bluuebunny/crossref_metadata_2025 huggingface dataset:
REVERSIBILITY OF SINGLE‐INCENTIVE SELECTIVE ASSOCIATIONS
Authors: Panlilio Leigh V. , Weiss Stanley J.
Published: March 2006

Rats were trained to press a lever in the presence of a tone‐light compound stimulus and not to press in its absence. In each of two experiments, schedules were designed to make the compound a conditioned punisher for one group and a conditioned reinforcer for the other. In Experiment 1, one group's responding produced food in the presence of the compound but not in its absence. The other group's responding terminated the compound stimulus, and food was presented only in its absence. When tone and light were later presented separately, light controlled more responding than did tone in the former group, but tone gained substantial control in the latter. The same effects were also observed within subjects when the training schedules were switched over groups. In Experiment 2, two groups avoided shock in the presence of the compound stimulus. In the absence of the compound, one group was not shocked, and the other received both response‐independent and response‐produced shock. When tone and light were presented separately, the former group's responding was mainly controlled by tone, but the latter group's responding was almost exclusively controlled by light. These effects were also observed within subjects when the training schedules were switched over groups. Thus, these single‐incentive selective association effects (appetitive in Experiment 1 and aversive in Experiment 2) were completely reversible. The schedules in which the compound should have been a conditioned reinforcer consistently produced visual control, and auditory control increased when the compound should have become a conditioned punisher. Currently accepted accounts of selective associations based on affinities between shock and auditory stimuli and between food and visual stimuli (i.e., stimulus‐reinforcer interactions) do not adequately address these results. The contingencies of reinforcement most recently associated with the compound and with its absence, rather than the nature of the reinforcer, determined whether auditory or visual stimulus control developed.
SHORTCOMINGS OF THE BEHAVIORAL COMPETITION THEORY OF CONTRAST: REANALYSIS OF MCLEAN (1992)
Authors: Williams Ben A. , Wixted John T.
Published: March 2006

McLean (1992) presented significant data showing that the occurrence of behavioral contrast in a multiple schedule was correlated with shifts in the frequency of reinforcers from a second source between components of the schedule, and interpreted his results as showing that contrast was due to changes in the degree of response competition within the constant component of the multiple schedule. Reanalysis of his data shows that there was an effect of reinforcement in the alternative component of the schedule independent of the shifts in reinforcers between components. Thus, the effect of relative rate of reinforcement cannot be ascribed, at least entirely, to the mechanisms proposed by the behavioral competition theory of contrast.
MOLECULAR AND MOLAR ANALYSES OF FIXED‐INTERVAL PERFORMANCE
Authors: Baron Alan , Leinenweber Antoinette
Published: March 2006

Fixed‐interval performances of rats were described either in terms of the individual intervals of the session or in terms of a single average interval constructed for the entire session. Responding in the individual intervals usually followed break‐and‐run and single response patterns rather than the scalloped pattern that emerged when the results were averaged. There was, however, a reasonable correspondence between the quarter‐life values calculated from individual intervals and those calculated from the averages. According to the pattern exhibited by the average interval, the probability of a response increased as the interval elapsed. The same conclusion was indicated by more molecular analyses of the conditional probabilities of pause terminations. The results showed that descriptions of fixed‐interval data in terms of overall averages reveal aspects of performance that are not immediately apparent within individual intervals.
THE BEHAVIORAL THEORY OF TIMING: REINFORCER RATE DETERMINES PACEMAKER RATE
Authors: Bizo Lewis A. , White K. Geoffrey
Published: March 2006

In the behavioral theory of timing, pulses from a hypothetical Poisson pacemaker produce transitions between states that are correlated with adjunctive behavior. The adjunctive behavior serves as a discriminative stimulus for temporal discriminations. The present experiments tested the assumption that the average interpulse time of the pacemaker is proportional to interreinforcer interval. Responses on a left key were reinforced at variable intervals for the first 25 s since the beginning of a 50‐s trial, and right‐key responses were reinforced at variable intervals during the second 25 s. Psychometric functions relating proportion of right‐key responses to time since trial onset, in 5‐s intervals across the 50‐s trial, were sigmoidal in form. Average interpulse times derived by fitting quantitative predictions from the behavioral theory of timing to obtained psychometric functions decreased when the interreinforcer interval was decreased and increased when the interreinforcer interval was increased, as predicted by the theory. In a second experiment, average interpulse times estimated from trials without reinforcement followed global changes in interreinforcer interval, as predicted by the theory. Changes in temporal discrimination as a function of interreinforcer interval were therefore not influenced by the discrimination of reinforcer occurrence. The present data support the assumption of the behavioral theory of timing that interpulse time is determined by interreinforcer interval.
A BEHAVIORAL ECONOMIC ANALYSIS OF CONCURRENTLY AVAILABLE MONEY AND CIGARETTES
Authors: DeGrandpre R. J. , Bickel Warren K. , Higgins Stephen T. , Hughes John R.
Published: March 2006

In economic terms, consumption of a reinforcer is determined by its price and the availability and price of other reinforcers. This study examined the effects of response‐requirement (i.e., price) manipulations on the self‐administration of two concurrently available reinforcers. Six cigarette smokers participated in 4‐hr sessions in which money and puffs on a cigarette were concurrently available according to fixed‐ratio schedules of reinforcement. Once stable responding was obtained with both reinforcers available at Fixed Ratio 100, the response requirement for one reinforcer was systematically varied (Fixed Ratio 1,000 and 2,500), while the other reinforcer remained scheduled at Fixed Ratio 100. Increasing the fixed‐ratio size for a reinforcer decreased its consumption, with a greater decrease occurring for monetary reinforcement. This finding was quantified in economic terms as own‐price elasticity, with elasticity coefficients greater for money than cigarettes. The effects of fixed‐ratio size on response output also differed across the two reinforcers. Although greater responding occurred for money at Fixed Ratio 100, increases in fixed‐ratio size (for money) decreased responding for money, whereas the same increase in fixed‐ratio size (for puffs) increased responding for puffs. Finally, increasing the fixed‐ratio size for one reinforcer had little effect on consumption of the other concurrently available reinforcer. This finding was quantified as cross‐price elasticity, with elasticity coefficients near 0.0 for most subjects, indicating little or no reinforcer interaction. The results indicate that the reinforcing effects of cigarettes and money in the setting studied here differed, and that the effects produced by changing the price of one reinforcer did not interact with the consumption of the other concurrently available reinforcer.
EFFECTS OF Δ9‐THC ON MARIJUANA SMOKING, DOSE CHOICE, AND VERBAL REPORT OF DRUG LIKING
Authors: Kelly Thomas H. , Foltin Richard W. , Emurian Cleeve S. , Fischman Marian W.
Published: March 2006

The effects of Δ9‐tetrahydrocannabinol content of marijuana on cigarette smoking, dose choice, and verbal report of drug “liking” by adult males living in a residential laboratory were investigated. Marijuana cigarettes were available during programmed intervals while subjects were engaged in recreational activities. The tetrahydrocannabinol content of the cigarettes remained constant each day, but was changed across days. Subjects provided written ratings of drug liking at the end of each day. In the first study, placebo or active (2.3% Δ9‐tetrahydrocannabinol) marijuana cigarettes were available for 1‐, 2‐, or 3‐day intervals at varying times of day. The number of cigarettes smoked was unrelated to tetrahydrocannabinol content, although verbal reports of drug liking were consistently higher when marijuana cigarettes containing tetrahydrocannabinol were smoked. In a second study, a choice procedure, consisting of four 3‐day blocks of 2 sample days and 1 choice day, was used. On sampling days, subjects smoked cigarettes varying in tetrahydrocannabinol content (0.0, 2.0, and 3.5%, w/w); on choice days they were allowed to choose between the two previously sampled doses. The number of cigarettes was not consistently related to tetrahydrocannabinol content. Ratings of drug liking were increased when marijuana cigarettes contained tetrahydrocannabinol, but ratings of marijuana containing 2.0% and 3.5% of the compound were similar. In contrast, subjects consistently chose the 3.5% dose over either the 0.0% or 2.0% dose. Dose choice was more sensitive to tetrahydrocannabinol content than either reports of drug liking or numbers of cigarettes smoked.
RESPONSE ACQUISITION BY SIAMESE FIGHTING FISH (BETTA SPLENDENS) WITH DELAYED VISUAL REINFORCEMENT
Authors: Lattal Kennon A. , Metzger Barbara
Published: March 2006

Male Siamese fighting fish, Betta splendens, swam through a ring in an aquarium, breaking a photocell beam and initiating an unsignaled, resetting delay interval. Following delays of 0 s, 10 s, or 25 s, a 15‐s mirror presentation released an aggressive display by the fish. Swimming through the ring increased in the absence of either a period of acclimatization to the reinforcer (analogous to magazine training when appetitive reinforcers are used) or explicit training of the response by the experimenters. Response rates were a decreasing function of delay duration. Other fish exposed to a schedule of response‐independent mirror presentations failed to acquire and maintain the response. The results demonstrate the robustness and generality of the phenomenon of response acquisition with delayed reinforcement. They further qualify earlier observations about behavioral mechanisms involved in the phenomenon.
TEMPORAL DISCRIMINATION LEARNING OF OPERANT FEEDING IN GOLDFISH (CARASSIUS AURATUS)
Authors: Gee Philip , Stephenson David , Wright Donald E.
Published: March 2006

Operant temporal discrimination learning was investigated in goldfish. In the first experiment, there was a fixed daily change in illumination. Eight subjects were trained to operate a lever that reinforced each press with food. The period during which responses were reinforced was then progressively reduced until it was 1 hr in every 24. The final 1‐hr feeding schedule was maintained over 4 weeks. The feeding period commenced at the same time each day throughout. The food dispensers were then made inactive, and a period of extinction ensued for 6 days. The pattern of responding suggested that the fish were able to exhibit temporal discrimination in anticipation of feeding time. This pattern of responding persisted for a limited number of days during the extinction procedure. The second experiment produced evidence that operant temporal discrimination could develop under continuous illumination.
WITHIN‐SESSION CHANGES IN RESPONDING DURING SEVERAL SIMPLE SCHEDULES
Authors: McSweeney Frances K. , Roll John M. , Weatherly Jeffrey N.
Published: March 2006

Pigeons' key pecking was reinforced by food delivered by several fixed‐interval, variable‐ratio, and differential‐reinforcement‐of‐low‐rate schedules. Rate of responding, number of responses per reinforcer, length of postreinforcement pause, running response rate, and the time required to collect an available reinforcer changed systematically within sessions when the schedules provided high rates of reinforcement, but usually not when they provided low rates. These results suggest that the factors that produce within‐session changes in responding are generally similar for different schedules of reinforcement. However, a separate factor may also contribute during variable‐ratio schedules. The results question explanations for within‐session changes that are related solely to the passage of time, to responding, and to one interpretation of attention. They support the idea that one or more factors related to reinforcement play a role.
THE EFFECT OF VARIABLE DELAYS ON SELF‐CONTROL
Authors: Chelonis John J. , King George , Logue A. W. , Tobin Henry
Published: March 2006

Five pigeons served as subjects in an experiment that examined the effects of variable as opposed to fixed delays on preference in a self‐control paradigm (choice between larger, more delayed and smaller, less delayed reinforcers). Nonindependent concurrent variable‐interval schedules were used to measure choice. When delays to the larger, more delayed reinforcers were variable as opposed to fixed, the subjects showed an increased preference for that alternative (the self‐control alternative). A series of regressions revealed that the hyperbolic decay model and incentive theory provided poor fits to the data, but a modified version of the generalized matching law provided an adequate fit. Together, consistent with a general prediction made by discounting models, the data supported the conclusion that variable delays can increase self‐control. However, specific discounting models were not able to explain the present data well.
BEHAVIORAL AND PHARMACOLOGICAL MODULATION OF RESPIRATION IN RHESUS MONKEYS
Authors: Howell Leonard L. , Landrum Alyson M.
Published: March 2006

Changes in respiration associated with schedule‐controlled behavior were determined in seated rhesus monkeys prepared with a pressure‐displacement head plethysmograph for monitoring ventilation continuously during behavioral experiments. Subjects were trained to press a lever under fixed‐ratio 40 and fixed‐interval 300‐s schedules of stimulus termination. Episodic increases in ventilation were closely associated with periods of responding under both schedules. Recurring episodes of increased ventilation occurred during fixed‐ratio responding, and were separated by brief 10‐s timeouts during which ventilation decreased. Under the fixed‐interval schedule, both ventilation and response rate typically increased as the 300‐s interval elapsed. The effects of cocaine, caffeine, and two adenosine agonists, 5′‐N‐ethylcarboxamidadenosine (NECA) and 2‐(carboxyethylphenylamino)adenosine‐5′‐carboxamide (CGS 21680), on behavior and respiration were determined using a cumulative‐dosing procedure. Drug‐induced suppression of behavior eliminated the episodic increases in ventilation during the performance components of both schedules. Schedule‐related increases in ventilation were compared to those produced by elevated levels of CO2 in inspired air. Exposure to 4% CO2 mixed in air increased ventilation in all subjects, and the combined effects of CO2 exposure and schedule‐controlled responding on respiration appeared to be additive. The results suggest that behavioral activities may increase ventilation through increased metabolic demand and increased CO2 production.
THE EFFECTS OF SMOKED MARIJUANA ON PROGRESSIVE‐INTERVAL SCHEDULE PERFORMANCE IN HUMANS
Authors: Dougherty Donald M. , Cherek Don R. , Roache John D.
Published: March 2006

In three experiments, 8 human subjects participated in a study of the effects of smoked marijuana on progressive‐interval schedule performance. A two‐component chained progressive‐interval fixed‐interval schedule of point delivery was used. In the progressive‐interval component, the interval length began at 20 s and increased either geometrically or arithmetically (by either 20 s, 40 s, 80 s, 100 s, or 160 s) on each subsequent interval. After this interval elapsed, a single button press produced the fixed‐interval component, with a total of five reinforcers of varying magnitude ($0.05, $0.20, or $0.40) available on a fixed‐interval 20‐s schedule. After the five reinforcer deliveries, the schedule returned to the initial progressive‐interval component. Several relationships were found among rates of responding, postreinforcement pauses, and drug administration in the progressive‐interval component: (a) Postreinforcement pauses increased as the temporal requirements of the progressive‐interval schedule increased; (b) rates of responding during successive progressive‐interval components rapidly decreased to low rates of responding after the first few progressions; (c) postreinforcement pauses decreased systematically as dose of smoked marijuana increased; and (d) rates of responding increased after smoking active marijuana but not after smoking placebo cigarettes. Results are discussed in the context of behavioral control and relevance to other studies that have investigated the effects of smoked marijuana on schedule performance.
LEAVING PATCHES: AN INVESTIGATION OF A LABORATORY ANALOGUE
Authors: Davison Michael , McCarthy Dianne
Published: March 2006

Five pigeons were trained on a procedure that has been used as a laboratory analogue to natural patch residence. Trials commenced with two responses available. One of these might provide a reinforcer if the patch was a prey patch; the other ended the residence time in the patch and, after a fixed travel time in blackout, produced another patch that might or might not provide a reinforcer. Patch residence also ended, and was followed by the same travel time, after a reinforcer was obtained or after a fixed maximum time was spent in the patch. The dependent variable was patch residence time, from the commencement of the patch to the time at which the subject emitted a response to exit from the patch or until the maximum patch residence time had elapsed. In Parts 1 to 3, the duration of the imposed travel time was varied from 0.25 to 16 s at three different probabilities (.05, .1, and .2) of food per second (λ) in prey patches. As reported in previous research, both increasing travel time and decreasing probabilities of reinforcers per second increased patch residence time. In Parts 4 to 7, the probability of prey trials (p) was varied in an irregular order from .1, through .2, .5, and .7, to .9 for different combinations of λ and travel time. Respectively, these were in Part 4, .05 per second and 0.25 s; in Part 5, .05 per second and 16 s; in Part 6, .2 per second and 0.25 s; and in Part 7, .2 per second and 16 s. A previously offered model, based on optimization assumptions, substantially and consistently underpredicted patch residence time. However, a modification of that model, which assumes that the subjects could not accurately discriminate the residence time that provided the minimum interreinforcer interval, described the data well. The same model also described previously reported residence times in a different species with a uniform distribution of prey‐arrival times.
RESISTANCE TO REINFORCEMENT CHANGE IN MULTIPLE AND CONCURRENT SCHEDULES ASSESSED IN TRANSITION AND AT STEADY STATE
Authors: McLean Anthony P. , Blampied Neville M.
Published: March 2006

Behavioral momentum theory relates resistance to change of responding in a multiple‐schedule component to the total reinforcement obtained in that component, regardless of how the reinforcers are produced. Four pigeons responded in a series of multiple‐schedule conditions in which a variable‐interval 40‐s schedule arranged reinforcers for pecking in one component and a variable‐interval 360‐s schedule arranged them in the other. In addition, responses on a second key were reinforced according to variable‐interval schedules that were equal in the two components. In different parts of the experiment, responding was disrupted by changing the rate of reinforcement on the second key or by delivering response‐independent food during a blackout separating the two components. Consistent with momentum theory, responding on the first key in Part 1 changed more in the component with the lower reinforcement total when it was disrupted by changes in the rate of reinforcement on the second key. However, responding on the second key changed more in the component with the higher reinforcement total. In Parts 2 and 3, responding was disrupted with free food presented during intercomponent blackouts, with extinction (Part 2) or variable‐interval 80‐s reinforcement (Part 3) arranged on the second key. Here, resistance to change was greater for the component with greater overall reinforcement. Failures of momentum theory to predict short‐term differences in resistance to change occurred with disruptors that caused greater change between steady states for the richer component. Consistency of effects across disruptors may yet be found if short‐term effects of disruptors are assessed relative to the extent of change observed after prolonged exposure.
PIGEONS' DISCRIMINATION OF PAINTINGS BY MONET AND PICASSO
Authors: Watanabe Shigeru , Sakamoto Junko , Wakita Masumi
Published: March 2006

Pigeons successfully learned to discriminate color slides of paintings by Monet and Picasso. Following this training, they discriminated novel paintings by Monet and Picasso that had never been presented during the discrimination training. Furthermore, they showed generalization from Monet's to Cezanne's and Renoir's paintings or from Picasso's to Braque's and Matisse's paintings. These results suggest that pigeons' behavior can be controlled by complex visual stimuli in ways that suggest categorization. Upside‐down images of Monet's paintings disrupted the discrimination, whereas inverted images of Picasso's did not. This result may indicate that the pigeons' behavior was controlled by objects depicted in impressionists' paintings but was not controlled by objects in cubists' paintings.
VISUAL SEARCH BY CHIMPANZEES (PAN): ASSESSMENT OF CONTROLLING RELATIONS
Authors: Tomonaga Masaki
Published: March 2006

Three experimentally sophisticated chimpanzees (Pan), Akira, Chloe, and Ai, were trained on visual search performance using a modified multiple‐alternative matching‐to‐sample task in which a sample stimulus was followed by the search display containing one target identical to the sample and several uniform distractors (i.e., negative comparison stimuli were identical to each other). After they acquired this task, they were tested for transfer of visual search performance to trials in which the sample was not followed by the uniform search display (odd‐item search). Akira showed positive transfer of visual search performance to odd‐item search even when the display size (the number of stimulus items in the search display) was small, whereas Chloe and Ai showed a transfer only when the display size was large. Chloe and Ai used some nonrelational cues such as perceptual isolation of the target among uniform distractors (so‐called pop‐out). In addition to the odd‐item search test, various types of probe trials were presented to clarify the controlling relations in multiple‐alternative matching to sample. Akira showed a decrement of accuracy as a function of the display size when the search display was nonuniform (i.e., each “distractor” stimulus was not the same), whereas Chloe and Ai showed perfect performance. Furthermore, when the sample was identical to the uniform distractors in the search display, Chloe and Ai never selected an odd‐item target, but Akira selected it when the display size was large. These results indicated that Akira's behavior was controlled mainly by relational cues of target—distractor oddity, whereas an identity relation between the sample and the target strongly controlled the performances of Chloe and Ai.
STIMULUS CONTROL IN THE USE OF LANDMARKS BY PIGEONS IN A TOUCH‐SCREEN TASK
Authors: Cheng Ken , Spetch Marcia L.
Published: March 2006

Pigeons were tested in a search task on the surface of a monitor on which their responses were registered by a touch‐sensitive device. A graphic landmark array was presented consisting of a square outline (the frame) and a colored “landmark.” The unmarked goal, pecks at which produced reward, was located near the center of one edge of the frame, and the landmark was near it. The entire array was displaced without rotation on the monitor from trial to trial. On occasional no‐reward tests, the following manipulations were made to the landmark array: (a) either the frame or the landmark was removed; (2) either one edge of the frame or the landmark was shifted; and (3) two landmarks were presented with or without the frame present. On these two‐landmark tests, the frame, when present, defined which was the “correct” landmark. When the frame was absent, the “correct” landmark was arbitrarily determined. Results showed that pecks of 2 pigeons were controlled almost solely by the landmark, pecks of 3 were controlled primarily by the landmark but the frame could distinguish the correct landmark, and 1 bird's behavior was controlled primarily by the frame. Stimulus control in this search task is thus selective and differs across individuals. Comparisons to other search tasks and to other stimulus control experiments are made.
HUMAN SYMBOLIC MATCHING‐TO‐SAMPLE PERFORMANCE: EFFECTS OF REINFORCER AND SAMPLE‐STIMULUS PROBABILITIES
Authors: Alsop Brent , Rowley Rachael , Fon Cristina
Published: March 2006

Four experiments, each with 6 human subjects, varied the distribution of reinforcers for correct responses and the probability of sample‐stimulus presentation in symbolic matching‐to‐sample procedures. Experiment 1 held the sample‐stimulus probability constant and varied the ratio of reinforcers obtained for correct responses on the two alternatives across conditions. There was a positive relation between measures of response bias and the ratio of reinforcers. Experiment 2 held the ratio of reinforcers constant and varied the sample‐stimulus probability across conditions. Unlike previous studies that used pigeons as subjects, there was a negative relation between bias and the ratio of sample‐stimulus presentations. In Experiment 3, the sample‐stimulus probability and the reinforcer ratio covaried across conditions. Response bias did not vary systematically across conditions. In Experiments 1 to 3, correct responses were reinforced intermittently. Experiment 4 used the same procedure as Experiment 3, but all correct responses now produced some scheduled consequence. There was a positive relation between response bias and the ratio of reinforcers. The results suggest that human performance in these tasks was controlled by both the relative frequency of reinforced responses and the relative frequency of nonreinforced responses.
REPRESENTING WITHIN‐SESSION RESPONSE RATES PROPORTIONALLY AND ENTIRELY
Authors: Schaal David W.
Published: March 2006

In this technical article, methods for collecting and representing response rates maintained by schedules of reinforcement are presented. First, the time in a session that each important event (e.g., responses, reinforcers) occurs is collected and stored by a computer. Another computer program is used, then, to convert each response to a percentage of the total responses in a session and to plot these percentages cumulatively as a function of the time in the session that they occurred. In this manner, response rates may be expressed proportionally (i.e., using the same y‐axis scale regardless of absolute response rate) without requiring the arbitrary selection of an interval over which responses are aggregated and expressed relative to the entire‐session rate. A property of these records is that deviations in the slope of the obtained record from the diagonal, which connects (x, y) = (start of session, 0%) to (x, y) = (end of session, 100%), occurring at any point and for any duration, represent changes in the local response rate from the entire‐session rate. This method of representing ongoing responding is illustrated by several records of key pecking of a pigeon on a variable‐interval 60‐s schedule of food reinforcement. Relative local response rates were also computed from these data at several levels of resolution (i.e., the time over which responses were aggregated), including the level typically employed by those interested in within‐session changes in response rates.
STIMULUS EFFECTS ON BEHAVIOR ALLOCATION IN THREE‐ALTERNATIVE CHOICE
Authors: Davison Michael
Published: March 2006

Six pigeons were trained on three‐alternative concurrent variable‐interval schedules that were available through a switching response and were signaled by colored stimuli. The discriminative stimuli for two of the schedules were always 560 nm and 630 nm, but the stimulus signaling the third alternative was varied across conditions over seven levels between these colors. For each third‐alternative stimulus condition, the relative frequency of reinforcers was varied over three conditions with 4:1 and 16:1 reinforcer ratios between each pair of alternatives. The distribution of responses between the alternatives was dependent jointly on the third‐alternative reinforcer rate and on the disparity between the stimulus signaling the third alternative and those signaling the other alternatives. A generalized matching approach was unable to provide invariant measures of the discriminability between constant stimuli, but a contingency‐discriminability approach provided excellent fits and sensible and invariant stimulus discriminability measures.
RESISTANCE TO CHANGE AS A FUNCTION OF STIMULUS—REINFORCER AND LOCATION—REINFORCER CONTINGENCIES
Authors: McLean Anthony P. , Campbell‐Tie Philippa , Nevin John A.
Published: March 2006

Pigeons responded on two keys in each component of a multiple concurrent schedule. In one series of conditions the distribution of reinforcers between keys within one component was varied so as to produce changes in ratios of reinforcer totals for key locations when summed across components. In a second series, reinforcer allocation between components was varied so as to produce changes in ratios of reinforcer totals for components, summed across key locations. In each condition, resistance to change was assessed by presenting response‐independent reinforcers during intercomponent blackouts and (for the first series) by extinction of responding on both keys in both components. Resistance to change for response totals within a component was always greater for the component with the larger total reinforcer rate. However, resistance to change for response totals at a key location was not a positive function of total reinforcement for pecking that key; indeed, relative resistance to extinction for the two locations showed a weak negative relation to ratios of reinforcer totals for key location. These results confirm the determination of resistance to change by stimulus—reinforcer contingencies.
DISCRIMINATION OF METHADONE AND COCAINE BY PIGEONS WITHOUT EXPLICIT DISCRIMINATION TRAINING
Authors: Schaal David W. , McDonald Michael P. , Miller Mark A. , Reilly Mark P.
Published: March 2006

Pigeons were trained to peck a key on a variable‐interval 2‐min schedule of food reinforcement. Prior to each session, either 2.0 mg/kg methadone (n = 3), 3.0 mg/kg cocaine (n = 4), or 5.6 mg/kg cocaine (n = 2) was administered. When each pigeon's rate of pecking was stable, a range of doses of the training drug and saline were administered prior to 20‐min extinction sessions separated by at least four training sessions. Rate of pecking during these extinction tests was generally an increasing function of dose, with the lowest rates obtained following saline and low doses and the highest rates obtained following doses near the training doses. Dose functions from pigeons trained with 5.6 mg/kg cocaine were steeper than those from pigeons trained with 3.0 mg/kg cocaine. Pigeons trained with methadone or 3.0 mg/kg cocaine were then given discrimination training, in which food reinforcement followed drug administration and 20‐min extinction sessions followed saline administration. Rates of pecking under these conditions quickly diverged until near‐zero rates were obtained following saline and high rates were obtained following drug. Discrimination training steepened dose functions for the training drugs, and the effects of several other substituted drugs depended on the pharmacology of the training drug. The pigeons trained with 5.6 mg/kg cocaine were tested with d‐amphetamine, methadone, and morphine prior to discrimination training. d‐Amphetamine increased rates dose dependently, and methadone and morphine did not. The results suggest that discriminative control by methadone and cocaine was established without explicit discrimination training.
WITHIN‐SESSION RESPONSE PATTERNS ON CONJOINT VARIABLE‐INTERVAL VARIABLE‐TIME SCHEDULES
Authors: Weatherly Jeffrey N. , McSweeney Frances K. , Swindell Samantha
Published: March 2006

Operant responding often changes within sessions, even when factors such as rate of reinforcement remain constant. The present study was designed to determine whether within‐session response patterns are determined by the total number of reinforcers delivered during the session or only by the reinforcers earned by the operant response. Four rats pressed a lever and 3 pigeons pecked a key for food reinforcers delivered by a conjoint variable‐interval variable‐time schedule. The overall rate of reinforcement of the conjoint schedule varied across conditions from 15 to 480 reinforcers per hour. When fewer than 120 reinforcers were delivered per hour, the within‐session patterns of responding on conjoint schedules were similar to those previously observed when subjects received the same total number of reinforcers by responding on simple variable‐interval schedules. Response patterns were less similar to those observed on simple variable‐interval schedules when the overall rate of reinforcement exceeded 120 reinforcers per hour. These results suggest that response‐independent reinforcers can affect the within‐session pattern of responding on a response‐dependent schedule. The results are incompatible with a response‐based explanation of within‐session changes in responding (e.g., fatigue), but are consistent with both reinforcer‐based (e.g., satiation) and stimulus‐based (e.g., habituation) explanations.
RELATIVE SENSITIVITY TO REINFORCER AMOUNT AND DELAY IN A SELF‐CONTROL CHOICE SITUATION
Authors: Ito Masato , Oyama Mariko
Published: March 2006

Rats were exposed to concurrent‐chains schedules in which a single variable‐interval schedule arranged entry into one of two terminal‐link delay periods (fixed‐interval schedules). The shorter delay ended with the delivery of a single food pellet; the longer day ended with a larger number of food pellets (two under some conditions and six under others). In Experiment 1, the terminal‐link delays were selected so that under all conditions the ratio of delays would exactly equal the ratio of the number of pellets. But the absolute duration of the delays differed across conditions. In one condition, for example, rats chose between one pellet delayed 5 s and six pellets delayed 30 s; in another condition rats chose between one pellet delayed 10 s and six pellets delayed 60 s. The generalized matching law predicts indifference between the two alternatives, assuming that the sensitivity parameters for amount and delay of reinforcement are equal. The rats' choices were, in fact, close to indifference except when the choice was between one pellet delayed 5 s and six pellets delayed 30 s. That deviation from indifference suggests that the sensitivities to amount and delay differ from each other depending on the durations of the delays. In Experiment 2, rats chose between one pellet following a 5‐s delay and six pellets following a delay that was systematically increased over sessions to find a point of indifference. Indifference was achieved when the delay to the six pellets was approximately 55 s. These results are consistent with the possibility that the relative sensitivities to amount and delay differ as a function of the delays.
SEPARATING THE EFFECTS OF TRIAL‐SPECIFIC AND AVERAGE SAMPLE‐STIMULUS DURATION IN DELAYED MATCHING TO SAMPLE IN PIGEONS
Authors: Hartl Josef A. , Dougherty Deirdra H. , Wixted John T.
Published: March 2006

Pigeons were studied in two experiments employing delayed matching‐to‐sample (DMTS) tasks in which the reduction in delay to reinforcement signaled by the onset of the sample stimulus was manipulated by varying sample‐stimulus duration. In Experiment 1, the duration of the sample stimulus was either 5 s or 10 s for one sample stimulus and 10 s or 20 s for the other. Subjects matched more frequently when the sample duration was 10 s following the sample associated with the shorter average duration. This finding is analogous to the memory distribution effect found by Honig (1987) in a successive DMTS task that varied retention interval. In Experiment 2, sample duration was either 5 s or 15 s. In Phases 1 and 3 each sample duration was correlated with a particular sample color, and in Phase 2 sample duration and color were uncorrelated. When sample duration was 5 s, subjects matched more frequently when sample duration and color were correlated than when they were uncorrelated. Overall, subjects matched more frequently when sample duration and color were correlated. The data from both experiments support Wixted's (1989) model, which states that one determinant of choice in a DMTS task is the delay‐reduction value of the sample stimulus.
JEAB AND JABA ON THE WORLD WIDE WEB: A REPORT TO READERS
Authors: Laties Victor G. , Preston Ray A. , Inglis Geoffrey B. , Pittelli Randal L.
Published: March 2006

The Journal of the Experimental Analysis of Behavior (JEAB) and the Journal of Applied Behavior Analysis (JABA) have both established home pages on the World Wide Web. Their addresses are:

http:www.envmed.rochester.eduwwwrapbehaviorjeabjeabhome.htm

http:www.envmed.rochester.eduwwwrapbehaviorjabajabahome.htm

An important feature of these pages is a powerful program that permits rapid full‐text searches of a database consisting of the nearly 5,000 abstracts that have accompanied articles published in JEAB since 1958 and in JABA since 1968. An electronic version of a single article from each issue of each journal is now made available soon after the paper edition of the journal appears.
PREFERENCE BETWEEN VARIABLE‐RATIO AND FIXED‐RATIO SCHEDULES: LOCAL AND EXTENDED RELATIONS
Authors: Field Douglas P. , Tonneau François , Ahearn William , Hineline Philip N.
Published: March 2006

Although it has repeatedly been demonstrated that pigeons, as well as other species, will often choose a variable schedule of reinforcement over an equivalent (or even richer) fixed schedule, the exact nature of that controlling relation has yet to be fully assessed. In this study pigeons were given repeated choices between concurrently available fixed‐ratio and variable‐ratio schedules. The fixed‐ratio requirement (30 responses) was constant throughout the experiment, wheareas the distribution of individual ratios making up the variable‐ratio schedule changed across phases: The smallest and largest of these components were varied gradually, with the mean variable‐ratio requirement constant at 60 responses. The birds' choices of the variable‐ratio schedule tracked the size of the smallest variable‐ratio component. A minimum variable‐ratio component at or near 1 produced strong preference for the variable‐ratio schedule, whereas increases in the minimum variable‐ratio component resulted in reduced preference for the variable‐ratio schedule. The birds' behavior was qualitatively consistent with Mazur's (1984) hyperbolic model of delayed reinforcement and could be described as approximate maximizing with respect to reinforcement value.
TOKEN REINFORCEMENT, CHOICE, AND SELF‐CONTROL IN PIGEONS
Authors: Jackson Kevin , Hackenberg Timothy D.
Published: March 2006

Pigeons were exposed to self‐control procedures that involved illumination of light‐emitting diodes (LEDs) as a form of token reinforcement. In a discrete‐trials arrangement, subjects chose between one and three LEDs; each LED was exchangeable for 2‐s access to food during distinct posttrial exchange periods. In Experiment 1, subjects generally preferred the immediate presentation of a single LED over the delayed presentation of three LEDs, but differences in the delay to the exchange period between the two options prevented a clear assessment of the relative influence of LED delay and exchange‐period delay as determinants of choice. In Experiment 2, in which delays to the exchange period from either alternative were equal in most conditions, all subjects preferred the delayed three LEDs more often than in Experiment 1. In Experiment 3, subjects preferred the option that resulted in a greater amount of food more often if the choices also produced LEDs than if they did not. In Experiment 4, preference for the delayed three LEDs was obtained when delays to the exchange period were equal, but reversed in favor of an immediate single LED when the latter choice also resulted in quicker access to exchange periods. The overall pattern of results suggests that (a) delay to the exchange period is a more critical determinant of choice than is delay to token presentation; (b) tokens may function as conditioned reinforcers, although their discriminative properties may be responsible for the self‐control that occurs under token reinforcer arrangements; and (c) previously reported differences in the self‐control choices of humans and pigeons may have resulted at least in part from the procedural conventions of using token reinforcers with human subjects and food reinforcers with pigeon subjects.
EFFECTS OF RESPONSE TYPE ON PIGEONS' SENSITIVITY TO VARIATION IN REINFORCER AMOUNT AND REINFORCER DELAY
Authors: Chelonis John J. , Logue A. W.
Published: March 2006

Twelve pigeons, divided into two groups, responded on concurrent nonindependent variable‐interval schedules to obtain access to grain by either pecking keys or pressing treadles. Either the amount of grain or the delay to the receipt of grain was varied in separate conditions to determine the sensitivity of relative responding to variation in reinforcer amount (sA), the sensitivity to variation in reinforcer delay (sD), and sA/sD, a measure related to self‐control. There were no significant differences between the two groups in the values of sA, sD, and sA/sD. These results suggest that the values of sA, sD, and sA/sD for pigeons may be similar across these two types of responses.
EFFECTS OF D‐AMPHETAMINE ON RESPONSE ACQUISITION WITH IMMEDIATE AND DELAYED REINFORCEMENT
Authors: LeSage Mark G. , Byrne Tom , Poling Alan
Published: March 2006

The present study examined in 8‐hour sessions the effects of d‐amphetamine (1.0, 5.6, and 10 mg/kg) on the acquisition of lever‐press responding in rats that were exposed to procedures in which water delivery was delayed by 0, 8, or 16 seconds relative to the response that produced it. Both nonresetting‐ and resetting‐delay conditions were studied. Although neither shaping nor autoshaping occurred, substantial levels of operative‐lever responding developed under all conditions in which responses produced water. The lowest dose (1.0 mg/kg) of d‐amphetamine either had no effect on or increased operative‐lever pressing, whereas higher doses typically produced an initial reduction in lever pressing. Nonetheless, overall rates of operative‐lever pressing at these doses were as high as, or higher than, those observed with vehicle. Thus, response acquisition was observed under all reinforcement procedures at all drug doses. In the absence of the drug, most responding occurred on the operative lever when reinforcement was immediate. Such differential responding also developed under both nonresetting‐ and resetting‐delay procedures when the delay was 8 seconds, but not when it was 16 seconds. d‐Amphetamine did not affect the development of differential responding under any procedure. Thus, consistent with d‐amphetamine's effects under repeated acquisition procedures, the drug had no detrimental effect on learning until doses that produced general behavioral disruption were administered.
WITHIN‐SESSION CHANGES IN RESPONDING DURING CONCURRENT SCHEDULES WITH DIFFERENT REINFORCERS IN THE COMPONENTS
Authors: McSweeney Frances K. , Swindell Samantha , Weatherly Jeffrey N.
Published: March 2006

Rats and pigeons responded on several concurrent schedules that provided different reinforcers in the two components (food and water for rats, Experiment 1; wheat and mixed grain for pigeons, Experiment 2). The rate of responding and the time spent responding on each component usually changed within the session. The within‐session changes in response rates and time spent responding usually followed different patterns for the two components of a concurrent schedule. For most subjects, the bias and sensitivity to reinforcement parameters of the generalized matching law, as well as the percentage of the variance accounted for, decreased within the session. Negative sensitivity parameters were sometimes found late in the session for the concurrent food‐water schedules. These results imply that within‐session changes in responding could cause problems for assessing the validity of quantitative theories of concurrent‐schedule responding when the components provide different reinforcers. They question changes in a general motivational state, such as arousal, as a complete explanation for within‐session changes in responding. The results are compatible with satiation for, or sensitization‐habituation to, the reinforcers as explanations.
WILLIAM NATHAN SCHOENFELD (1915–1996): INNOVATIVE SCIENTIST, INSPIRING TEACHER, RELENTLESS QUESTIONER, COMPLICATED MAN
Authors: Hearst Eliot
Published: March 2006

The scientific and academic contributions of the late William N. Schoenfeld (1915–1996) are large and, together with his personal qualities as a researcher, thinker, and teacher, supply the themes for this memorial essay on his work and life.
CONDITIONED REINFORCEMENT DYNAMICS IN THREE‐LINK CHAINED SCHEDULES
Authors: Williams Ben A.
Published: March 2006

In two experiments rats were trained on three‐link concurrent‐chains schedules of reinforcement. In Experiment 1, additional entries to one terminal link were added during one of the middle links to a baseline schedule that was otherwise equal for the two chains, and, depending on the condition, these additional terminal‐link presentations ended either in food or in no food. When food occurred, preference was always in favor of the chain with the additional terminal‐link presentations (which also entailed a higher rate of reinforcement). When no food occurred at the end of the additional terminal links, the outcome depended on the nature of the stimuli associated with these additional terminal links. When stimuli different from the reinforced baseline terminal links were used for the no‐food terminal links, preference was against the choice alternative that led to the extra periods of extinction. When the same stimulus was used for the two kinds of terminal links, preference was near indifference, that is, significantly greater than when different stimuli were used. In Experiment 2, rats learned repeated reversals of a simultaneous discrimination under a three‐link concurrent‐chains schedule, in which the food or no‐food choice outcomes were delayed until the end of the chain. Different conditions were defined by the point in the chain at which differential stimuli occurred. When the middle and terminal links provided no differential stimuli, discrimination was acquired more slowly than when differential stimuli occurred in both links. When differential stimuli occurred in the middle but not the terminal links, acquisition rates were intermediate. Both experiments together show that the effects of stimuli in a chain schedule are due partly to the time to food correlated with the stimuli and partly to the time to the next conditioned reinforcer in the sequence.