bluuebunny/crossref_metadata_2025 huggingface dataset:
BEHAVIORAL AND PHARMACOLOGICAL VARIABLES AFFECTING RISKY CHOICE IN RATS
Authors: Kaminski Barbara J. , Ator Nancy A.
Published: March 2006

The effects of manipulations of response requirement, intertrial interval (ITI), and psychoactive drugs (ethanol, phencyclidine, and d‐amphetamine) on lever choice under concurrent fixed‐ratio schedules were investigated in rats. Responding on the “certain” lever produced three 45‐mg pellets, whereas responding on the “risky” lever produced either 15 pellets (p = .33) or no pellets (p = .67). Rats earned all food during the session, which ended after 12 forced trials and 93 choice trials or 90 min, whichever occurred first. When the response requirement was increased from 1 to 16 and the ITI was 20 s, percentage of risky choice was inversely related to fixed‐ratio value. When only a single response was required but the ITI was manipulated between 20 and 120 s (with maximum session duration held constant), percentage of risky choice was directly related to length of the ITI. The effects of the drugs were investigated first at an ITI of 20 s, when risky choice was low for most rats, and then at an ITI of 80 s, when risky choice was higher for most rats. Ethanol usually decreased risky choice. Phencyclidine did not usually affect risky choice when the ITI was 20 s but decreased it in half the rats when the ITI was 80 s. For d‐amphetamine, the effects appeared to be related to baseline probability of risky choice; that is, low probabilities were increased and high probabilities were decreased. Although increase in risky choice as a function of the ITI is at variance with previous ITI data, it is consistent with foraging data showing that risk aversion decreases as food availability decreases. The pharmacological manipulations showed that drug effects on risky choice may be influenced by the baseline probability of risky choice, just as drug effects can be a function of baseline response rate.
MOLAR VERSUS MOLECULAR AS A PARADIGM CLASH
Authors: Baum William M.
Published: March 2006

The molar view of behavior arose in response to the demonstrated inadequacy of explanations based on contiguity. Although Dinsmoor's (2001) modifications to two‐factor theory render it irrefutable, a more basic criticism arises when we see that the molar and molecular views differ paradigmatically. The molar view has proven more productive.
THE MOLARITY OF MOLECULAR THEORY AND THE MOLECULARITY OF MOLAR THEORY
Authors: Bersh Philip J.
Published: March 2006

Dinsmoor (2001) rejects shock‐frequency reduction as a reinforcer for avoidance behavior, and considers this to be an invalidation of so‐called molar avoidance theory. This is a narrow view of operant avoidance theory, for which shock‐frequency reduction is by no means the only reinforcer.
ARE RESPONSES IN AVOIDANCE PROCEDURES “SAFETY” SIGNALS?
Authors: Branch Marc N.
Published: March 2006

Dinsmoor's (2001) position has the advantage of parsimony in that it relies on well‐established principles rather than a separate process—shock‐frequency reduction—to account for avoidance. Other advantages are that it blends well with what is known about the effectiveness of momentary contiguities in the study of positive reinforcement and that it might provide an account of why different response forms seem to condition at different rates. Despite these advantages, the view needs elaboration about the temporal characteristics of response‐associated stimuli, the functions that “warning” stimuli may have, and especially about how “safety” is established.
A FEW MINOR SUGGESTIONS
Authors: Michael Jack , Clark John W.
Published: March 2006

We agree with almost all of the analysis in this excellent presentation of the molecular view of avoidance behavior. A few suggestions are made as follows: Referring to response‐generated stimuli as “readily observable” seems not quite right for the kinesthetic components of such stimuli, although their scientific legitimacy is not questioned. Interpreting response‐generated stimuli as a form of positive reinforcement is contested, and an alternative interpretation is offered. A possibly simpler interpretation of the Sidman (1962) two‐lever experiment is suggested. We question Dinsmoor's (2001) explanation for warning stimuli not being avoided, except for the reference to the weakness of third‐order conditioning effects. A final question is raised regarding the nature of the variables that are responsible for the momentary evocation of the avoidance response.
EXPLAINING AVOIDANCE: TWO FACTORS ARE STILL BETTER THAN ONE
Authors: Baron Alan , Perone Michael
Published: March 2006

Two‐factor theory remains a viable account of avoidance behavior. By emphasizing the interplay of respondent and operant contingencies, two‐factor theory encourages the analysis of stimuli that mediate molar consequences and incorporates control by local events as well as events that are temporally remote, improbable, or cumulative.
OVERMATCHING IN RATS: THE BARRIER CHOICE PARADIGM
Authors: Aparicio Carlos F.
Published: March 2006

The barrier choice paradigm was used to impose a cost on rats' behavior of traveling between two levers: Pressing on two levers was reinforced with food on concurrent random‐interval schedules, but rats had to climb over a barrier to move from one lever to another. The height of the barrier separating the levers was increased from 30.5 to 45.7 cm across two phases that involved various pairs of random‐interval schedules. With the 30.5‐cm barrier, the generalized matching law showed slopes equal to or slightly above 1.0 for response and time allocation. With the 45.7‐cm barrier, the generalized matching law showed slopes above 1.2 for responses, indicating that sensitivity to reinforcement increased with increasing barrier height. For time allocation the slopes remained close to 1.0; sensitivity to reinforcement did not seem to increase with increasing barrier height. The role of locomotion effort in choice situations is discussed.
RISK‐SENSITIVE CHOICE IN HUMANS AS A FUNCTION OF AN EARNINGS BUDGET
Authors: Pietras Cynthia J. , Hackenberg Timothy D.
Published: March 2006

Risky choice in 3 adult humans was investigated across procedural manipulations designed to model energy‐budget manipulations conducted with nonhumans. Subjects were presented with repeated choices between a fixed and a variable number of points. An energy budget was simulated by use of an earnings budget, defined as the number of points needed within a block of trials for points to be exchanged for money. During positive earnings‐budget conditions, exclusive preference for the fixed option met the earnings requirement. During negative earnings‐budget conditions, exclusive preference for the certain option did not meet the earnings requirement, but choice for the variable option met the requirement probabilistically. Choice was generally risk averse (the fixed option was preferred) when the earnings budget was positive and risk prone (the variable option was preferred) when the earnings budget was negative. Furthermore, choice was most risk prone during negative earnings‐budget conditions in which the earnings requirement was most stringent. Local choice patterns were also frequently consistent with the predictions of a dynamic optimization model, indicating that choice was simultaneously sensitive to short‐term choice contingencies, current point earnings, and the earnings requirement. Overall, these results show that the patterns of risky choice generated by energy‐budget variables can also be produced by choice contingencies that do not involve immediate survival, and that risky choice in humans may be similar to that shown in nonhumans when choice is studied under analogous experimental conditions.
REVIEW OF THE WAR BETWEEN MENTALISM AND BEHAVIORISM: ON THE ACCESSIBILITY OF MENTAL PROCESSES BY WILLIAM R. UTTAL
Authors: Reese Hayne W.
Published: March 2006

Uttal's goals in writing this book are (a) to demonstrate that the war between mentalism and behaviorism is unwinnable because both sides are fundamentally flawed and (b) to describe a new version of behaviorism that resolves the conflict. The book is generally well written and contains many interesting and important points, but the goals are not attained because of weaknesses in some of the crucial analyses. For example, key terms such as mind and behavior are not defined; the scientific admissibility of inference is denied for philosophical reasons that are not relevant to inference as actually used; the accessibility of mind is both explicitly denied and implicitly assumed; two kinds of reductionism—between and within domains—are acknowledged but the distinction is not consistently maintained; and the proposed new behaviorism ignores rather than solves the old problems.
SECOND‐ORDER SCHEDULES OF TOKEN REINFORCEMENT WITH PIGEONS: EFFECTS OF FIXED‐ AND VARIABLE‐RATIO EXCHANGE SCHEDULES
Authors: Foster Theresa A. , Hackenberg Timothy D. , Vaidya Manish
Published: March 2006

Pigeons' key pecks produced food under second‐order schedules of token reinforcement, with light‐emitting diodes serving as token reinforcers. In Experiment 1, tokens were earned according to a fixed‐ratio 50 schedule and were exchanged for food according to either fixed‐ratio or variable‐ratio exchange schedules, with schedule type varied across conditions. In Experiment 2, schedule type was varied within sessions using a multiple schedule. In one component, tokens were earned according to a fixed‐ratio 50 schedule and exchanged according to a variable‐ratio schedule. In the other component, tokens were earned according to a variable‐ratio 50 schedule and exchanged according to a fixed‐ratio schedule. In both experiments, the number of responses per exchange was varied parametrically across conditions, ranging from 50 to 400 responses. Response rates decreased systematically with increases in the fixed‐ratio exchange schedules, but were much less affected by changes in the variable‐ratio exchange schedules. Response rates were consistently higher under variable‐ratio exchange schedules than under comparable fixed‐ratio exchange schedules, especially at higher exchange ratios. These response‐rate differences were due both to greater preratio pausing and to lower local rates under the fixed‐ratio exchange schedules. Local response rates increased with proximity to food under the higher fixed‐ratio exchange schedules, indicative of discriminative control by the tokens.
RESISTANCE TO CHANGE OF OPERANT VARIATION AND REPETITION
Authors: Doughty Adam H. , Lattal Kennon A.
Published: March 2006

A multiple chained schedule was used to compare the relative resistance to change of variable and fixed four‐peck response sequences in pigeons. In one terminal link, a response sequence produced food only if it occurred infrequently relative to 15 other response sequences (vary). In the other terminal link, a single response sequence produced food (repeat). Identical variable‐interval schedules operated in the initial links. During baseline, lower response rates generally occurred in the vary initial link, and similar response and reinforcement rates occurred in each terminal link. Resistance of responding to prefeeding and three rates of response‐independent food delivered during the intercomponent intervals then was compared between components. During each disruption condition, initial‐ and terminal‐link response rates generally were more resistant in the vary component than in the repeat component. During the response‐independent food conditions, terminal‐link response rates were more resistant than initial‐link response rates in each component, but this did not occur during prefeeding. Variation (in vary) and repetition (in repeat) both decreased during the response‐independent food conditions in the respective components, but with relatively greater disruption in repeat. These results extend earlier findings demonstrating that operant variation is more resistant to disruption than is operant repetition and suggest that theories of response strength, such as behavioral momentum theory, must consider factors other than reinforcement rate. The implications of the results for understanding operant response classes are discussed.
DETERMINANTS OF REINFORCER ACCUMULATION DURING AN OPERANT TASK
Authors: McFarland Jennifer M. , Lattal Kennon A.
Published: March 2006

Responses by rats on an earn lever made available food pellets that were delivered to a food cup by responses on a second, collect, lever. The rats could either collect and immediately consume or accumulate (defined as the percentage of multiple earn responses and as the number of pellets earned before a collect response) earned pellets. In Experiment 1, accumulation varied as a function of variations in the earn or collect response requirements and whether the earn and collect levers were proximal (31 cm) or distal (248 cm) to one another. Some accumulation occurred under all but one of the conditions, but generally was higher when the earn and collect levers were distal to one another, particularly when the earn response requirement was fixed‐ratio (FR) 1. In Experiment 2, the contributions of responses and time to accumulation were assessed by comparing an FR 20 earn response requirement to a condition in which only a single earn response was required at the end of a time interval nominally yoked to the FR interval. When 248 cm separated the earn and collect levers, accumulation was always greater in the FR condition, and it was not systematically related to reinforcement rate. In Experiment 3, increasing the earn response requirement with a progressive‐ratio schedule that reset only with a collect response increased the likelihood of accumulation when the collect and earn levers were 248 cm apart, even though such accumulation increased the next earn response requirement. Reinforcer accumulation is an understudied dimension of operant behavior that relates to the analysis of such phenomena as hoarding and self‐control, in that they too involve accumulating versus immediately collecting or consuming reinforcers.
A PRECURSOR TO THE RELATIONAL EVALUATION PROCEDURE: SEARCHING FOR THE CONTEXTUAL CUES THAT CONTROL EQUIVALENCE RESPONDING
Authors: Cullinan Veronica A. , Barnes‐Holmes Dermot , Smeets Paul M.
Published: March 2006

The precursor to the relational evaluation procedure (pREP) is a go/no‐go successive discrimination procedure for examining stimulus equivalence. Previous research has shown that it does not readily produce equivalence responding unless some matching‐to‐sample (MTS) procedures are incorporated into the experimental sequence. Two experiments attempted to identify contextual cues that would generate equivalence responding on the pREP. Experiment 1 examined the effects of using abstract symbols or various verbal labels as response options on the pREP. Only the words same and different, when used as response options, reliably produced equivalence responding across 4 subjects. Experiment 2 examined different pretraining preparations designed to attach the functions of the words same and different to abstract symbols that could then be used as response options on the pREP. The most effective pretraining procedure involved multiple‐exemplar training during which subjects were trained to respond to abstract symbols in the presence of pairs of stimuli that were either formally the same or different. The abstract symbols were subsequently used as response options with the pREP, and all subjects reliably demonstrated equivalence responding. The findings suggest that the relations of same and different may be fundamental to equivalence responding. These findings are discussed in terms of what they suggest about the nature of the equivalence phenomenon specifically and derived relational responding more generally.
UNIVERSAL PLOTKINISM: A REVIEW OF HENRY PLOTKIN'S DARWIN MACHINES AND THE NATURE OF KNOWLEDGE
Authors: Wynne C. D. L.
Published: March 2006

Plotkin's Darwin Machines and the Nature of Knowledge (1993) is a major contribution to the field of evolutionary epistemology and universal Darwinism. Evolutionary epistemology is the idea that evolution is a knowledge‐gaining process. Universal Darwinism holds that processes of variation and selection can be observed at different levels from the primary level of biological evolution (where genes code for phenotypes) through to individual learning and culture (where the units of variation and selection are not so clear cut). Although antithetical to behaviorism, large parts of Plotkin's thesis can be recast in nonmentalistic terms and exploited by behavior analysts. In particular, Plotkin's arguments for a strong commonality of process between biological evolution and individual learning offer directions for progress on questions that have long interested behavior analysts, such as: Why do some organisms learn? How did learning evolve? What is the relation between behavior and evolution? Although the paths of connection between evolution and individual behavior that Plotkin sketches are not yet fully clear of confusion, his is undoubtedly a very stimulating direction to explore.
EFFECTS OF PRIMARY REINFORCEMENT ON PIGEONS' INITIAL‐LINK RESPONDING UNDER A CONCURRENT‐CHAINS SCHEDULE WITH NONDIFFERENTIAL TERMINAL LINKS
Authors: Ploog Bertram O.
Published: March 2006

The effect of primary reinforcement on initial‐link responding under concurrent‐chains schedules with nondifferential terminal links was assessed in 12 pigeons. The initial and terminal links were variable‐interval schedules (always the same for both alternatives). The positions (left or right key) of the initial‐link stimuli (red or green) were randomized while the correlation between color and food amount remained constant within each condition. The terminal‐link stimuli were always presented on the center key. Except in two control groups and conditions, the terminal‐link stimuli were the same color (nondifferential, blue or yellow). Over six conditions, the differences in food amount and the durations of the initial‐ and terminal‐link schedules were manipulated. In 57 of 60 cases, birds generated choice proportions above .50 in favor of the initial‐link stimulus that was correlated with the larger reinforcer. There was some indication that preference increased with shortened terminal‐link durations. Because the terminal‐link stimuli were nondifferential, differential responding in the initial links cannot be explained easily by conditioned reinforcement represented by the terminal‐link stimuli. Thus, primary reinforcement has a direct effect on initial‐link responding in concurrent‐chains schedules.
DISRUPTION OF TEMPORALLY ORGANIZED BEHAVIOR BY MORPHINE
Authors: Knealing Todd W. , Schaal David W.
Published: March 2006

Four pigeons pecked keys in two different procedures commonly used in the study of timing, or temporal discrimination. Sessions consisted of 40 trials. During half of the trials, two keys were presented for 50 s. Left‐key pecks were reinforced according to a variable‐interval 67.86‐s schedule during the first 25 s of the trial, and right‐key pecks were not reinforced. During the second 25 s of the trial, right‐key pecks were reinforced according to the same schedule, and left‐key pecks were not reinforced. In the other half of the 40‐trial session, the center key was presented. The majority of these trials arranged fixed‐interval 25‐s schedules. Occasionally a probe, or peak‐interval, trial was presented. These trials were 100 s in duration and terminated without reinforcement. These two procedures were used to examine the effects of morphine on indexes of timing and on patterns of responding. Morphine altered behavior in a rate‐dependent manner in both procedures. Low baseline (saline) response rates were increased following morphine administration, and high baseline rates were either unaffected or decreased slightly. Rate‐dependent effects appeared as leftward shifts in the timing index for two‐key trials and decreases in the index of curvature for fixed‐interval trials. Despite large changes in response rates, no consistent shift of the peak time was observed during peak‐interval trials. These results are discussed primarily in terms of rate dependency; that is, rates of responding following drug administration tend to be determined in large part by rates of responding under baseline conditions.
THE GENERALITY OF SELECTIVE OBSERVING
Authors: Gaynor Scott T. , Shull Richard L.
Published: March 2006

Four rats obtained food pellets by poking a key and 5‐s presentations of the discriminative stimuli by pressing a lever. Every 1 or 2 min, the prevailing schedule of reinforcement for key poking alternated between rich (either variable‐interval [VI] 30 s or VI 60 s) and lean (either VI 240 s, VI 480 s, or extinction) components. While the key was dark (mixed‐schedule stimulus), no exteroceptive stimulus indicated the prevailing schedule. A lever press (i.e., an observing response), however, illuminated the key for 5 s with either a steady liht (S1), signaling the rich reinforcement schedule, or a blinking light (S2), signaling the lean reinforcement schedule. One goal was to determine whether rats would engage in selective observing (i.e., a pattern of responding that maintains contact with S1 and decreases contact with S2). Such a pattern was found, in that a 5‐s presentation of S1 was followed relatively quickly by another observing response (which likely produced another 5‐s period of S1), whereas exposure to S2 resulted in extended breaks from observing. Additional conditions demonstrated that the rate of observing remained high when lever presses were effective only when the rich reinforcement schedule was in effect (S1 only condition), but decreased to a low level when lever presses were effective only during the lean reinforcement component (S2 only condition) or when lever presses had no effect (in removing the mixed stimulus or presenting the multiple‐schedule stimuli). These findings are consistent with relativistic conceptualizations of conditioned reinforcement and extend the generality of selective observing to procedures in which the experimenter controls the duration of stimulus presentations, the schedule components both offer intermittent food reinforcement, and rats serve as subjects.
TIME OF SUPPLEMENTAL FEEDING ALTERS THE EFFECTS OF COCAINE ON LEVER PRESSING OF RATS
Authors: Ross Linda , Schaal David W.
Published: March 2006

The present experiment assessed the effects of cocaine on the lever pressing of 4 rats maintained during 15‐min sessions by a fixed‐ratio 50 schedule of food reinforcement. Across phases, supplemental food was provided either immediately or 2 hr after sessions. Two rats began the experiment in the delayed‐feeding condition, and 2 began the experiment in the immediate‐feeding condition. Rates of lever pressing of 2 rats sometimes decreased to low levels near the ends of sessions when supplemental feeding was provided immediately, but were consistently high throughout sessions when supplemental feeding was delayed. Cocaine (1.0 to 17.0 or 30.0 mg/kg) was administered intraperitoneally 15 min prior to test sessions. In most cases, cocaine suppressed response rates at lower doses under immediate‐feeding conditions. Decreases in overall response rates were correlated with dose‐dependent increases in the time rats spent not responding. It is suggested that delaying the time of postsession feeding increased response strength, as indicated by greater resistance to the rate‐suppressive effects of cocaine.
RESPONSE RATE VIEWED AS ENGAGEMENT BOUTS: RESISTANCE TO EXTINCTION
Authors: Shull Richard L. , Gaynor Scott T. , Grimes Julie A.
Published: March 2006

Rats obtained food pellets by nose poking a lighted key, the illumination of which alternated every 50 s during a session between blinking and steady, signaling either a relatively rich (60 per hour) or relatively lean (15 per hour) rate of reinforcement. During one training condition, all the reinforcers in the presence of the rich‐reinforcement signal were response dependent (i.e., a variable‐interval schedule); during another condition only 25% were response dependent (i.e., a variable‐time schedule operated concurrently with a variable‐interval schedule). An extinction session followed each training block. For both kinds of training schedule, and consistent with prior results, response rate was more resistant to extinction in the presence of the rich‐reinforcement signal than in the presence of the lean‐reinforcement signal. Analysis of interresponse‐time distributions from baseline showed that differential resistance to extinction was not related to baseline differences in the rate of initiating response bouts or in the length of bouts. Also, bout‐initiation rate (like response rate) was most resistant to extinction in the presence of the rich‐reinforcement signal. These results support the proposal of behavioral momentum theory (e.g., Nevin & Grace, 2000) that resistance to extinction in the presence of a discriminative stimulus is determined more by the stimulus—reinforcer (Pavlovian) than by the stimulus—response—reinforcer (operant) contingency.
PREFERENCE AND RESISTANCE TO CHANGE WITH CONSTANT‐ AND VARIABLE‐DURATION TERMINAL LINKS: INDEPENDENCE OF REINFORCEMENT RATE AND MAGNITUDE
Authors: Grace Randolph C. , Bedell Melissa A. , Nevin John A.
Published: March 2006

Pigeons responded in a three‐component multiple concurrent‐chains procedure in which the variable‐interval reinforcement schedules were the same across components but magnitudes differed across components. The terminal links were arranged either as a variable delay followed by presentation of a reinforcer (“variable duration”) or as a fixed period of access to the schedule during which a variable number of reinforcers could be earned (“constant duration”). Relative reinforcement rate was varied parametrically across both types of conditions. After baseline training in each condition, resistance to change of terminal‐link responding was assessed by delivering food during the initial links according to a variable‐time schedule. Both preference and resistance to change were more sensitive to reinforcement‐rate differences in the constant‐duration conditions. Sensitivities of preference and resistance to change to relative reinforcement rate did not change depending on relative reinforcement magnitude. Taken together, these results confirm and extend those of prior studies, and suggest that reinforcement rate and magnitude combine additively to determine preference and resistance to change. A single structural relation linking preference and resistance to change describes all the data from this and several related studies.
CONCURRENT SCHEDULES: SHORT‐ AND LONG‐TERM EFFECTS OF REINFORCERS
Authors: Landon Jason , Davison Michael , Elliffe Douglas
Published: March 2006

Five pigeons were trained on concurrent variable‐interval schedules in a switching‐key procedure. The overall rate of reinforcement was constant in all conditions, and the ratios of reinforcers obtainable on the two alternatives were varied over seven levels. Each condition remained in effect for 65 sessions, and the last 50 sessions of data from each condition were analyzed. The most recently obtained reinforcer had the largest effect on current preference, but each of the eight previously obtained reinforcers had a small measurable effect. These effects were larger when the reinforcer ratio was more extreme. A longer term effect of reinforcement was also evident, which changed as a function of the reinforcer ratio arranged. More local analyses showed regularities at a reinforcer‐by‐reinforcer level and large transient movements in preference toward the just‐reinforced alternative immediately following reinforcers, followed by a return to stable levels that were related to the reinforcer ratio in effect. The present data suggest that the variables that control choice have both short‐ and long‐term effects and that the short‐term effects increased when the reinforcer ratios arranged were more extreme.
RESPONSE‐INITIATED IMAGING OF OPERANT BEHAVIOR USING A DIGITAL CAMERA
Authors: Iversen Iver H.
Published: March 2006

A miniature digital camera, QuickCam® Pro 3000, intended for use with video e‐mail, was modified so that snapshots were triggered by operant behavior emitted in a standard experimental chamber. With only minor modification, the manual shutter button on the camera was replaced with a simple switch closure via an I/O interface controlled by a PC computer. When the operant behavior activated the I/O switch, the camera took a snapshot of the subject's behavior at that moment. To illustrate the use of the camera, a simple experiment was designed to examine stereotypy and variability in topography of operant behavior under continuous reinforcement and extinction in 6 rats using food pellets as reinforcement. When a rat operated an omnidirectional pole suspended from the ceiling, it also took a picture of the topography of its own behavior at that moment. In a single session after shaping of pole movement (if necessary), blocks of continuous reinforcement, in which each response was reinforced, alternated with blocks of extinction (no reinforcement), with each block ending when 20 responses had occurred. The software supplied with the camera automatically stored each image and named image files successively within a session. The software that controlled the experiment also stored quantitative data regarding the operant behavior such as consecutive order, temporal location within the session, and response duration. This paper describes how the two data types—image information and numerical performance characteristics—can be combined for visual analysis. The experiment illustrates in images how response topography changes during shaping of pole movement, how response topography quickly becomes highly stereotyped during continuous reinforcement, and how response variability increases during extinction. The method of storing digital response‐initiated snapshots should be useful for a variety of experimental situations that are intended to examine behavior change and topography.
STABILITY OF FUNCTIONAL EQUIVALENCE AND STIMULUS EQUIVALENCE: EFFECTS OF BASELINE REVERSALS
Authors: Wirth Oliver , Chase Philip N.
Published: March 2006

Functional equivalence and stimulus equivalence classes were established, reversed, and tested for stability with college students. Functional stimulus classes were established using a task in which students were trained to say nonsense words in the presence of arbitrarily assigned sets of symbols. Computer‐controlled speech‐recognition technology was used to record and analyze students' vocal responses for accuracy. After the establishment of stimulus classes was demonstrated with a transfer‐of‐function test, the effects of reversing selected baseline simple discriminations were assessed during an additional transfer‐of‐function test and a follow‐up test that occurred several weeks later. With the same students, stimulus equivalence classes were established and demonstrated with computerized matching‐to‐sample procedures. The effects of reversing selected baseline conditional discriminations also were assessed during a postreversal equivalence test and a follow‐up test. Both functional stimulus classes and stimulus equivalence were sensitive to contingency reversals, but the reversals with stimulus equivalence classes affected stimulus class organization whereas reversals with functional stimulus classes did not. Follow‐up performances were largely consistent with the original baseline contingencies. The similarities and differences between stimulus equivalence and functional equivalence are related to the specific contingencies that select responding in the presence of the stimuli that form the classes.
LINEAR MODELING OF STEADY‐STATE BEHAVIORAL DYNAMICS
Authors: Palya William L. , Walter Donald , Kessel Robert , Lucke Robert
Published: March 2006

The observed steady‐state behavioral dynamics supported by unsignaled periods of reinforcement within repeating 2,000‐s trials were modeled with a linear transfer function. These experiments employed improved schedule forms and analytical methods to improve the precision of the measured transfer function, compared to previous work. The refinements include both the use of multiple reinforcement periods that improve spectral coverage and averaging of independently determined transfer functions. A linear analysis was then used to predict behavior observed for three different test schedules. The fidelity of these predictions was determined.
THE WATERSHED YEARS OF 1958–1962 IN THE HARVARD PIGEON LAB
Authors: Catania A. Charles
Published: March 2006

During the years 1958–1962, the final years of support by the National Science Foundation for B. F. Skinner's Pigeon Lab in Memorial Hall at Harvard University, 20 or so pigeon experiments (plus some with other organisms) ran concurrently 7 days a week. The research style emphasized experimental analyses, exploratory procedures, and the parametric exploration of variables. This reminiscence describes some features of the laboratory, the context within which it operated, and the activities of some of those who participated in it.
RELATIVE REINFORCING EFFECTS OF DIFFERENT ORAL ETHANOL DOSES IN RHESUS MONKEYS
Authors: Stewart Robert B. , Wang Nian‐Sheng , Bass April A. , Meisch Richard A.
Published: March 2006

The relative reinforcing effects of different doses of orally delivered ethanol were evaluated. Mouth‐contact responding by rhesus monkeys was measured under concurrent fixed‐ratio fixed‐ratio schedules of liquid delivery (0.67 ml/delivery) from each of two spouts during daily 3‐hr sessions. Experiment 1 examined persistence of responding with ethanol (2%, 8%, and 32% wt/vol) and water available. When fixed‐ratio values from 8 to 128 were tested, the number of ethanol deliveries obtained per session decreased as the response requirement increased. The decrease in deliveries was less at higher than at lower ethanol concentrations, however. Experiment 2 examined choice between two ethanol concentrations under concurrent fixed‐ratio 16 schedules (4% vs. 8%, 4% vs. 16%, 8% vs. 16%, 2% vs. 8%, 2% vs. 32%, 8% vs. 32%). Higher concentrations (16%, 32%) generally maintained more responding than concurrently available concentrations of 8% or less. An exception was the observation of a preference for 8% over 32% ethanol. When the fixed‐ratio value was increased, however, the relative preference for these two doses was reversed so that 32% ethanol maintained more responding than 8% ethanol. Thus, the direction of the preference depended on the size of the response requirement. These results indicate that the reinforcing effects of ethanol increase with dose.
DRUG DISCRIMINATION UNDER CONCURRENT VARIABLE‐RATIO VARIABLE‐RATIO SCHEDULES
Authors: McMillan D. E. , Hardwick W. C. , Li Mi
Published: March 2006

Pigeons were trained to discriminate 5 mg/kg pentobarbital from saline under concurrent variable‐ratio (VR) VR schedules, in which responses on the pentobarbital‐biased lever were reinforced under the VR schedule with the smaller response requirements when pentobarbital was given before the session, and responses on the saline‐biased key were reinforced under the VR schedule with the larger response requirements. When saline was administered before the session, the reinforcement contingencies associated with the two response keys were reversed. When responding stabilized under concurrent VR 20 VR 30, concurrent VR 10 VR 40, or concurrent VR 5 VR 50 schedules, pigeons responded almost exclusively on the key on which fewer responses were required to produce the reinforcer. When other doses of pentobarbital and other drugs were substituted for the training dose, low doses of all drugs produced responding on the saline‐biased key. Higher doses of pentobarbital and chlordiazepoxide produced responding only on the pentobarbital‐biased key, whereas higher doses of ethanol and phencyclidine produced responding only on this key less often. d‐Amphetamine produced responding primarily on the saline‐biased key. When drugs generalized to pentobarbital, the shape of the generalization curve under concurrent VR VR schedules was more often graded than quantal in shape. Thus, drug discrimination can be established under concurrent VR VR schedules, but the shapes of drug‐discrimination dose—response curves under concurrent VR VR schedules more closely resemble those seen under interval schedules than those seen under fixed‐ratio schedules. Graded dose—response curves under concurrent VR VR schedules may relate to probability matching and difficulty in discriminating differences in reinforcement frequency.
HUMAN GROUP CHOICE: DISCRETE‐TRIAL AND FREE‐OPERANT TESTS OF THE IDEAL FREE DISTRIBUTION
Authors: Madden Gregory J. , Peden Blaine F. , Yamaguchi Tetsuo
Published: March 2006

Ideal free distribution theory predicts that foragers will form groups proportional in number to the resources available in alternative resource sites or patches, a phenomenon termed habitat matching. Three experiments tested this prediction with college students in discrete‐trial simulations and a free‐operant simulation. Sensitivity to differences in programmed reinforcement rates was quantified by using the sensitivity parameter of the generalized matching law (s). The first experiment, replicating prior published experiments, produced a greater degree of undermatching for the initial choice (s 5 0.59) compared to final choices (s 5 0.86). The second experiment, which extended prior findings by allowing only one choice per trial, produced comparable undermatching (s 5 0.82). The third experiment used free‐operant procedures more typical of laboratory studies of habitat matching with other species and produced the most undermatching (s 5 0.71). The results of these experiments replicated previous results with human groups, supported predictions of the ideal free distribution, and suggested that undermatching represents a systematic deviation from the ideal free distribution. These results are consistent with a melioration account of individual behavior as the basis for group choice.
FROM PATTERNS TO PROSPERITY: A REVIEW OF RACHLIN'S THE SCIENCE OF SELF‐CONTROL
Authors: Fantino Edmund , Stolarz‐Fantino Stephanie
Published: March 2006

The Science of Self‐Control (Rachlin, 2000) presents a clear overview of research and theory on self‐control, emphasizing important recent research by Rachlin and his students on temporally extended behavioral patterning as an aid to curbing impulsive decisions. We found the book well suited as a textbook in a graduate seminar on self‐control, particularly because it lucidly presents several provocative ideas about self‐control, decision making, addiction, and general theories of behavior. Of particular interest are his discussion of the “primrose path” to addiction and his behavioral research on the “prisoner's dilemma” as it relates to self‐control. Although we take some issue with teleological behaviorism, the theory of behavior advocated by Rachlin, we recommend this book to anyone interested in self‐control.
OBSERVING BEHAVIOR: EFFECTS OF RATE AND MAGNITUDE OF PRIMARY REINFORCEMENT
Authors: Shahan Timothy A.
Published: March 2006

Four experiments examined the free‐operant observing behavior of rats. In Experiment 1, observing was a bitonic function of random‐ratio schedule requirements for the primary reinforcer. In Experiment 2, decreases in the magnitude of the primary reinforcer decreased observing. Experiment 3 examined observing when a random‐ratio schedule or a yoked random‐time schedule of primary reinforcement was in effect across conditions. Removing the response requirement for the primary reinforcer increased observing, suggesting that the effects of the random‐ratio schedule in Experiment 1 likely were due to an interaction between observing and responding for the primary reinforcer. In Experiment 4, decreasing the rate of primary reinforcement by increasing the duration of a random‐time schedule decreased observing monotonically. Overall, these results suggest that observing decreases with decreases in the rate or magnitude of the primary reinforcer, but that behavior related to the primary reinforcer can affect observing and potentially affect measurement of conditioned reinforcing value.
EFFECTS OF D‐AMPHETAMINE IN A TEMPORAL DISCRIMINATION PROCEDURE: SELECTIVE CHANGES IN TIMING OR RATE DEPENDENCY?
Authors: Odum Amy L. , Lieving Lori M. , Schaal David W.
Published: March 2006

Two experiments evaluated rate dependency and a neuropharmacological model of timing as explanations of the effects of amphetamine on behavior under discriminative control by time. Four pigeons pecked keys during 60‐trial sessions. On each trial, the houselight was lit for a particular duration (5 to 30 s), and then the key was lit for 30 s. In Experiment 1, the key could be lit either green or blue. If the key was lit green and the sample was 30 s, or if the key was lit blue and the sample was 5 s, pecks produced food on a variable‐interval 20‐s schedule. The rate of key pecking increased as a function of sample duration when the key was green and decreased as a function of sample duration when the key was blue. Acute d‐amphetamine (0.1 to 3.0 mg/kg) decreased higher rates of key pecking and increased lower rates of key pecking as predicted by rate dependency, but did not shift the timing functions leftward (toward overestimation) as predicted by the neuropharmacological model. These results were replicated in Experiment 2, in which the key was lit only one color during sessions, indicating that the effects were not likely due to disruption of discriminative control by key color. These results are thus consistent with rate dependency but not with the predictions of the neuropharmacological model.
NAVIGATION IN THE MORRIS SWIM TASK AS A BASELINE FOR DRUG DISCRIMINATION: A DEMONSTRATION WITH MORPHINE
Authors: Ziegler David , Keith Julian R. , Pitts Raymond C. , Galizio Mark
Published: March 2006

A morphine versus saline discrimination was demonstrated using the Morris swim task as the behavioral baseline. The apparatus was a large circular pool filled with water made opaque by floating polypropylene pellets. Rats were placed in the tank in randomly selected locations (12 trials per session) and could escape by swimming to a platform submerged 2 cm below the surface. Morphine (5.6 mg/kg) or saline was injected prior to training sessions. The position of the platform in a given session depended on the drug condition, thus forming the basis for discriminative responding. Three of the 4 rats acquired the discrimination, as evidenced by direct swims to the condition‐appropriate platform. Generalization probe sessions were conducted following acquisition. Probe sessions were preceded by injections of morphine (0, 1.0, 3.0, 5.6, or 10.0 mg/kg) and involved placing the rat in the pool for 1 min without a platform. Swim patterns revealed a gradient, with probe swimming more concentrated in the area of the morphine platform position after higher morphine doses. In addition, dose‐dependent increases in the likelihood of swimming first to the morphine‐associated platform location were obtained. These results illustrate the generality of drug discrimination across different behavioral procedures, and of particular interest with respect to spatial learning, demonstrate interoceptive stimulus control of navigation.
THE FUNCTION, MECHANISM, AND EVOLUTION OF LEARNING AND BEHAVIOR: A REVIEW OF SARA J. SHETTLEWORTH'S COGNITION, EVOLUTION, AND BEHAVIOR
Authors: Zeiler Michael D.
Published: March 2006

Behavior is a property of living animals and is therefore a biological phenomenon. This book shows us what it looks like to have a truly biological science of behavior. Such a science needs to discover the laws that control behavior as it is occurring, and it is this that behavior analysts and other psychologists interested in animal behavior and learning have done so well. The science also needs to explain, however, the role that behavior plays in the life of the individual and in the existence of the species, and this has not been part of the agenda for most psychologists. Shettleworth addresses all of these questions about behavior. She views learning in terms of what it accomplishes for the individual and then provides insight into its causal laws and its evolution. All of this is accomplished with a critical eye and unremitting rigor. These accomplishments occur in the context of a theory based on a unique combination of domain‐general and domain‐specific processes that takes a major step in the direction of showing what students of animal behavior and animal learning have to offer each other.
CATEGORIZATION, CONCEPT LEARNING, AND BEHAVIOR ANALYSIS: AN INTRODUCTION
Authors: Zentall Thomas R. , Galizio Mark , Critchfield Thomas S.
Published: March 2006

Categorization and concept learning encompass some of the most important aspects of behavior, but historically they have not been central topics in the experimental analysis of behavior. To introduce this special issue of the Journal of the Experimental Analysis of Behavior (JEAB), we define key terms; distinguish between the study of concepts and the study of concept learning; describe three types of concept learning characterized by the stimulus classes they yield; and briefly identify several other themes (e.g., quantitative modeling and ties to language) that appear in the literature. As the special issue demonstrates, a surprising amount and diversity of work is being conducted that either represents a behavior‐analytic perspective or can inform or constructively challenge this perspective.
THE FORMATION OF A GENERALIZED CATEGORIZATION REPERTOIRE: EFFECT OF TRAINING WITH MULTIPLE DOMAINS, SAMPLES, AND COMPARISONS
Authors: Fields Lanny , Reeve Kenneth F. , Matneja Priya , Varelas Antonios , Belanich James , Fitzer Adrienne , Shamoun Kim
Published: March 2006

The present experiment explored the effects of three variables on the spontaneous categorization of stimuli in perceptually distinct and novel domains. Each of six stimulus domains was created by morphing two images that were the domain endpoints. The endpoints of the domains were male and female faces, two abstract drawings, a car and a truck, two banded‐elevation satellite land images, a tree and a cat, and two false‐color satellite images. The stimulus variants at each end of a domain defined two potential perceptual classes. Training was conducted in a matching‐to‐sample format and used stimuli from one or two domains, one or three variants per class as samples, and one or three variants per class as comparisons. The spontaneous categorization of stimuli in the untrained stimulus domains showed the emergence of a generalized categorization repertoire. The proportion of spontaneously categorized stimuli in the new domains was positively related to the number of domains and samples used in training, and was inversely related to the number of comparisons used in training. Differential reaction times demonstrated the discriminability of the stimuli in the emergent classes. This study is among the first to provide an empirical basis for a behavior‐analytic model of the development of generalized categorization repertoires in natural settings.
THE CURRENCY OF PROCUREMENT COST
Authors: Collier George , Johnson Deanne F. , Mathis Carl
Published: March 2006

As the number of instrumental responses required to procure access to food is increased, animals decrease the frequency of initiating meals and increase meal size, conserving total intake while limiting the increase in the overall cost of feeding. In two studies, one using wheel turns and one using bar presses as the instrumental response, we asked whether freely feeding laboratory rats measure cost according to the energy or the time they expend. In each study we varied both the price (i.e., number of wheel turns or bar presses) and the force required to make a response (i.e., torque on the wheel or weight of the bar). Price affected both procurement time (from the first to the last procurement response) and procurement work, whereas torque and bar weight affected work without altering time in most cases. Meal patterns were altered by all manipulations of price, but changes in torque and bar weight had little effect on meal patterns, except in the conditions in which they altered procurement time. These results suggest that time is a critical currency of procurement cost in rats.