bluuebunny/crossref_metadata_2025 huggingface dataset:
A COMPARISON OF RATIO AND INTERVAL REINFORCEMENT SCHEDULES WITH COMPARABLE INTERREINFORCEMENT TIMES
Authors: Capehart George W. , Eckerman David A. , Guilkey Marilyn , Shull Richard L.
Published: March 2006

Pigeons were trained to peck keys on fixed‐ratio and fixed‐interval schedules of food reinforcement. Both schedules produced a pattern of behavior characterized as pause and run, but the relation of pausing to time between reinforcers differed for the two schedules even when mean time between reinforcers was the same. Pausing in the fixed ratio occupied less of the time between reinforcers for shorter interreinforcer times. For two of three birds, the relation was reversed at longer interreinforcer times. As an interreinforcer time elapsed, there was an increasing tendency to return to responding for the fixed interval, but a roughly constant tendency to return to responding for the fixed‐ratio schedule. In Experiment 1 these observations were made for both single‐reinforcement schedules and multiple schedules of fixed‐ratio and fixed‐interval reinforcement. In Experiment 2 the observations were extended to a comparison of fixed‐ratio versus variable‐interval reinforcement schedules, where the distribution of interreinforcement times in the variable interval approximated that for the fixed ratio.
PREFERENCE FOR FREE CHOICE OVER FORCED CHOICE IN PIGEONS
Authors: Catania A. Charles , Sagvolden Terje
Published: March 2006

In a six‐key chamber variable‐interval initial links of concurrent‐chain schedules operated on two lower white keys. Terminal links operated on four upper keys; green keys were correlated with fixed‐interval reinforcement and red keys with extinction. Free‐choice terminal links arranged three green keys and one red key; forced‐choice terminal links arranged one green key and three red keys. Thus, terminal links were equivalent in number, variety, and information value (in bits) of the keylights. Preferences (relative initial‐link rates) were studied both with location of the odd key color varying over successive terminal links and with the odd color fixed at key locations that had controlled either relatively high or relatively low terminal‐link response rates. Free choice was consistently preferred to forced choice. Magnitude of preference did not vary systematically with terminal‐link response rate or stimulus control by green and red keys. The origins of free‐choice preference could be ontogenic or phylogenic: organisms may learn that momentarily preferred alternatives are more often available in free than in forced choice, and evolutionary contingencies may favor the survival of organisms that prefer free to forced choice.
SELECTIVE ANTAGONISM OF THE RATE‐DECREASING EFFECT OF d‐AMPHETAMINE BY CHLORPROMAZINE IN A REPEATED‐ACQUISITION TASK
Authors: Thompson Donald M.
Published: March 2006

Pigeons acquired a different four‐response chain each session by responding sequentially on three keys in the presence of four colors. The response chain was maintained by food presentation under a fixed‐ratio schedule. When d‐amphetamine was administered alone, the overall response rate decreased and the percent errors increased with increasing doses. When a small dose of chlorpromazine, which was ineffective when given alone, was administered in combination with d‐amphetamine, the rate‐decreasing effect was antagonized. The antagonism was selective, however, in that the error‐increasing effect of d‐amprotamine was augmented by chlorpromazine. The nature of the joint effect of the two drugs thus depended on the behavioral measure: rate vs. accuracy.
EFFECTS OF INSTRUCTIONAL CONSTRAINTS ON HUMAN FIXED‐INTERVAL PERFORMANCE
Authors: Buskist W. F. , Bennett R. H. , Miller H. L.
Published: March 2006

Several groups of human subjects were exposed to a variety of experimental conditions involving a fixed‐interval 27‐second schedule of reinforcement in compound with instructions to constrain in the number of responses within the interreinforcement interval and/or the duration of the experimental session. One group was further exposed to a contingency involving the placement of responses within the IRI. A diversity of patterns of performance was observed, including those typically associated with animal subjects exposed to FI schedules. Generally, the imposition of instructions to minimize session duration reduced post‐reinforcement pausing and increased overall reinforcement density from those levels obtained with only instructions to expend a given number of responses per reinforcer. The results are seen to underscore the sensitivity of human fixed‐interval performance and the contribution of extra‐experimental contingencies.
PREPOSITIONAL PHRASES SPOKEN AND HEARD
Authors: Lee Vicki L.
Published: March 2006

The relation between verbal and nonverbal behavior with common syntactic properties was investigated, using retarded and nonretarded children. Reinforcement was contingent on either verbal or nonverbal responses whereas responses of the other repertoire had no experimental consequences. Changes sometimes occurred in the unreinforced (collateral) repertoire, but they were always changes in the stimulus control of pre‐existing topographies. A contingency involving responses of one repertoire never instated new topographies in the collateral repertoire. This suggested that the problem of “cross‐modality generalization” should be reformulated to distinguish explicitly between instating new topographies and changing the stimulus control of pre‐existing topographies. The result confirmed Skinner's hypothesis about “the same response spoken and heard” and clarified some anomalies in previous studies.
THE FOLLOWING SCHEDULE OF REINFORCEMENT AS A FUNDAMENTAL DETERMINANT OF STEADY STATE CONTRAST IN MULTIPLE SCHEDULES
Authors: Williams Ben A.
Published: March 2006

Two experiments investigated whether steady‐state interactions in multiple schedules depend exclusively on the following schedule of reinforcement. Experiment 1 used a four‐component multiple schedule in which two components were associated with the same constant schedule of reinforcement, and where rate of reinforcement was varied in the component that followed one of these. Contrast effects were reliable only in the component that preceded the point of reinforcement variation, although some contrast did occur otherwise. In those instances where contrast other than the following‐schedule effect did occur, it was accounted for by the effect of the preceding schedule, an effect for which there were consistent individual differences among subjects, and which varied with component duration. Experiment 2 used a three‐component schedule, in which reinforcement rate was varied in the middle component. The results were consistent with Experiment 1, as the following‐schedule effect was the only consistent effect that occurred, although an effect of the preceding schedule did occur for some subjects under some conditions, and was especially evident early in training. The conclusion from both experiments is that there is no general effect of relative rate of reinforcement apart from the sum of the effects of the preceding and following schedules, and that the following‐schedule effect is the fundamental cause of steady‐state interactions.
BURYING BY RATS IN RESPONSE TO AVERSIVE AND NONAVERSIVE STIMULI
Authors: Poling Alan , Cleary James , Monaghan Michael
Published: March 2006

Previous investigations have shown that rats bury a variety of conditioned and unconditioned aversive stimuli. Such burying has been considered as a species‐typical defensive reaction. In the present studies, rats buried spouts filled with Tabasco sauce, or condensed milk to which a taste aversion was conditioned, but did not bury water‐filled spouts or spouts filled with a palatable novel food (apple juice) to which a taste aversion was not conditioned. However, in other experiments rats consistently and repeatedly buried Purina Rat Chow, Purina Rat Chow coated with quinine, and glass marbles. This indicates that a variety of stimuli, not all aversive or novel, evoke burying by rats. Whereas the behavior may reasonably be considered as a species‐typical defensive behavior in some situations, the wide range of conditions that occasion burying suggests that the behavior has no single biological function.
REINFORCEMENT BY AN IMPRINTING STIMULUS VERSUS WATER ON SIMPLE SCHEDULES IN DUCKLINGS
Authors: DePaulo Peter , Hoffman Howard S.
Published: March 2006

Ducklings (5 to 28 days old) were trained to peck a pole on fixed‐ratio, fixed‐interval, and multiple schedules using brief presentation of an imprinting stimulus as the response‐contingent event. Other ducklings of the same age were trained similarly except that reinforcement consisted of access to water. With water reinforcement the typical fixed‐ratio (“break‐run”), fixed‐interval (“scallop”), and multiple schedule response patterns were readily established and consistently maintained. With the imprinting stimulus these schedule effects were inconsistent in some subjects and virtually nonexistent in others, despite extended training. Schedule control with the imprinting stimulus was not improved by the use of a reinforcement signaling procedure which enhances responding reinforced by electrical brain stimulation on intermittent schedules. However, the overall rates of responding and the extinction functions generated after reinforcement with water versus the imprinting stimulus were comparable. These findings imply that control by temporal and discriminative stimuli may be relatively weak when a young organism's behavior is reinforced by presentation of an imprinting stimulus.
THE EFFECTS OF MODIFYING CONSUMMATORY BEHAVIOR ON THE TOPOGRAPHY OF THE AUTOSHAPED PECKING RESPONSE IN PIGEONS
Authors: Premock Mark , Klipec William D.
Published: March 2006

The autoshaped responses of two debeaked pigeons that had developed modified eating behavior were compared to the autoshaped responses of three control subjects that ate grain normally. The control subjects exhibited keylight responding that was judged normal by two independent raters. The debeaked subjects pecked the key and ate grain with both normal and modified responses. The results of this study demostrate that an autoshaping procedure using grain as an appetitive stimulus may be used to establish a response that is not biologically preorganized.
RELATIONSHIP BETWEEN RESPONSE RATE AND REINFORCEMENT FREQUENCY IN VARIABLE‐INTERVAL SCHEDULES: III. THE EFFECT OF d‐AMPHETAMINE
Authors: Bradshaw C. M. , Ruddle H. V. , Szabadi E.
Published: March 2006

Four rats were exponsed to variable‐interval schedules specifying a range of different reinforcement frequencies. The effects of two doses of d‐amphetamine (1.6 and 3.2 μmol/kg) upon performance maintained under each schedule were examined. In the case of each rat, the response rates observed under control conditions (no injection or injection of the vehicle alone) were increasing, negatively accelerated functions of reinforcement frequency, the data conforming closely to Herrnstein's (1970) equation. In each rat, d‐amphetamine (3.2 μmol/kg) significantly reduced the value of the constant Rmax, which expresses the theoretical maximum response rate. In each rat, the value of KH, which expresses the reinforcement frequency needed to obtain the half‐maximal response rate, was also reduced, although this only achieved statistical significance in the case of one rat. When the proportional change in response rate in the presence of the drug was plotted against the response rate under control conditions on double logarithmic co‐ordinates, linear functions of negative slope were obtained; in each rat the slope was steeper and the value of the control response rate at which d‐amphetamine exerted no effect was lower in the case of the higher dose (3.2 μmol/kg) than in the case of the lower dose (1.6 μmol/kg).
THE EFFECTS OF BRIEF‐STIMULUS PRESENTATIONS IN FIXED‐RATIO SECOND‐ORDER SCHEDULES
Authors: Cohen Steven L. , Calisto George
Published: March 2006

Pigeons' responses were reinforced according to a three‐component multiple schedule. In Component 1, key pecks produced food according to a fixed‐ratio second‐order schedule with fixed‐ratio units. Here, a fixed number of fixed‐ratio units produced food, and the brief stimulus terminating each unit also accompanied food. Responses in Component 2 produced food on an identical schedule except that the brief stimulus was not paired with food. Component 3 contained a simple fixed‐ratio schedule whose response requirement equaled that of Components 1 and 2. Across conditions the size of the fixed‐ratio unit (five, ten, twenty, forty, and eighty responses) and the total number of responses per reinforcement were parametrically manipulated. The highest response rates and shortest preratio pauses were observed in Component 3 (no brief stimulus). The lowest rates and longest pauses were found in the component with paired brief‐stimulus presentations, indicating that the food‐paired brief stimulus suppressed responding. The suppressive effects were greatest when the fixed‐ratio units were small (e.g., fixed‐ratio 5) and the total fixed‐ratio requirement was large (e.g., fixed‐ratio 160). Under no conditions did the paired brief stimulus facilitate responding. The nonpaired brief stimulus also suppressed responding but to a lesser extent. The suppressive effects of nonpaired brief stimuli were greatest when the fixed‐ratio units were small and the total response requirement was large. These data suggest that the suppressive effects of the brief stimuli may have masked the conditioned‐reinforcing effects reported in other studies, and that conditions that maximize suppression in second‐order schedules involve the use of fixed‐ratio schedule units and the presentation of many brief stimuli per reinforcer.
OPTIMIZATION AND THE MATCHING LAW AS ACCOUNTS OF INSTRUMENTAL BEHAVIOR
Authors: Baum William M.
Published: March 2006

The interaction between instrumental behavior and environment can be conveniently described at a molar level as a feedback system. Two different possible theories, the matching law and optimization, differ primarily in the reference criterion they suggest for the system. Both offer accounts of most of the known phenomena of performance on concurrent and single variable‐interval and variable‐ratio schedules. The matching law appears stronger in describing concurrent performances, whereas optimization appears stronger in describing performance on single schedules.
THE LEGACY OF GUTTMAN AND KALISH (1956): 25 YEARS OF RESEARCH ON STIMULUS GENERALIZATION
Authors: Honig Werner K. , Urcuioli Peter J.
Published: March 2006

This paper is a selective review of the methods, problems, and findings in the area of operant stimulus generalization over the 25 years since the publication of the original paper by Guttman and Kalish (1956) on discriminability and spectral generalization in the pigeon. The paper falls into five main sections, which encompass the main themes and problems stemming from the Guttman and Kalish work and its immediate successors. The first section addresses the relationship between stimulus generalization and stimulus control, as well as the variety of testing procedures and dependent variables used to measure generalization. The next section reviews the limited literature on the effects of early rearing on the generalization gradient. The relationship between discriminability among test stimuli and the slope of the spectral gradient is discussed in the third section, with emphasis upon recent reassessments of the pigeon's hue discriminability function. The fourth section reviews the topic of inhibitory stimulus control, one which developed with the discovery of the peak shift following intradimensional discrimination training. Problems of definition and measurement are discussed in conjunction with the gradient forms used to index inhibitory control. The last section is devoted to attentional effects and the two principal theories postulated to account for them. A survey of different attentional paradigms is provided and the possible role of constant irrelevant stimuli as a source of control is examined. A brief conclusion summarizes the contribution of the generalization technique toward an understanding of the nature and acquisition of stimulus control.
STIMULUS CONTROL OF RESPONDENT AND OPERANT KEY PECKING: A SINGLE KEY PROCEDURE
Authors: Marcucella Henry
Published: March 2006

Pigeons' responses to a uniformly illuminated response key were either reinforced on a variable‐interval one‐minute schedule of reinforcement or extinguished for one‐minute periods. When 1.5 second signals were presented at the beginning of each component, so as to differentially predict reinforcement, the pigeons pecked at the signals, at rates higher than rates during the remainder of the component. When the brief signals were not differentially predictive of reinforcement, pecking in their presence decreased to near zero levels. Similar results were obtained with signals based upon colors and upon line orientations. Changes in rates of (unreinforced) pecking occurred during the signal whether pigeons responded differentially during the remainder of the component or not. Experiment II demonstrated that the presence of the signal correlated with extinction was not necessary for pecking to develop at the signal which preceded the component in which responding was intermittently reinforced. The experiments demonstrated a clear dissociation of respondent control from operant control of a response. In addition, operant behavior was shown to be relatively insensitive to differing rates of reinforcement, as compared to the sensitivity of respondent behavior to differing rates of reinforcement produced by the very same operant behavior.
AUTOSHAPING IN THE RAT: EFFECTS OF OMISSION ON THE FORM OF THE RESPONSE
Authors: Davey Graham C. L. , Oakley David , Cleland Gary G.
Published: March 2006

Two experiments were conducted to investigate the effect of an omission contingency on behavior related to and characterizing autoshaped lever contacts in the rat. In Experiment I an omission contingency imposed on autoshaped lever contacts forceful enough to produce a press (.078N) resulted in a significant decrease in lever presses, but had no effect on frequency of lever touches (contacts of insufficient force to produce a press) or rate of food tray entry during lever presentation. In contrast, rats which received a similar number of lever‐food pairings, but whose behavior had no programmed consequences (yoked control subjects), showed an increase in lever press rate, a significant decrease in rate of food tray entry, and no change in rate of lever‐touches. In Experiment II, the effect of a similar omission contingency on the topography of lever contact responses was investigated. Prior to omission training subjects contacted the lever primarily by pawing it. Following omission training this behavior was suppressed, with a subsequent increase in lever contacts characterized as nosing. Yoked control subjects showed no significant changes in lever contact topography. The results indicate that (1) an omission contingency does not simply eliminate wholesale those topographies which incur the contingency but produces subtle adaptive changes in lever contact topography; and (2) the nature of the autoshaped response in the rat does not appear to be rigid enough to depend solely upon the nature of the unconditioned stimulus or the conditioned stimulus, but can also be determined by the relationships existing between the animal's behavior and these stimuli.
CHANGES IN A MULTIPLE‐RESPONSE REPERTOIRE DURING RESPONSE‐CONTINGENT PUNISHMENT AND RESPONSE RESTRICTION: SEQUENTIAL RELATIONSHIPS
Authors: Dunham Philip J. , Grantmyre Jane
Published: March 2006

A multiple‐response baseline of four activities was established using gerbils as subjects. When one of the baseline responses was punished (Experiment 1) or restricted (Experiments 2 and 3), only the most probable of the alternative baseline responses increased. The response most likely to follow the punished or restricted responses during baseline sessions was also suppressed during subsequent punishment or response‐restriction treatment.
DISTINGUISHING BETWEEN DISCRIMINATIVE AND MOTIVATIONAL FUNCTIONS OF STIMULI
Authors: Michael Jack
Published: March 2006

A discriminative stimulus is a stimulus condition which, (1) given the momentary effectiveness of some particular type of reinforcement (2) increases the frequency of a particular type of response (3) because that stimulus condition has been correlated with an increase in the frequency with which that type of response has been followed by that type of reinforcement. Operations such as deprivation have two different effects on behavior. One is to increase the effectiveness of some object or event as reinforcement, and the other is to evoke the behavior that has in the past been followed by that object or event. “Establishing operation” is suggested as a general term for operations having these two effects. A number of situations involve what is generally assumed to be a discriminative stimulus relation, but with the third defining characteristic of the discriminative stimulus absent. Here the stimulus change functions more like an establishing operation than a discriminative stimulus, and the new term, “establishing stimulus,” is suggested. There are three other possible approaches to this terminological problem, but none are entirely satisfactory.
FAILURE TO PRODUCE RESPONSE VARIABILITY WITH REINFORCEMENT
Authors: Schwartz Barry
Published: March 2006

Two experiments attempted to train pigeons to produce variable response sequences. In the first, naive pigeons were exposed to a procedure requiring four pecks on each of two keys in any order, with a reinforcer delivered only if a given sequence was different from the preceding one. In the second experiment, the same pigeons were exposed to this procedure after having been trained successfully to alternate between two specific response sequences. In neither case did any pigeon produce more than a few different sequences or obtain more than 50% of the possible reinforcers. Stereotyped sequences developed even though stereotypy was not reinforced. It is suggested that reinforcers have both hedonic and informative properties and that the hedonic properties are responsible for sterotyped repetition of reinforced responses, even when stereotypy is negatively related to reinforcer delivery.
RESPONSES AND PAUSES: DISCRIMINATION AND A CHOICE CATASTROPHE
Authors: Zeiler Michael D. , José Miguel Solano N.
Published: March 2006

Pigeons produced a stimulus change either by responding or by not responding for a specified time period (by pausing). They then had to choose between two responses to obtain food. One choice was correct if the first component had been completed by a response; the other was correct if the component had been completed by a pause. The pigeons usually chose correctly, thereby indicating that they used their own prior behavior as a discriminative stimulus. Fixed pause requirements did not produce equal first component completions by a response and by a pause. To obtain equality, the pause requirement was titrated as a function of current performance. Titration resulted in equal completions and also produced accurate discrimination. In addition to showing that pigeons discriminated whether they had responded or paused, the data displayed the discontinuous functions predicted by catastrophe theory. Another procedure used forced choice rather than titration to produce equal completions by pausing and responding and also showed accurate discrimination of behavior.
HUMAN PERFORMANCE ON CONJUNCTIVE FIXED‐INTERVAL FIXED‐RATIO SCHEDULES
Authors: Duvinsky Jerry D. , Poppen Roger
Published: March 2006

Eighteen young adults performed a lever‐pulling task for money. Subjects were initially exposed to a fixed‐interval 80‐second schedule and subsequently to one of three conjunctive schedules in which the added fixed‐ratio requirement was set at either 10, 80, or 120 responses. Three fixed‐interval response patterns emerged: high constant rate, intermediate rate, or low rate, with most subjects displaying the last. Conjunctive performance was related to the subjects' prior fixed‐interval patterns and the conjunctive ratio requirements. Low‐rate subjects tended to optimize reinforcement (maximum reinforcers for minimum responses) on conjunctive schedules. Response rate was directly related to ratio requirements. Subjects' performance closely corresponded to their verbal statements of the contingencies.
SENSORY SUPERSTITION ON MULTIPLE INTERVAL SCHEDULES
Authors: Starr Bettie C. , Staddon J. E. R.
Published: March 2006

Pigeons were exposed to multiple schedules in which an irregular repeating sequence of five stimulus components was correlated with the same reinforcement schedule throughout. Stable, idiosyncratic, response‐rate differences developed across components. Components were rank‐ordered by response rate; an approximately linear relation was found between rank order and the deviation of mean response rate from the overall mean rate. Nonzero slopes of this line were found for multiple fixed‐interval and variable‐time schedules and for multiple variable‐interval schedules both when number of reinforcements was the same in all components and when it varied. The steepest function slopes were found in the variable schedules with relatively long interfood intervals and relatively short component durations. When just one stimulus was correlated with all components of a multiple variable‐interval schedule, the slope of the line was close to zero. The results suggest that food‐rate differences are not essential to engender response‐rate differences among stimuli. Rate differences may be induced initially by different reactions to the stimuli and subsequently maintained by food.
CHANGEOVER DELAY EFFECTS ON TOPOGRAPHICALLY TAGGED DISCRIMINATIVE BEHAVIOR
Authors: White K. Geoffrey
Published: March 2006

In a multiple variable‐interval extinction schedule, pigeons' responses on an operant key were differentially reinforced in the presence of discriminative stimuli located on a signal key. Changeover delays of zero, one, two, or four seconds specified the time following a signal‐key response within which an operant‐key response was not reinforced. Systematic reduction of signal‐key response rates with increasing changeover‐delay duration indicated that signal‐key responding was largely maintained by reinforcement of adventitious signal‐key/operant‐key response chains.
EFFECTS ON SPELLING OF TRAINING CHILDREN TO READ
Authors: Lee Vicki L. , Pegler Anne M.
Published: March 2006

Experiment 1 investigated whether training subjects to read words aloud would induce correct written spelling of the words even though spelling had no experimental consequences. Training in reading was followed by a weak increment in correct spelling. Experiment 2 investigated whether overtraining in reading would improve spelling more. Spelling improved as overtraining continued until the subjects spelled all the words correctly. Experiments 3 and 4 investigated the components of overtraining responsible for this improvement in spelling. Initial training in reading followed by repeated opportunities to look at (but not say aloud) the printed words resulted in the same gradual improvement in spelling as seen in Experiment 2. The results were related to Skinner's theory of verbal behavior and to studies of the relationship between speaking and instruction‐following in children.
CONTROL OF ADOLESCENTS' ARBITRARY MATCHING‐TO‐SAMPLE BY POSITIVE AND NEGATIVE STIMULUS RELATIONS
Authors: Stromer Robert , Osborne J. Grayson
Published: March 2006

In Experiment 1, four developmentally delayed adolescents were taught an A‐B matching‐to‐sample task with nonidentical stimuli: given Sample A1, select Comparison B1; given A2, select B2. During nonreinforced test trials, appropriate matching occurred when B stimuli appeared as samples and A stimuli as comparisons, i.e., the sample and comparison functions were symmetrical (B‐A matching). During A‐B or B‐A matching test trials in which familiar samples and correct comparisons were presented along with novel comparisons, the subjects selected the correct comparisons. In tests with familiar samples and both incorrect and novel comparisons, subjects selected the novel comparisons, demonstrating control by both positive (“matching”) and negative (“nonmatching”) stimulus relations in A‐B and B‐A arrays. In Experiment 2, 12 developmentally delayed subjects were taught a two‐stage arbitrary‐matching task (e.g., A‐B, C‐B matching). Test sessions showed sample‐comparison symmetry (e.g., B‐A, B‐C matching) and derived sample‐comparison relations (e.g., A‐C, C‐A matching) for 11 subjects. These subjects also demonstrated control by positive and negative stimulus relations in the derived relations.
CHOICE AS A DEPENDENT MEASURE IN AUTOSHAPING: SENSITIVITY TO FREQUENCY AND DURATION OF FOOD PRESENTATION
Authors: Picker Mitchell , Poling Alan
Published: March 2006

Previous investigations have shown that rate, latency, and percentage of trials with at least one response are somewhat insensitive measures of the strength of autoshaped responding. In the present studies, these measures were contrasted with the allocation of responding during simultaneous choice tests, a measure of response strength frequently used in operant paradigms. In two experiments, nine pigeons were exposed to a forward pairing autoshaping procedure. Training sessions consisted of the successive presentation of three stimuli, each followed by food on either 100%, 50%, or 0% of the trials. Choice testing involved the simultaneous presentation of the three stimuli. In Experiment I, all pigeons consistently directed their initial choice responses and the majority of subsequent responses to the stimulus always followed by food, despite the fact that during training sessions the response rates of most birds were highest in the presence of the stimulus followed by food on 50% of the trials. In Experiment II, rate, latency, and percentage of trials with at least one response did not change appreciably as a function of duration of feeder presentations. However, choice responding was lawfully affected by duration of feeder presentations. These data suggest that choice is perhaps a more sensitive measure of the strength of autoshaped responding than other, more commonly employed, indices.
BRIEFLY DELAYED REINFORCEMENT: AN INTERRESPONSE TIME ANALYSIS
Authors: Lattal Kennon A. , Ziegler D. Rand
Published: March 2006

Key‐peck responding of pigeons was compared under VI or DRL schedules arranging immediate reinforcement and briefly (.5 sec) delayed reinforcement. Delays were either signaled by a blackout in the chamber, unsignaled, or unsignaled with an additional requirement that responding not occur during the .5 sec interval immediately preceding reinforcement (response delay). Relative to the immediate reinforcement condition, response rates increased during the unsignaled delay, decreased during the signaled delay, and were inconsistent during the response delay condition. An analysis of interresponse times (IRTs) under the different conditions revealed a substantial increase in the frequency of short (0 to .5 sec) IRTs during the unsignaled condition and generally during the response delay conditions compared to that during the immediate reinforcement baseline. Signaled delays decreased the frequency of short (0 to .5 sec) IRTs relative to the immediate reinforcement condition. The results suggest that brief unsignaled delays and, in many instances, response delays increase the frequency of short IRTs by eliminating constraints on responding.
INCENTIVE PROCESSES AND THE PEAK SHIFT
Authors: Weiss Stanley J. , Dacanay Robert J.
Published: March 2006

Intradimensional operant discrimination schedules were employed, which eliminated the covariation of response and reinforcement rates that are found on most operant baselines. In Phase 1, one keylight (S1) controlled an increase in pigeons' treadle pressing, relative to another keylight (S2), while being correlated with a decrease in frequency of reinforcement. In Phase 2 both treadle pressing and reinforcement increased in the presence of one keylight, relative to the second. In Phase 1 the relatively flat treadle‐press generalization gradients peaked at S1, whereas the peaks of those in Phase 2 were shifted from S1 in a direction away from S2. It was postulated that these positive and negative stimulus‐reinforcement contingencies influence the likelihood of obtaining peak shift through the operation of a classically conditioned “central motive state.” How response‐reinforcement and stimulus‐reinforcement contingencies might contribute to the development of inhibitory effects of S2 is discussed. Autoshaped key pecking also was produced by these procedures. During manipulations of stimuli, the gradients obtained for autoshaped key pecking were narrow and sharply peaked at the food‐correlated stimulus (S2) in Phase 1. This failure to obtain peak shift for an elicited response suggests a difference in discriminative processes operating in classical and instrumental learning.
THE “WHERE IS IT?” REFLEX: AUTOSHAPING THE ORIENTING RESPONSE
Authors: Buzsáki György
Published: March 2006

The goal of this review is to compare two divergent lines of research on signal‐centered behavior: the orienting reflex (OR) and autoshaping. A review of conditioning experiments in animals and humans suggests that the novelty hypothesis of the OR is no longer tenable. Only stimuli that represent biological “relevance” elicit ORs. A stimulus may be relevant a priori (i.e., unconditioned) or as a result of conditioning. Exposure to a conditioned stimulus (CS) that predicts a positive reinforcer causes the animal to orient to it throughout conditioning. Within the CS‐US interval, the initial CS‐directed orienting response is followed by US‐directed tendencies. Experimental evidence is shown that the development and maintenance of the conditioned OR occur in a similar fashion both in response‐independent (classical) and response‐dependent (instrumental) paradigms. It is proposed that the conditioned OR and the signal‐directed autoshaped response are identical. Signals predicting aversive events repel the subject from the source of the CS. It is suggested that the function of the CS is not only to signal the probability of US occurrence, but also to serve as a spatial cue to guide the animal in the environment.
CONDITIONAL DISCRIMINATION VS. MATCHING TO SAMPLE: AN EXPANSION OF THE TESTING PARADIGM
Authors: Sidman Murray , Tailby William
Published: March 2006

A subject's performance under a conditional‐discrimination procedure defines conditional relations between stimuli: “If A1, then B1; if A2, then B2.” The procedure may also generate matching to sample. If so, the stimuli will be related not only by conditionality, but by equivalence: A1 and B1 will become equivalent members of one stimulus class, A2 and B2 of another. One paradigm for testing whether a conditional‐discrimination procedure has generated equivalence relations uses three sets of stimuli, A, B, and C, three stimuli per set. Subjects learn to select Set‐B and Set‐C comparisons conditionally upon Set‐A samples. Having been explicitly taught six sample‐comparison relations, A1B1, A1C1, A2B2, A2C2, A3B3, and A3C3, subjects prove immediately capable of matching the B‐ and C‐stimuli; six new relations emerge (B1C1, B2C2, B3C3, C1B1, C2B2, C3B3). The 12 stimulus relations, six taught and six emergent, define the existence of three three‐member stimulus classes, A1B1C1, A2B2C2, and A3B3C3. This paradigm was expanded by introducing three more stimuli (Set D), and teaching eight children not only the AB and AC relations but DC relations also—selecting Set‐C comparisons conditionally upon Set‐D samples. Six of the children proved immediately capable of matching the B‐ and D‐stimuli to each other. By selecting appropriate Set‐B comparisons conditionally upon Set‐D samples, and Set‐D comparisons conditionally upon Set‐B samples, they demonstrated the existence of three four‐member stimulus classes, A1B1C1D1, A2B2C2D2, and A3B3C3D3. These larger classes were confirmed by the subjects' success with the prerequisite lower‐level conditional relations; they were also able to select Set‐D comparisons conditionally upon samples from Sets A and C, and to do the BC and CB matching that defined the original three‐member classes. Adding the three DC relations therefore generated 12 more, three each in BD, DB, AD, and CD. Enlarging each class by one member brought about a disproportionate increase in the number of emergent relations. Ancillary oral naming tests suggested that the subject's application of the same name to each stimulus was neither necessary nor sufficient to establish classes of equivalent stimuli.
SPATIAL AND TEMPORAL RELATIONS IN CONDITIONED REINFORCEMENT AND OBSERVING BEHAVIOR
Authors: Bowe Craig A. , Dinsmoor James A.
Published: March 2006

In Experiment 1, depressing one perch produced stimuli indicating which of two keys, if pecked, could produce food (spatial information) and depressing the other perch produced stimuli indicating whether a variable‐interval or an extinction schedule was operating (temporal information). The pigeons increased the time they spent depressing the perch that produced the temporal information but did not increase the time they spent depressing the perch that produced the spatial information. In Experiment 2, pigeons that were allowed to produce combined spatial and temporal information did not acquire the perch pressing any faster or maintain it at a higher level than pigeons allowed to produce only temporal information. Later, when perching produced only spatial information, the time spent depressing the perch eventually declined. The results are not those implied by the statement that information concerning biologically important events is reinforcing but are consistent with an interpretation in terms of the acquisition of reinforcing properties by a stimulus associated with a higher density of primary reinforcement.
CHOICE BETWEEN RESPONSE UNITS: THE RATE CONSTANCY MODEL
Authors: Zeiler Michael D. , Blakely Thomas F.
Published: March 2006

In a conjoint schedule, reinforcement is available simultaneously on two or more schedules for the same response. The present experiments provided food for key pecking on both a random‐interval and a differential‐reinforcement‐of‐low‐rate (DRL) schedule. Experiment 1 involved ordinary DRL schedules; Experiment 2 added an external stimulus to indicate when the required interresponse time had elapsed. In both experiments, the potential reinforcer frequency from each component was varied by means of a second‐order fixed‐ratio schedule, and the DRL time parameter was changed as well. Response rates were described by a model stating that time allocation to each component matches the relative frequency of reinforcement for that component. When spending time in a given component, the subject is assumed to respond at the rate characteristic of baseline performance. This model appeared preferable to the absolute‐rate version of the matching law. The model was shown to be applicable to multiple‐response concurrent schedules as well as to conjoint schedules, and it described some of the necessary conditions for response matching, undermatching, and bias. In addition, the pigeons did not optimize reinforcer frequency.
EFFECTS OF BARBITURATES AND OTHER SEDATIVE HYPNOTICS IN PIGEONS TRAINED TO DISCRIMINATE PHENCYCLIDINE FROM SALINE
Authors: McMillan D. E. , Wenger G. R.
Published: March 2006

Pigeons were trained to peck the center key (lighted white) of three response keys to turn off the center keylight and to light one of the side keys with a red keylight and the other side key with a green keylight. Five responses (fixed‐ratio component) on either side key relighted the center key. Food was delivered following 10 fixed‐ratio components on the red key if 1.5 mg/kg phencyclidine had been given before the session, or 10 fixed‐ratio components on the green key if saline had been given before the session. The position of the red and green keylights on the side keys varied randomly each time they were lighted by a peck on the center key. Subsequently, increasing doses of phencyclidine, barbital, amobarbital, phenobarbital, methaqualone, methyprylon, diazepam, oxazepam, and d‐amphetamine were substituted for the training dose of phencyclidine, using a cumulative dosing procedure. At low doses of the sedative hypnotics, birds pecked the keylight color associated with saline. At higher doses, birds pecked both key colors. At the highest doses of pentobarbital and amobarbital, some birds responded almost exclusively on the color associated with phencyclidine. When responding on keys of both colors occurred following administration of phencyclidine or other sedative hypnotics, this responding was controlled by key position rather than by key color.
AN INTERRESPONSE‐TIME ANALYSIS OF RESPONDING MAINTAINED BY SCHEDULES OF RESPONSE‐PRODUCED ELECTRIC SHOCK
Authors: Howell L. L. , Byrd L. D. , Marr M. J.
Published: March 2006

The present study investigated ratio contingencies to evaluate factors that may determine the maintenance of responding when electric shock is the consequent event. Initially, squirrel monkeys (Saimiri sciureus) were exposed to a continuous‐avoidance schedule to initiate bar pressing. Subsequently, a multiple random‐interval variable‐ratio yoked schedule of response‐produced shock was used to maintain and to compare interval and ratio performance. A microcomputer recorded and stored the number of responses and interresponse times occurring between successive shock presentations during a given random‐interval component, and these numbers determined the ratio requirements during the subsequent ratio component. Responding was maintained for more than 80 sessions in two of three monkeys under the multiple schedule with the ratio yoked to the interval component. Responding during the ratio component persisted in only one monkey, however, when the components were no longer yoked. An analysis of the interresponse times immediately preceding shock under the multiple yoked schedule revealed that the terminal interresponse times were longer under the interval schedule than under the ratio contingency. The interresponse‐time analysis indicated that differential interresponse‐time relationships may be major determinants of the maintenance of behavior controlled by schedules of electric‐shock presentation.
FAST ACQUISITION OF COOPERATION AND TRUST: A TWO‐STAGE VIEW OF TRUSTING BEHAVIOR
Authors: Schmid Tom L. , Hake Don F.
Published: March 2006

Trustful behavior was defined in terms of the consecutive numbers of matching‐to‐sample problems worth money that each subject worked during sessions that ended in an equitable distribution. Two stages of acquisition are inherent in this definition; the first stage requires acquisition of an equitable method of distributing reinforcers (cooperation) to show that the within‐session deviations (trust) from equity that develop during the second stage are temporary and are not part of an inequitable method of distributing reinforcers. Previous research has indicated that a contingency to trust is necessary to override the aversiveness of the inequity inherent in trusting and to produce consistent and maximal trust (half of the problems worked consecutively by each subject). The present experiment examined such a contingency. The trust contingency was an increased requirement for changing the direction of problem allocation. Only the subject who had been allocated a problem could change that allocation, by pulling a lever 45 or more times. On the other hand, no separate responses were required to allow the person who worked the last problem to also work the next one (passive trust). Hence, giving a problem was the only way to increase the distribution of problems to the other person and hence prevent oneself from receiving all of the reinforcers. All eight pairs of subjects cooperated from the outset. Trusting behavior developed for all four pairs exposed to the contingency to trust and expanded to maximal levels by the second session for three of the four pairs.
A PARAMETRIC ANALYSIS OF THE RELATIONSHIP BETWEEN FOOD QUANTITY AND RUMINATION
Authors: Rast Jim , Johnston James M. , Drum Cheryl
Published: March 2006

Rumination is the chronic regurgitation, chewing, and reswallowing of previously ingested food. The study reported here, using a parametric design, examined the control of rumination by the quantity of food eaten at meals. The subjects were three profoundly retarded individuals who chronically emitted this behavior. The quantity of food by weight ingested daily was varied in 10‐oz steps in both ascending and descending series (data were collected only after breakfasts and lunches). Ruminating decreased when food quantity increased and increased when food quantity decreased. In addition, there was a similar inverse interaction between breakfast food quantity and post‐lunch ruminating. The data showed relatively rapid transitions in both frequency and duration at each meal size for all subjects. The data establish a clear functional relation between the quantity of food ingested and ruminating.
CHOOSING BETWEEN PREDICTABLE SHOCK SCHEDULES: LONG‐VERSUS SHORT‐DURATION SIGNALS
Authors: Badia Pietro , Abbott Bruce , Schoen Lawrence
Published: March 2006

Two experiments asssessed the relative aversiveness of different duration preshock signals (5 and 20 seconds) and different duration stimuli identifying shock‐free periods. In the first experiment, the responding of 15 of 18 rats was maintained when it produced changes from a predictable‐shock condition with a 5‐second preshock signal to an identical schedule with a 20‐second preshock signal; responding was not maintained when it produced the opposite changes. These results occurred with intershock intervals of both 120 seconds and 240 seconds. The second experiment assessed whether changing to the 20‐second schedule was maintained by properties of the preshock signals identifying the shock periods or by properties of the stimuli identifying the shock‐free periods. Four subjects were given training with the two signaled schedules in an operant chamber and then later given off‐baseline preference tests in a shuttlebox. When given a choice between preshock signals, subjects chose the 5‐second signals over the 20‐second signals. However, when given a choice between stimuli identifying shock‐free periods, subjects chose the stimulus identifying the shorter shock‐free periods (i.e., the one previously correlated with the 20‐second signals). These findings are discussed within the Rescorla and Wagner model of stimulus compounds and within the context of safety as a contrast phenomenon.
ACCURACY VERSUS SPEED IN THE GENERALIZED EFFORT OF LEARNING‐DISABLED CHILDREN
Authors: Eisenberger Robert , Mitchell Maureen , McDermitt Maureen , Masterson Fred A.
Published: March 2006

Reinforcement of effortful performance in a given academic task has been found to increase the subsequent performance of other academic tasks. The learned‐effort hypothesis assumes that individuals learn which dimensions of task performance are correlated with reinforcement of high effort, and generalize across tasks. Therefore, reinforcement of increased effort in a given dimension of one task should result in greater generalized effort in the same dimension of transfer performance than in another dimension. In accord with this view, preadolescent learning‐disabled students who Received points for high reading accuracy subsequently produced more accurate drawings and stories than did students whose points had been based upon high reading speed or upon mere completion of the reading task. Students who Received points for high reading speed subsequently constructed stories more quickly than did children whose points had been based upon high reading accuracy or upon reading‐task completion. Consistent with the more explicit and frequent feedback for accuracy than for speed in most academic tasks, generalized accuracy was much more durable than generalized speed.