bluuebunny/crossref_metadata_2025 huggingface dataset:
CHOICE, CHANGEOVER, AND TRAVEL
Authors: Baum William M.
Published: March 2006

Since foraging in nature can be viewed as instrumental behavior, choice between sources of food, known as “patches,” can be viewed as choice between instrumental response alternatives. Whereas the travel required to change alternatives deters changeover in nature, the changeover delay (COD) usually deters changeover in the laboratory. In this experiment, pigeons were exposed to laboratory choice situations, concurrent variable‐interval schedules, that were standard except for the introduction of a travel requirement for changeover. As the travel requirement increased, rate of changeover decreased and preference for a favored alternative strengthened. When the travel requirement was small, the relations between choice and relative reinforcement revealed the usual tendencies toward matching and undermatching. When the travel requirement was large, strong overmatching occurred. These results, together with those from experiments in which changeover was deterred by punishment or a fixed‐ratio requirement, deviate from the matching law, even when a correction is made for cost of changeover. If one accepted an argument that the COD is analogous to travel, the results suggest that the norm in choice relations would be overmatching. This overmatching, however, might only be the sign of an underlying strategy approximating optimization.
MEMORY FOR TWO STIMULUS‐RESPONSE ITEMS IN PIGEONS
Authors: Jitsumori Masako , Sugimoto Sukeo
Published: March 2006

Six pigeons served in a discrete‐trial experiment on short‐term memory. Combinations of three key positions and two ordinal positions, yielding six possible sequences of stimulus‐response pairs, were used as lists of items. A retention interval separated list presentation from the test phase in which two (for Group 1) or three (for Group 2) keys were illuminated with either red or green light. A reinforcer was delivered if a subject pecked the key of the first item on a red trial and the key of the second item on a green trial. When the retention interval was lengthened from one to five or nine seconds, a systematic loss of stimulus control resulted. Lengthening the interval between items from one to eight seconds had a much smaller effect for the birds in Group 1, whereas a systematic loss of stimulus control was found in red trials for the birds in Group 2. The functional relations between choice accuracy and delay provided an empirical basis for analysis of what relations among temporal events can become discriminative stimuli.
FORAGING IN A SIMULATED NATURAL ENVIRONMENT: THERE'S A RAT LOOSE IN THE LAB
Authors: Mellgren Roger L.
Published: March 2006

Rats were required to earn their food in a large room having nine boxes placed in it, each of which contained food buried in sand. In different phases of the experiment the amount of time allowed for foraging, the amount of food available in each food patch, and the location of the different available amounts were varied. The rats exhaustively sampled all patches each session but seemed to have fairly strong preferences for certain locations over others. If position preferences were for patches containing small amounts of food, the sensitivity to amount available was increased so that when location was compensated for, a pattern of optimal foraging was evident. The importance of environmental constraints in producing optimal behavior and the relation of the observed behavior to laboratory findings are discussed.
RESPONSE SUPPRESSION BY VISUAL STIMULI PAIRED WITH POSTSESSION d‐AMPHETAMINE INJECTIONS IN THE PIGEON
Authors: Glowa John R. , Barrett James E.
Published: March 2006

Responding of pigeons, maintained under a fixed‐interval 3‐minute schedule of food presentation, was decreased on days that the color of the lights illuminating the food magazine was changed and d‐amphetamine (1.0 mg/kg, i.m.) was injected after the session. Responding was not decreased by keylight color changes paired with postsession d‐amphetamine or by postsession injections of saline. Administration of pentobarbital (3.0 to 5.6 mg/kg), but not d‐amphetamine (.3 to 3.0 mg/kg), before the session increased rates of responding suppressed by drug‐paired magazine lights. Responding maintained under a fixed‐ratio 30‐response schedule was not decreased when differently colored magazine lights were paired with a low (.3 mg/kg) postsession dose of d‐amphetamine; with high (3.0 mg/kg) postsession doses, however, responding was completely suppressed after two pairings. The effects of pairing magazine stimuli with an intermediate (1.0 mg/kg) postsession dose of d‐amphetamine depended upon the magnitude of prior postsession doses. After being paired with a low dose, stimuli paired with 1.0 mg/kg did not suppress responding. After being paired with a high dose, stimuli paired with 1.0 mg/kg completely suppressed responding. The suppression of food‐maintained responding by stimuli paired with postsession drug administration depends upon both behavioral and pharmacological variables.
DRUG EFFECTS ON REPEATED ACQUISITION: COMPARISON OF CUMULATIVE AND NON‐CUMULATIVE DOSING
Authors: Thompson Donald M. , Moerschbaecher Joseph M. , Winsauer Peter J.
Published: March 2006

Pigeons acquired a different four‐response chain each session by responding sequentially on three keys in the presence of a sequence of four colors. The response chain was maintained by food presentation under a fixed‐ratio schedule. Errors produced a brief timeout but did not reset the chain. Each day there were four 15‐minute sessions, with a 10‐minute intersession interval. Cumulative dose‐effect curves for phencyclidine, pentobarbital, and d‐amphetamine were obtained by giving an injection before each of the four sessions; successive injections increased the cumulative dose in equally spaced logarithmic steps. For comparison, non‐cumulative doses of each drug (i.e., doses not preceded by other doses on the same day) were also tested. As the cumulative dose of each drug increased, the overall response rate decreased, the percent errors increased, and there was less within‐session error reduction (acquisition). With phencyclidine and pentobarbital, the rate‐decreasing and error‐increasing effects tended to be greater with a non‐cumulative dose than with the corresponding cumulative dose. In contrast, with d‐amphetamine, the effects were considerably greater with the cumulative doses. The results indicate that although the cumulative‐dosing procedure saved a substantial amount of time in determining dose‐effect curves, there were quantitative differences in effects between cumulative and non‐cumulative doses.
TIMING THE SECOND RESPONSE IN TWO‐RESPONSE AVOIDANCE
Authors: Fairhurst Stephen , Gibbon John
Published: March 2006

Rats were trained on a free‐operant avoidance task requiring two lever presses within R seconds, with the opportunity for each response distinguished by differing stimuli. Response latencies at a variety of response‐shock intervals were found to be proportional to the time available for the response. These results are shown to be consonant with a scalar expectancy model of timing behavior.
HILL‐CLIMBING BY PIGEONS
Authors: Hinson John M. , Staddon J. E. R.
Published: March 2006

Pigeons were exposed to two types of concurrent operant‐reinforcement schedules in order to determine what choice rules determine behavior on these schedules. In the first set of experiments, concurrent variable‐interval, variable‐interval schedules, key‐peck responses to either of two alternative schedules produced food reinforcement after a random time interval. The frequency of food‐reinforcement availability for the two schedules was varied over different ranges for different birds. In the second series of experiments, concurrent variable‐ratio, variable‐interval schedules, key‐peck responses to one schedule produced food reinforcement after a random time interval, whereas food reinforcement occurred for an alternative schedule only after a random number of responses. Results from both experiments showed that pigeons consistently follow a behavioral strategy in which the alternative schedule chosen at any time is the one which offers the highest momentary reinforcement probability (momentary maximizing). The quality of momentary maximizing was somewhat higher and more consistent when both alternative reinforcement schedules were time‐based than when one schedule was time‐based and the alternative response‐count based. Previous attempts to provide evidence for the existence of momentary maximizing were shown to be based upon faulty assumptions about the behavior implied by momentary maximizing and resultant inappropriate measures of behavior.
AUTOSHAPED RESPONDING: A BASELINE FOR STUDYING STIMULUS PREFERENCE
Authors: Catania A. Charles , Owens Marian Colleen , Lossberg Virginia von
Published: March 2006

In an autoshaping procedure with pigeons, trials consisted of the illumination of two keys, each with a different color, and then a response‐independent feeder operation. Over successive conditions, all key‐color pairs were arranged from the set of amber, red, green, and blue lamps. During sessions with a given pair, the left‐right configuration of the colors varied irregularly, and the two colors alternated in illuminating the feeder. With one red and one green key, for example, red appeared sometimes on the left and sometimes on the right, and the feeder was alternately lit red or green on successive trials. Both total pecks and proportion of trials with at least one peck on a key of a given color were generally greater for red and amber than for green and blue, and relations among preferences were generally transitive across different color pairs. Repeating the procedure with decreased red and amber intensities and increased green and blue intensities reduced red and amber pecking relative to green and blue pecking, implying that differences in responding were determined more strongly by intensive than by chromatic properties of the stimuli.
PREFERENCE FOR MIXED VERSUS CONSTANT DELAYS OF REINFORCEMENT: EFFECT OF PROBABILITY OF THE SHORT, MIXED DELAY
Authors: Rider David P.
Published: March 2006

Preference for mixed versus constant delays of reinforcement was studied with a concurrent‐chain procedure. Lever pressing by rats in concurrently available variable‐interval 60‐second initial links occasionally produced mutually exclusive terminal‐link reinforcement delays. A constant delay of reinforcement (either 15 seconds or 30 seconds) composed one terminal link and mixed delays (.2 second and twice the value of the constant delay) were arranged in the other terminal link. The proportion of .2‐second delays in the mixed‐delay terminal link took on values of 0, .1, .25, .5, .75, .9, and 1.0 over experimental conditions. Based on relative rates of responding in the initial links, preference for the mixed delays was a negatively accelerated function of the proportion of short, mixed delays. Three of five rats preferred the mixed delays to the constant delays when the proportion of short, mixed delays was .1 or higher, and all five rats preferred the mixed delays when the proportion of short, mixed delays was .25 or higher. Neither Squires and Fantino's (1971) delay‐reduction model of choice nor a model based on the harmonic mean reinforcement delay provided a close estimate of choice proportions over the range of short‐delay proportions studied. The delay‐reduction model underestimated choice for the mixed delays at low and intermediate proportions of short delays, and the harmonic‐mean‐delay model overestimated choice for the mixed delays at intermediate and high proportions of short delays.
STEADY‐STATE PERFORMANCE ON FIXED‐, MIXED‐, AND RANDOM‐RATIO SCHEDULES
Authors: Mazur James E.
Published: March 2006

Three groups of rats pressed a lever for milk reinforcers on various simple reinforcement schedules (one schedule per condition). In Group M, each pair of conditions included a mixed‐ratio schedule and a fixed‐ratio schedule with equal average response:reinforcer ratios. On mixed‐ratio schedules, reinforcement occurred with equal probability after a small or a large response requirement was met. In Group R, fixed‐ratio and random‐ratio schedules were compared in each pair of conditions. For all subjects in these two groups, the frequency distributions of interresponse times of less than one second were very similar on all ratio schedules, exhibiting a peak at about .2 seconds. For comparison, subjects in Group V responded on variable‐interval schedules, and few interresponse times as short as .2 seconds were recorded. The results suggest that the rate of continuous responding is the same on all ratio schedules, and what varies among ratio schedules is the frequency, location, and duration of pauses. Preratio pauses were longer on fixed‐ratio schedules than on mixed‐ratio or random‐ratio schedules, but there was more within‐ratio pausing on mixed‐ratio and random‐ratio schedules. Across a single trial, the probability of an interruption in responding decreased on fixed‐ratio schedules, was roughly constant on random‐ratio schedules, and often increased and then decreased on mixed‐ratio schedules. These response patterns provided partial support for Mazur's (1982) theory that the probability of instrumental responding is directly related to the probability of reinforcement and the proximity of reinforcement.
BEHAVIOR INDUCED BY PERIODIC FOOD DELIVERY: THE EFFECTS OF INTERFOOD INTERVAL
Authors: Innis Nancy K. , Simmelhag‐Grant Virginia L. , Staddon J. E. R.
Published: March 2006

Pigeons were exposed to fixed‐time schedules of food presentation ranging from five to 300 seconds. Although consistent, stereotyped response patterns developed during interfood intervals on all schedules, there were distinct differences in the behavior observed on schedules with short, as opposed to long, intervals. During the shorter intervals, responses were performed quite vigorously, a feeder‐directed terminal response was observed, and most activities were localized near the feeder. On the longer schedules, no feeder‐directed terminal response developed, although the birds were usually near the feeder at the end of intervals. The predominant response involved moving about the chamber, often pacing along one of the walls. Performance during short intervals is accounted for quite well by the antagonistic‐motivational state hypothesis suggested by Staddon (1977); however, performance during longer intervals is not. Behavior during interfood intervals may more accurately be classified as reflecting a single (food) motivational state and described simply in terms of Craig's (1918) appetitive behavior.
FIXED‐INTERVAL PERFORMANCE: THE DYNAMICS OF BEHAVIOR AND THE INTERVAL LENGTH
Authors: Wearden J. H. , Lowe C. F.
Published: March 2006

Postreinforcement pauses from successive intervals under various fixed‐interval schedules (ranging from 15 seconds to 480 seconds in length) were subjected to lag‐1 autocorrelation analysis. Results from both rats and pigeons suggested that there was a consistent tendency for pause values in successive intervals to be weakly positively related. This tendency did not appear to change systematically with interval length and was exhibited both when the reinforcer magnitude was constant and when it was variable at different interval values. The findings do not support suggestions that the dynamic properties of performance under fixed‐interval schedules vary systematically with interval length, and are in the opposite direction from some previous findings suggesting that measures of behavior (such as post‐reinforcement pause length or number of responses) in successive intervals are inversely related.
THE MICROANALYSIS OF FIXED‐INTERVAL RESPONDING
Authors: Gentry G. David , Weiss Bernard , Laties Victor G.
Published: March 2006

The fixed‐interval schedule of reinforcement is one of the more widely studied schedules in the experimental analysis of behavior and is also a common baseline for behavior pharmacology. Despite many intensive studies, the controlling variables and the pattern of behavior engendered are not well understood. The present study examined the microstructure and superstructure of the behavior engendered by a fixed‐interval 5‐ and a fixed‐interval 15‐minute schedule of food reinforcement in the pigeon. Analysis of performance typical of fixed‐interval responding indicated that the scalloped pattern does not result from smooth acceleration in responding, but, rather, from renewed pausing early in the interval. Individual interresponse‐time (IRT) analyses provided no evidence of acceleration. There was a strong indication of alternation in shorter‐longer IRTs, but these shorter‐longer IRTs did not occur at random, reflecting instead a sequential dependency in successive IRTs. Furthermore, early in the interval there was a high relative frequency of short IRTs. Such a pattern of early pauses and short IRTs does not suggest behavior typical of reinforced responding as exemplified by the pattern found near the end of the interval. Thus, behavior from clearly scalloped performance can be classified into three states: postreinforcement pause, interim behavior, and terminal behavior.
ANOTHER LOOK AT CONTRAST IN MULTIPLE SCHEDULES
Authors: Williams Ben A.
Published: March 2006

Recent research on multiple schedule interactions is reviewed. Contrary to formulations that view contrast as the result of elicited behavior controlled by the stimulus‐reinforcer contingency (e.g., additivity theory), the major controlling variable is the relative rate of reinforcement, which cannot be reduced to some combination of stimulus‐reinforcer and response‐reinforcer effects. Other recent theoretical formulations are also reviewed and all are found to face serious counterevidence. The best description of the available data continues to be in terms of the “context of reinforcement,” but Herrnstein's (1970) formulation of the basis of such context effects appears to be inadequate. An alternative conception is provided by Catania's concept of “inhibition by reinforcement,” by which rate of responding is inversely related to the average rate of reinforcement in the situation. Such a conception is related to Gibbon's recent scalar‐expectancy account of autoshaping and Fantino's delay‐reduction model of conditioned reinforcement, suggesting that a common set of principles determines several diverse conditioning phenomena. However, the empirical status of such a description remains uncertain, because recent evidence shows that schedule interactions are temporally asymmetric, depending primarily upon the conditions of reinforcement that follow a schedule component.
EATING AND DRINKING: AN ECONOMIC ANALYSIS
Authors: Rachlin Howard , Krasnoff John
Published: March 2006

Food‐deprived rats were exposed to various schedules of food delivery; water‐deprived rats were exposed to various schedules of water delivery. Eating and drinking were measured over sessions and at points throughout sessions. The symmetries and asymmetries of food and water consumption were explored in terms of: (1) substitutability of food versus water, and of food and water on the one hand versus leisure on the other, (2) constraints imposed by various schedules of food and water, and (3) the tendency of rats to maximize utility within the imposed constraints.
TEMPORAL CONSTRAINT ON CHOICE: SENSITIVITY AND BIAS IN MULTIPLE SCHEDULES
Authors: McLean Anthony P. , White K. Geoffrey
Published: March 2006

In multiple schedules of reinforcement, ratios of responses in successive components are relatively insensitive to ratios of obtained reinforcers. An analysis is proposed that attributes changes in absolute response rates to concurrent interactions between programmed reinforcement and extraneous reinforcement in other components. The analysis predicts that ratios of responses in successive components vary with reinforcer ratios, qualified by a term describing the reinforcement context, that is, programmed and extraneous reinforcers. Two main predictions from the analysis were confirmed in an experiment in which pigeons' responses were reinforced in the components of a multiple schedule and analog extraneous reinforcement was scheduled for an alternative response in each component. Sensitivity of response and time ratios to reinforcer ratios in the multiple schedules varied as a function of the rate of extraneous reinforcers. Bias towards responding in one component of the multiple schedule varied as an inverse function of the ratios of extraneous reinforcer rate in the two components. The data from this and previous studies of multiple‐concurrent performance were accurately predicted by our analysis and supported our contention that the allocation of behavior in multiple‐schedule components depends on the relative values of concurrently‐available reinforcers within each component.
RATIO RESPONDING AS A FUNCTION OF CONCURRENT AVOIDANCE SCHEDULES, YOKED SHOCKS, AND RATIO VALUE
Authors: Wood Keith A. , Happ Alan J. , Adams Calvin K.
Published: March 2006

Fixed‐ratio food‐reinforced responding in rats was studied alone and with concurrent shock avoidance or with concurrent response‐independent shocks matched to those that occurred in the avoidance condition. Under each condition, fixed‐ratio size was increased over successive daily sessions. Fixed‐ratio response rate generally passed through a maximum as a function of fixed‐ratio size. Decreased fixed‐ratio responding at values beyond the maximum occurred when (1) the time to complete a fixed ratio approximated the response‐shock interval of the avoidance schedule, (2) the shock rate increased, and/or (3) the ratio requirements were so high that ratio strain occurred. Avoidance rates decreased slightly as fixed‐ratio size increased.
QUANTIFICATION OF RATS' BEHAVIOR DURING REINFORCEMENT PERIODS
Authors: Gunn Kenneth P.
Published: March 2006

What is treated as a single unit of reinforcement often involves what could be called a reinforcement period during which two or more acts of ingestion may occur, and each of these may have associated with it a series of responses, some reflexive, some learned, that lead up to ingestion. Food‐tray presentation to a pigeon is an example of such a “reinforcement period.” In order to quantify this behavior, a continuous‐reinforcement schedule was used as the reinforcement period and was chained to a fixed‐ratio schedule. Both fixed‐ratio size and reinforcement‐period duration were manipulated. Rats were used as subjects, food as reinforcement, and a lever press as the operant. Major findings included (a) a rapid decline in response rates during the first 15 to 20 seconds of the reinforcement periods, and (b) a strong positive relationship between these response rates and the size of the fixed ratio. Also revealed was a short scallop not normally found in fixed‐ratio response patterns, whose length was a function of fixed‐ratio size and reinforcement‐period duration. It is suggested that rapidly fluctuating excitatory processes can account for many of these findings and that such processes are functionally significant in terms of behavioral compensation.
EFFECTS OF CRITERION‐LEVEL PROBING ON DEMONSTRATING NEWLY ACQUIRED DISCRIMINATIVE BEHAVIOR
Authors: Stella M. Elizabeth , Etzel Barbara
Published: March 2006

The purpose of the study was to determine whether probes of the final criterion‐level discrimination administered during and after training provided an accurate measure of acquisition. Training and probe stimuli were designed to make training and probe trials initially very discriminable and then progressively less discriminable as training progressed. Initially, the discrimination required on probe trials was more difficult than the discrimination required on training trials. However, this difference in difficulty was gradually eliminated as training stimuli were topographically altered and made identical to probe stimuli by the end of training. Results showed that while correct responding was maintained throughout training, error patterns occurred on all probe trials administered during training. Error patterns developed regardless of whether probe trials occurred only at the beginning of training sessions (temporally discriminable probes) or were randomly interspersed in the training sessions (temporally indiscriminable probes). Probe error patterns seemed to be controlled by the stimulus properties of training and probe trials. Thus, probes did not measure acquisition as it occurred during training. Probe error patterns were maintained when probes were administered after completion of training. This final measure of acquisition did not agree with the demonstration of acquisition provided by the final training trial. The results suggest that probe trials can measure a different stimulus‐response relationship from that trained when training starts with an easier or known discrimination and probes involve a final or criterion test of a more difficult or unknown discrimination. Stimulus control of correct responses versus error patterns is discussed.
MEASURES OF RESPONSE BIAS AT MINIMUM‐DETECTABLE LUMINANCE LEVELS IN THE PIGEON
Authors: McCarthy Dianne
Published: March 2006

Using an operant analogue of the yes‐no detection task, six pigeons were trained to detect luminance changes under two different reinforcement‐scheduling procedures. In the first, an uncontrolled reinforcement‐ratio procedure, the relative frequency of food reinforcers obtained for correct detections was free to vary with the birds' behavior as luminance levels were changed. In the second, a controlled reinforcement‐ratio procedure, changes in preference could not alter the relative distribution of food reinforcers between the two response alternatives. Extreme response biases developed as luminance was decreased to threshold in the uncontrolled procedure. No progressive changes in response bias as a function of decreasing luminance were seen in the controlled procedure. Absolute thresholds for light intensity were lower in the controlled than in the uncontrolled procedure.
STIMULUS‐FOOD RELATIONS AND FREE‐OPERANT POSTPONEMENT OF TIMEOUT FROM RESPONSE‐INDEPENDENT FOOD PRESENTATION
Authors: Galbicka Gregory , Branch Marc N.
Published: March 2006

Grain was briefly presented to food‐deprived pigeons intermittently and response‐independently except during signaled timeouts. During Experiment 1, key pecks postponed the next timeout for a specified interval. Rates of pecking during time in were inversely related to the length of time pecking postponed the next timeout. Response‐independent presentation of temporal distributions of timeouts exactly matched to a preceding postponement condition decreased pecking rates during Experiment 2. These results indicate that key pecking of pigeons can be controlled by response‐dependent postponement of timeout, but that responses elicited by stimulus‐reinforcer relations inherent in timeout‐postponement procedures may substantially modify rates and patterns of pecking.
CHOICE FOR APERIODIC VERSUS PERIODIC RATIO SCHEDULES: A COMPARISON OF CONCURRENT AND CONCURRENT‐CHAINS PROCEDURES
Authors: Rider David P.
Published: March 2006

Choice between mixed‐ratio schedules, consisting of equiprobable ratios of 1 and 99 responses per reinforcement, and fixed‐ratio schedules of food reinforcement was assessed by two commonly used procedures: concurrent schedules and concurrent‐chains schedules. Rats were trained under concurrent fixed‐ratio mixed‐ratio schedules, in which both ratio schedules were simultaneously available, and under a concurrent‐chains schedule, in which access to one of the mutually exclusive ratio schedules comprising the terminal links was contingent on a single “choice” response. The distribution of responses between the two ratio schedules was taken as the choice proportion under the concurrent procedure, and the distribution of “choice” responses was taken as the choice proportion under the concurrent‐chains procedure. Seven of eight rats displayed systematic choice; of those, each displayed nearly exclusive choice for fixed‐ratio 35 to the mixed‐ratio schedule under the concurrent procedure, but each displayed nearly exclusive choice for the mixed‐ratio schedule to fixed‐ratio 35 under the concurrent‐chains procedure. Thus, preference for a fixed or a mixed schedule of reinforcement depended on the procedure used to assess preference.
SEPARATING THE EFFECTS OF SALIENCE AND DISPARITY ON THE RATE OF OBSERVING
Authors: Dinsmoor James A. , Bowe Craig A. , Dout Debra L. , Martin Louise T. , Mueller Kay L. , Workman Jane D.
Published: March 2006

Pigeons producing deliveries of grain on a mixed variable‐interval, extinction schedule by pecking a center key could also produce discriminative stimuli on concurrent variable‐interval schedules by pecking the left or right observing key. The stimuli produced by each observing key were varied independently. In the first experiment, the negative discriminative stimulus was at the far end of the spectrum from the key illumination accompanying the mixed schedule and from the positive discriminative stimulus. When the magnitude of the difference between the latter two stimuli (salience) was varied, more pecks occurred on the observing key producing the larger of the two differences than on the key producing the smaller difference. In the second experiment, the stimulus accompanying the mixed schedule was at the far end of the spectrum, and the magnitude of the difference between the two discriminative stimuli (disparity) was varied. The proportion of pecks occurring on each observing key shifted systematically in the direction of the key producing the larger difference. The salience of the discriminative stimuli and their disparity each has an independent influence on the frequency of observing when the other is controlled, but the effect of the salience appears to be the more substantial.
FACTORS AFFECTING CHOICE OF SIGNALED OR UNSIGNALED FOOD SCHEDULES
Authors: Harsh John , Badia Pietro , Ryan Kathy
Published: March 2006

Choice between signaled and unsignaled food schedules was assessed in two experiments using a shuttlebox. Experiment 1 examined preference with both a five‐second signal and a thirty‐second signal. Subjects preferred the unsignaled side with a five‐second signal but preferred the signaled side with a thirty‐second signal. Experiment 2 assessed preference using either a commitment procedure (a shuttle response resulted in exposure to the schedule for a fixed time) or a noncommitment procedure (each shuttle response changed the schedule in effect). Subjects preferred the signaled condition with the commitment procedure but the unsignaled condition with the noncommitment procedure. These results indicate that the discrepant findings of earlier studies are due to procedural differences involving signal duration and choice commitment. The data are consistent with a conditioned reinforcement interpretation of choice.
GERBILS IN SPACE: PERFORMANCE ON THE 17‐ARM RADIAL MAZE
Authors: Wilkie Donald M. , Slobin Peter
Published: March 2006

In Experiment 1 six hungry gerbils received six trials per day on a 17‐arm radial maze. During each trial the subjects were allowed to choose freely among the arms, each of which contained a food pellet, until each arm had been visited once or until eight minutes had elapsed. An error was recorded when the subject entered a previously visited arm. The gerbils quickly learned not to re‐enter previously visited arms and generally made errors on fewer than 15% of entries, performance comparable to that of the rat and superior to that of other species tested in the radial arm maze. The intertrial‐interval duration did not affect accuracy of arm choices during acquisition but did influence asymptotic accuracy. Accuracy did not change systematically over the six trials. A high proportion of arm entries were to nearby arms. Errors occurred most often towards the end of a trial. Odor cues were not important. When the number of trials per day was reduced from six to one, accuracy deteriorated slightly. In Experiment 2 neither the transposition of extramaze cues nor the placement of the maze in a different room had large disruptive effects on accuracy. In Experiment 3 the addition of three explicit intramaze brightness cues aided accuracy, perhaps by permitting the subjects to decompose the large maze into three smaller mazes, although there was no direct evidence that this was the case. Implications of a number of these results for models of spatial maze performance were discussed.
EFFECTS OF d‐AMPHETAMINE ON SELF‐AGGRESSION AND POSTURING IN STUMPTAIL MACAQUES
Authors: Peffer‐Smith P. G. , Smith E. O. , Byrd L. D.
Published: March 2006

The behavioral effects of d‐amphetamine sulfate were studied in adult male stumptail macaques living within a large heterogeneous group in an outdoor enclosure. Among five subjects that received a range of doses (.01 to .3 mg/kg), d‐amphetamine increased self‐aggressive behavior and abnormal posturing in subjects that exhibited these types of behavior prior to drug administration, but it had no effect in subjects not exhibiting those activities in the absence of the drug. For the former subjects, the dose‐effect curves for self‐aggression were of an inverted U‐shape analogous to the effect of d‐amphetamine on schedule‐controlled behavior. Over the range of doses studied, the curve for abnormal posturing was monotonic. The data indicate that d‐amphetamine can have effects on untrained behavior in individual animals in a quasinatural environment that are qualitatively and quantitatively similar to the behavioral effects observed in other laboratory environments, and that d‐amphetamine does not evoke or increase a behavioral response in individual subjects that do not exhibit the response in the absence of the drug.
MATCHING, MAXIMIZING, AND HILL‐CLIMBING
Authors: Hinson John M. , Staddon J. E. R.
Published: March 2006

In simple situations, animals consistently choose the better of two alternatives. On concurrent variable‐interval variable‐interval and variable‐interval variable‐ratio schedules, they approximately match aggregate choice and reinforcement ratios. The matching law attempts to explain the latter result but does not address the former. Hill‐climbing rules such as momentary maximizing can account for both. We show that momentary maximizing constrains molar choice to approximate matching; that molar choice covaries with pigeons' momentary‐maximizing estimate; and that the “generalized matching law” follows from almost any hill‐climbing rule.
UNDERMATCHING AND OVERMATCHING AS DEVIATIONS FROM THE MATCHING LAW
Authors: Wearden J. H.
Published: March 2006

A model of performance under concurrent variable‐interval reinforcement schedules that takes as its starting point the hypothetical “burst” structure of operant responding is presented. Undermatching and overmatching are derived from two separate, and opposing, tendencies. The first is a tendency to allocate a certain proportion of response bursts randomly to a response alternative without regard for the rate of reinforcement it provides, others being allocated according to the simple matching law. This produces undermatching. The second is a tendency to prolong response bursts that have a high probability of initiation relative to those for which initiation probability is lower. This process produces overmatching. A model embodying both tendencies predicts (1) that undermatching will be more common than overmatching, (2) that overmatching, when it occurs, will tend to be of limited extent. Both predictions are consistent with available data. The model thus accounts for undermatching and overmatching deviations from the matching law in terms of additional processes added on to behavior allocation obeying the simple matching relation. Such a model thus enables processes that have been hypothesized to underlie matching, such as some type of reinforcement rate or probability optimization, to remain as explanatory mechanisms even though the simple matching law may not generally be obeyed.
DURATION‐REDUCTION OF AVOIDANCE SESSIONS AS NEGATIVE REINFORCEMENT
Authors: Mellitz Mark , Hineline Philip N. , Whitehouse Wayne G. , Laurence Michael T.
Published: March 2006

Five rats were exposed to a shock‐postponement procedure in which responses on each of two levers initially had equivalent effects. After an initial training sequence that ensured at least some responding on each lever, an additional consequence was made conjointly operative on the previously less‐preferred lever for each animal. Each response on this lever continued to postpone shock, but also reduced the session duration by one minute. The conjoint contingencies were operative until, through session‐shortening responses and the passage of time, the session was scheduled to end in two minutes; during the final two minutes the session‐shortening contingency was disabled while the shock‐postponement contingency continued to be operative on both levers. When responding shifted to a predominance on the session‐shortening lever, the conjoint contingency was shifted to the other lever; for four of the five rats this reversal was followed by two additional reversals. Two of the rats' responding showed clear, strong, and unambiguous sensitivity to the session‐shortening contingency. The responding of two others was also systematically controlled by that contingency, but the effects were less clearcut. The fifth animal showed an initial shift when session‐shortening was introduced, but its subsequent behavior proved insensitive to reversals of procedure. The results clearly indicate a sensitivity of behavior to events on a time scale quite distinct from that of immediate consequences. They also support an interpretation of avoidance sessions, considered in their entirety, as events whose contingent relationship to behavior can affect that behavior—even in the absence of stimuli that delineate those relationships. Finally, these results support an interpretation of aversively based conditioning within a broader context, analogous to the “open versus closed economy” interpretation of appetitively controlled behavior.
THE ASSUMPTIONS UNDERLYING THE GENERALIZED MATCHING LAW
Authors: Prelec Drazen
Published: March 2006

Allen (1981) derived the power‐function generalization of the matching law from a functional equation involving relative response rates on three concurrently available schedules of reinforcement. This paper defines the conditions (relative homogeneity and independence) under which a more general class of behavioral laws reduces to the power law. The proof also removes two deficiencies of Allen's result (discussed by Houston, 1982), which are, first, that his derivation produces a power law without a bias coefficient, and second, that it holds only for experiments with three or more concurrent schedules.
CONCURRENT VARIABLE‐INTERVAL SCHEDULE PERFORMANCE: FIXED VERSUS MIXED REINFORCER DURATIONS
Authors: Davison Michael , Hogsden Ian
Published: March 2006

Six pigeons were trained on concurrent variable‐interval schedules. Two different reinforcer durations were arranged on the left key, and which of these was delivered was determined probabilistically. A single reinforcer duration was arranged on the right key. In Parts 1 and 3 of the experiment, the probability of the left‐key reinforcer durations (1 and 7 seconds in Part 1; 3 and 10 seconds in Part 3) was varied from 0 to 1, keeping the schedules constant and the right‐key reinforcer at 3 seconds. Response allocation to the left key fell as the probability of the shorter left‐key reinforcer duration was increased. In Part 2, one left‐key reinforcer duration was 3 seconds and the other was varied from 0 to 10 seconds, while again the schedules and right‐key reinforcer duration (3 seconds) were kept constant. Left‐key response allocation increased as the varied reinforcer duration on the left key increased. An extension of the generalized matching law failed to provide a good description of response allocation in these procedures. In Part 4, the left‐ and right‐key reinforcer durations were 3 seconds and the variable‐interval schedules were varied. Response allocation was well described by the generalized matching law. Part 5 arranged equal variable‐interval schedules on the left and right keys, 3‐second reinforcers on the right key, and the left‐key reinforcer durations were varied from 1 to 10 seconds. The relationship between the log response and reinforcer‐duration ratios was nonlinear. The effects of varying reinforcer durations in concurrent schedules cannot be described using the generalized matching law with constant parameters. It is suggested more generally that this quantitative relation may not describe performance either when reinforcing situations differ in duration (e.g., with delayed reinforcers) or when response requirements differ in duration.
TESTING THE REINFORCING PROPERTIES OF S—: A REPLICATION OF LIEBERMAN'S PROCEDURE
Authors: Mueller Kay L. , Dinsmoor James A.
Published: March 2006

A critical issue in testing theories of observing is whether the stimulus associated with extinction (the S—) reinforces observing responses. In previous experiments, subjects have been trained to make observing responses that produce both the S— and the stimulus correlated with reinforcement (the S+). Then, either the S+ or the S— has been withheld. Conflicting results have been attributed to differences among species. In the present experiments, pecking one key by master pigeons was reinforced with grain on a variable‐ratio extinction schedule. Yoked pigeons received the grain on a variable‐interval, extinction schedule controlled by the variable‐ratio performances of the master birds. For both groups, concurrent pecking on a second key was reinforced on a variable‐interval schedule with displays of discriminative stimuli. Subsequently, either the S+ or the S— was eliminated from the procedure. Omission of S+ produced a large decrease, as predicted by traditional conditioned reinforcement accounts of observing. By itself, S— did not maintain observing. A smaller and less reliable decrease, comparable to that obtained by Lieberman (1972) with rhesus monkeys, occurred when S— was eliminated. This replication with pigeons of Lieberman's results indicates that they are not species‐specific, and the fact that observing was not maintained by S— alone suggests that the decrease obtained when S— was omitted is not attributable to the reinforcing power of S—.
CONFIRMATION OF LINEAR SYSTEM THEORY PREDICTION: CHANGES IN HERRNSTEIN'S k AS A FUNCTION OF CHANGES IN REINFORCER MAGNITUDE
Authors: McDowell J. J. , Wood Helena M.
Published: March 2006

Eight human subjects pressed a lever on a range of variable‐interval schedules for 0.25¢ to 35.0¢ per reinforcement. Herrnstein's hyperbola described seven of the eight subjects' response‐rate data well. For all subjects, the y‐asymptote of the hyperbola increased with increasing reinforcer magnitude and its reciprocal was a linear function of the reciprocal of reinforcer magnitude. These results confirm predictions made by linear system theory; they contradict formal properties of Herrnstein's account and of six other mathematical accounts of single‐alternative responding.
SEPARATING RESPONSE DEPENDENCY AND RESPONSE‐REINFORCER CONTIGUITY WITHIN A RECYCLING CONJUNCTIVE SCHEDULE
Authors: Keenan Michael , Leslie Julian C.
Published: March 2006

A procedure is described which disrupts response‐reinforcer contiguity and response dependency and which demonstrates how the location of the response dependency in interval schedules can be regarded as a controlling variable in its own right. Rats' lever pressing produced sucrose on a recycling conjunctive fixed‐time 30‐second fixed‐ratio 1 schedule of reinforcement. Reinforcement occurred only at the end of the fixed‐time component on this schedule and only if a response had occurred during that component. This produced a pause‐respond‐pause pattern during the interreinforcer interval for all animals. When the location of the response dependency was then restricted to a 10‐second period in the middle of the fixed‐time component, the pattern was accentuated and response rates increased for all animals, while postreinforcement pauses decreased sharply for two animals. When responding was required in the first 10 seconds of the fixed‐time component, responding peaked earlier in the interval for all animals. Response rates were slightly below those in the previous conditions, while postreinforcement pauses were between 2 and 6 seconds across animals.
VERBAL BEHAVIOR AT A PROCEDURAL LEVEL IN THE CHIMPANZEE
Authors: Savage‐Rumbaugh E. Sue
Published: March 2006

Ape language research has typically employed cognitive descriptions of ape competencies. Recently, Epstein, Lanza, and Skinner (1980) attempted to simulate some of the ape findings with pigeons. They also used cognitive terms to describe their results, but with “tongue‐in‐cheek.” In the hope of bringing about a better understanding of the ape research, this paper describes the main aspects of one ape language project, using a behavior‐analytic framework. It then briefly compares and contrasts, from that perspective, the training programs used with pigeons and with apes. It is concluded that the behavior‐analytic framework, and the procedures devised to produce language skills in apes, provide strong support for several of the major positions set forth in Skinner's (1957) Verbal Behavior.
THE FORMATION OF VISUAL STIMULUS EQUIVALENCES IN CHILDREN
Authors: Lazar Ronald M. , Davis‐Lang Deborah , Sanchez Lisette
Published: March 2006

Four normal children were presented a series of matching‐to‐sample tasks, using five sets of visual stimuli designated A, B, C, D, and E. Stimulus equivalences were established by matching stimuli from one set to those from another set. Each set consisted of three stimuli, so matching set A to set D meant that each stimulus in set A served as a sample with all three stimuli in set D as comparisons. Subjects were first taught AD and DC matching and were then able to perform AC/CA matching without additional training. After ED was taught directly, CE/EC and AE/EA performances emerged. Following CB training, three new equivalences were demonstrated: AB/BA, EB/BE, and DB/BD. Oral naming of each stimulus showed that subjects had not assigned a common label to stimuli in the same class, indicating that naming is not necessary for the formation of stimulus equivalences. The absence of response mediation suggests that matching to sample can form direct stimulus‐stimulus associations. The data also provide support for the notion that generative performances are outcomes of existing stimulus‐control relationships.
TIME REALLOCATION IN A MULTIRESPONSE ENVIRONMENT: EFFECTS OF RESTRICTING RESPONSE CLASSES
Authors: Lyons Charles A. , Cheney Carl D.
Published: March 2006

Four adult male rats were each placed for three hours daily into an apparatus that provided individual compartments for six separate location‐defined responses. The available responses consisted of: (1) the opportunity to turn off room lighting, producing darkness; (2) the opportunity to view a female rat; (3) the opportunity to turn off white noise; (4) the opportunity to drink; (5) the opportunity to eat; and (6) “other,” representing time in the hallway between compartments. Each subject underwent a series of conditions characterized as an A‐B‐A‐C‐A design. Manipulations consisted of the removal of a low‐probability response (darkness) and of a high‐probability response (escape from noise) in a counterbalanced manner across subjects. The dependent measure for all subjects was the percentage of total session time spent in each compartment. Four predictive rules concerning the redistribution of behavior after response restriction were tested, including the constant‐ratio rule, equal time redistribution, the most probable alternative, and the sequential‐dependency rule. The results indicate no support for any of the four predictive rules and suggest that empirical assessment of restriction effects is necessary in reinforcement studies involving temporally extended responses.