bluuebunny/crossref_metadata_2025 huggingface dataset:
PIGEONS RESPOND TO PRODUCE PERIODS IN WHICH REWARDS ARE INDEPENDENT OF RESPONDING1
Authors: Neuringer Allen
Published: March 2006

Pecks by pigeons on a response key produced an ON state during which intermittent rewards were freely available, i.e., independently of responding. Pecks during the ON state caused it to remain ON. If no pecks occurred, the state changed to OFF—the key color changed—and rewards were not presented. The state remained OFF until the next response. Thus, responses controlled the state in the chamber but did not cause immediate reinforcement. Four dimensions of the schedule were varied: the rates of response‐independent rewards during ON; the duration of ON produced by each peck; the pattern of rewards during ON; and the presence vs absence of exteroceptive cues during ON and OFF. The results showed that rates of responding were primarily controlled by the duration of ON produced by each response. When each response caused a long period of ON, pecks occurred infrequently; when each response caused a brief period of ON, pecks were frequent.
SCHEDULE‐INDUCED MIRROR RESPONDING IN THE PIGEON1
Authors: Cohen Perrin S. , Looney Thomas A.
Published: March 2006

Two pigeons that were previously exposed to a multiple schedule of reinforcement in the presence of a stuffed and a live pigeon, and two of three naive pigeons, responded on a mirror during exposure to multiple fixed‐ratio, fixed‐ratio schedules of reinforcement for key pecking. Both the topography and temporal pattern of mirror responding were comparable to schedule‐induced “attack” on live and stuffed targets. Rate of target responding was reduced when either the mirror was covered with paper or when the multiple schedule was removed. A reversal in the relationship between reinforcement schedules and discriminative stimuli demonstrated that mirror responding was controlled by the stimulus correlated with the higher fixed‐ratio schedule. With one component of the multiple schedule held constant at fixed ratio 25 and the ratio requirement of the other component varying from 25 to 150, there was an inverted U‐shaped relationship between rate of mirror responding and fixed‐ratio schedule in the varied component. As in Flory's study (1969b) there was an inverted U‐shaped relationship between target responding and inter‐food intervals. The combined results of these studies suggest that the relationship between rate of target responding and reinforcement schedules is controlled primarily by the inter‐food intervals resulting from the schedules.
RELATIVE DELAY OF REINFORCEMENT AND CHOICE1
Authors: Hursh Steven R. , Fantino Edmund
Published: March 2006

Pigeons' responses on either of two concurrently available keys each associated with variable‐interval 60‐sec schedules occasionally changed the schedule on that key to a terminal‐link interval schedule providing access to gain while the other key became inoperative. Experiment I compared simple fixed‐ and mixed‐interval schedules in the terminal links, and showed that for all subjects and schedules the distribution of responses during the concurrent initial links was accurately described by the relative inverse delay of reinforcement squared. Experiment II extended the generality of this formulation to a situation in which rate of reinforcement was constant and delay alone was varied.
INTERACTION OF FREQUENCY AND MAGNITUDE OF REINFORCEMENT ON CONCURRENT PERFORMANCES1
Authors: Todorov Joao Claudio
Published: March 2006

Frequency and magnitude of reinforcement were varied in concurrent variable‐interval variable‐interval schedules of reinforcement. The relative response rate to the two stimuli did not support the notion that choice approximately matches relative total access to food (the product of frequency and magnitude of reinforcement in one schedule divided by the sum of products of frequency and magnitude in both schedules). Relative response rates matched relative reinforcement value when that measure was adjusted to give more emphasis to reinforcement frequency than to reinforcement duration.
FACILITATION AND SUPPRESSION OF RESPONDING UNDER TEMPORALLY DEFINED SCHEDULES OF NEGATIVE REINFORCEMENT1
Authors: Kadden Ronald M.
Published: March 2006

Two parameters for scheduling aversive stimulus presentations were studied systematically by specifying concurrent and independent probabilities of electric shock delivery for the occurrence and for the non‐occurrence of a lever‐press response. After preliminary training on a free‐operant shock‐avoidance schedule, 16 rhesus monkeys were divided into four groups, each group being assigned one shock distribution on a continuum from fixed interval to a widely ranging variable interval. Within groups, each subject was successively exposed to three values of response‐dependence of shock delivery on a continuum from response‐independent shock to complete dependence of shock on response occurrence (“punishment”). Introduction of shock following avoidance training produced initial response facilitation followed by suppression. Responding during both the facilitation and suppression periods was maximal when the shock schedule was periodic and response independent. Responding decreased as the inter‐shock intervals were made more variable across groups, and as shock delivery was made increasingly response dependent within individual subjects.
SHOCK INTENSITY AND DURATION INTERACTIONS ON FREE‐OPERANT AVOIDANCE BEHAVIOR1
Authors: Leander J. David
Published: March 2006

Shock intensities (1 to 4 mA) and shock durations (0.3 to 0.75 sec) were concurrently varied over a range commonly used in free‐operant avoidance studies using a lever‐press response. Response rates were a positive linear function of the log of the product of intensity times duration. Shock rates were a negative linear function of that log. The increase in response rates was primarily due to a selective increase in the conditional probability of making responses with long interresponse times. The disproportionality of receiving shocks early in the session (warm‐up) was also a linear function of the log of the intensity‐duration product, with increasing disproportionality as the value of the intensity‐duration product was increased. Thus, with all measures of the avoidance performance, shock intensity and shock duration combine in a multiplicative fashion to determine the avoidance performance.
BEHAVIORAL CONTRAST WITH TIMEOUT, BLACKOUT, OR EXTINCTION AS THE NEGATIVE CONDITION1
Authors: Sadowsky Stephen
Published: March 2006

When either a timeout period (darkening the response key) or a blackout period (darkening both chamber and response key) was alternated with a stimulus associated with variable‐interval reinforcement, behavioral contrast was obtained. Either peak contrast or maintained contrast occurred, depending on whether or not responding was evidenced during the negative condition. These results are contrary to recent accounts emphasizing the role of non‐reinforced responding in the production of contrast, but are consistent with interpretations emphasizing the aversiveness of the negative condition.
DISCRIMINATION OF A RESPONSE‐INDEPENDENT COMPONENT IN A MULTIPLE SCHEDULE1
Authors: Weisman R. G. , Ramsden Marna
Published: March 2006

Pigeons were trained to respond in non‐differential reinforcement pre‐discrimination training, with a multiple variable‐interval 1‐min variable‐interval 1‐min schedule. Each bird then received discrimination training with a multiple variable‐interval 1‐min variable‐time 1‐min schedule. Thus, discrimination training was between response‐dependent (variable‐interval) and response‐independent (variable‐time) schedules with the rate of reinforcement equated. In Experiment I, only three sessions of non‐differential reinforcement preceded discrimination training and for half the birds, a 0° line was correlated with the response‐dependent schedule; for the remaining birds the 0° line was correlated with the response‐independent schedule. Post‐discrimination gradients of excitatory stimulus control were obtained from the former group, while the latter group showed little evidence of post‐discrimination stimulus control by the 0° line. Differential responding to the variable‐time schedule was not accompanied by behavioral contrast to the variable‐interval schedule. In Experiment II, 20 sessions of non‐differential reinforcement preceded discrimination training and the 0° line was correlated with variable‐time reinforcement for each bird. Differential responding to the 0° line was accompanied by negative induction to the variable‐interval schedule and by inhibitory stimulus control about the 0° line during a post‐discrimination generalization test.
THE EFFECT OF THE BLACKOUT METHOD ON ACQUISITION AND GENERALIZATION1
Authors: Wildemann Donald G. , Holland James G.
Published: March 2006

In discrimination training with the Lyons' blackout method, pecks to the negative stimulus are prevented by darkening the chamber each time the subject approaches the negative stimulus. Stimulus generalization along a stimulus dimension was measured after training with this method. For comparison, generalization was also measured after reinforced responding to the positive stimulus without discrimination training, and after discrimination training by extinction of pecks to the negative stimulus. The blackout procedure and the extinction of pecks to the negative stimulus both produced a peak shift in the generalization gradients. The results suggest that after discrimination training in which the positive and negative stimulus are on the same continuum, the blackout method produces extinction‐like effects on generalization tests.
CONTINUOUS, FIXED‐RATIO, AND FIXED‐INTERVAL REINFORCEMENT IN HONEY BEES
Authors: Grossmann Klaus E.
Published: March 2006

Bees learned to enter a Plexiglas tube and to suck small portions of sugar solution; every entry or every fifth entry was reinforced. During an extinction phase, the bees on the fixed‐ratio schedule emitted twice as many responses as did those given continuous reinforcement. Bees on a fixed‐interval schedule of reinforcement emitted lower response rates than did those given fixed‐ratio reinforcement. By extending the conditioning procedure for several days, it was possible to maintain responding with fixed‐ratio schedules requiring 30 responses per reinforcement and with fixed‐interval values up to 90 sec. Under fixed‐interval schedules, response rates did not increase toward the end of the reinforcement intervals.
FIXED‐INTERVAL SCHEDULES OF INTRAVENOUS COCAINE PRESENTATION IN RATS1
Authors: Dougherty John , Pickens Roy
Published: March 2006

Fixed‐interval schedules of intravenous cocaine presentation were examined as a function of injection dose (0.32 to 0.64 mg/kg) and interval duration (200 to 400 sec) in two rats. Cocaine was found to exert a dose‐related temporal control over the initiation of responding that was unaffected by the fixed‐interval contingency. Fixed‐interval pause duration was linearly related to injection dose and was the same duration as the interresponse time found on continuous reinforcement schedules of cocaine presentation. The fixed‐interval pause remained constant with changes in interval duration. Characteristic fixed‐interval patterns of responding were observed. However, overall response rates were inversely related to injection dose and directly related to interval duration. Running response rates varied unsystematically with both variables. These findings are at variance with results typically found in studies of fixed‐interval food and electric shock presentation.
FIXED‐INTERVAL SCHEDULE OF COCAINE REINFORCEMENT: EFFECT OF DOSE AND INFUSION DURATION1
Authors: Balster Robert L. , Schuster Charles R.
Published: March 2006

Rhesus monkeys were trained on a fixed‐interval 9‐min limited‐hold 3‐min schedule of intravenous cocaine reinforcement. A 15‐min timeout followed each reinforcement or limited‐hold expiration. An identical schedule of food reinforcement was interspersed in the session to assess rate‐modifying effects of the drug infusions not specific to drug reinforcement. In one experiment, response rate for cocaine reinforcement was shown to be a positive function of reinforcement magnitude for a dose range from 0 to 800 ug/kg/inj. At these doses, there was little effect on food reinforced responding except at the highest dose, where responding decreased. Results of the second experiment indicated that increasing the duration of the cocaine infusion produced a change in response rate similar to decreasing unit dose. The response rate change for a given increase in infusion duration was less at a unit dose of 400 ug/kg than at 200 ug/kg.
THE FORM OF THE AUTO‐SHAPED RESPONSE WITH FOOD OR WATER REINFORCERS1
Authors: Jenkins H. M. , Moore Bruce R.
Published: March 2006

The relation between the form of auto‐shaped responses to the lighting of a key and the consummatory responses of pecking grain and drinking water was examined in pigeons. Responses on the key were analyzed by means of high‐speed photography, recordings of the force of contact, and judges' ratings of response‐form based on film and videotape recordings. The first experiment showed that food‐deprived birds presented grain as a reinforcer responded on the key with a grain‐pecking movement, while water‐deprived birds presented water as a reinforcer responded with drinking‐like movements. The second and third experiments showed that the resemblance between auto‐shaped and consummatory responses does not require the dominance of the deprivational state appropriate to the reinforcer. Changing the dominant state of deprivation did not immediately change the form of the key response, and in subjects simultaneously deprived of food and water, the form of response depended on the reinforcer. In the fourth and fifth experiments, subjects simultaneously deprived of food and water received one stimulus signalling food and another signalling water in a random series. In most subjects, the response to each stimulus resembled the consummatory response to the particular reinforcer that was signalled by the stimulus. This result demonstrates the role of association between a stimulus and a reinforcer in producing a resemblance of the auto‐shaped response to the consummatory response.
MAINTENANCE OF KEY PECKING BY RESPONSE‐INDEPENDENT FOOD PRESENTATION: THE ROLE OF THE MODALITY OF THE SIGNAL FOR FOOD1
Authors: Schwartz Barry
Published: March 2006

Three pigeons were exposed to a series of procedures in which periods of response‐independent food presentation, on a variable‐time schedule, alternated with periods in which food was never presented. The stimuli that signalled periods of food availability or nonavailability varied from one procedure to the next, and were sometimes key colors, sometimes tones, and sometimes compounds of both. Key pecking was initiated and maintained when key color was a signal for food; key pecking was not initiated when a tone was the signal for food. However, control of key pecking that was already established could be transferred from key color to tone, and subsequently, initiated by the tone. It is suggested that for pigeons, pre‐experimental relationships exist among food, visual stimuli, and pecking, and that a similar relationship, which includes auditory stimuli, must be induced in the laboratory.
ON THE DEVELOPMENT OF STIMULUS CONTROL1
Authors: Heinemann Eric G. , Avin Edward
Published: March 2006

Pigeons were trained to peck one key when presented with white noise at any of five intensities lower than a reference intensity, and to peck another key when presented with white noise at any of five intensities greater than the reference intensity. The shape of the stimulus control curves (proportion of responses to one key versus stimulus intensity) changed from a horizontal line at the beginning of training to the sigmoid form of typical psychometric functions at the end of training. The development of stimulus control is described in terms of a model based on the theory of signal recognition and a concept of attention.
STEADY STATE RESPONDING BASED UPON SIMPLE AND COMPOUND STIMULI1
Authors: Zuckerman David C.
Published: March 2006

Two pigeons were trained to perform discrimination tasks along two dimensions, wavelength of a circular spot of light and orientation of a white line. Discriminability among stimuli along these dimensions was established for both subjects by means of a steady state testing procedure. The two dimensions were then combined by superimposing the white line upon the colored background. Subjects were given a series of tests in which a correct response could be made on the basis of either of the two components of the stimulus compounds. Discriminability among these redundant compound stimuli was found to be better than that among wavelength and tilt stimuli alone. A second series of tests was administered using both redundant and conflicting compound stimuli. The results of this test series are consistent with a response strategy in which subjects first examine both elements of a compound and then emit a choice response on the basis of the element that best predicts reinforcement.
THE EFFECT UPON SIMPLE ANIMAL BEHAVIOR OF DIFFERENT FREQUENCIES OF REINFORCEMENT, PART II: SEPARATE CONTROL OF THE REINFORCEMENT OF DIFFERENT IRTs
Authors: Anger Douglas
Published: March 2006

Rats' responding was stabilized for over 35 days on 4‐min variable‐interval reinforcement. Reinforcements per hour for 4‐sec wide classes of interresponse times were then separately controlled by adjusting those for each class to the variable‐interval values that had just prevailed. This produced little or no change in interresponse times, indicating that the new procedure was substantially equivalent to a variable‐interval schedule. The variable‐interval schedule produced a high and stable conditional probability of interresponse times in the 0‐ to 4‐sec class, associated with a peak in reinforcements per hour for this class. Reducing the reinforcements per hour for this class while raising that for another class (by 3.3 reinforcements per hour) significantly reduced the conditional probability of 0‐ to 4‐sec interresponse times. Restoring the 3.3 reinforcements per hour to the 0‐ to 4‐sec class significantly elevated the conditional probability of interresponse times in this class. Hence, it is concluded that the distribution of interresponse times produced by a subject during some variable‐interval schedules is determined partly by the relative reinforcement of different interresponse times that the variable‐interval schedule provided.

(Reprinted from Part II of the Final Report of Research under Contract DA‐49‐007‐MD‐408 with the Medical Research and Development Board, Office of the Surgeon General, Department of the Army, 31 December 1954. Edwin B. Newman, Responsible Investigator; Douglas Anger, Research Assistant and author of report. Experimental work done in the Psychological Laboratories of Harvard University.)
TIME ALLOCATION AND NEGATIVE REINFORCEMENT1
Authors: Baum William M.
Published: March 2006

Pigeons' standing on one or the other side of a chamber was reinforced with timeout from electric shock on two concurrent variable‐interval schedules. For two pigeons, the ratio of time spent on the left to time spent on the right approximately matched the ratio of timeouts obtained on the left to timeouts obtained on the right. The data of two other birds deviated from this relation, although in opposite directions. Overall, the results suggest that reduction in rate of electric shock plays a role in behavioral allocation analogous to that played by rate of positive reinforcement. It appears possible to describe aversive control and positive control within the same conceptual framework—that provided by the matching relation.
BEHAVIORAL REGULATION OF GRAVITY: SCHEDULE EFFECTS UNDER ESCAPE‐AVOIDANCE PROCEDURES1
Authors: Clark Fogle C. , Lange Karl O. , Belleville Richard E.
Published: March 2006

Squirrel monkeys were restrained in a centrifuge capsule and trained to escape and avoid increases in artificial gravity. During escape‐avoidance, lever responses reduced centrifugally simulated gravity or postponed scheduled increases. The effect of variation in the interval of postponement (equal to the duration of decrease produced by escape responses) was studied under a multiple schedule of four components. Three components were gravity escape‐avoidance with postponement times of 20, 40, and 60 sec. The fourth component was extinction. Each component was associated with a different auditory stimulus. Rate of responding decreased with increasing postponement time and higher mean g‐levels occurred at shorter intervals of postponement. Effects of the schedule parameter on response rate and mean g‐level were similar to effects of the schedule on free‐operant avoidance and on titration behavior maintained by shock.
THE RELATIVE AVERSIVENESS OF SIGNALLED VERSUS UNSIGNALLED SHOCK‐PUNISHMENT1
Authors: MacDonald Larry
Published: March 2006

Six rats were trained on a two‐component multiple schedule with each component consisting of a two‐link chain schedule. Differential response suppression in the two initial links, as well as in the two terminal links of the chain schedules, was used as a measure of the relative aversiveness of stimulus events in the two terminal links. When signalled and unsignalled shock‐punishment (in addition to equal numbers of food reinforcers) were scheduled in the separate terminal links, subjects responded at lower rates in the initial link preceding unsignalled shock‐punishment than in the initial link preceding signalled shock‐punishment. Similarly, subjects responded at lower rates in the terminal link containing unsignalled shock‐punishment than in the terminal link containing signalled shock‐punishment. Reversing the terminal‐link positions of signalled and unsignalled shock‐punishment led to a reversal of the differential response suppression in the two initial and the two terminal links of the chain schedules. These results indicate that signalled punishment is relatively less aversive than unsignalled punishment and support an “information hypothesis”, which assumes that a condition in which information is provided about the onset of environmental events, even negative events such as shock punishment, is more reinforcing than a condition in which such information is absent.
A TEST OF THE EFFECTIVENESS OF THE DIFFERENTIAL‐REINFORCEMENT‐OF‐LOW‐RATE SCHEDULE
Authors: Richardson W. Kirk
Published: March 2006

Pigeons and rats were used in a yoked‐control design that equated the reinforcement distributions of differential‐reinforcement‐of‐low‐rate and variable‐interval schedules. Both a between‐subjects design and a within‐subjects design found response rate higher for the variable‐interval schedule than for the differential‐reinforcement‐of‐low‐rate schedule, thus demonstrating the effectiveness of the differential‐reinforcement‐of‐low‐rate contingency. The interresponse‐time distributions were unimodal for all subjects under the variable‐interval schedule and bimodal for pigeons under the differential‐reinforcement‐of‐low‐rate schedule. The interresponse‐time distributions for rats under the differential‐reinforcement‐of‐low‐rate schedule were also bimodal in three of four cases but the height of the modes at the shorter intenesponse times were small in both absolute value and in relation to the height of the modes at the shorter interresponse times of the pigeons' distributions.
OBSERVING RESPONSES IN PIGEONS: EFFECTS OF SCHEDULE COMPONENT DURATION AND SCHEDULE VALUE1
Authors: Branch Marc N.
Published: March 2006

Pigeons were exposed to a procedure under which five pecks on one response key (the observing key) changed the schedule on a second key (the food key) from a mixed schedule to a multiple schedule for 25 sec. In Experiment I, a random‐ratio 50 schedule alternated with extinction. The duration of the random‐ratio 50 schedule component was varied between 1.25 and 320 sec, and extinction was scheduled for a varying time, ranging from the duration of the random‐ratio 50 to four times that value. Each set of values was scheduled for a block of sessions. Before observing‐key pecks were allowed at each set of parameter values, the pigeons were exposed to a condition where the mixed and multiple schedule alternated every 10 min, and observing‐key pecks were not permitted. Rates of pecking on the observing key were high for all values of random‐ratio component durations except 1.25 sec. Experiment II was conducted with the random‐ratio component duration equal to 40 sec, and the random‐ratio schedule was varied from random‐ratio 50 to 100, 200, and 400. Observing‐key pecking rates were high for all values of the random‐ratio schedule except random‐ratio 400. In both experiments, observing response rates were relatively little affected, suggesting that neither schedule component duration nor schedule value is a strong determinant of observing responses.
LATENCY DIFFERENTIATION OF HITS AND FALSE ALARMS IN AN OPERANT‐PSYCHOPHYSICAL TEST1
Authors: Terman Michael , Terman Jiuan S.
Published: March 2006

Rats detected the luminance difference of standard and comparison stimuli in a go/no‐go procedure. A key press was reinforced by brain stimulation only when the key's luminance was 10.53 ft‐L (36.01 cd/m2), and key presses to dimmer comparison values produced a 5‐sec timeout. These asymmetrical reinforcement contingencies maximized the bias toward hits and false alarms (“yes” reports), and thus the number of latencies available for analysis. False alarm latencies exceeded hit latencies, with the magnitude of differentiation proportional to luminance difference, demonstrating stimulus control on the very occasions that errors (key presses to comparison luminances) were emitted. Overall latencies decreased when the standard‐comparison luminance difference was made smaller, suggesting a reduction in observing time when the stimuli became indiscriminable.
CHOICE OF HIGHER DENSITY SIGNALLED SHOCK OVER LOWER DENSITY UNSIGNALLED SHOCK1
Authors: Badia Pietro , Coker Charles , Harsh John
Published: March 2006

Unsignalled, inescapable shocks were presented to four albino rats in Experiment 1. By pressing a lever subjects could change the condition to signalled shock for 3‐min periods after which unsignalled shock was automatically reinstated. All subjects changed from unsignalled to signalled shock when shock density was the same or when the density of signalled shock was two times greater than unsignalled shock. When the density of signalled shock was four times that of unsignalled shock, three subjects changed to the higher density schedule. One subject changed to a density of signalled shock eight times that of unsignalled shock. The second study showed that the two shock schedules most similar in Experiment 1 were discriminably different because subjects chose lower over higher shock densities when both densities were unsignalled. An analysis stressing safe (signal absent) and unsafe (signal present) periods was discussed.
BEHAVIORAL INTERACTIONS AND STIMULUS CONTROL DURING CONDITIONAL DISCRIMINATIONS1
Authors: Wilkie Donald M.
Published: March 2006

Two pigeons were exposed to factorial combinations of two values of line tilt and two frequencies of houselight flashes. During each of four baseline stages, key pecking in the presence of all four combinations was reinforced according to a variable‐interval schedule. The baseline phases were followed by four different conditional discrimination training procedures in which reinforcement availability for pecking in the presence of the line tilts depended upon the houselight frequency. The subjects acquired each conditional discrimination. Behavioral contrast occurred during the acquisition and abolition of the discriminations. Generalization tests, given after each conditional discrimination, revealed that both the line tilt and houselight frequency dimensions controlled pecking only after conditional discriminations in which reinforcement availability depended upon the value of both dimensions.
CHOICE BETWEEN RESPONSE RATES1
Authors: Hawkes Larry , Shimp Charles P.
Published: March 2006

Three pigeons were required to peck a single key at a higher and a lower rate, corresponding to two classes of shorter and longer concurrently reinforced interresponse times. Food reinforcers arranged by a single variable‐interval schedule were randomly allocated to the two reinforced interresponse times. The absolute durations of reinforced interresponse times were varied while the total reinforcements per hour was held constant and the relative duration, i.e., the relative reciprocal, of the shorter reinforcer class was held constant at 0.70. Preference for the higher rate of responding, as measured by the relative frequency of responses terminating interresponse times in the shorter reinforced class, depended on the absolute reinforced response rates. Preference for the higher reinforced rate increased from a level of near‐indifference (0.50) at high reinforced response rates, through the matching level (0.70) at intermediate reinforced response rates, to a virtually exclusive preference (>0.90) at low reinforced response rates. These results resemble corresponding preference functions obtained with two‐key concurrent‐chains schedules and thereby provide another sense in which it may be said that interresponse‐time distributions from interval schedules estimate preference functions for the component response rates corresponding to different classes of reinforced interresponse times.
THE ROLE OF AUTOPECKING IN BEHAVIORAL CONTRAST1
Authors: Redford M. Elaine , Perkins Charles C.
Published: March 2006

Four groups of four pigeons each were studied on two different multiple schedules. The cues correlated with the schedule components were localized on the response key for two groups and were not localized for the others. Two groups worked on multiple schedules with variable interval 15‐sec in both components, and variable interval 15‐sec in one component and extinction in the other. The other two groups had identical procedures except that food was presented on a response‐independent variable‐time schedule. Variable‐interval birds with localized stimuli showed marked behavioral contrast; variable‐interval birds with non‐localized stimuli showed no behavioral contrast. Variable‐time birds with keylight stimuli acquired high rates of autopecking, which changed as treatment changed in a manner that paralleled rate changes, resulting in behavioral contrast for variable‐interval birds. Variable‐time birds with non‐localized stimuli key pecked only at a low rate. The findings indicate that behavioral contrast in pigeons may result from the autopecking that is obtained with stimulus‐contingent food presentation.
BEHAVIORAL PARAMETERS OF DRUG ACTION: SIGNALLED AND RESPONSE‐INDEPENDENT REINFORCEMENT1
Authors: Thompson Donald M. , Corr Peter B.
Published: March 2006

Four pigeons were initially trained under a multiple variable‐interval 1‐min variable‐interval 1‐min schedule of food reinforcement. For two of the pigeons, a signal was then presented whenever the reinforcer was available in one component; this resulted in positive contrast. For the other two pigeons, the reinforcer was presented independently of responding on a variable‐time schedule in one component; this resulted in negative induction. After 30 to 50 sessions, however, a similar degree of differential responding occurred under both multiple schedules, i.e., high rates in the variable‐interval component and low rates in the other component. Reinforcement frequency remained about the same in each of the schedule components. The stable performances then served as baselines for studying drug effects. In the high‐rate component of both multiple schedules, small doses of d‐amphetamine increased responding, whereas larger doses decreased responding. In the low‐rate component of both multiple schedules, there was no rate‐increasing effect at any dose of d‐amphetamine; such an effect was found, however, with phenobarbital at a dose that decreased responding in the high‐rate component. The drug effects thus depended on the interaction of pharmacologic variables (specific drug and dose) with behavioral variables (schedule components).
FORMAL PROPERTIES OF THE MATCHING LAW1
Authors: Herrnstein R. J.
Published: March 2006

The matching law implies that any form of behavior approaches an asymptotic frequency as its reinforcement approaches 100 per cent of the total reinforcement being obtained at a given time. This asymptote is formally independent of the kind or quantity of drive or reinforcement associated with the response in question or with any competing response.
AUDITORY DELAYED MATCHING IN THE BOTTLENOSE DOLPHIN1
Authors: Herman Louis M. , Gordon Judith A.
Published: March 2006

A bottlenose dolphin, already highly proficient in two‐choice auditory discriminations, was trained over a nine‐day period on auditory delayed matching‐to‐sample and then tested on 346 unique matching problems, as a function of the delay between the sample and test sounds. Each problem used new sounds and was from five to 10 trials long, with the same sound used as the sample for all trials of a problem. At each trial, the sample was projected underwater for 2.5 sec, followed by a delay and then by a sequence of two 2.5‐sec duration test sounds. One of the test sounds matched the sample and was randomly first or second in the sequence, and randomly appeared at either a left or right speaker. Responses to the locus of the matching test sound were reinforced. Over nine, varying‐sized blocks of problems, the longest delay of a set of delays in a block was progressively increased from 15 sec initially to a final value of 120 sec. There was a progressive increase across the early blocks in the percentage of correct Trial 1 responses. A ceiling‐level of 100% correct responses was then attained over the final six blocks, during which there were 169 successive Trial 1 responses bracketed by two Trial 1 errors (at 24‐ and 120‐sec delays). Performance on trials beyond the first followed a similar trend. Finally, when the sample duration was decreased to 0.2 sec or less, matching performance on Trial 1 of new problems dropped to chance levels.
THE LAW OF EFFECT AND A VOIDANCE: A QUANTITATIVE RELATIONSHIP BETWEEN RESPONSE RATE AND SHOCK‐FREQUENCY REDUCTION1
Authors: de Villiers Peter A.
Published: March 2006

Two experiments were conducted to investigate the quantitative relationship between response rate and reinforcement frequency in single and multiple variable‐interval avoidance schedules. Responses cancelled delivery of shocks that were scheduled by variable‐interval schedules. When shock‐frequency reduction was taken as the measure of reinforcement, the relationship between response rate and reinforcement frequency on single variable‐interval avoidance schedules was accurately described by Herrnstein's (1970) equation for responding on single variable‐interval schedules of positive reinforcement. On multiple variable‐interval avoidance schedules with brief components, asymptotic relative response rate matched relative shock‐frequency reduction. The results suggest that many interactions between response rates and shock‐frequency reduction in avoidance can be understood within the framework of the generalized matching relation, as applied by Herrnstein (1970) to positive reinforcement.
ON THE FORM OF THE RELATION BETWEEN RESPONSE RATES IN A MULTIPLE SCHEDULE1
Authors: Nevin John A.
Published: March 2006

Three pigeons received training on multiple variable‐interval schedules with brief alternating components, concurrently with a fixed‐interval schedule of food reinforcement on a second key. Fixed‐interval performance exhibited typical increases in rate within the interval, and was independent of multiple‐schedule responding. Responding on the multiple‐schedule key decreased as a function of proximity to reinforcement on the fixed‐interval key. The overall relative rate of responding in one component of the multiple schedule roughly matched the overall relative rate of reinforcement. Within the fixed interval, response rate during one multiple‐schedule component was a monotonic, negatively accelerated function of response rate during the other component. To a first approximation, the data were described by a power function, where the exponent depended on the relative rate of reinforcement obtained in the two components. The relative rate of responding in one component of the multiple schedule increased as a function of proximity to fixed‐interval reinforcement, and often exceeded the overall obtained relative rate of reinforcement. The form of the function relating response rates is discussed in relation to findings on rate‐dependent effects of drugs, chaining, and the relation between response rate and reinforcement rate in single‐schedule conditions.
ABSENCE OF SHOCK‐ELICITED AGGRESSION IN PIGEONS1
Authors: Rashotte Michael E. , Dove L. Duane , Looney Thomas A.
Published: March 2006

Two pigeons that attacked a taxidermically prepared target pigeon during a schedule of positive reinforcement for key pecking, and two that did not, were shocked through implanted electrodes in the presence of the target. Shock intensities of 2 and 4 mA, durations of 0.1 and 1.3 sec, and frequencies of 2, 6, 20, and 35 per minute were delivered across 16 sessions with 180 shocks per session. No pigeon attacked the target; one pecked the shockplug on its back. The two pigeons that had not attacked during the positive reinforcement schedules were conditioned to peck the target for food reinforcement before another 16 sessions of shock. No attack was observed in these shock sessions. During subsequent positive reinforcement of key pecking, the target was attacked by the two pigeons that had originally attacked and by one that had not. Absence of shock‐elicited attack in these pigeons may be related to the parameters of the experiment or may be yet another instance of the absence of shock‐elicited attack in the class Aves. At least under the present conditions, it was not possible to predict the level of attack during electric shock from the level of attack during schedules of positive reinforcement for key pecking.
UBIQUITY OF SCHEDULE‐INDUCED POLYDIPSIA1
Authors: Gilbert R. M.
Published: March 2006

Spaced feeding of individual food pellets to food‐deprived rats induced excessive drinking after pellet delivery if water was continuously available. When access to water was restricted to a portion of the inter‐pellet interval, and competition from food‐reinforced bar pressing was removed, excessive drinking occurred whenever drinking was possible. This finding extends the generality of accounts of excessive behavior that implicate induction by apparently unrelated scheduling characteristics of the environment.
VARIABILITY OF RESPONDING ON A CONCURRENT SCHEDULE AS A FUNCTION OF BODY WEIGHT1
Authors: McSweeney Frances K.
Published: March 2006

Five pigeons pecked for food reinforcers on a concurrent variable‐interval one‐minute, variable‐interval four‐minute schedule. Each bird's body weight was varied from 80% of its free‐feeding weight to 95% and then by 5% steps to 110% or until weight gains ceased. The coefficient of variation, but not the standard deviation, of the daily rate of responding on each of the component schedules increased with increases in body weight.
PUNISHMENT OF OBSERVING BY THE NEGATIVE DISCRIMINATIVE STIMULUS1
Authors: Mulvaney Dallas E. , Dinsmoor James A. , Jwaideh Alice R. , Hughes Lawson H.
Published: March 2006

To determine the effect of a negative discriminative stimulus on the response producing it, two pigeons were each studied in a three‐key conditioning chamber. During alternating periods of unpredictable duration, pecking the center (food) key either was reinforced with grain on a variable‐interval schedule or was never reinforced. On equal but independent variable‐interval schedules, pecking either of the side (observing) keys changed the color of all keys for 30 sec from yellow to either green or red. When the schedule on the center key was variable‐interval reinforcement, the color was green (positive discriminative stimulus); when no reinforcements were scheduled, the color was red (negative discriminative stimulus). Since pecking the side keys did not affect grain deliveries, changes in the rate of pecking could not be ascribed to changes in the frequency of primary reinforcement. In subsequent sessions, red was withheld as one of the possible consequences of pecking a given side key. When red was omitted, the rate on that key increased, and when red was restored, the rate decreased. It was concluded that red illumination of the keys, the negative discriminative stimulus, had a suppressive effect on the response that produced it.
SIGNAL DETECTION METHODS FOR MEASUREMENT OF UTILITY IN ANIMALS1
Authors: Wright Anthony A. , Nevin John A.
Published: March 2006

Analytic methods of signal detection theory were employed to assess the utility of reinforcers. Four pigeons were trained to detect the presence or absence of a stimulus by pecking one of two side keys in a trial‐by‐trial choice paradigm. The relative rate of positive reinforcement for correct choices was varied to offset the biasing effects of electric shock for incorrect right side‐key choices. The effects of relative rate of reinforcement on bias were similar at all shock intensities even though the subjects' sensitivity changed during the course of the experiment. The relative rate of reinforcement required to produce equal bias was calculated and plotted against shock intensity to generate utility functions. The relative rate of reinforcement necessary to offset the bias induced by shock was an increasing function of shock intensity.
RESPONSE STRENGTH IN MULTIPLE SCHEDULES1
Authors: Nevin John A.
Published: March 2006

In several different experiments, pigeons were trained with one schedule or condition of food reinforcement for pecking in the presence of one key color, and a different schedule or condition in the presence of a second key color. After responding in both of these multiple schedule components stabilized, response‐independent food was presented during dark‐key periods between components, and the rates of pecking in both schedule components decreased. The decrease in responding relative to baseline depended on the frequency, magnitude, delay, or response‐rate contingencies of reinforcement prevailing in that component. When reinforcement was terminated, decreases in responding relative to baseline rates were ordered in the same way as with response‐independent food. The relations between component response rates were power functions. Internal consistencies in the data, in conjunction with parallel findings in the literature, suggest that the concept of response strength summarizes the effects of diverse procedures, where response strength is identified with relative resistance to change. The exponent of the power function relating response rates may provide the basis for scaling response strength.
EVIDENCE OF COMPLEMENTARY AFTERIMAGES IN THE PIGEON1
Authors: Williams Jon L.
Published: March 2006

Key pecking of pigeons was reinforced on a variable‐interval schedule when ambient illumination came from a green light, but not when it came from a red, yellow, or white light. The different hues were randomly presented for periods of 30 sec each, with the restriction that white never followed red. After discriminative control was established, the pigeons were tested with the same procedure used during training, except that white sometimes followed red. Significantly more responses were made during white‐following‐red than during white following either green or yellow. These findings indicate that, in changing from red to white, complementary afterimages can be induced in pigeons for a brief period of time. By providing behavioral evidence for afterimages in the pigeon, this technique may be useful to research in comparative neurophysiology, animal discrimination learning, and theories of color vision.
STIMULUS CONTROL OF RESPONDING DURING A FIXED‐INTERVAL REINFORCEMENT SCHEDULE1
Authors: Wilkie Donald M.
Published: March 2006

During training sessions, pecks by pigeons on a response key illuminated by a vertical line of white light resulted in reinforcement and an ensuing blackout according to a fixed‐interval schedule. Training sessions were followed by dimensional stimulus control test sessions during which the orientation of the line present throughout the fixed interval was varied. Inverted U‐shaped (excitatory) gradients of responding, with maximum responding occurring in the presence of the vertical line, were observed during the terminal part of the fixed interval. U‐shaped (inhibitory) gradients of responding, with minimum responding occurring in the presence of the vertical line, were observed during the early part of the fixed interval when the preceding interval had terminated with reinforcement and blackout but not when the preceding interval had terminated with blackout only. These results suggest that the dimensional control by the stimulus present throughout the fixed interval is of a conditional variety. Whether the fixed‐interval stimulus exerts inhibitory or excitatory dimensional control depends upon the presence and absence, respectively, of stimuli associated with reinforcement.
THE EFFECT OF PHYSICAL RESTRAINT ON BEHAVIOR UNDER THE DIFFERENTIAL‐REINFORCEMENT‐OF‐LOW‐RATE SCHEDULE1
Authors: Richardson W. Kirk , Loughead Tomas E.
Published: March 2006

Previous studies have identified and manipulated collateral behavior to assess the effect of collateral behavior on performance under the differential‐reinforcement‐of‐low‐rate (DRL) schedule. However, conclusions could not be applied to subjects not observed to engage in collateral behavior. The present study used a technique that prevented the occurrence of the types of collateral behavior typically observed in the pigeon. This technique did not require the identification of collateral behavior in the subjects. The exclusion of the types of collateral behavior typically observed in pigeons resulted in higher response rates and lower reinforcement rates under large DRL values but had no effect at lower DRL values. It was concluded that collateral behavior is necessary for low response rates and high reinforcement rates under large DRL values.
PREFERENCE FOR INTERMITTENT REINFORCEMENT1
Authors: Kendall Stephen B.
Published: March 2006

Two experiments were conducted demonstrating that under certain conditions pigeons may peck at a higher rate on a key that produces intermittent reinforcement following a delay than on one that always produces reinforcement following the same delay duration. In both experiments, concurrent chain schedules were employed. In Experiment I, a single peck on one key led to a white light and a delay of 15 sec, which always terminated with food. A peck on the other key led to its illumination by one of two colored lights and a delay period of 15 sec. The delay was followed by either food presentation or timeout, either one lasting 3 sec. In a control group, the lights on this key were not correlated with food or timeout. Under the correlated stimuli, birds more often pecked the key leading to intermittent reinforcement, whereas with uncorrelated stimuli they pecked the key leading to the white light and 100% reinforcement. In Experiment II, concurrent variable‐interval schedules were employed in the first link. The results showed generally that the relative rate was higher on the key leading to intermittent reinforcement when the stimuli were correlated with reinforcement and timeout than on the key leading to 100% reinforcement. There was some indication that this performance was affected by (1) the duration of the delay, (2) the percentage of reinforcement on the key yielding the higher percentage of reinforcement (the key with the white light), and (3) prior experimental conditions.