bluuebunny/crossref_metadata_2025 huggingface dataset:
EFFECT OF DELAY‐INTERVAL STIMULI ON DELAYED SYMBOLIC MATCHING TO SAMPLE IN THE PIGEON
Authors: Wilkie Donald M. , Summers Russel J. , Spetch Marcia L.
Published: March 2006

In Experiment 1, food‐deprived pigeons received delayed symbolic matching to sample training in a darkened Skinner box. Trials began with the illumination of the grain feeder lamp (no food sample), or illumination of this lamp, accompanied by the raising of the feeder tray (food sample). After a delay of a few seconds, the two side response keys were illuminated, one with red and one with green light, with positions counterbalanced over trials. Pecking the red (green) comparison produced grain reinforcement if the trial had started with food (no food); pecking red after a no‐food sample or green after a food sample was not reinforced. Once matching performance was stable, four stimuli were presented during the delay interval, and their effects on matching accuracy were evaluated. Both illumination of the houselight and the center key with white geometric forms decreased matching accuracy, whereas presentation of a tone and vibration of the test chamber did not. In Experiment 2, pecking the red center key was reinforced with food according to a variable interval schedule. The effects of occasional brief presentations of the four stimuli used in the first experiment on ongoing pecking were assessed. The houselight and form disturbed key pecking, but the tone and vibration did not. Thus, stimuli that interfered with delayed matching also interfered with simple operant behavior. Implications of these results for theories of remembering are discussed.
DETERMINANTS OF CONTRAST IN THE SIGNAL‐KEY PROCEDURE: EVIDENCE AGAINST ADDITIVITY THEORY
Authors: Williams Ben A. , Heyneman Nicholas
Published: March 2006

Two experiments are reported that challenge the interpretation of previous results with the signal‐key procedure, in which the discriminative stimuli are located on a response key different from the key associated with the operant response requirement. Experiment 1 replicated the procedure of Keller (1974), and found that contrast effects on the operant key occurred reliably for only one of four subjects. High rates to the signal key initially occurred for only one subject, but modifications of the procedure produced substantial rates to the signal key for all subjects. In all cases, however, signal‐key behavior was greatly reduced by the addition of a changeover delay which prevented reinforcement within 2 seconds of the last peck to the signal key, suggesting that signal‐key pecking was maintained primarily by adventitious reinforcement. Experiment 2 modified the signal‐key procedure by using three response keys, so that the discriminative stimuli on the signal key controlled different responses during all phases of training. With this modification, reliable contrast effects on the operant key occurred for all subjects, suggesting that the failure to find contrast in previous studies has been due to the confounding of changes in the discrimination requirements with changes in relative rate of reinforcement. The results challenge the additivity theory of contrast, and suggest that “elicited” behavior plays a minor role, if any, in the determination of contrast effects in multiple schedules.
GENERALIZATION PEAK SHIFT IN RATS UNDER CONDITIONS OF POSITIVE REINFORCEMENT AND AVOIDANCE
Authors: Weiss Stanley J. , Schindler Charles W.
Published: March 2006

Rats were trained to discriminate between two click frequencies. One frequency was associated with either variable‐interval food reinforcement (Experiment 1) or free‐operant avoidance (Experiment 2). The other frequency was associated with the absence of food in Experiment 1 and the absence of shock in Experiment 2. On a click frequency generalization test, the rats in both experiments showed positive peak shift with the shape of the relative gradients being very similar. This is the first reported instance of peak shift in rats when responding was maintained by an avoidance contingency. Nondifferentially trained controls showed that this shift was due exclusively to associative processes, with nonassociative stimulus factors in themselves apparently making no contribution to increased rates at particular stimulus values. These results show the comparability of appetitive and aversive control and support the position that gradient differences do not result from approach versus avoidance per se.
CHOOSING SCHEDULES OF SIGNALED APPETITIVE EVENTS OVER SCHEDULES OF UNSIGNALED ONES
Authors: Badia Pietro , Ryan Kathy , Harsh John
Published: March 2006

Two experiments were completed allowing albino rats to choose between signaled and unsignaled reward conditions. These experiments examined the effects on preference of (1) response dependent versus response‐independent reward and, (2) food pellets versus chocolate milk as the reward. All subjects preferred the signaled condition over the unsignaled condition, whether exposed to response‐dependent, or to response‐independent delivery of rewards. Preference was controlled most effectively by presenting both the signal itself and the correlated stimulus identifying the signaled condition. The signal presented alone (Extinction 3) controlled preference more effectively than did the stimulus correlated with the signaled condition (Extinction 2). The second experiment showed that the quality of the reinforcer (pellets and chocolate milk) did not affect preference for signaled reward since all subjects preferred the signaled condition at levels comparable to those observed in Experiment 1, with food pellets. These results, along with others, argue against species differences, response‐dependency, and reinforcer quality as variables affecting the direction of preference.
EFFECTS OF SIGNALED AND UNSIGNALED SHOCK ON SCHEDULE‐CONTROLLED LEVER PRESSING AND SCHEDULE‐INDUCED LICKING: SHOCK INTENSITY AND BODY WEIGHT
Authors: Hymowitz Norman
Published: March 2006

Schedule‐controlled lever pressing and schedule‐induced licking were studied in rats under a multiple fixed‐interval fixed‐interval schedule of food reinforcement. Following acquisition of stable rates of pressing and licking, a multiple variable‐time variable‐time schedule of electric‐shock delivery was superimposed upon the baseline schedule. In only one component of the multiple schedule, a 5‐sec stimulus preceded each shock (signaled shock). In the other component shock was unsignaled. Several shock intensities (Experiment 1) and body weights (Experiment 2) were studied. Lever pressing and licking were affected similarly by experimental manipulations, although with parametric differences. Depending upon shock intensity and body weight, rates of lever pressing and licking were hardly suppressed, suppressed primarily in the unsignaled shock component (differential suppression), or markedly suppressed in both components. Differential suppression during components with signaled and unsignaled shock and conditioned suppression of responding during the pre‐shock stimulus appeared not to be functionally related. Differential suppression depended more on the discriminability of shock‐free time, and on shock intensity, body weight, and the type of response than on the “preparatory” behavior preceding shock.
EFFECTS OF CHLORDIAZEPOXIDE AND d‐AMPHETAMINE ON RESPONDING SUPPRESSED BY CONDITIONED PUNISHMENT
Authors: Valentine Joseph O. , Barrett James E.
Published: March 2006

Key pecking by two pigeons, maintained under a variable‐interval two‐minute schedule of food presentation, was suppressed when each response produced a five‐second visual stimulus that was occasionally paired with shock. Stimulus‐shock pairings occurred independently of responding according to a variable‐time six‐minute schedule for one bird or once per session for the other bird. The effects of chlordiazepoxide and d‐amphetamine were assessed on this baseline of behavior suppressed by conditioned punishment. Chlordiazepoxide produced dose‐related increases in the rate of punished responding, whereas d‐amphetamine produced only decreases. In addition, chlordiazepoxide produced dose‐related increases in response rate during the response‐produced and response‐independent stimulus presentations; d‐amphetamine, however, only decreased responding during stimulus presentations.
DISCRETE‐TRIAL CHOICE IN PIGEONS: EFFECTS OF REINFORCER MAGNITUDE
Authors: Young John S.
Published: March 2006

The preference of pigeons for large reinforcers which occasionally followed a response versus small reinforcers which invariably followed a response was studied in a discrete‐trial situation. Two differently colored keys were associated with the two reinforcement alternatives, and preference was measured as the proportion of choice trials on which the key associated with uncertain reinforcement was pecked. A combination of choice and guidance trials insured that received distributions of reinforcement equalled the scheduled distributions. For five of six subjects, preference for the uncertain reinforcer appeared to be a linear function of the magnitude of the certain reinforcer. In addition, there was greater preference for the response alternative associated with uncertain reinforcement than would be expected on the basis of net reinforcer value.
RELATIONSHIP BETWEEN RESPONSE RATE AND REINFORCEMENT FREQUENCY IN VARIABLE‐INTERVAL SCHEDULES: II. EFFECT OF THE VOLUME OF SUCROSE REINFORCEMENT
Authors: Bradshaw C. M. , Ruddle H. V. , Szabadi E.
Published: March 2006

Three rats were exposed to variable‐interval schedules specifying a range of different reinforcement frequencies, using three different volumes of .32 molar sucrose (.10, .05, and .02 milliliters) as the reinforcer. With each of the three volumes, the rates of responding of all three rats were increasing, negatively accelerated functions of reinforcement frequency, the data conforming closely to Herrnstein's equation. In each rat the value of the constant KH, which expresses the reinforcement frequency needed to obtain the half‐maximal response rate, increased with decreasing reinforcer volume, the values obtained with .02 milliliters being significantly greater than the values obtained with .10 milliliters. The values of the constant Rmax, which expresses the theoretical maximum response rate, were not systematically related to reinforcer volume. The effect of reinforcer volume upon the relationship between response rate and reinforcement frequency is thus different from the effect of the concentration of sucrose reinforcement: In a previous experiment (Bradshaw, Szabadi, & Bevan, 1978) it was found that sucrose concentration influenced the values of both constants, Rmax increasing and KH decreasing with increasing sucrose concentration.
CONTRAST AND UNDERMATCHING AS A FUNCTION OF REINFORCER DURATION AND QUALITY DURING MULTIPLE SCHEDULES
Authors: Ettinger R. H. , McSweeney Frances K. , Norman Wayne D.
Published: March 2006

Eight pigeons pecked keys under multiple variable‐interval two‐minute variable‐interval two‐minute schedules. In Experiment 1, the reinforcers were 2, 4, or 8 seconds access to a food magazine. In Experiments 2 and 3, the reinforcers were grains that had been determined to be most‐, moderately‐, or non‐preferred. Both positive and negative behavioral contrast occurred when the reinforcers in one component were held constant and the duration or type of reinforcer obtained in the other component varied. Undermatching occurred when the relative rate of responding during a component was plotted as a function of the relative duration of the reinforcers in that component.
UNDERMATCHING AND CONTRAST WITHIN COMPONENTS OF MULTIPLE SCHEDULES
Authors: McLean Anthony P. , White K. Geoffrey
Published: March 2006

Six multiple variable‐interval schedules each comprised one variable‐interval sixty second component and an alternated component which was varied. Four pigeons' responses were recorded in five successive subintervals of each component. Response rate changes across subintervals revealed instances of local contrast and small local induction effects in the changed component. In the constant component, smaller local contrast and larger local induction effects obtained. Accordingly, the magnitude of behavioral contrast, defined as an inverse relation between response rate in the constant component and reinforcement rate in the changed component, did not change reliably across subintervals of the constant component. Ratios of response rates in initial subintervals were highly sensitive to reinforcement ratios. Sensitivity decreased sharply over the first two‐fifths of the components and remained constant for the remainder. The results demonstrated that changes in multiple schedule sensitivity are a function of time since the alternation of successive components.
SELF‐CONTROL IN PIGEONS UNDER THE MISCHEL PARADIGM
Authors: Grosch James , Neuringer Allen
Published: March 2006

Walter Mischel studied self‐control in preschool children in the following manner: if the child waited for an interval to end, he or she received the more preferred of two reinforcers; if the child responded to terminate the interval by ringing a bell, the less preferred reinforcer was given. We used an analogous procedure to study self‐control in pigeons: if the bird waited for a trial to end, it received the more preferred reinforcer; if the bird terminated the trial by pecking a key, the less preferred reinforcer was given. We explored the effects on self‐control of a number of variables analogous to those studied by Mischel and co‐workers, e.g., presence versus absence of reinforcers, of alternative responses, and of stimuli during the wait interval; prior experience of the subjects; and test paradigm. The results obtained with pigeons paralleled the results obtained by Mischel with human children.
SELECTIVE PUNISHMENT OF INTERRESPONSE TIMES
Authors: Galbicka Gregory , Branch Marc N.
Published: March 2006

Lever pressing by two squirrel monkeys was maintained under a variable‐interval 60‐second schedule of food presentation. When response‐dependent electric shock was made contingent on comparatively long interresponse times, response rate increased, and further increases were obtained when the minimum interresponse‐time requirement was decreased. When an equal proportion of responses produced shock without regard to interresponse time, rates decreased. Thus, shock contingent on long interresponse times selectively decreased the relative frequency of those interresponse times, and increased the relative frequency of shorter interresponse times, whereas shock delivered independent of interresponse times decreased the relative frequency of shorter interresponse times while increasing the frequency of longer ones. The results provide preliminary evidence that interresponse times may be differentiated by punishment, further supporting the notion that interresponse times may be considered functional units of behavior.
RESPONDING UNDER SEQUENCE SCHEDULES OF ELECTRIC SHOCK PRESENTATION
Authors: Gardner Michael L. , Malagodi E. F.
Published: March 2006

Lever pressing by squirrel monkeys was examined under second‐order schedules of electric shock presentation in which different discriminative stimuli were associated with consecutive components (sequence schedules). Components were always two‐minute fixed‐interval schedules, and three different overall schedules were studied. Under an overall eight‐minute fixed‐interval schedule, the first component completion after at least eight minutes had elapsed produced electric shock. The number of components actually completed ranged from one to four; thus, different discriminative stimuli were occasionally associated with electric shock presentation. Under an overall “yoked” variable‐ratio schedule, electric shock was presented after completion of a variable number of components; the required number and the distribution of components were matched to those obtained under the overall eight‐minute fixed‐interval schedule. Under an overall fixed‐ratio schedule, electric shock was presented after completion of four components (chained schedule). Under all three sequence schedules, responding in early components was characterized by a pause followed by a single response after the end of the two‐minute interval; responding in later components was characterized by a shorter pause followed by positively accelerated responding. Manipulation of overall schedules of shock presentation in these complex behavioral situations produced changes in responding comparable to those ordinarily obtained after similar manipulation of dependencies under both single and second‐order schedules of food presentation. These experiments extend the range of conditions and levels of complexity under which responding can be maintained by presentation of electric shock.
CHOICE BETWEEN FOOD AND HEROIN: EFFECTS OF MORPHINE, NALOXONE, AND SECOBARBITAL
Authors: Griffiths Roland R. , Wurster Richard M. , Brady Joseph V.
Published: March 2006

Baboons responded on a choice task on which discrete trials involved choosing between an intravenous injection of heroin (.32 or 1.0 mg/kg) or the availability of food pellets. An intertrial interval of three hours followed the completion of each trial. Under baseline conditions baboons consistently completed the eight available trials each day. Typically, animals chose heroin on three or four trials a day and food on the remaining trials. Animals tended to space the selection of heroin rather than choosing heroin on consecutive trials. A series of single‐day experimental manipulations was undertaken to characterize performance further. Manipulation of the heroin dose produced shifts in the relative frequency of choosing the drug option which were inversely related to dose. Manipulation of number of pellets per food trial produced little change in distribution of choices. Noncontingent administration of morphine produced dose‐related decreases in relative frequency of heroin choices, and at higher doses decreased the number of trials completed. Noncontingent naloxone produced dose‐related increases in the relative frequency of heroin choices. Noncontingent secobarbital had no effect on distribution of choices, and high doses reduced the number of trials completed per day. The results suggest that morphine and naloxone produce shifts in this choice behavior by selectively interacting with the reinforcing properties of the option involving heroin.
PAIRED BASELINE PERFORMANCE AS A BEHAVIORAL IDEAL
Authors: Allison James
Published: March 2006

Several recent theories view performance under the constraints of a schedule as an attempt to approach the basepoint, the total amount of the instrumental response and the total amount of the contingent response seen in the absence of schedule constraint. Some new analyses of experiments on concurrent ratio schedules, and simple ratio schedules offering an optional magnitude of contingent reward, tested this view directly. In each of the five experiments examined the organism rejected the chance of a closer approach to the basepoint, and thereby failed in addition to maximize the rate of reinforcement.
BEHAVIORAL CONTRAST AND THE AUTOMAINTAINED KEY PECK
Authors: Wesp Richard K. , Lattal Kennon A.
Published: March 2006

In two experiments behavioral contrast was demonstrated during discrimination training in a positive automaintenance procedure. During the baseline condition in each experiment, a key was transilluminated for eight seconds by one of two colors (CS) following a variable intertrial interval signaled by a dark key. Keylight transillumination terminated with a response‐independent food presentation. In the first experiment, food was eliminated during one CS for up to fifty sessions. After reinstatement of food following each CS, the discrimination was reversed. Six of the eight subjects showed positive behavioral contrast, i.e., response rates increased during the CS associated with food as they decreased during the CS associated with no food. The effect was replicated in Experiment II, but it did not occur when both the food and its associated CS were eliminated. These results were comparable to those obtained with operant discrimination training procedures (behavioral contrast) and with Pavlovian discrimination training. The results suggest that additivity theories of behavioral contrast may be insufficient to account for these data.
DIFFERENTIAL RESPONDING WITHOUT DIFFERENTIAL REINFORCEMENT: INTENSITY DIFFERENCE, CONTINUUM POSITION, AND REINFORCEMENT DENSITY EFFECTS
Authors: Raslear Thomas G.
Published: March 2006

The response rates of five groups of rats were observed during exposure to different intensities of a four kilohertz tone within a two‐component multiple schedule of nondifferential reinforcement. Response rates were found to be higher during the multiple schedule component which contained the higher intensity tone. Larger differences in response rates between the two multiple schedule components occurred with greater intensity separations (30 versus 20 decibels). At the 30 decibel separation a low absolute magnitude produced larger response rate differences than a high absolute magnitude, while at the 20 decibel separation a high absolute magnitude produced larger response rate differences. Increases in reinforcement density were accompanied by decreases in response rate differences between high and low intensity components only when over‐all response rates also increased.
ESCAPE FROM FREEDOM: CHOOSING NOT TO CHOOSE IN PIGEONS
Authors: Hayes Steven C. , Kapust Jeffery , Leonard Susan R. , Rosenfarb Irwin
Published: March 2006

Preference for the availability of food‐reinforcement alternatives was investigated with Rachlin and Green's (1972) concurrent‐chains self‐control paradigm. The terminal link of one chain made available a choice between immediate access to food for T seconds and delayed access to food for 4 seconds. The terminal link of the other chain provided only delayed access to food. When T was reduced to .25 seconds, pigeons began to select the delayed‐access key in both terminal links. Even so, the pigeons strongly preferred constraint over choice. This effect could not be accounted for by differences in the actual amount of food obtained in the terminal links, by avoidance of the immediate‐reinforcement key when not presented as part of a choice, or by avoidance of a multi‐key terminal link. Rather, constraint was preferred over freedom. Apparently, the preference for choice is determined by the particular type of choice offered.
THE ROLE OF INTERMITTENT FOOD IN THE INDUCTION OF ATTACK IN PIGEONS
Authors: Yoburn Byron C. , Cohen Perrin S. , Campagnoni Frank R.
Published: March 2006

The present experiments evaluated whether transitions in reinforcer probability are necessary to induce attack in pigeons. In Experiment I, three of six pigeons exposed to response‐contingent constant‐probability food schedules and a photograph of a conspecific as a target exhibited sustained postreinforcement attack on the target. The postreinforcement pattern of attack developed over the course of the experiment and was accompanied by a reduction in the rate of postreinforcement key pecking and an increase in the postreinforcement pause in key pecking. These effects on key pecking resulted in unprogrammed variations in the probability of reinforcement which may have been responsible for the induction of attack. In Experiment II, the attack‐inducing properties of a constant‐probability response‐independent food schedule were compared to a periodic food schedule matched for overall rate of food delivery and to a no‐food condition. In addition to attack, the spatial location of the subjects was monitored during each interfood interval. The periodic and aperiodic food schedules generated very different patterns of spatial location. Postfood attack was induced by both food schedules, although the constant‐probability schedule induced attack in fewer birds. The no‐food condition was not effective in inducing attack in any birds. These experiments indicate that intermittent food schedules without reductions in reinforcer probability are sufficient to induce attack in some pigeons, although not as effective as schedules with transitions in reinforcer probability.
EFFECTS OF DIAZEPAM ON SCHEDULE‐CONTROLLED AND SCHEDULE‐INDUCED BEHAVIOR UNDER SIGNALED AND UNSIGNALED SHOCK
Authors: Hymowitz Norman
Published: March 2006

Schedule‐controlled lever pressing and schedule‐induced licking were studied in rats under a multiple fixed‐interval fixed‐interval schedule of food reinforcement upon which was superimposed a multiple variable‐time variable‐time schedule of electric‐shock delivery. Shocks were signaled in one component of the multiple schedule and unsignaled in the other. The effects of diazepam upon the suppression of behavior during the signal (conditioned suppression) and during signaled and unsignaled shock (differential suppression) were studied under several shock intensities (Experiment 1) and at increased body weight (Experiment 2). In each study, diazepam led to dose‐dependent increases in the rate of pressing and licking during signaled and unsignaled shock, but had little effect on conditioned suppression. The rate‐enhancing effects of diazepam depended upon the intensity of shock, nature of the response, and whether or not shocks were signaled. The data was discussed in terms of (1) implications for understanding the effects of signaled and unsignaled shock on behavior, (2) the effects of diazepam on behavior suppressed by response‐independent shock, and (3) comparison between operant and schedule‐induced behavior.
AUTOSHAPING AS A PSYCHOPHYSICAL PARADIGM: ABSOLUTE VISUAL SENSITIVITY IN THE PIGEON
Authors: Passe Dennis H.
Published: March 2006

A classical conditioning procedure (autoshaping) was used to determine absolute visual threshold in the pigeon. This method provides the basis for a standardized visual psychophysical paradigm.
UNINSTRUCTED HUMAN RESPONDING: SENSITIVITY OF LOW‐RATE PERFORMANCE TO SCHEDULE CONTINGENCIES
Authors: Shimoff Eliot , Catania A. Charles , Matthews Byron A.
Published: March 2006

College students' presses on a telegraph key occasionally turned on a light in the presence of which button presses produced points later exchangeable for money. Initially, responding was maintained by low‐rate contingencies superimposed on either random‐interval or random‐ratio schedules. Later, the low‐rate contingencies were relaxed. Low‐rate key pressing had been established for some students by shaping and for others by demonstration and written instructions. After the low‐rate contingencies were relaxed, higher response rates generally did not increase point earnings with random‐interval scheduling, but did so with random‐ratio scheduling. In both cases, shaped responding usually increased, and instructed responding usually continued at an unchanged low rate. The insensitivity of instructed responding typically occurred despite contact with the contingencies. The differential sensitivity to schedule contingencies of shaped responding relative to instructed responding is consistent with the different properties of contingency‐governed and rule‐governed behavior and is not rate‐dependent.
STIMULUS CONTROL OF DELAYED MATCHING IN PIGEONS: DIRECTED FORGETTING
Authors: Kendrick Donald F. , Rilling Mark , Stonebraker Thomas B.
Published: March 2006

Pigeons were trained in delayed matching‐to‐sample with two postsample stimuli. A postsample R‐cue signaled that a matching choice phase would follow. A postsample F‐cue signaled that a matching choice phase would not follow. Previous research found reduced matching accuracy on F‐cued probe trials when comparison stimuli were presented in the choice phase. The present four experiments systematically varied the events following an F‐cue to determine the conditions under which the F‐cue reduces delayed‐matching accuracy. When F‐cues and R‐cues controlled different behavior, matching on probe trials was poor. When both cues controlled the same behavior, matching on probe trials was good. This result is best explained by the theory that comparison stimuli retrieve the sample representation, but only in the behavioral context established by the R‐cue. The present research supports the view that response‐produced stimuli serve a contextual role in animal short‐term memory.
PRECURRENT SELF‐PROMPTING OPERANTS IN CHILDREN: “REMEMBERING”
Authors: Parsons Joseph A. , Taylor Douglas C. , Joyce Teresa M.
Published: March 2006

In Experiment I, one of three forms of collateral behavior was trained: Differential collateral behavior specific in form to one of two discriminative stimuli; Common collateral behavior of a single form regardless of the stimulus; or Nondifferential collateral behavior of either form regardless of the stimulus. Children were next given a short‐delay matching‐to‐sample task in which the discriminative stimuli served as samples, and the children's previously trained collateral behavior terminated the delay and presented the comparison stimuli. Subjects engaging in sample‐specific collateral behavior immediately acquired matching. Subjects engaging in sample‐nonspecific collateral behavior failed to acquire matching or did so gradually. In Experiment II the minimal delay in the matching task was varied in a mixed sequence, first with collateral behavior required, and then with collateral behavior prohibited. When emitting collateral behavior Common and Nondifferential subjects showed delay‐related decrements in matching while Differential subjects did not. When not emitting collateral behavior all subjects showed delay‐related decrements in matching. Common and Nondifferential subjects matched more accurately when prohibited from emitting collateral behavior. Differential subjects matched more accurately when emitting collateral behavior. The results accord with Skinner's (1953, 1968) analysis of precurrent operants.
STIMULUS STRINGING BY PIGEONS
Authors: Richardson W. Kirk , Warzak William J.
Published: March 2006

Pigeons were trained to peck one, two, three, and then four colors in a predetermined sequence from a five‐key array where, over trials, each color appeared equally often in each position of the array. Incorrect pecks resulted in a buzzer and trial termination, with the same array presented for the next trial. Correct pecks produced feedback and correct strings could produce food. All subjects performed at a high level of accuracy with no difference at asymptote between a continuous and a mixed spectral sequence as the required order. Transfer to a new set of arrays had little effect on accuracy. Errors forward in the sequence had the highest probability, followed by repeat errors, backward errors, and dark‐key errors. Some arrays had a higher level of accuracy than others but a corresponding systematic variable could not be identified.
THREE VERSIONS OF THE ADDITIVE THEORIES OF BEHAVIORAL CONTRAST
Authors: McSweeney Frances K. , Ettinger R. H. , Norman Wayne D.
Published: March 2006

The additive theories of behavioral contrast state that contrast will occur only when two types of responses interact during multiple schedules. Three more specific versions of the theories may be defined according to how they distinguish these two types of responses. A strong version physically distinguishes them. A second version distinguishes them according to the theoretical processes which control them. A weak version distinguishes them on the basis of the environmental relations which control them. Only the weak version of the theories is currently testable. The weak theory should be tested by establishing each of the two environmental relations independently and then combining them to assess their effect on behavior. Because this test is not usually performed, many of the results which have been taken to support or contradict the additive theories are actually ambiguous.
THE LOCAL ORGANIZATION OF BEHAVIOR: DISCRIMINATION OF AND MEMORY FOR SIMPLE BEHAVIORAL PATTERNS
Authors: Shimp Charles P.
Published: March 2006

A procedure was developed to enable nonverbal organisms to report what they remember of the temporal organization of their recent behavior. A baseline behavior with known temporal structure was established by a concurrent variable‐interval variable‐interval schedule for two temporal patterns of behavior (two different classes of reinforced interresponse times). The five pigeon subjects emitted these two temporal patterns on a center key and were occasionally given a short‐term memory probe for their most‐recently‐emitted pattern. The probes consisted of symbolic delayed matching‐to‐sample tests, in which a response on a green side key was reinforced if the most recent pattern belonged to the shorter reinforced class, and a response to a red side key was reinforced if the most recent pattern belonged to the longer reinforced class. All subjects could report with over ninety percent accuracy what their most recently emitted behavioral pattern was when a retention interval separating the pattern from the memory probe was only .1 seconds. The retention interval was then manipulated, and it was found that recall for a pattern was frequently above chance after a delay of as much as eight seconds. Thus, pigeons can remember their most recent interresponse time not only right after it is emitted, but for several seconds thereafter. In other conditions, the patterns themselves were manipulated. It was found that as the patterns became more similar, discrimination became poorer. These results agree with the view that reinforcement tends to organize and integrate the local structure of behavior to the extent to which that structure is remembered.
CONCURRENT FIXED‐INTERVAL VARIABLE‐RATIO SCHEDULES AND THE MATCHING RELATION
Authors: Rider David P.
Published: March 2006

Five rats responded under concurrent fixed‐interval variable‐ratio schedules of food reinforcement. Fixed‐interval values ranged from 50‐seconds to 300‐seconds and variable‐ratio values ranged from 30 to 360; a five‐second changeover delay was in effect throughout the experiment. The relations between reinforcement ratios obtained from the two schedules and the ratios of responses and time spent on the schedules were described by Baum's (1974) generalized matching equation. All subjects undermatched both response and time ratios to reinforcement ratios, and all subjects displayed systematic bias in favor of the variable‐ratio schedules. Response ratios undermatched reinforcement ratios less than did time ratios, but response ratios produced greater bias than did time ratios for every subject and for the group as a whole. Local rates of responding were generally higher on the variable‐ratio than on the fixed‐interval schedules. When responding was maintained by both schedules, a period of no responding on either schedule immediately after fixed‐interval reinforcement typically was followed by high‐rate responding on the variable‐ratio schedule. At short fixed‐interval values, when a changeover to the fixed‐interval schedule was made, responding usually continued until fixed‐interval reinforcement was obtained; at longer values, a changeover back to the variable‐ratio schedule usually occurred when fixed‐interval reinforcement was not forthcoming within a few seconds, and responding then alternated between the two schedules every few seconds until fixed‐interval reinforcement finally was obtained.
SECOND‐ORDER SCHEDULES WITH PAIRED AUDITORY BRIEF STIMULI
Authors: Fantino Edmund
Published: March 2006

Pigeons were exposed to multiple second‐order schedules of paired and unpaired brief stimuli in which responding on the main key was reinforced according to a fixed‐interval thirty‐second schedule by a brief stimulus (a tone in the paired schedule) and advancement to the next segment of the second‐order schedule. In Experiment 1, a response on the second key was required during the tone in its fourth and final presentation to produce food. Responses during earlier brief stimuli indicated the extent to which the final brief stimulus was discriminated from preceding ones. Responding was comparable during all tones, extending prior findings with visual paired brief stimuli and weakening explanations of subjects' failure to discriminate between brief‐stimulus presentations in terms of elicited responding. In Experiment 2 the number of fixed‐interval segments comprising the second‐order schedules varied from one through eight. Although main‐key response rates increased across segments in both experiments, they increased much less sharply with a variable number of segments. These results suggest that the increase in main‐key response rates across segments is due primarily to a degree of temporal discrimination not reflected on the second key. Main‐key response rates were higher on paired auditory brief‐stimulus schedules than on unpaired visual brief‐stimulus schedules, especially in Experiment 2, thus further extending findings with visual brief stimuli to second‐order schedules with auditory brief stimuli.
EFFECTS OF FIXED‐TIME SHOCKS AND BRIEF STIMULI ON FOOD‐MAINTAINED BEHAVIOR OF RATS
Authors: Keenan Michael , Leslie Julian C.
Published: March 2006

When a fixed‐time schedule of shocks was presented to rats lever pressing for food on a random‐interval schedule, a pattern of behavior developed with a high rate of pressing after shock declining to near zero before the next shock was delivered. Once this pattern had stabilized, one‐quarter of the shocks were replaced with brief auditory stimuli (tones) in a random sequence. Tone maintained behavior similar to shock, although tone was never paired with shock. Both tone and shocks elicited responding when presented at various times as probe stimuli, and responding was usually totally suppressed if neither stimulus occurred at the beginning of the fixed‐time interval. When other stimuli were paired with tone and shock, only those paired with tone gained discriminative control and elicited responding. These findings suggest that stimuli that signal a shock‐free, or safe, period will maintain the pattern of behavior generated by shock on a fixed‐time schedule. There is a parallel between this phenomenon and the control of behavior on second‐order schedules of positive reinforcement with nonpaired brief stimuli.
EARLY AND LATE INTRODUCTION OF PROBES AND STIMULUS CONTROL ACQUISITION IN FADING
Authors: Fields Lanny
Published: March 2006

College students learned to name Braille patterns presented visually using a fading procedure in which Braille patterns were superimposed on letter names after which letter names were attenuated. Measurement of acquisition was accomplished by presenting probes—consisting of the Braille stimuli only—throughout fading. Effects of probes upon acquisition were assessed by introducing probes early or late in fading. Fewer fading levels were needed for Braille elements to acquire control when probes were introduced early rather than late. When probes were introduced late, all subjects learned to name the Braille elements as the letters were being faded out. When probes were introduced early, however, most subjects learned to name the Braille elements as they were being faded in. Since virtually no errors occurred during compound‐stimulus presentations, the probe procedure did not induce errors during acquisition. Quantitative analysis of probe data suggested that inclusion of probes enhanced the control acquired by the Braille elements during compound‐stimulus presentations. The reported effects may have been due to differences in the relative frequency of reinforcement presented during compounds and probes.
SELECTIVE ANTAGONISM OF THE ERROR‐INCREASING EFFECT OF MORPHINE BY NALOXONE IN A REPEATED‐ACQUISITION TASK
Authors: Thompson Donald M. , Moerschbaecher Joseph 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. Errors produced a brief timeout but did not reset the chain. When either morphine or naloxone was administered alone, the overall response rate decreased with increasing doses. The rate‐decreasing effect was accompanied by an increase in percent errors with morphine but not with naloxone. Both effects of morphine were antagonized by doses of naloxone that were ineffective when given alone. The antagonism was selective in that naloxone (3 mg/kg) completely blocked the error‐increasing effect but not the rate‐decreasing effect of the higher doses of morphine. The view that naloxone is a specific narcotic antagonist was supported by the finding that naloxone failed to antagonize the rate‐decreasing and error‐increasing effects of d‐amphetamine, pentobarbital, and phencyclidine.
NOTE ON DELAY‐INTERVAL ILLUMINATION EFFECTS ON RETENTION IN MONKEYS (Cebus apella)
Authors: Salmon D. P. , D'Amato M. R.
Published: March 2006

Two monkeys experienced with delayed matching to sample were given a 30‐day baseline training period during which the delay interval was illuminated. Both subjects showed an increase in matching accuracy when shifted to dark delay intervals, and accuracy declined when the illuminated delay interval was reinstituted. These results, as well as earlier reports of facilitation of delayed matching behavior by dark delay intervals, support the view that the absolute level of delay‐interval illumination can importantly affect visual retention in monkeys and may be indicative of significant differences in the retention mechanisms employed by monkeys and birds.
DYNAMIC EQUILIBRIUM ON A CYCLIC‐INTERVAL SCHEDULE WITH A RAMP
Authors: McDowell J. J. , Sulzen Helena M.
Published: March 2006

Five human subjects pressed a panel for money on a cyclic‐interval schedule that arranged recurring periods of linearly increasing reinforcement rates (ramps). Response rate versus time functions for all subjects showed recurring periods of linearly increasing response rates. The responding of four of the five subjects was in phase with the reinforcement input. The remaining subject showed a two‐minute phase shift. These results suggest that organisms may act like simple amplifiers on cyclic‐interval schedules, that is, the form of the input signal is not changed by the organism, but is returned with amplification. By analogy with the variable‐interval case, the controlling variable on cyclic‐interval schedules with rate ramps may be the constant reinforcement acceleration that is arranged by the schedule.
STIMULUS GENERALIZATION OF SCHEDULE‐INDUCED POLYDIPSIA
Authors: Hamm Robert J. , Porter Joseph H. , Kaempf George L.
Published: March 2006

Five rats were exposed to an intradimensional discrimination by associating two tones of different frequency with the components of a multiple random‐time 30‐sec, extinction schedule of food presentation. After schedule‐induced polydipsia developed and the intermittent schedule of food presentation established stable differential licking rates during the stimuli associated with the multiple schedule, a stimulus generalization test was conducted. When generalization testing was conducted by presenting stimuli that varied on the frequency dimension during the random‐time 30‐sec component of the multiple schedule, all five rats demonstrated moderately sloping symmetrical gradients. Thus, schedule‐induced polydipsia can be brought under the control of stimuli other than the food pellet.
EFFECTS OF PROMPTING AND REINFORCEMENT OF ONE RESPONSE PATTERN UPON IMITATION OF A DIFFERENT MODELED PATTERN
Authors: Bondy Andrew S.
Published: March 2006

Twelve preschool children participated in a study of the effects of explicit training on the imitation of modeled behavior. The responses trained involved a marble‐dropping pattern that differed from the modeled pattern. Training consisted of physical prompts and verbal praise during a single session. No prompts or praise were used during test periods. After operant levels of the experimental responses were measured, training either preceded or was interposed within a series of exposures to modeled behavior that differed from the trained behavior. Children who were initially exposed to a modeling session immediately imitated, whereas those children who were initially trained immediately performed the appropriate response. Children initially trained on one pattern generally continued to exhibit that pattern even after many modeling sessions. Children who first viewed the modeled response and then were exposed to explicit training of a different response reversed their response pattern from the trained response to the modeled response within a few sessions. The results suggest that under certain conditions explicit training will exert greater control over responding than immediate modeling stimuli.
PHENCYCLIDINE DISCRIMINATION IN THE PIGEON USING COLOR TRACKING UNDER SECOND‐ORDER SCHEDULES
Authors: McMillan D. E. , Cole‐Fullenwider D. A. , Hardwick W. C. , Wenger G. R.
Published: March 2006

Pigeons were trained to track different key colors, depending on whether they had been injected with phencyclidine or saline prior to the session. A second‐order schedule was used to generate large numbers of responses prior to the initial food delivery. The procedure offers several advantages over traditional procedures for studying drug discrimination.
CHOICE AND BEHAVIORAL PATTERNING
Authors: Shimp Charles P.
Published: March 2006

Ten pigeons pecked left and right keys in a discrete‐trials experiment in which access to food was contingent upon changeovers to the right key after particular runs of left‐key pecks. In each of three sets of conditions, two run lengths were reinforced according to a concurrent variable‐interval schedule: reinforcement followed runs of either 1 or 2, 1 or 4, or 2 or 4 left‐key pecks preceding changeovers. The intertrial interval separating successive pecks was varied from .5 to 10.0 sec, and the relative frequency of reinforcement for the shorter of the two reinforced runs was varied from 0 to .75. The contingencies established local behavioral patterning that roughly approximated that required for reinforcement. For a fixed pair of reinforced run lengths, preference for the shorter of the two frequently increased as the intertrial interval increased and therefore as the minimum temporal durations of both reinforced runs increased. Preference for the shorter of the two also increased as its corresponding relative frequency of reinforcement increased. Both of these effects on preference were qualitatively similar to corresponding effects in previous research with two different kinds of reinforced behavioral patterns, interresponse times and interchangeover times. In all these experiments, analytical units were found in the temporal patterns of behavior, not in the behavior immediately contiguous with a reinforcer. It is suggested that a particular local temporal pattern of behavior is established to the extent to which it is repeatedly remembered when reinforcers are delivered, regardless of whether the delivery of a reinforcer is explicitly contingent upon that pattern.
STIMULUS DISCRIMINABILITY IN FREE‐OPERANT AND DISCRETE‐TRIAL DETECTION PROCEDURES
Authors: McCarthy Dianne , Davison Michael , Jenkins Peter E.
Published: March 2006

Six pigeons were trained to discriminate different light intensities in four experimental procedures. Experiment 1 compared stimulus discriminability in a yes‐no signal‐detection task with discriminability measures obtained from two free‐operant procedures. Discriminability estimates were significantly lower in the detection procedure. Experiment 2 showed this lowered discriminability to be a function of the delay between stimulus presentation and the availability of the choice‐response keys in the standard detection task. In addition, reinforcement sensitivity was lowest when correct choice responses were intermittently, rather than continuously, reinforced.