bluuebunny/crossref_metadata_2025 huggingface dataset:
VARIABLE‐RATIO VERSUS VARIABLE‐INTERVAL SCHEDULES: RESPONSE RATE, RESISTANCE TO CHANGE, AND PREFERENCE
Authors: Nevin John A. , Grace Randolph C. , Holland Shasta , McLean Anthony P.
Published: March 2006

Two experiments asked whether resistance to change depended on variable‐ratio as opposed to variable‐interval contingencies of reinforcement and the different response rates they establish. In Experiment 1, pigeons were trained on multiple random‐ratio random‐interval schedules with equated reinforcer rates. Baseline response rates were disrupted by intercomponent food, extinction, and prefeeding. Resistance to change relative to baseline was greater in the interval component, and the difference was correlated with the extent to which baseline response rates were higher in the ratio component. In Experiment 2, pigeons were trained on multiple variable‐ratio variable‐interval schedules in one half of each session and on concurrent chains in the other half, in which the terminal links corresponded to the multiple‐schedule components. The schedules were varied over six conditions, including two with equated reinforcer rates. In concurrent chains, preference strongly overmatched the ratio of obtained reinforcer rates. In multiple schedules, relative resistance to response‐independent food during intercomponent intervals, extinction, and intercomponent food plus extinction depended on the ratio of obtained reinforcer rates but was less sensitive than was preference. When reinforcer rates were similar, both preference and relative resistance were greater for the variable‐interval schedule, and the differences were correlated with the extent to which baseline response rates were higher on the variable‐ratio schedule, confirming the results of Experiment 1. These results demonstrate that resistance to change and preference depend in part on response rate as well as obtained reinforcer rate, and challenge the independence of resistance to change and preference with respect to response rate proposed by behavioral momentum theory.
A TUNED‐TRACE THEORY OF INTERVAL‐TIMING DYNAMICS
Authors: Staddon J. E. R. , Chelaru I. M. , Higa J. J.
Published: March 2006

Animals on interval schedules of reinforcement can rapidly adjust a temporal dependent variable, such as wait time, to changes in the prevailing interreinforcement interval. We describe data on the effects of impulse, step, sine‐cyclic, and variable‐interval schedules and show that they can be explained by a tuned‐trace timing model with a one‐back threshold‐setting rule. The model can also explain steady‐state timing properties such as proportional and Weber law timing and the effects of reinforcement magnitude. The model assumes that food reinforcers and other time markers have a decaying effect (trace) with properties that can be derived from the rate‐sensitive property of habituation (the multiple‐time‐scale model). In timing experiments, response threshold is determined by the trace value at the time of the most recent reinforcement. The model provides a partial account for the learning of multiple intervals, but does not account for scalloping and other postpause features of responding on interval schedules and has some problems with square‐wave schedules.
EVIDENCE AGAINST A CONSTANT‐DIFFERENCE EFFECT IN CONCURRENT‐CHAINS SCHEDULES
Authors: Mazur James E.
Published: March 2006

Savastano and Fantino (1996) reported that in concurrent‐chains schedules, initial‐link choice proportions remained constant as terminal‐link durations increased as long as the subtractive difference between the two terminal‐link schedules remained constant. Two experiments with pigeons were conducted to examine this constant‐difference effect. Both experiments used equal variable‐interval schedules as initial links. The terminal links were fixed delays to reinforcement in Experiment 1 and variable delays to reinforcement in Experiment 2. The durations of the terminal links were varied across conditions, but the difference between pairs of terminal links was always 10 s. In both experiments, preference for the shorter terminal link became less extreme as terminal‐link durations increased, so a constant‐difference effect was not found. It is argued, however, that this choice situation does not provide clear evidence for or against delay‐reduction theory versus other theories of choice.
PRERATIO PAUSING: EFFECTS OF AN ALTERNATIVE REINFORCER ON FIXED AND VARIABLE‐RATIO RESPONDING
Authors: Derenne Adam , Baron Alan
Published: March 2006

Seven rats responding under fixed‐ratio or variable‐ratio schedules of food reinforcement had continuous access to a drinking tube inserted into the operant chamber. Under different conditions they could drink either tap water or one of two saccharin solutions. In a baseline condition, the drinking bottle was empty. Preratio pausing was observed with both schedules, more so with the fixed‐ratio than the variable‐ratio schedule, and increasing the concentration of the saccharin solution increased the duration of pausing. Comparisons with baseline performances revealed that the additional pausing was largely, but not entirely, spent drinking. The results support the view that pausing under ratio schedules is a consequence of competition between the scheduled reinforcer and alternative reinforcers that also are available within the experimental environment.
BETWEEN THE WAVES: HARVARD PIGEON LAB 1955–1960
Authors: Gollub Lewis R.
Published: March 2006

Six or more graduate students were active in and around the Pigeon Lab in the spring of 1955 and also in 1960, but when I arrived in the fall of 1955 there were none. Looking back in 2001 at that period I can appreciate the unique opportunity for research that I had, as well as the exceptional and productive groups of graduate students who had recently finished their study and research and those who would carry on the tradition of excellence.
MOLECULAR ANALYSES OF THE PRINCIPAL COMPONENTS OF RESPONSE STRENGTH
Authors: Killeen Peter R. , Hall Scott S. , Reilly Mark P. , Kettle Lauren C.
Published: March 2006

Killeen and Hall (2001) showed that a common factor called strength underlies the key dependent variables of response probability, latency, and rate, and that overall response rate is a good predictor of strength. In a search for the mechanisms that underlie those correlations, this article shows that (a) the probability of responding on a trial is a two‐state Markov process; (b) latency and rate of responding can be described in terms of the probability and period of stochastic machines called clocked Bernoulli modules; and (c) one such machine, the refractory Poisson process, provides a functional relation between the probability of observing a response during any epoch and the rate of responding. This relation is one of proportionality at low rates and curvilinearity at higher rates.
EFFECTS OF REINFORCER MAGNITUDE ON RESPONDING UNDER DIFFERENTIAL‐REINFORCEMENT‐OF‐LOW‐RATE SCHEDULES OF RATS AND PIGEONS
Authors: Doughty Adam H. , Richards Jerry B.
Published: March 2006

Experiment 1 investigated the effects of reinforcer magnitude on differential‐reinforcement‐of‐low‐rate (DRL) schedule performance in three phases. In Phase 1, two groups of rats (n 5 6 and 5) responded under a DRL 72‐s schedule with reinforcer magnitudes of either 30 or 300 ml of water. After acquisition, the water amounts were reversed for each rat. In Phase 2, the effects of the same reinforcer magnitudes on DRL 18‐s schedule performance were examined across conditions. In Phase 3, each rat responded under a DRL 18‐s schedule in which the water amounts alternated between 30 and 300 ml daily. Throughout each phase of Experiment 1, the larger reinforcer magnitude resulted in higher response rates and lower reinforcement rates. The peak of the interresponse‐time distributions was at a lower value under the larger reinforcer magnitude. In Experiment 2, 3 pigeons responded under a DRL 20‐s schedule in which reinforcer magnitude (1‐s or 6‐s access to grain) varied from session to session. Higher response rates and lower reinforcement rates occurred under the longer hopper duration. These results demonstrate that larger reinforcer magnitudes engender less efficient DRL schedule performance in both rats and pigeons, and when reinforcer magnitude was held constant between sessions or was varied daily. The present results are consistent with previous research demonstrating a decrease in efficiency as a function of increased reinforcer magnitude under procedures that require a period of time without a specified response. These findings also support the claim that DRL schedule performance is not governed solely by a timing process.
GROUP FORAGING SENSITIVITY TO PREDICTABLE AND UNPREDICTABLE CHANGES IN FOOD DISTRIBUTION: PAST EXPERIENCE OR PRESENT CIRCUMSTANCES?
Authors: Bell Kenneth E. , Baum William M.
Published: March 2006

The ideal free distribution theory (Fretwell & Lucas, 1970) predicts that the ratio of foragers at two patches will equal the ratio of food resources obtained at the two patches. The theory assumes that foragers have “perfect knowledge” of patch profitability and that patch choice maximizes fitness. How foragers assess patch profitability has been debated extensively. One assessment strategy may be the use of past experience with a patch. Under stable environmental conditions, this strategy enhances fitness. However, in a highly unpredictable environment, past experience may provide inaccurate information about current conditions. Thus, in a nonstable environment, a strategy that allows rapid adjustment to present circumstances may be more beneficial. Evidence for this type of strategy has been found in individual choice. In the present experiments, a flock of pigeons foraged at two patches for food items and demonstrated results similar to those found in individual choice. Experiment 1 utilized predictable and unpredictable sequences of resource ratios presented across days or within a single session. Current foraging decisions depended on past experience, but that dependence diminished when the current foraging environment became more unpredictable. Experiment 2 repeated Experiment 1 with a different flock of pigeons under more controlled circumstances in an indoor coop and produced similar results.
CATEGORIZING A MOVING TARGET IN TERMS OF ITS SPEED, DIRECTION, OR BOTH
Authors: Herbranson Walter T. , Fremouw Thane , Shimp Charles P.
Published: March 2006

Pigeons categorized a moving target in terms of its speed and direction in an adaptation of the randomization procedure used to study human categorization behavior (Ashby & Maddox, 1998). The target moved according to vectors that were sampled with equal probabilities from two slightly overlapping bivariate normal distributions with the dimensions of speed and direction. On the average, pigeons categorized optimally in that they attended to either speed or direction alone, or divided attention between them, as was required by different reinforcement contingencies. Decision bounds were estimated for individual pigeons for each attentional task. Average slopes and y intercepts of these individually estimated decision bounds closely approximated the corresponding values for optimal decision bounds. There is therefore at least one task in which pigeons, on the average, display flexibility and quantitative precision in allocating attention to speed and direction when they categorize moving targets.
THE FORMATION OF LINKED PERCEPTUAL CLASSES
Authors: Fields Lanny , Matneja Priya , Varelas Antonios , Belanich James , Fitzer Adrienne , Shamoun Kim
Published: March 2006

Multiple‐exemplar training with stimuli in four domains induced two new fill‐based (A19 and A29) and satellite‐image‐based (B19 and B29) perceptual classes. Conditional discriminations were established between the endpoints of the A19 and B19 classes as well as the A29 and B29 classes. The emergence of linked perceptual classes was evaluated by the performances occasioned by nine cross‐class probes that contained fill variants as samples and satellite variants as comparisons, along with nine other cross‐class probes that consisted of satellite variants as samples and fill variants as comparisons. The 18 probes were first presented serially and then concurrently. Class‐consistent responding indicated the emergence of linked perceptual classes. Of the linked perceptual classes, 70% emerged during the initial serial test. An additional 20% of the linked perceptual classes emerged during the subsequently presented concurrent test block. Thus, linked perceptual classes emerged on an immediate or delayed basis. Linked perceptual classes, then, share structural and functional similarities with equivalence classes, generalized equivalence classes, cross‐modal classes, and complex naturally occurring categories, and may clarify processes such as intersensory perception.
FAILURE TO FIND EVIDENCE OF STIMULUS GENERALIZATION WITHIN PICTORIAL CATEGORIES IN PIGEONS
Authors: Sutton Jennifer E. , Roberts William A.
Published: March 2006

Pigeons' key pecks were reinforced in the presence of pictures from one of two categories, cats or cars. A single picture associated with reinforcement was used in Experiment 1, and 20 pictures from the same category were associated with reinforcement in Experiment 2. Pigeons then were presented with novel test pictures from the training category and from the other, previously unseen, category. During Session 1 of testing, pigeons pecked no more often at pictures from the reinforced category than at pictures from the previously unseen category. When pigeons were trained with pictures associated with reinforcement or its absence from different categories in Experiment 3, differential responding to novel pictures from different categories appeared during Session 1. These findings argue against a process of automatic stimulus generalization within natural categories and in favor of the position that category distinctions are not made until members of at least two categories are compared with one another.
BRIEF PRESENTATIONS ARE SUFFICIENT FOR PIGEONS TO DISCRIMINATE ARRAYS OF SAME AND DIFFERENT STIMULI
Authors: Wasserman Edward A. , Young Michael E. , Peissig Jessie J.
Published: March 2006

Four pigeons first learned to discriminate 16‐item arrays of same from different pictorial stimuli. They were then tested with reduced exposure to the pictorial arrays, brought about by changes in the stimulus viewing requirement under fixed‐ratio (FR) and fixed‐interval (FI) schedules. Increasing the FR requirement enhanced discriminative performance up to 10 pecks; increasing the FI requirement enhanced discriminative performance up to 5 s. Exposures to the stimulus arrays averaging only 2 s supported reliable discrimination. Pigeons thus discriminate same from different stimuli with considerable speed, suggesting that same—different discrimination behavior is of substantial adaptive significance.
SEA LIONS AND EQUIVALENCE: EXPANDING CLASSES BY EXCLUSION
Authors: Kastak Colleen Reichmuth , Schusterman Ronald J.
Published: March 2006

Experiments have shown that human and nonhuman subjects are capable of performing new arbitrary stimulus—stimulus relations without error. When subjects that are experienced with matching‐to‐sample procedures are presented with a novel sample, a novel comparison, and a familiar comparison, most respond by correctly selecting the novel comparison in the presence of the new sample. This exclusion paradigm was expanded with two California sea lions that had previously formed two 10‐member equivalence classes in a matching‐to‐sample procedure. Rather than being presented with a novel sample on a given trial, the sea lions were presented with a randomly selected familiar member of one class as the sample. One of the comparisons was a randomly selected familiar member of the alternative class, and the other was a novel stimulus. When required to choose which comparison matched the sample, the subjects reliably rejected the familiar comparison, and instead selected the unfamiliar one. Next, the sea lions were presented with transfer problems that could not be solved by exclusion; they immediately grouped the new stimuli into the appropriate classes. These findings show that exclusion procedures can rapidly generate new stimulus relations that can be used to expand stimulus classes.
NAMING AND CATEGORIZATION IN YOUNG CHILDREN: VOCAL TACT TRAINING
Authors: Lowe C. Fergus , Horne Pauline J. , Harris Fay D. A. , Randle Valerie R. L.
Published: March 2006

In three experiments, 2‐ to 4‐year‐old children, following pretraining with everyday objects, were presented with arbitrary stimuli of differing shapes. In Experiment 1A, 9 subjects were trained one common tact response, “zag,” to three of these and a second tact, “vek,” to another three. In category match‐to‐sample Test 1, 4 subjects sorted accurately when required only to look at the sample before selecting from five comparisons. The remaining 5 subjects succeeded in Test 2, in which they were required to tact the sample before selecting comparisons. Experiment 1B showed, for 2 of these subjects, that tact training with 12 arbitrary stimuli established two six‐member classes that were still intact 6 weeks later. In Experiment 2, 3 new subjects participated in a common tact training procedure that ensured that none of the exemplars from the same class were presented together prior to the test for three‐member classes. Two subjects passed category Test 1 and the third passed Test 2. Tests showed subjects' listener behavior in response to hearing /zog/ and /vek/ to be in place. These experiments indicate that common naming is effective in establishing arbitrary stimulus classes and that category match‐to‐sample testing provides a robust measure of categorization.
THE COMPETITION‐AMONG‐RELATIONS‐IN‐NOMINALS THEORY OF CONCEPTUAL COMBINATION: IMPLICATIONS FOR STIMULUS CLASS FORMATION AND CLASS EXPANSION
Authors: Gagné Christina L.
Published: March 2006

One way in which new concepts are added to the conceptual system is through conceptual combination. The competition‐among‐relations‐in‐nominals (CARIN) theory (Gagné & Shoben, 1997) proposes that conceptual combination involves specifying a thematic relation (e.g., noun MADE OF modifier) to link the constituent concepts (e.g., chocolate and bee). This theory claims that relations have different strengths for various concepts that correspond to how often a modifier and relation have been paired in previous encounters with combined concepts and that this relational knowledge strongly affects the ease with which combined concepts can be formed. A mathematical model that incorporates key claims of the theory is presented, and empirical findings that are relevant to evaluating the CARIN theory are reviewed. The parallels between the CARIN theory and approaches to stimulus class formation are also discussed.
PSYCHOLOGICAL ESSENTIALISM: A REVIEW OF E. MARGOLIS AND S. LAURENCE (EDS.), CONCEPTS: CORE READINGS
Authors: Palmer David C.
Published: March 2006

Concepts: Core Readings (1999) is an edited volume of articles representing five major theories of concepts within cognitive psychology. Of the five, only the prototype theory can be interpreted in terms arising from a behavioral analysis. Two conceptual problems pervade nearly all of the papers in the volume. The first is an implicit commitment to essentialism; concepts are reified and are commonly discussed as though they have essential properties. Second, the theories suffer from a defective theory of verbal behavior. No distinction is made between verbal operants and words drawn from a hat.
FROM MOLECULAR TO MOLAR: A PARADIGM SHIFT IN BEHAVIOR ANALYSIS
Authors: Baum William M.
Published: March 2006

A paradigm clash is occurring within behavior analysis. In the older paradigm, the molecular view, behavior consists of momentary or discrete responses that constitute instances of classes. Variation in response rate reflects variation in the strength or probability of the response class. The newer paradigm, the molar view, sees behavior as composed of activities that take up varying amounts of time. Whereas the molecular view takes response rate and choice to be “derived” measures and hence abstractions, the molar view takes response rate and choice to be concrete temporally extended behavioral allocations and regards momentary “responses” as abstractions. Research findings that point to variation in tempo, asymmetry in concurrent performance, and paradoxical resistance to change are readily interpretable when seen in the light of reinforcement and stimulus control of extended behavioral allocations or activities. Seen in the light of the ontological distinction between classes and individuals, extended behavioral allocations, like species in evolutionary taxonomy, constitute individuals, entities that change without changing their identity. Seeing allocations as individuals implies that less extended activities constitute parts of larger wholes rather than instances of classes. Both laboratory research and everyday behavior are explained plausibly in the light of concrete extended activities and their nesting. The molecular view, because it requires discrete responses and contiguous events, relies on hypothetical stimuli and consequences to account for the same phenomena. One may prefer the molar view on grounds of elegance, integrative power, and plausibility.
EVOLUTION, BEHAVIOR PRINCIPLES, AND DEVELOPMENTAL SYSTEMS: A REVIEW OF GOTTLIEB'S SYNTHESIZING NATURE‐NURTURE: PRENATAL ROOTS OF INSTINCTIVE BEHAVIOR
Authors: Schneider Susan M.
Published: March 2006

Gottlieb's developmental psychobiology book provides a base for reexamining the place of the experimental analysis of behavior in the life sciences. His experimental program demonstrating the critical function of the environment in the development of a species‐typical behavior helped force an acceptance of probabilistic epigenesis, the acknowledgment that the developmental genome‐environment system is fully interactional. (Indeed, nature vs. nurture is deader than a doornail.) The repercussions for evolutionary biology and the roles and categorizations of genes, behavior, and environment in behavior‐environment relations are explored in light of current knowledge, including specific implications for the experimental analysis of behavior.
PREFERENCE REVERSALS WITH FOOD AND WATER REINFORCERS IN RATS
Authors: Green Leonard , Estle Sara J.
Published: March 2006

Rats were given a choice between a smaller, immediately available reward and a larger reward available after a delay. In one phase, the reward was food and in another phase, the reward was water. Constant delays were added between the choice presentation and the delivery of the reward alternatives. As the time between choice and reward delivery increased from 0 to 25 s, all rats (except one in the water phase) reversed their preference from the smaller, sooner alternative to the larger, later alternative. These findings extend the generality of the preference‐reversal animal model to qualitatively different reinforcers. Furthermore, the presence of both impulsive and self‐control choices within the same animal is consistent with the view that self‐control may be understood as choice behavior, and that species differences in self‐control may be differences in degree, not kind.
RESPONDING FOR SUCROSE AND WHEEL‐RUNNING REINFORCEMENT: EFFECTS OF SUCROSE CONCENTRATION AND WHEEL‐RUNNING REINFORCER DURATION
Authors: Belke Terry W. , Hancock Stephanie D.
Published: March 2006

Six male albino rats were placed in running wheels and exposed to a fixed‐interval 30‐s schedule of lever pressing that produced either a drop of sucrose solution or the opportunity to run for a fixed duration as reinforcers. Each reinforcer type was signaled by a different stimulus. In Experiment 1, the duration of running was held constant at 15 s while the concentration of sucrose solution was varied across values of 0, 2.5, 5, 10, and 15%. As concentration decreased, postreinforcement pause duration increased and local rates decreased in the presence of the stimulus signaling sucrose. Consequently, the difference between responding in the presence of stimuli signaling wheel‐running and sucrose reinforcers diminished, and at 2.5%, response functions for the two reinforcers were similar. In Experiment 2, the concentration of sucrose solution was held constant at 15% while the duration of the opportunity to run was first varied across values of 15, 45, and 90 s then subsequently across values of 5, 10, and 15 s. As run duration increased, postreinforcement pause duration in the presence of the wheel‐running stimulus increased and local rates increased then decreased. In summary, inhibitory aftereffects of previous reinforcers occurred when both sucrose concentration and run duration varied; changes in responding were attributable to changes in the excitatory value of the stimuli signaling the two reinforcers.
YOU CAN LEAD AN APE TO A TOOL, BUT …: A REVIEW OF POVINELLI'S FOLK PHYSICS FOR APES: THE CHIMPANZEE'S THEORY OF HOW THE WORLD WORKS
Authors: Machado Armando , Silva Francisco J.
Published: March 2006

We reviewed Daniel Povinelli's book, Folk physics for apes: The chimpanzee's theory of how the world works. After a summary of the book's contents, we analyzed two sets of experiments on chimpanzees' folk psychology: one that explored whether chimpanzees understand that others see (i.e., that apes have internal visual experiences) and another that examined whether chimpanzees can distinguish intended from unintended actions. The conceptual scaffolding on which these studies were conceived was sufficiently faulty that their outcomes were virtually assured a priori. We then analyzed two sets of experiments on chimpanzees' folk physics, reinforcing our view that conceptual confusion guaranteed that certain key predictions about the outcome of these studies could not be supported. A unifying reason for this conceptual confusion is that the author devalues understanding that results from programmatic conditioning. We closed the review by relating Povinelli's findings and conclusions to behavior analysis and by explaining why behavior analysts should read this book
CONTINGENCY DISCRIMINABILITY, MATCHING, AND BIAS IN THE CONCURRENT‐SCHEDULE RESPONDING OF POSSUMS (TRICHOSURUS VULPECULA)
Authors: Bron Angela , Sumpter Catherine E. , Foster T. Mary , Temple William
Published: March 2006

Six possums (Trichosurus vulpecula) responded under dependent concurrent variable‐interval variable‐interval schedules of reinforcement. Over 15 conditions, barley—carob was one reinforcer with the other reinforcer consisting of Coco Pops®, coconut, or a barley—carob mixture with 0%, 2%, 4%, or 6% salt added to the barley. The schedules were both variable‐interval 40 s. As has been found with other species, behavior on the concurrent schedules was biased by the type of feed, with the 6% salt and the coconut giving the greatest biases towards the barley—carob mixture. The schedules were varied over 17 conditions using the barley—carob mixture alone or the barley—carob mixture versus the mixture with 4% or 6% salt. Both the contingency‐discriminability model (Davison & Jenkins, 1985) and the generalized matching law described the data from the three sets of conditions equally well. Both gave similar measures of bias; however, some of the parameter values found with the contingency discriminability model were uninterpretable. Thus, any argument for this model based on the interpretability of the parameter values becomes weak. It is worth retaining the generalized matching law as a descriptor of such data.
THE EFFECT OF SIGNALED REINFORCEMENT ON RATS' FIXED‐INTERVAL RESPONDING
Authors: Reed Phil
Published: March 2006

Four experiments examined the effect on rats' response rate of presenting a brief (500 ms) stimulus simultaneously with the delivery of food on fixed‐interval (FI) schedules. In Experiment 1, reinforcement signals that were spatially diffuse (both tones and lights) elevated rates of responding, but responding was attenuated by localized visual stimuli. The remaining experiments examined the signal‐induced potentiation of responding. In Experiment 2, a tone reinforcement signal potentiated response rates on an FI schedule, but attenuated response rates on a variable‐interval (VI) schedule. This difference was obtained even though the overall rate of responding was equated on the two schedules before the introduction of the signal. Signal‐induced potentiation of responding occurred over a range of FI values employed in Experiment 3. In Experiment 4, presenting a reinforcement signal when high local rates of response had occurred immediately before reinforcement resulted in potentiated rates of responding on an FI schedule. The opposite effect on response rate occurred when the reinforcement signal followed only low local rates of response. These results indicate that a variety of factors influence the effects of a reinforcement signal. They imply, however, that the local rate of response at the time of reinforcement is a key factor in establishing the nature of the signaling effect.
BUILDING BLOCKS OF SELF‐CONTROL: INCREASED TOLERANCE FOR DELAY WITH BUNDLED REWARDS
Authors: Ainslie George , Monterosso John R.
Published: March 2006

Impulsive choice can be defined as temporary preference for a smaller‐sooner reward (SS) over a larger‐later reward (LL). Hyperbolic discounting implies that impulsive choices will occur less when organisms choose between a series of SSs versus LLs all at once than when they choose between single SS versus LL pairs. Eight rats were exposed to two conditions of an intertemporal choice paradigm using sucrose solution as reward. In both conditions, the LL was 150 μl delayed by 3 s, while the SS was an immediate reward that ranged from 25–150 μl across sessions. Preference for the LL was greater when the chosen reward was automatically delivered three times in succession (bundled) than when it was chosen singly and delivered after each choice. For each of the 8 rats, the estimated SS amount that produced indifference was higher in the bundled condition than in the single condition. Because bundling in humans may be based on the perception that one's current choice is predictive of future choices, the data presented here may demonstrate an important building block of self‐control.
AN ANALYSIS OF GENERALIZED CONTEXTUAL CONTROL OF CONDITIONAL DISCRIMINATIONS
Authors: Serna Richard W. , Pérez‐González Luis Antonio
Published: March 2006

This research asked whether performance engendered by contextual control procedures would generalize to novel matching‐to‐sample stimulus arrangements. Two studies were conducted with young adult participants. In Study 1, participants first were trained to perform the contextually controlled conditional discrimination, X‐AB, where the sample‐comparison relations A1B1 and A2B2 were reinforced in the presence of contextual stimulus X1, but the relations A1B2 and A2B1 were reinforced in the presence of X2. Then, a new conditional discrimination, CD, was established via an unreinforced‐conditional‐selection procedure. Next, participants were tested for X‐CD contextual control performance. Participants selected the originally established CD relations in the presence of X1, but the opposite relations in the presence of X2. Next, an additional conditional relation, EF, was established. Then, participants received trials consisting of entirely novel contextual stimuli, Z1 and Z2, and EF samples and comparisons. Selections were consistent with contextual control; that is, participants selected the originally established EF relations in the presence of one of the novel contextual Z stimuli, but selected the opposite EF relations in the presence of the other contextual Z stimulus. Study 2 systematically replicated these results with naive participants and demonstrated the necessity of first establishing a conditional discrimination prior to tests for generalized contextual control. The findings are discussed in terms of unreinforced conditional selection, stimulus classes, and new ways in which contextual control performances can emerge.
CONCURRENT‐SCHEDULE PERFORMANCE IN TRANSITION: CHANGEOVER DELAYS AND SIGNALED REINFORCER RATIOS
Authors: Krägeloh Christian U. , Davison Michael
Published: March 2006

Six pigeons were trained in experimental sessions that arranged six or seven components with various concurrent‐schedule reinforcer ratios associated with each. The order of the components was determined randomly without replacement. Components lasted until the pigeons had received 10 reinforcers, and were separated by 10‐s blackout periods. The component reinforcer ratios arranged in most conditions were 27:1, 9:1, 3:1, 1:1, 1:3, 1:9 and 1:27; in others, there were only six components, three of 27:1 and three of 1:27. In some conditions, each reinforcement ratio was signaled by a different red—yellow flash frequency, with the frequency perfectly correlated with the reinforcer ratio. Additionally, a changeover delay was arranged in some conditions, and no changeover delay in others. When component reinforcer ratios were signaled, sensitivity to reinforcement values increased from around 0.40 before the first reinforcer in a component to around 0.80 before the 10th reinforcer. When reinforcer ratios were not signaled, sensitivities typically increased from zero to around 0.40. Sensitivity to reinforcement was around 0.20 lower in no‐changeover‐delay conditions than in changeover‐delay conditions, but increased in the former after exposure to changeover delays. Local analyses showed that preference was extreme towards the reinforced alternative for the first 25 s after reinforcement in changeover‐delay conditions regardless of whether components were signaled or not. In no‐changeover‐delay conditions, preference following reinforcers was either absent, or, following exposure to changeover delays, small. Reinforcers have both local and long‐term effects on preference. The former, but not the latter, is strongly affected by the presence of a changeover delay. Stimulus control may be more closely associated with longer‐term, more molar, reinforcer effects.
BOUTS OF RESPONDING FROM VARIABLE‐INTERVAL REINFORCEMENT OF LEVER PRESSING BY RATS
Authors: Shull Richard L. , Grimes Julie A.
Published: March 2006

Four rats obtained food pellets by lever pressing. A variable‐interval reinforcement schedule assigned reinforcers on average every 2 min during one block of 20 sessions and on average every 8 min during another block. Also, at each variable‐interval duration, a block of sessions was conducted with a schedule that imposed a variable‐ratio 4 response requirement after each variable interval (i.e., a tandem variable‐time variable‐ratio 4 schedule). The total rate of lever pressing increased as a function of the rate of reinforcement and as a result of imposing the variable‐ratio requirement. Analysis of log survivor plots of interresponse times indicated that lever pressing occurred in bouts that were separated by pauses. Increasing the rate of reinforcement increased total response rate by increasing the rate of initiating bouts and, less reliably, by lengthening bouts. Imposing the variable‐ratio component increased response rate mainly by lengthening bouts. This pattern of results is similar to that reported previously with key poking as the response. Also, response rates within bouts were relatively insensitive to either variable.
RAPID ACQUISITION OF PREFERENCE IN CONCURRENT CHAINS
Authors: Grace Randolph C. , Bragason Orn , McLean Anthony P.
Published: March 2006

We report two experiments using a concurrent‐chains procedure in which one terminal‐link schedule was fixed‐interval 8 s and the alternative schedule changed randomly from day to day. In Experiment 1, the alternative schedule varied between 4 s and 16 s according to a pseudorandom binary sequence similar to the one used by Hunter and Davison (1985). Similar to results with concurrent schedules, pigeons' response allocation in the initial link was most sensitive to the schedules arranged in the current session, although some effect of prior history was evident. Overall sensitivity was lower than for comparable data from steady‐state research. In Experiment 2, a unique value between 2 s and 32 s was used for the alternative‐schedule delay in each session. Sensitivity levels were similar to Experiment 1 and remained unchanged across 61 sessions of training. For all subjects, sensitivity was greater when the alternative‐schedule delay was greater than 8 s compared with when it was less than 8 s. Generalized‐matching plots revealed evidence of clustering of data points into two groups for some pigeons, suggesting that a process similar to a categorical discrimination may have at least partly determined response allocation. Overall, this research shows that pigeons' initial‐link response allocation can adjust rapidly to frequent changes in the terminal links.
THE RESISTANCE TO CHANGE OF OBSERVING
Authors: Shahan Timothy A. , Magee Adam , Dobberstein Andria
Published: March 2006

Observing responses produce contact with discriminative stimuli and have been considered analogous to attending. Many studies have examined the effects of reinforcement rate on the resistance to change of simple operant behavior, but nothing is known about the resistance to change of observing. Two experiments examined the effects of primary reinforcement rate on the resistance to change of observing behavior of pigeons. In Experiment 1, a multiple schedule of observing‐response procedures was arranged. In a rich component, observing responses produced stimuli correlated with a high rate of random‐interval (RI) reinforcement or extinction. In a lean component, observing responses produced stimuli correlated with a lower rate of RI reinforcement or extinction. In both components, observing responses produced the multiple‐schedule stimuli on a fixed‐interval 0.75‐s schedule. In Experiment 2, a similar procedure was used, but observing in the rich and lean components produced schedule‐correlated stimuli on an RI 15‐s schedule. Observing in the rich component occurred at a higher rate and was more resistant to disruptions produced by presession feeding and response‐independent food deliveries during intercomponent intervals. Despite more frequent observing during unsignaled periods of extinction than unsignaled periods of RI reinforcement, observing during extinction periods was less resistant to change. In addition, replicating the usual result, responding on the food key was generally more resistant to change in the presence of stimuli associated with higher reinforcement rates. These results suggest that quantitative descriptions of resistance to change derived with simple food‐maintained responding may be applicable to observing, and perhaps by extension, to attending.
SCIENCE AND HUMAN BEHAVIOR: A TUTORIAL IN BEHAVIOR ANALYSIS
Authors: Michael Jack
Published: March 2006

B. F. Skinner's Science and Human Behavior (1953) became the main source of my understanding of behavior during my first semester as a college professor in 1955 at Kansas University. It has continued to exert a major influence throughout my career as the basis for a completely deterministic science of behavior, as a handbook to be consulted as a first step in dealing with any issue in behavior analysis, and as a tutorial in behavioral interpretive analysis—in the use of a small number of behavioral concepts and principles to understand behavior of all degrees of complexity. I describe four general interpretive orientations or maxims that are of broad significance for behavior analysis, and also two underappreciated major theoretical contributions.
SCIENCE AND HUMAN BEHAVIOR, DUALISM, AND CONCEPTUAL MODIFICATION
Authors: Zuriff G. E.
Published: March 2006

Skinner's Science and Human Behavior is in part an attempt to solve psychology's problem with mind‐body dualism by revising our everyday mentalistic conceptual scheme. In the case of descriptive mentalism (the use of mentalistic terms to describe behavior), Skinner offers behavioral “translations.” In contrast, Skinner rejects explanatory mentalism (the use of mental concepts to explain behavior) and suggests how to replace it with a behaviorist explanatory framework. For experiential mentalism, Skinner presents a theory of verbal behavior that integrates the use of mentalistic language in first‐person reports of phenomenal experience into a scientific framework.
HUMAN RISKY CHOICE UNDER TEMPORAL CONSTRAINTS: TESTS OF AN ENERGY‐BUDGET MODEL
Authors: Pietras Cynthia J. , Locey Matthew L. , Hackenberg Timothy D.
Published: March 2006

Risk‐sensitive foraging models predict that choice between fixed and variable food delays should be influenced by an organism's energy budget. To investigate whether the predictions of these models could be extended to choice in humans, risk sensitivity in 4 adults was investigated under laboratory conditions designed to model positive and negative energy budgets. Subjects chose between fixed and variable trial durations with the same mean value. An energy requirement was modeled by requiring that five trials be completed within a limited time period for points delivered at the end of the period (block of trials) to be exchanged later for money. Manipulating the duration of this time period generated positive and negative earnings budgets (or, alternatively, “time budgets”). Choices were consistent with the predictions of energy‐budget models: The fixed‐delay option was strongly preferred under positive earnings‐budget conditions and the variable‐delay option was strongly preferred under negative earnings‐budget conditions. Within‐block (or trial‐by‐trial) choices were also frequently consistent with the predictions of a dynamic optimization model, indicating that choice was simultaneously sensitive to the temporal requirements, delays associated with fixed and variable choices on the upcoming trial, cumulative delays within the block of trials, and trial position within a block.
TIME AND RATE MEASURES IN CHOICE TRANSITIONS
Authors: Cerutti D. T. , Staddon J. E. R.
Published: March 2006

Three experiments with pigeons studied the relation between time and rate measures of behavior under conditions of changing preference. Experiment 1 studied a concurrent chain schedule with random‐interval initial links and fixed‐interval terminal links; Experiment 2 studied a multiple chained random‐interval fixed‐interval schedule; and Experiment 3 studied simple concurrent random‐interval random‐interval schedules. In Experiment 1, and to a lesser extent in the other two experiments, session‐average initial‐link wait‐time differences were linearly related to session‐average response‐rate differences. In Experiment 1, and to a lesser extent in Experiment 3, ratios of session‐average initial‐link wait times and response rates were related by a power function. The weaker relations between wait and response measures in Experiment 2 appear to be due to the absence of competition between responses. In Experiments 1 and 2, initial‐link changes lagged behind terminal‐link changes. These findings may have implications for the relations between fixed‐ and variable‐interval procedures and suggest that more attention should be paid to temporal measures in studies of free‐operant choice.
NAMING AND CATEGORIZATION IN YOUNG CHILDREN: II. LISTENER BEHAVIOR TRAINING
Authors: Horne Pauline J. , Lowe C. Fergus , Randle Valerie R. L.
Published: March 2006

Following pretraining with everyday objects, 1‐ to 4‐year‐old children received listener training with three pairs of arbitrary stimuli of differing shapes. For each pair, 9 children were trained to select one stimulus in response to the spoken word /zog/ and the other to the spoken word /vek/. Next, in the look‐at‐sample category match‐to‐sample test, none categorized the six stimuli correctly when asked to look at the sample before selecting from five comparisons. Seven of these children failed a subsequent test of corresponding speaker behavior (tact test); following tact training, 5 of them passed either a repeat of the look‐at‐sample category test (2 subjects) or an alternative category test (3 subjects) in which they were required to tact the sample before selecting comparisons. The remaining 2 failed both category tests. Of the 2 who passed the tact test, 1 passed the tact‐sample category test; the other failed to complete category testing. Two children were next given a second stimulus set. One passed the look‐at‐sample category test and the tact test; the other failed both tests but passed the tact‐sample category test after tact training. The results show that 1‐ to 4‐year‐old children may learn listener behavior without corresponding speaker behavior. The results also show that common listener behavior is not sufficient to establish arbitrary stimulus classes, and they are consistent with the proposition that naming may be necessary for categorization of such stimuli.
BOUTS OF RESPONDING: THE RELATION BETWEEN BOUT RATE AND THE RATE OF VARIABLE‐INTERVAL REINFORCEMENT
Authors: Shull Richard L. , Grimes Julie A. , Bennett J. Adam
Published: March 2006

By nose poking a lighted key, rats obtained food pellets on either a variable‐interval schedule of reinforcement or a schedule that required an average of four additional responses after the end of the variable‐interval component (a tandem variable‐interval variable‐ratio 4 schedule). With both schedule types, the mean variable interval was varied between blocks of sessions from 16 min to 0.25 min. Total rate of key poking increased similarly as a function of the reinforcer rate for the two schedule types, but response rate was higher with than without the four‐response requirement. Analysis of log survivor plots of interresponse times showed that key poking occurred in bouts. The rate of initiating bouts increased as a function of reinforcer rate but was either unaffected or was decreased by adding the four‐response requirement. Within‐bout response rate was insensitive to reinforcer rate and only inconsistently affected by the four‐response requirement. For both kinds of schedule, the ratio of bout time to between‐bout pause time was approximately a power function of reinforcer rate, with exponents above and below 1.0.
CHOICE IN A VARIABLE ENVIRONMENT: VISIT PATTERNS IN THE DYNAMICS OF CHOICE
Authors: Baum William M. , Davison Michael
Published: March 2006

Molar and molecular views of behavior imply different approaches to data analysis. The molecular view privileges moment‐to‐moment analyses, whereas the molar view supports analysis of more and less extended activities. In concurrent performance, the molar view supports study of both extended patterns of choice and more local patterns of visiting the choice alternatives. Analysis of the present data illustrated the usefulness of investigating order at various levels of extendedness. Seven different reinforcer ratios were presented within each session, without cues to identify them, and pigeons pecked at two response keys that delivered food on variable‐interval schedules. Choice changed rapidly within components as reinforcers were delivered and, following each reinforcer, shifted toward the alternative that produced it. If several reinforcers were delivered consecutively by one alternative, choice favored that alternative, but shifted more slowly with each new reinforcer. A discontinuation of such a series of reinforcers by the delivery of a reinforcer by the other alternative resulted in a large shift of choice toward that alternative. These effects were illuminated by analysis of visits to the two alternatives. Changes in visit length occurred primarily in the first postreinforcer visit to the repeatedly reinforced alternative. All other visits tended to be brief and equal. Performance showed multiple signs of moving in the direction of a fix‐and‐sample pattern that characterized steady‐state performance in earlier experiments with many sessions of maintaining each schedule pair. The analyses of extended and local patterns illustrate the flexibility of a molar view of behavior.