of 8, 16, 32, or 64 s. For rats in one condition, responses on a second (no‐consequences) lever had no programmed consequences. For rats in another condition, responses on a second (cancellation) lever during a delay initiated by a response on the reinforcement lever prevented delivery of the scheduled reinforcer; responses on the cancellation lever at other times had no programmed consequences. Under both conditions and at all delays, most subjects emitted more responses on the reinforcement lever than did control rats that never received water emitted on either lever. At 8‐s delays, both conditions engendered substantially more responding on the reinforcement lever than on the other lever, and performance closely resembled that of immediate‐reinforcement controls. At delays of 16 and 32 s, however, there was clear differential responding on the two levers under the cancellation condition but not under the other condition. When the delay was 64 s, differential responding on the two levers did not occur consistently under either condition. These findings provide strong evidence that the behavior of rats is sensitive to consequences delayed by 8, 16, and 32 s, but only equivocal evidence of such sensitivity to consequences delayed 64 s. They also indicate that acquisition depends, in part, on the measure of performance used to index it.
EFFECTS OF REWARD DISTRIBUTION AND PERFORMANCE FEEDBACK ON COMPETITIVE RESPONDING
Authors: Schmitt David R.
Published: March 2006

To implement competitive contingencies, one must select a distribution of unequal rewards and a schedule of feedback for competitors regarding one another's performance. This study investigated three bases for distributing rewards and two performance feedback conditions. Pairs of college students competed over a series of 2‐min contests in which the competitive response was a knob pull. A sum of money was divided using a proportional distribution or one of two fixed reward distributions. In the proportional distribution, a subject's proportion of the sum was his or her proportion of the total number of responses. The two fixed distributions were divisions of 100%/0% or 67%/33%. Also, in every contest either subject could make a response that would end the contest prematurely and give both subjects the same amount—a sum equal to 33% of the competitive total. In the two feedback conditions, cumulative responses by each subject were either shown to both subjects during the contest or were not shown. The proportional distribution was clearly superior to either of the fixed distributions in number of responses produced across contests. The proportional distribution with feedback produced the largest number of competitive responses, and the 100%/0% distribution without feedback produced the smallest number. Differences among distributions typically emerged only during later blocks of contests. Fixed distributions of rewards often produced decelerating rates of responding, with losing competitors ending the contests before they were completed. Response‐rate decreases were greatest for pairs in which the 2 subjects differed most in their response rates and proportion of wins. The presence of feedback had a small effect, increasing responding for some pairs in the 100%/0% distribution. Performance patterns were interpreted in terms of the consequences arranged for the individual participants by the reward distributions and differences in performance between competitors.
RUN LENGTH, VISIT DURATION, AND REINFORCERS PER VISIT IN CONCURRENT PERFORMANCE
Authors: MacDonall James S.
Published: March 2006

The contingencies in each alternative of concurrent procedures consist of reinforcement for staying and reinforcement for switching. For the stay contingency, behavior directed at one alternative earns and obtains reinforcers. For the switch contingency, behavior directed at one alternative earns reinforcers but behavior directed at the other alternative obtains them. In Experiment 1, responses on the main lever, in S1, incremented stay and switch schedules and obtained a stay reinforcer when it became available. Responses on the switch lever changed S1 to S2 and obtained switch reinforcers when available. In S2, neither responses on the main lever nor on the switch lever were reinforced, but a switch response changed S2 to S1. Run lengths and visit durations were a function of the ratio of the scheduled probabilities of reinforcement (staying/switching). From run lengths and visit durations, traditional concurrent performance was synthesized, and that synthesized performance was consistent with the generalized matching law. Experiment 2 replicated and extended this analysis to concurrent variable‐interval schedules. The synthesized results challenge any theory of matching that requires a comparison among the alternatives.
SOME LOGICAL FUNCTIONS OF JOINT CONTROL
Authors: Lowenkron Barry
Published: March 2006

Constructing a behavioral account of the language‐related performances that characterize responding to logical and symbolic relations between stimuli is commonly viewed as a problem for the area of stimulus control. In response to this problem, the notion of joint control is presented here, and its ability to provide an interpretative account of these kinds of performances is explored. Joint control occurs when the currently rehearsed topography of a verbal operant, as evoked by one stimulus, is simultaneously evoked by another stimulus. This event, the onset of joint stimulus control by two stimuli over a common response topography, then sets the occasion for a response appropriate to this special relation between the stimuli. Although the mechanism described is simple, it seems to have broad explanatory properties. In what follows, these properties are applied to provide a behavioral interpretation of two sorts of fundamental, putatively cognitive, performances: those based on logical relations and those based on semantic relations. The first includes responding to generalized conceptual relations such as identity, order, relative size, distance, and orientation. The second includes responding to relations usually ascribed to word meaning. These include relations between words and objects, the specification of objects by words, name‐object bidirectionality, and the recognition of objects from their description. Finally, as a preview of some further possibilities, the role of joint control in goal‐oriented behavior is considered briefly.
EFFECTS OF STEP SIZE AND BREAK‐POINT CRITERION ON PROGRESSIVE‐RATIO PERFORMANCE
Authors: Stafford David , Branch Marc N.
Published: March 2006

Key pecking by pigeons was maintained by arithmetic progressive‐ratio schedules of food delivery Successive conditions arranged different step sizes, and each condition remained in effect until behavior appeared stable. Each session continued until a period of time passed in which no key pecks were recorded (the break‐point criterion); both a 5‐min and a 15‐min criterion were tested across a range of step sizes. Average breaking points (i.e, the largest ratio completed) were relatively unaffected by step‐size magnitude, whereas the average number of ratios completed and average response rates generally declined across increasing step sizes. Within sessions, preratio pauses were relatively short and fairly constant in duration as the ratio increased; pause durations increased rapidly near the end of a session. The relation between the average number of completed ratios and step size was described well by a power function [y = b(xa), in which y represents the average number of completed ratios, x represents the step size, and a and b are fitted parameters]. Increasing the break‐point criterion from 5 to 15 min resulted in increased values of b, whereas parameter a was relatively unaffected and was close to −1 (consistent with the lack of effect of step size on breaking point). This function also provided an excellent description of data drawn from previous reports.
CATEGORIZATION OF NATURAL MOVEMENTS BY PIGEONS: VISUAL CONCEPT DISCRIMINATION AND BIOLOGICAL MOTION
Authors: Dittrich Winand H. , Lea Stephen E. G. , Barrett Jacqueline , Gurr Philip R.
Published: March 2006

In three experiments, pigeons were exposed to a discriminated autoshaping procedure in which categories of moving stimuli, presented on videotape, were differentially associated with reinforcement. All stimuli depicted pigeons making defined responses. In Experiment 1, one category consisted of several different scenes of pecking and the other consisted of scenes of walking, flying, head movements, or standing still. Four of the 4 birds for which pecking scenes were positive stimuli discriminated successfully, whereas only 1 of the 4 for which pecking was the negative category did so. In the pecking‐positive group, there were differences between the pecking rates in the presence of the four negative actions, and these differences were consistent across subjects. In Experiment 2, only the categories of walking and pecking were used; some but not all birds learned this discrimination, whichever category was positive, and these birds showed some transfer to new stimuli in which the same movements were represented only by a small number of point lights (Johansson's “biological motion” displays). In Experiment 3, discriminations between pecking and walking movement categories using point‐light displays were trained. Four of the 8 birds discriminated successfully, but transfer to fully detailed displays could not be demonstrated. Pseudoconcept control groups, in which scenes from the same categories of motion were used in both the positive and negative stimulus sets, were used in Experiments 1 and 3. None of the 8 pigeons trained under these conditions showed discriminative responding. The results suggest that pigeons can respond differentially to moving stimuli on the basis of movement cues alone.
A CENTURY OF EFFECT: LEGACIES OF E. L. THORNDIKE'S ANIMAL INTELLIGENCE MONOGRAPH
Authors: Lattal Kennon A.
Published: March 2006

Edward L. Thorndike's monograph, Animal Intelligence: An Experimental Study of the Associative Processes in Animals, is reviewed with respect to three contemporary issues: the relation between human behavior and that of other animals, the law of effect, and research methods for studying behavior. Thorndike employed an experimental analysis, rather than relying on either anecdote or naturalistic observation, to study problem solving and other behavioral processes of cats, dogs, and chicks. His analysis focused on whether the similarities between humans and other animals were homologous, that is, functionally equivalent, or whether they were merely analogous in form. Concluding the latter, he used the law of effect, not stated as such until long after the monograph was published, to account for the behavioral processes he studied, without appeal to reason or other cognitive mechanisms. His combination of applying experimental methods to the study of animal behavior and his insistence on objectivity in behavioral description were prescient of such later behaviorists as Watson and Skinner.
RESPONSE FORM, FORCE, AND NUMBER: EFFECTS ON CONCURRENT‐SCHEDULE PERFORMANCE
Authors: Sumpter Catherine E. , Temple William , Foster T. Mary
Published: March 2006

Six hens responded on concurrent variable‐interval (key‐peck) variable‐interval (door‐push) schedules of reinforcement in which the second‐order (fixed‐ratio) requirements on the alternatives (Experiment 1) or the required door forces (Experiment 2) were varied. The key‐peck and door‐push response (measured as fixed‐ratio completion) and time data were well described by the generalized matching law. However, the manipulations of fixed‐ratio requirement and required response force differed in their effects. The manipulations of fixed‐ratio size affected the response and time measures differently, producing fairly constant, multiplicative biases only in terms of response allocation. It was argued that variations in fixed‐ratio size necessarily change the time allocated to that response unit, and thus changes in time bias were not necessarily a fundamental effect of changing the ratio. In contrast, the changes in response bias were a fundamental result of changes in ratio size. The response‐force manipulations produced similar bias shifts in terms of response and time allocation, but they appeared to combine with relative reinforcement rate to affect choice interactively. Specifically, behavior appeared to be biased towards the least effortful (i.e., key‐peck) response, but the increases in door force had a larger effect on bias when the hens were making this response infrequently (on a lean schedule). The different effects of the fixed‐ratio and response‐force manipulations on concurrent performance were partially accounted for by the differing times required to complete each response unit under those manipulations, but this would not account for the interaction. The interaction would be consonant with increased response effort decreasing the effective value of the associated reinforcement schedule.
STIMULUS EQUIVALENCE: EFFECTS OF A DEFAULT‐RESPONSE OPTION ON EMERGENCE OF UNTRAINED STIMULUS RELATIONS
Authors: Innis Andrew , Lane Scott D. , Miller Erin R. , Critchfield Thomas S.
Published: March 2006

Default‐response options, intended to measure uncertainty, sometimes are included in discrete‐choice measurement in an attempt to clarify stimulus control of remaining response options. Recent experiments have used a default‐response procedure to investigate emergent stimulus relations, but no study to date has compared effects of different default‐response procedures on emergence of the untrained relations that define stimulus equivalence. Five groups of college undergraduates (each n = 16) completed a conditional discrimination training procedure to instate the stimulus relations prerequisite to three three‐member equivalence classes; a training review intermingling all of the explicitly trained relations; and tests for emergent relations. The groups differed in terms of (a) presence versus absence of a “none” option during emergent relations tests and (b) the amount of experience with “catch trials” in which “none” was the correct selection. Stimulus equivalence was demonstrated in 94% of subjects in a control group who were trained and tested without the “none” response option and without catch trials and in 41% of subjects in the “none” groups. Among subjects in the “none” groups who failed to demonstrate equivalence initially, 95% did so when retested under control‐group conditions. Across “none” groups, probability of equivalence class formation was positively correlated with amount of experimental experience with catch trials in preliminary training and equivalence testing. Among the emergent relations defining stimulus equivalence, reflexivity was most often precluded by the “none” option, although there was evidence of group differences in relation specificity. These results suggest that a default‐response option can interfere with the formation of emergent relations, and that the effects are contextually sensitive. Although there may be advantages to employing default‐response procedures in studies of emergent stimulus relations, the responses they control should be viewed as behavior under specific stimulus control rather than a generic expression of uncertainty
REVERSED SCHEDULE EFFECTS IN CLOSED AND OPEN ECONOMIES
Authors: Zeiler Michael D.
Published: March 2006

Pigeons received food according to either fixed‐interval, fixed‐ratio, or random‐interval schedules in both closed and open feeding economies. In the closed economy, they were not food deprived, they controlled the amount of food received at each meal, and they had no other source of food. In the open economy, each feeding bout consisted of one feeder cycle, and the pigeons received supplemental feeding as needed to maintain them at 80% of their free‐feeding weights. Response rate always increased with larger schedule requirements in the closed economy, but it either decreased steadily or increased and then decreased in the open economy. Initial pauses lengthened with longer fixed intervals or fixed ratios (FR) in the open economy but less so in the closed economy. Responding continued under FR 10,000 schedules in the closed economy, but never survived FR 400 in the open economy. In the open economy, fixed‐interval schedules could maintain far more behavior than could either fixed ratios or random intervals. Familiar concepts such as matching and arousal can describe at least some of the behavior in the open economy, but current theory does not apply well to behavior in the closed economy. An explanation of economy‐dependent effects might begin with the possibility that the two economies invoke different evolved survival strategies. These strategies influence behavior by means of different mechanisms and laws. The strategy for the closed economy may relate to weight conservation, but that for the open economy may be based on energy conservation.
EQUIVALENCE CLASS ESTABLISHMENT, EXPANSION, AND MODIFICATION IN PRESCHOOL CHILDREN
Authors: Saunders Richard R. , Drake Kathleen M. , Spradlin Joseph E.
Published: March 2006

Preschool children were taught four two‐choice match‐to‐sample conditional discriminations with 10 arbitrary visual stimuli. For 6 participants, 2 of the 10 stimuli served as the sample, or conditional, stimuli in all discriminations. For 5 additional participants, the same pair of stimuli served as the discriminative, or comparison, stimuli in all discriminations. Equivalence classes were established with more participants in the latter group, replicating prior research with participants with retardation. Four participants, in whom equivalence classes were established and who were available for further participation, were exposed to new conditional discriminations without trial‐by‐trial feedback and involving some novel and some familiar stimuli. Consistent conditional responding was observed, and tests for inclusion of the novel stimuli in the original classes showed class expansion. Training to reverse the unreinforced conditional performances produced a reversal of class membership in 3 of 4 participants, an outcome not consistent with other studies. The results are discussed with respect to the interaction of class structure and size.
CAN A DECAY PROCESS EXPLAIN THE TIMING OF CONDITIONED RESPONSES?
Authors: Gallistel C. R.
Published: March 2006

To explain time‐scale invariant distributions of response latencies, it appears to be necessary to postulate scalar noise in the remembered intervals, against which the subjective measure of the currently elapsing interval is compared. At least in some cases, the observed variability cannot be due to variability in the subjective intervals written to memory; it must come from noise (variability) in the reading of a memory. The Staddon and Higa proposal offers no explanation for the observed variability, and it is unclear what noise assumption would yield the observed variability, given their assumption that intervals are timed by a nonlinear decay process. The decay process cannot plausibly be represented by the logarithmic function, because it begins and ends at infinity. The assumption of any form of nonlinear timing is inconsistent with the most important result of the time‐left experiment, which is that the changeover time increases linearly with the comparison‐standard difference.
MULTIPLE TIME SCALES IS WELL NAMED
Authors: Gibbon John
Published: March 2006

Staddon and Higa's article is a critique of scalar expectancy theory, and a proposed alternative, multiple time scales. The critique is generally flawed, both factually and logically. The alternative is bewildering in its flexibility, opaque in its quantitative description, and never addressed to real data.
TOLERANCE IN A RIGOROUS SCIENCE
Authors: Shimp Charles P.
Published: March 2006

Scientists often evaluate other people's theories by the same standards they apply to their own work; it is as though scientists may believe that these criteria are independent of their own personal priorities and standards. As a result of this probably implicit belief, they sometimes may make less useful judgments than they otherwise might if they were able and willing to evaluate a specific theory at least partly in terms of the standards appropriate to that theory. Journal editors can play an especially constructive role in managing this diversity of standards and opinion.
MOLAR AND MOLECULAR CONTROL IN VARIABLE‐INTERVAL AND VARIABLE‐RATIO SCHEDULES
Authors: Cole Mark R.
Published: March 2006

Response rates are typically higher under variable‐ratio than under variable‐interval schedules of reinforcement, perhaps because of differences in the dependence of reinforcement rate on response rate or because of differences in the reinforcement of long interresponse times. A variable‐interval‐with‐added‐linear‐feedback schedule is a variable‐interval schedule that provides a response rate/reinforcement rate correlation by permitting the minimum interfood interval to decrease with rapid responding. Four rats were exposed to variable‐ratio 15, 30, and 60 food reinforcement schedules, variable‐interval 15‐, 30‐, and 60‐s food reinforcement schedules, and two versions of variable‐interval‐with‐added‐linear‐feedback 15‐, 30‐, and 60‐s food reinforcement schedules. Response rates on the variable‐interval‐with‐added‐linear‐feedback schedule were similar to those on the variable‐interval schedule; all three schedules led to lower response rates than those on the variable‐ratio schedules, especially when the schedule values were 30. Also, reinforced interresponse times on the variable‐interval‐with‐added‐linear‐feedback schedule were similar to those on variable interval and much longer than those produced by variable ratio. The results were interpreted as supporting the hypothesis that response rates on variable‐interval schedules in rats are lower than those on comparable variable‐ratio schedules, primarily because the former schedules reinforce long interresponse times.
THE EFFECTS OF DIFFERING RESPONSE TYPES AND PRICE MANIPULATIONS ON DEMAND MEASURES
Authors: Sumpter Catherine E. , Temple William , Foster T. Mary
Published: March 2006

Animals' behavioral needs have become an important component of animal welfare legislation. Behavioral economics provides a framework for the study of such needs. A function, analogous to a demand function relating consumption rate to price, can be obtained by increasing the price (or work) required for access to a commodity. This experiment investigated the effects of different response types and price manipulations on these functions. Six hens pushed a door or pecked a key for food under open economic conditions (short experimental sessions and supplementary food). In Part 1, the number of door pushes required (fixed‐ratio schedule) was increased each session, and the force needed to push the door was increased across conditions. In Part 2, the force needed to push the door was increased session to session, and the fixed‐ratio schedule was increased across conditions. In Part 3, the number of key pecks required was increased each session. Both response types produced similarly shaped (approximately linear in logarithmic coordinates and downward sloping) demand functions when price was increased by increasing the number of responses required. These imply an elastic demand for food under these conditions. In contrast, increasing the force required to push the door resulted in highly curvilinear functions. These functions indicated little change in consumption across lower door forces and abrupt drops in consumption at higher force requirements, implying mixed elasticity in the animals' demand for food. The differences between the shapes of the two functions seem to arise from the different ways that the two price manipulations alter the time taken to complete the work required. Increasing the fixed‐ratio requirement necessarily increases the time needed to complete each response unit, whereas increasing the force requirement does not. The different shapes of the functions were robust when either force or number was varied across sessions and the value of the other was varied over conditions. They were also robust when the price increases were taken from different conditions, showing that the shapes of the functions were independent of the place in the experiment in which the price was examined. Unit price (which combines number and force into a single price measure) unified the data from the two price manipulations to a large degree, producing moderately curved functions. However, there was some variance around the unit price functions, and this was attributable to the different shapes of the underlying functions. The data suggest that different price manipulations may give different measures of animal demand but that unit price might provide some unification.
PREFERENCE AFTER TRAINING WITH DIFFERENTIAL CHANGEOVER DELAYS
Authors: Williams Ben A. , Bell Matthew C.
Published: March 2006

Pigeons were trained on a multiple schedule in which each component consisted of concurrent variable‐interval (VI) 30‐s VI 60‐s schedules. The two components of the multiple schedule differed only in terms of the changeover delays (COD): For one component short CODs were employed, and in the second component long CODs were used. After approximate matching was obtained in each component, probe tests involving new combinations of stimuli were presented (e.g., the VI 30‐s schedule from each component) to determine how the different CODs affected preference. Despite shorter CODs producing higher changeover rates, the COD value had no systematic effect on preference on the probe trials. However, differences in reinforcement rate always produced preference for the schedule with the higher reinforcement rate. The results thus show that the the pattern of changeover behavior per se is not a critical determinant of choice in the probe‐trial procedure.
A DISCRIMINATION ANALYSIS OF TRAINING‐STRUCTURE EFFECTS ON STIMULUS EQUIVALENCE OUTCOMES
Authors: Saunders Richard R. , Green Gina
Published: March 2006

Experiments designed to establish stimulus equivalence classes frequently produce differential outcomes that may be attributable to training structure, defined as the order and arrangement of baseline conditional discrimination training trials. Several possible explanations for these differences have been suggested. Here we develop a hypothesis based on an analysis of the simple simultaneous and successive discriminations embedded in conditional discrimination training and testing within each of the training structures that are typically used in stimulus equivalence experiments. Our analysis shows that only the comparison‐as‐node (many‐to‐one) structure presents all the simple discriminations in training that are subsequently required for consistently positive outcomes on all tests for the properties of equivalence. The sample‐as‐node (one‐to‐many) training structure does not present all the simple discriminations required for positive outcomes on either the symmetry or combined transitivity and symmetry (equivalence) tests. The linear‐series training structure presents all the simple discriminations required for consistently positive outcomes on tests for symmetry, but not for symmetry and transitivity combined (equivalence) or transitivity alone. Further, the difference in the number of simple discriminations presented in comparison‐as‐node training versus the other training structures is larger when the intended class size is greater than three or the number of classes is larger than two. We discuss the relevance of this analysis to interpretations of stimulus equivalence research, as well as some methodological and theoretical implications.
FOOD AND COCAINE SELF‐ADMINISTRATION BY BABOONS: EFFECTS OF ALTERNATIVES
Authors: Foltin Richard W.
Published: March 2006

The effects of the availability of an alternative reinforcer on responding maintained by food pellets or drug solutions were examined in 8 adult male baboons (Papio hamadrayas anubis). During daily 23‐hr experimental sessions, baboons had access to both food pellets and fluid under a two‐choice procedure, in which the response requirement, under a fixed‐ratio schedule, differed for the two commodities. There were no restrictions on access to water, which was continuously available from a spout at the rear of each cage. In Experiment 1, the fixed‐ratio requirement, or cost, for fluid delivery remained constant while the fixed‐ratio requirement for pellets was changed every 2 or 3 days when (a) no fluid, (b) a dilute dextrose vehicle, (c) 0.008 mg/kg per delivery cocaine, (d) 0.016 mg/kg per delivery cocaine, or (e) 0.032 mg/kg per delivery cocaine was available concurrently. In Experiment 1, progressively increasing the response requirement for pellets decreased pellet intake, but for 4 baboons pellet intake at maximum pellet cost was lower when cocaine, compared to the vehicle, was available. Increasing the response requirement for pellets had variable effects on vehicle intake. However, increasing the response requirement for pellets increased intake of at least one dose of cocaine to a greater extent than vehicle in all 8 baboons. Thus, cocaine could be considered a more effective economic substitute than vehicle for pellets. Experiment 2 systematically varied the order in which the response requirements for a pellet delivery were presented and added a control condition in which cocaine doses, yoked to the amount self‐administered, were given three times during the session by the experimenter. Again, pellet intake at maximal pellet cost was lower when cocaine, compared to the vehicle, was available. In contrast, experimenter‐given cocaine doses did not alter responding maintained by pellets. Thus, the effects of self‐administered cocaine on responding maintained by food pellets differed from the effects of experimenter‐given cocaine on responding maintained by food pellets.
FALSIFICATION OF MATCHING THEORY: CHANGES IN THE ASYMPTOTE OF HERRNSTEIN'S HYPERBOLA AS A FUNCTION OF WATER DEPRIVATION
Authors: McDowell J. J. , Dallery Jesse
Published: March 2006

Five rats pressed levers on variable‐interval schedules of water reinforcement at various levels of water deprivation. In one phase of the experiment, three deprivation conditions that replicated conditions in Heyman and Monaghan (1987) were arranged, along with three less extreme deprivation conditions. In a second phase, water deprivation was arranged so that subjects were exposed to a greater range of access to water per day. Herrnstein's hyperbola described the rats' response‐rate data well. The y asymptote, k, of the hyperbola appeared roughly constant over the conditions that replicated those of Heyman and Monaghan, but decreased markedly when less extreme deprivation conditions were included. In addition, k varied systematically when the second method of arranging deprivation was used. These results falsify a strong form of matching theory and confirm predictions made by linear system theory.