bluuebunny/crossref_metadata_2025 huggingface dataset:
TEMPORAL CONTROL ON PERIODIC SCHEDULES: SIGNAL PROPERTIES OF REINFORCEMENT AND BLACKOUT1
Authors: Starr Bettie C. , Staddon J. E. R.
Published: March 2006

Pigeons were exposed to periodic food‐reinforcement schedules in which intervals ended with equal probability in either reinforcement or brief blackout. The effects on the pattern of key pecking of sequential probability of reinforcement, interval duration, and time to reinforcement opportunity were investigated in three experiments. The major results were: (1) at short absolute interval durations, time to reinforcement opportunity determined both postreinforcement and postblackout pause (time to first key peck within an interval); (2) at long intervals, postblackout pause was consistently shorter than postreinforcement pause, even if both events signalled the same time to the next reinforcement opportunity (omission effect); (3) when reinforcement and blackout signalled different times to the next reinforcement opportunity, within the same experiment, there was some evidence for interactions analogous to behavioral contrast.
FIXED‐RATIO DISCRIMINATION: EFFECTS OF RESPONSE‐PRODUCED BLACKOUTS1
Authors: Lydersen Tore , Crossman E. K.
Published: March 2006

For three pigeons, reinforcement depended upon a left side‐key response after execution of a fixed ratio 10 on the center key, and upon a right side‐key response after fixed ratio 20. Each response during the fixed ratios produced a 0.5‐sec blackout. The time between the first and last response in fixed ratio 10 was then equated with the time between the first and last response in fixed ratio 20 by increasing the blackout duration. The accuracy of side‐key choice was disrupted, thereby suggesting that time, rather than number of responses, controlled choice responding. When the time between the first and last response was equated during both ratios, asymptotic accuracy was approximately equal to (two birds) or somewhat higher than (one bird) that obtained previously. The results of probes with intermediate fixed ratios and blackouts suggested that control of side‐key choice had transferred from the time between the first and last response in ratios to blackout duration.
TEMPORAL INHIBITION: EFFECTS OF CHANGES IN RATE OF REINFORCEMENT AND RATE OF RESPONDING1
Authors: Carr Edward G. , Reynolds G. S.
Published: March 2006

Pigeons were trained to key peck on several multiple schedules in which the first of two components was always a simple fixed‐interval schedule. The rate of responding at the beginning of the constant fixed‐interval schedule was found to decrease with increases in the rate of reinforcement associated with the other component of the multiple schedule, but remained unchanged with decreases in the rate of responding associated with the other component. These results were interpreted as being consistent with the view that the presence and magnitude of the temporal inhibitory effects observed in a given fixed‐interval schedule are a function of the properties of reinforcing stimuli, rather than of changes in the rate of responding associated with the time interval immediately preceding the fixed interval in question.
NEGATIVELY REINFORCED KEY PECKING1
Authors: Lewis Paul , Lewin Lew , Stoyak Mike , Muehleisen Penny
Published: March 2006

A reinforcement‐switching procedure was used to produce negatively reinforced key pecking in pigeons. First, key pecking on a chain schedule (fixed‐interval 10‐sec variable‐interval 60‐sec) was conditioned using grain reinforcement. Second, intermittent shock in the initial link was introduced at a low intensity and gradually increased. Third, food reinforcement in the terminal link was eliminated. With shock at 90 V occurring on the average every 3 sec, initial‐link pecking was maintained with no terminal‐link food. Three of four pigeons responded consistently at shock intensities of 90, 70, and 50 V but not at 30 V. A fourth pigeon responded at but not below 90 V. Rate of response was directly related to shock frequency. Eliminating food deprivation did not affect the negatively reinforced performance.
RESPONSE‐DEPENDENT SHOCK IN SECOND‐ORDER FIXED‐RATIO SCHEDULES OF FOOD PRESENTATION1
Authors: Weisman R. G. , Davis E. R.
Published: March 2006

Three pigeons key pecked under second‐order schedules in which the completion of two successive fixed‐ratio 50 components constituted a reinforcement cycle. Tandem, chained, and brief‐stimulus second‐order schedules were studied when completion of the initial fixed‐ratio 50 component delivered brief intense electric shock in every nth reinforcement cycle and n assumed values between one and nine. During sessions without shock, the brief‐stimulus (unpaired with food) schedule generated higher rates of responding in the initial component than did the tandem schedule. Electric shock engendered increased time to the fifth response and a repeated pause‐run pattern of not responding and responding, particularly in the initial component, even with shock scheduled in every ninth reinforcement cycle. The results were consistent with those reported for shock of a shorter duration scheduled in every reinforcement cycle. The overall rate of responding decreased as a function of increasing shock density and was lower in brief‐stimulus than in tandem schedules.
THE DISCRIMINATIVE CONTROL OF FREE‐OPERANT AVOIDANCE DESPITE EXPOSURE TO SHOCK DURING THE STIMULUS CORRELATED WITH NONREINFO R CEMENT
Authors: Bersh Philip J. , Lambert Joseph V.
Published: March 2006

Four rats were trained in darkness on a free‐operant avoidance procedure in which shocks occurred randomly, but lever presses could reduce their frequency. Discrimination training followed, during which responses in light continued to reduce shock frequency, but responses in darkness had no effect. During each cycle, the light period was 4 min, while darkness lasted only until a 20‐sec interval had elapsed without a response. This no‐response requirement was increased to 40 sec for three animals and eventually to 60 sec for two of them. Discriminative control developed, despite a greater shock density in the dark, with response rate and number of responses per shock maintained or increasing during light and decreasing to very low values in darkness. Two animals were later exposed to a procedure in which shock density was unaffected by responding either in light or darkness. A 60‐sec no‐response requirement was continued in the dark. Discriminative control persisted through 42 sessions for one animal and required 45 sessions to approach extinction for the other animal. The role of the light as a potential conditioned reinforcer of other behavior in the dark was implicated in the development and persistence of discriminative control. These data support shock‐frequency reduction as reinforcement for avoidance behavior.
ANIMAL PSYCHOPHYSICS: IMPROVEMENTS IN THE TRACKING METHOD1
Authors: Harrison J. M. , Turnock M. T.
Published: March 2006

It is difficult to maintain stimulus control in animal psychophysical studies using the tracking method. Loss of stimulus control is characterized by wandering thresholds and responses in the absence of the stimulus. Rats were trained to make a variable number of licking responses to turn on an auditory stimulus. A response on a lever in the presence of the stimulus was reinforced with food. Two procedures were added to improve stimulus control. First, lever responses in the absence of the stimulus raised the intensity of the stimulus at the next presentation; second, rate of reinforcement in the threshold region was maintained at about the same level as that in the suprathreshold region by reducing the number of licking responses required to turn on the stimulus. Using these two procedures, stimulus control was improved and maintained and reliable auditory intensity thresholds were obtained.
INHIBITORY CONTROL AND ERRORLESS DISCRIMINATION LEARNING1
Authors: Karpicke John , Hearst Eliot
Published: March 2006

Pigeons learned to discriminate between a positive stimulus (white key) and a negative stimulus (red or green key, depending on the subject) via Terrace's fading procedure. Generalization tests, conducted with intermittent reinforcement for key pecking at various wavelengths, yielded minima at the value of the negative stimulus in most “errorless” birds. Terrace's contrary finding of flat gradients in errorless subjects probably resulted from a floor‐effect (i.e., virtually zero responding) produced by his extinction‐test procedure. The present and other findings do not support Terrace's conclusions that the negative stimulus of an errorless discrimination is behaviorally neutral; inhibition apparently develops to the nonreinforced stimulus even during errorless discrimination learning. A negative correlation between stimulus and reinforcer seems the crucial factor in producing an inhibitory stimulus.
THE ROLE OF THE PECK‐FOOD CONTINGENCY ON FIXED‐INTERVAL SCHEDULES1
Authors: Staddon J. E. R. , Frank Janice A.
Published: March 2006

Pigeons were trained to peck on a fixed‐interval schedule of food reinforcement and then exposed to three schedules in which there was either no, or an indirect, relation between pecking and food delivery: (a) a conjunctive schedule in which food was delivered at fixed intervals, providing at least one peck was emitted in the interval; (b) a recycling version of the conjunctive schedule that essentially eliminated occasional peck‐food contiguities (recycling conjunctive); (c) delivery of food at fixed intervals independently of the birds' behavior (fixed time). The rates and patterns of pecking sustained by these procedures depended on interfood interval and relative proximity of pecks to food.
KEY PECKING IN PIGEONS PRODUCED BY PAIRING KEYLIGHT WITH INACCESSIBLE GRAIN1
Authors: Zentall Thomas R. , Hogan David E.
Published: March 2006

In Experiment I, keylight was paired with inaccessible grain delivery (under two conditions of keylight intensity) to determine if autoshaping would occur in the absence of primary reinforcement. In Experiment II, the procedure was repeated with accessible grain, for comparison. In Experiment III, the procedures were repeated with explicitly unpaired presentations of keylight and either inaccessible or accessible grain. The results indicated that key pecking occurred as quickly in the presence of keylight pairings with inaccessible grain as with accessible grain, though (except for one bird) key pecking was not maintained with inaccessible grain. Furthermore, compared to the dim keylight, the bright keylight greatly suppressed key pecking when paired with inaccessible grain, and reduced the rate of key pecking when paired with accessible grain. Little key pecking occurred in groups exposed to explicitly unpaired presentations of keylight (whether bright or dim) and grain (whether accessible or inaccessible). When the birds in Experiment III were retested with explicitly paired presentations of keylight and grain, little key pecking was observed, suggesting suppressive effects of prior explicitly unpaired presentations. It is suggested that the effects of key‐brightness manipulation were produced by the association of grain with cues other than the response key, or by distraction produced by partial illumination of the grain hopper.
CONCURRENT ASSESSMENT OF SCHEDULE AND INTENSITY CONTROL ACROSS SUCCESSIVE DISCRIMINATIONS1
Authors: Raslear Thomas G. , Pierrel‐Sorrentino Rosemary , Brissey Catherine
Published: March 2006

Two chinchillas were trained on a series of two‐valued auditory intensity discriminations. Lever presses were reinforced when no tone was present and not reinforced in the presence of a four‐kiloHertz tone. The intensity of the nonreinforced tone was successively decreased, increasing the difficulty of the discrimination, until differential responding resembled that on a mixed schedule (no‐tone‐no‐tone). Response data were partitioned in such a way as to provide a continuing assessment of the relative amounts of control exerted by the reinforcement schedule and the sound intensity, respectively. Control by reinforcement density was a direct function of discrimination difficulty, whereas the control exerted by intensity was inversely related to difficulty. For these chinchillas, the absolute threshold value obtained at four kiloHertz was about two decibels referenced to 20 microNewtons per meter squared.
AUDITORY SENSITIVITY AND EQUAL LOUDNESS IN THE SQUIRREL MONKEY (SAIMIRI SCIUREUS)1
Authors: Green Swayzer
Published: March 2006

The effects of the type of reinforcer on auditory sensitivity and equal‐loudness data were determined in the squirrel monkey. The monkeys, restrained and provided with earphones, were conditioned to depress and hold a bar down in the presence of a stimulus light and then to terminate the holding response after onset of a tone. In Experiment 1, the specified behavior sequence postponed electric shock; in Experiment 2, a food reinforcer was dependent on bar release during the tone. The shape of the auditory sensitivity function and the acuity level at each frequency were the same for the two procedures. The audible frequency range extended from below 0.125 kHz (lowest frequency used) to 46 kHz. Sensitivity was maximum at 8 kHz. Latency of bar release following tone onset served as the basic data for constructing a family of equal‐loudness contours. The type of reinforcer appeared not to be a determinant of either the shape of individual loudness contours or the pattern of family of equal‐loudness functions. At the lower sound‐pressure levels, the equal‐loudness contours closely paralleled the threshold curves. At more‐intense levels, the contours tended to flatten and depend less on frequency.
CONTROL OF RESPONDING BY SOUND LOCATION IN MONKEYS: RAPID ACQUISITION IN DARKNESS1
Authors: Downey Paul , Harrison J. M.
Published: March 2006

Rapid control of responding by sound location is obtained in squirrel monkeys when sound stimuli are presented from one of two loudspeakers, each one adjacent to a response key. With this arrangement of loudspeakers and response keys, squirrel monkeys quickly learn to respond on the key near the source of the sound stimulus, and this pattern is the same whether or not responses near the sound source are differentially reinforced. This result may depend on a pre‐experimental tendency in squirrel monkeys to orient head and eyes toward a sound, which would lead the animal to look at the response key in front of the loudspeaker producing the sound. The present experiment sought to determine whether visual stimuli are necessary for rapid control of responding by sound location. Two monkeys were trained in darkness in a sound‐localization task similar to that described above. Results were similar to those obtained from animals trained in light, indicating that visual stimuli are not required for rapid acquisition of sound‐localization behavior in monkeys.
CONDITIONED SUPPRESSION OF BEHAVIOR MAINTAINED BY INTRACRANIAL STIMULATION AS A FUNCTION OF STIMULATION INTENSITY1
Authors: Russell P. J. D.
Published: March 2006

Conditioned suppression was demonstrated in two experiments with rats lever pressing on a fixed‐ratio 1 schedule for lateral hypothalamic intracranial stimulation (ICS). In Experiment I, conditioned suppression of responding for low‐intensity ICS was obtained with a moderate intensity of foot shock. In Experiment II, low and high intensities of ICS were alternated within the same session and the same animal. The suppression that was exhibited with low‐intensity ICS was minimal or absent with high‐intensity stimulation, despite the pairing of foot shock with each warning stimulus. Conditioned suppression was a function of ICS intensity, and was independent of response rates. The inverse relationship between ICS intensity and degree of suppression is consistent with a motivational analysis of conditioned suppression. Previous reports of resistance to suppression of behaviors maintained by ICS may now be attributed to the use of high‐intensity stimulation.
VOCALIZATIONS OF WHITE CARNEAUX PIGEONS DURING EXPERIMENTS ON SCHEDULE‐INDUCED AGGRESSION1
Authors: Rashotte Michael E. , Katz Harold N. , Griffin Robert W. , Wright Anita C.
Published: March 2006

Two types of vocalizations of White Carneaux pigeons were identified in experiments on schedule‐induced aggression and were given pictorial representation in sound spectrograms. Characteristics of these vocalizations are examined in the context of previous descriptions of vocalizations of several varieties of pigeons during aggressive and sexual encounters in naturalistic settings. These earlier descriptions portrayed vocalizations with mnemonic phrases and the symbols of dictionary pronunciation. Data are presented that indicate that the analysis of social encounters between pigeons during schedule‐induced aggression may be aided by employing these and other vocalizations as dependent variables.
REINFORCEMENT OF BEHAVIORAL PATTERNS: SHAPING A SCALLOP1
Authors: Hawkes Larry , Shimp Charles P.
Published: March 2006

Temporal patterns of key pecking by pigeons were shaped by a schedule in which the delivery of food was contingent upon a measure of the overall extent to which the temporal pattern of behavior within a 5‐sec trial conformed to a required pattern. This pattern approximated a constant rate of change in the rate of key pecking throughout the 5‐sec trial. In comparison with behavior maintained by a classical fixed‐interval 5‐sec schedule, the new schedule controlled a better approximation to a “scallop” within individual trials and greatly reduced intersubject variability. These results are consistent with the view that the delivery of a reinforcer after a behavioral pattern a few seconds in duration may strengthen the entire pattern as a unit, or operant. The response topography contiguous with reinforcement may be a negligible fraction of the strengthened operant. One implication of this view is that mean response rate for such brief responses as key pecks and lever presses is a byproduct of whatever patterns are strengthened, and generally will not reveal fundamental controlling relationships, whenever a reinforcer is not contiguous with all the behavior on which it is contingent.
CHOICE AND RESPONSE CONTINGENCIES1
Authors: Moore Jay , Fantino Edmund
Published: March 2006

Two experiments investigated the extent to which response contingencies influence the choice between two schedules of reinforcement by exposing pigeons to a concurrent‐chains procedure in which reinforcers in one terminal link were response‐independent, and in the other terminal link, response‐dependent. In Experiment 1, the pigeons were indifferent between an aperiodic, response‐independent schedule and an aperiodic, response‐dependent schedule that required a minimum rate of responding. This finding limits the generality of a required‐rate contingency as a determinant of choice, which contingency had been previously demonstrated in a context of periodic reinforcement to evoke preference for an alternate schedule. In Experiment 2, the pigeons preferred a periodic, response‐independent schedule to a periodic, response‐dependent schedule that shared a feature with a required‐rate schedule: there was a requirement to respond early in the interreinforcement interval, when responding produced reinforcement only later. The results of the two experiments suggest the following general interpretation: pigeons prefer a second schedule to the extent that the response contingencies of the first schedule must be satisfied during discriminable periods of nonreinforcement.
CHOICE FOR SIGNALLED OVER UNSIGNALLED SHOCK AS A FUNCTION OF SHOCK INTENSITY1
Authors: Harsh John , Badia Pietro
Published: March 2006

Choice between a signalled shock schedule and an unsignalled one was examined at various shock intensities. Three rats were given the opportunity to change from the unsignalled schedule to the signalled one at intensity values between 0.15 mA and 1.0 mA. Steps were usually 0.15 mA and both ascending and descending series were given. For two other rats, shock intensity increased from 0.20 mA to 1.0 mA in 0.20‐mA increments; for two additional rats, shock intensity was first 3.0 mA and was then reduced to 1.0 mA. Subjects tended to remain in the unsignalled schedule at the lower shock intensities, but spent most of each session under the signalled schedule at the higher intensities (1.0 mA and 3.0 mA). In addition, the time spent in the signalled schedule tended to vary systematically with shock intensity over at least part of the range of intensity values. It was concluded that the relationship between shock intensity and choice behavior is similar to the relationship between intensity and behavior in procedures involving avoidance, escape, and punishment.
BEHAVIORAL SIMILARITY AS A REINFORCER FOR PRESCHOOL CHILDREN
Authors: Gladstone Bruce W. , Cooley James
Published: March 2006

Three experiments evaluated whether behavioral similarity provided by an adult could serve as a reinforcer for the modelling behavior of four preschoolers. In each experiment, sessions consisted of two kinds of trials: (1) experimenter‐modelled trials, when the child's imitation of modelled motor responses was reinforced with praise and tokens, and (2) child‐modelled trials when experimenter imitation of child‐modelled responses was contingent upon the child's modelling one of three alternative responses: operation of a ball, horn, or clicker. Experiment I showed that the children consistently modelled whichever responses the experimenter imitated. Experiment II determined whether that performance was due to differences in the amount of experimenter behavior following imitated versus nonimitated child models or to experimenter imitation. Neither reducing nor increasing the amount of experimenter behavior following the children's nonimitated models altered their modelling of imitated responses. Experiment III evaluated whether experimenter imitation of child models was a reinforcer because the child's imitative responses were reinforced on experimenter‐modelled trials. In Experiment III, the children's nonimitation of experimenter‐models was reinforced with praise and tokens on a schedule of differential reinforcement of other behavior, yet they continued to model experimenter‐imitated responses on child‐modelled trials. These results indicate behavioral similarity was reinforcing, though no conditioning history through which it acquired that function was demonstrated.
THE EFFECTS OF VARYING THE DISTRIBUTION OF GENERALIZATION STIMULI WITHIN A CONSTANT RANGE UPON THE BISECTION OF A SOUND‐INTENSITY INTERVAL BY RATS1
Authors: Raslear Thomas G.
Published: March 2006

Two male, albino rats were trained on a two‐valued, self‐paced, discrete‐trials auditory discrimination. In the presence of a high‐intensity stimulus (90 decibels SPL, 4 kiloHertz), response A was reinforced; in the presence of a low‐intensity stimulus (50 decibels SPL, 4 kiloHertz), response B was reinforced. When discrimination performance was asymptotic, stimuli intermediate in intensity were presented with the training stimuli in a maintained generalization paradigm. Generalization gradients were derived from the relative frequencies of response A in the presence of each stimulus. A relative frequency of 0.50 was then determined and used as the bisection point of the intensity interval defined by the 90‐ and 50‐decibel stimuli. The bisection point varied with the distribution of the stimuli presented in generalization. This effect was similar to context effects seen in human psychophysics.
THE REINFORCEMENT VALUE OF SCHEDULE‐INDUCED DRINKING1
Authors: Cohen Ira L.
Published: March 2006

The effect of food reinforcement schedules on the reinforcement value of drinking water was evaluated. Food‐deprived rats were exposed to concurrent, identical variable‐time schedules of food presentation, the food thus being delivered independently of the rats' behavior. When the relative amount of time spent in a schedule component stabilized, an opportunity to drink water was introduced into one schedule component. The value of the variable‐time schedules was varied from 60 to 90 to 270 sec. The relative amount of time spent in the schedule component associated with drinking water was a decreasing function of food frequency for two animals and remained constant for the third. Drinking rates were direct functions of food frequency, and the amount of water drunk per pellet was an inverse function of food frequency. The reinforcement value of drinking water, according to the Matching Law, was a direct function of the frequency of food presentation. It was concluded that food reinforcement schedules indirectly influence rates of drinking by altering the reinforcement value of drinking water and that certain properties of schedule‐induced drinking can be accounted for in terms of the reinforcement value of drinking water, the rate of drinking, and the frequency of food presentation.
POSITIVE AND NEGATIVE BEHAVIORAL CONTRAST IN THE RAT1
Authors: Gutman Arthur , Sutterer James R. , Brush F. Robert
Published: March 2006

Three groups of rats received either 8, 23, or 53 sessions of multiple variable‐interval variable‐interval baseline training before being shifted to a multiple extinction variable‐interval schedule. The rate of responding during the unaltered component was higher for the groups shifted to multiple extinction variable‐interval than for control groups remaining on multiple variable‐interval variable‐interval (positive contrast). Furthermore, when the multiple variable‐interval variable‐interval schedule was re‐instated, stable negative contrast was found in the groups that had received 23 or 53 baseline sessions, but not for the group that had received only eight sessions. Positive and negative contrast were also demonstrated in the eight and 23‐session groups when the multiple extinction variable‐interval and multiple variable‐interval variable‐interval schedules were re‐administered in further phases of the experiment. These results suggest that both positive and negative behavioral contrast can be obtained reliably in a species other than the pigeon.
REPEATED ACQUISITION OF RESPONSE SEQUENCES: STIMULUS CONTROL AND DRUGS1
Authors: Thompson Donald M.
Published: March 2006

Pigeons obtained food by making four responses on three keys in a specified sequence, e.g., left, right, center, right. Under the “tandem‐learning” condition, all three keys were the same color throughout the response sequence, and the sequence was changed from session to session. After total errors per session (overall accuracy) and within‐session error reduction (learning) had stabilized, the effects of varying doses of phenobarbital and chlordiazepoxide were assessed. For comparison, the drug tests were also conducted under a “performance” condition, in which the response sequence was the same from session to session, and under corresponding “chain‐learning” and “chain‐performance” conditions, where different colored keylights were associated with the response sequence. Under all four baseline conditions, the largest dose of each drug impaired overall accuracy. Under the two learning conditions, the error rate decreased across trials within each session, but the degree of negative acceleration was less in the drug sessions than in the control sessions. In contrast, under the two performance conditions, the error rate was relatively constant across trials, but was higher in the drug sessions than in the control sessions. Of the four baselines, the chain‐learning condition was the most sensitive to the drug effects.
PARTIAL AVOIDANCE CONTINGENCIES1
Authors: Neffinger G. G. , Gibbon John
Published: March 2006

Rats were trained in a discrete‐trial paradigm with no intertrial interval. The first response changed an auditory stimulus for the remainder of the trial. Shocks were delivered only at the end of the trial cycle. Avoidance contingencies were defined by the conditional probability of shock, given no response (P0), and the conditional probability of shock given a response (P1). The maximal avoidance contingency was P0 = 1.0, P1 = 0, and noncontingent conditions were those for which P0 = P1. In Experiment I, after training on the maximal contingency, three groups of subjects experienced either P0 = P1 = 0, P0 = P1 = 0.5, or P0 = P1 = 1.0. Eight of 10 subjects stopped responding under the noncontingent conditions. Experiment II studied partial contingencies by varying P0 and P1. For one group, P0 was reduced holding P1 = 0. Responding decreased to zero as P0 approached zero. A second group was studied under P1 > 0, holding P0 = 1.0. For three of the six rats in this group, responding decreased to zero with increasing P1. The other three maintained responding as P1 was increased up to the noncontingent, P1 = P0 = 1.0 value. The P0 group was also studied with P0 = P1 > 0, and half of these subjects responded. The results demonstrated two modes of response to weakening or eliminating the avoidance contingency. Some subjects were sensitive to contingency only, and insensitive to changes in shock density. Approximately one half of the subjects were sensitive to both contingency and shock density. This shared control was observed only when P1 > 0.
TIME ALLOCATION IN HUMAN VIGILANCE1
Authors: Baum William M.
Published: March 2006

Three human subjects detected unpredictable signals by pressing either of two telegraph keys. The relative frequencies with which detections occurred for the two alternatives were varied. The procedure included a changeover delay and response cost for letting go of a key. All subjects matched the relative time spent holding each key to the relative number of detections for that key, in conformity with the matching law. One subject's performance, which at first deviated from the relation, came into conformity with it when response cost was increased. Another subject's performance approximated matching more closely when the changeover delay was increased. The results confirm and extend the notions that choice consists in time allocation and that all behavior can be measured on the common scale of time.
COMPOUNDING OF DISCRIMINATIVE STIMULI CORRELATED WITH CHAINED AND MULTIPLE SCHEDULES1
Authors: Miller Laurence
Published: March 2006

In studies of stimulus compounding (1) the stimuli are presented randomly, (2) primary reinforcement is correlated with each stimulus, (3) a specific response is emitted during each stimulus, and (4) the response is necessary to produce the reinforcer. The present experiments assessed the importance of these procedures by (1) presenting light and tone stimuli in fixed order, (2) removing reinforcement (food) during one stimulus, (3) preventing the response (lever pressing) from being emitted, and (4) eliminating the contingency between lever pressing and food. These variables were presented in various combinations within the context of chained and multiple schedules. When the stimuli were combined in the schedule component correlated with each stimulus, the frequency of lever pressing increased in most instances (additive summation). This suggests that the effect of combining stimuli was not closely tied to the specific procedures used in previous experiments. However, presenting the stimuli in a fixed order did have an effect: the level of responding to the compound was generally greatest when the stimuli were combined in the component correlated with the higher frequency of lever pressing to the single stimulus. Additive summation failed to occur consistently when response‐independent food was correlated with each stimulus, and when both lever pressing and food were eliminated during one stimulus.
UNEQUAL REINFORCER MAGNITUDES AND RELATIVE PREFERENCE FOR COOPERATION IN THE DYAD1
Authors: Shimoff Eliot , Matthews Byron A.
Published: March 2006

College‐student subjects, who were paired with a confederate, chose to respond either independently or cooperatively for money reinforcers. The subject's relative preference for cooperation was assessed by a procedure (analogous to the psychophysical method of limits) in which response choice was monitored as reinforcer magnitude for one response mode was systematically varied while the other remained constant. Relative preference for cooperation was assessed when the confederate's payoff for cooperation was greater than the subject's (Experiment I) and when the confederate's payoff for independent responding was less than the subject's (Experiment II). For some subjects, changes in the confederate's reinforcer magnitudes resulted in shifts in relative preference for cooperation, which reduced the earnings differences, even though these preference shifts reduced the subject's absolute earnings. For those subjects for whom within‐dyad differences in reinforcer magnitude produced no effect, a changeover button was introduced that allowed the subject to eliminate the payoff difference without reducing her own earnings; some subjects used this changeover button to eliminate earnings differences. Thus, the behavior of subjects varied, in part, as a function of reinforcer magnitudes provided for the confederate.
MAXIMIZING AND MATCHING ON CONCURRENT RATIO SCHEDULES1
Authors: Herrnstein R. J. , Loveland Donald H.
Published: March 2006

Pigeons on concurrent variable‐ratio variable‐ratio schedules usually, though not always, maximize reinforcements per response. When the ratios are equal, maximization implies no particular distribution of responses to the two alternatives. When the ratios are unequal, maximization calls for exclusive preference for the smaller ratio. Responding conformed to these requirements for maximizing, which are further shown to be consistent with the conception of reinforcement implicit in the matching law governing relative responding in concurrent interval schedules.
INHIBITORY STIMULUS CONTROL FOLLOWING ERRORLESS DISCRIMINATION LEARNING1
Authors: Rilling Mark , Caplan Harry J. , Howard R. C. , Brown Charles H.
Published: March 2006

Three generalization procedures were used to investigate inhibitory stimulus control following discrimination learning with few errors. Three groups of pigeons acquired a discrimination between a green stimulus (the positive stimulus) and a vertical or horizontal line (the negative stimulus) through differential autoshaping followed by multiple schedule presentation of the two stimuli with gradually increasing stimulus durations. Genereralization testing was along a line‐tilt continuum. For one group, the test involved a resistance‐to‐reinforcement procedure in which responses to all line tilts were reinforced on a variable‐interval schedule. For a second group, also tested with the resistance‐to‐reinforcement procedure, the lines were superimposed on the green field that formerly served as the positive stimulus. A third group was tested in extinction with the combined stimuli. Control groups had no discrimination training but responding to green was nondifferentially reinforced. The control subjects responded more to all line tilts during testing than did the comparable experimental subjects, indicating that the negative stimulus had become an inhibitory stimulus. Both resistance‐to‐reinforcement groups revealed inhibitory gradients around the negative stimulus, but the gradient for the extinction group was relatively flat. These data are consistent with others that modify Terrace's early conclusion concerning the failure of inhibition to develop during errorless training.
TRANSFER OF HUE MATCHING IN PIGEONS1
Authors: Urcuioli Peter J. , Nevin John A.
Published: March 2006

Pigeons were trained on a modified three‐key matching‐to‐sample procedure, in which only one comparison key (rather than two) was lighted after an observing response to the center‐key standard. Pecks on keys of matching comparison hues were reinforced. When nonmatching hues appeared as the initially lighted comparisons, the nonmatching hue terminated and the matching hue appeared on the other side key only if the pigeon did not peck the nonmatching comparison for 4.8 sec. Pecks to the nonmatching hue reset the 4.8‐sec delay interval. Three hues were used during acquisition. During transfer tests, two novel hues were substituted individually or together for one or two of the training hues. Latencies to the novel side‐key hue were shortest when a novel matching hue appeared as the standard on the center key, and were essentially identical to baseline matching latencies. In contrast, when a novel hue appeared as either a standard or comparison in a nonmatching combination, latencies increased with increasing separation between the novel hue and the nonmatching hue. These transfer data demonstrate the concept of hue matching.
SECOND‐ORDER SCHEDULES: DISCRIMINATION OF COMPONENTS,1
Authors: Squires Nancy , Norborg James , Fantino Edmund
Published: March 2006

Pigeons were exposed to a series of second‐order schedules in which the completion of a fixed number of fixed‐interval components produced food. In Experiment 1, brief (2 sec) stimulus presentations occurred as each fixed‐interval component was completed. During the brief‐stimulus presentation terminating the last fixed‐interval component, a response was required on a second key, the brief‐stimulus key, to produce food. Responses on the brief‐stimulus key before the last brief‐stimulus presentation had no scheduled consequences, but served as a measure of the extent to which the final component was discriminated from preceding components. Whether there were one, two, four, or eight fixed‐interval components, responses on the brief‐stimulus key occurred during virtually every brief‐stimulus presentation. In Experiment 2, an attempt was made to punish unnecessary responses on the brief‐stimulus key, i.e., responses on the brief‐stimulus key that occurred before the last component. None of the pigeons learned to withhold these responses, even though they produced a 15‐sec timeout and loss of primary reinforcement. In Experiment 3, different key colors were associated with each component of a second‐order schedule (a chain schedule). In contrast to Experiment 1, brief‐stimulus key responses were confined to the last component. It was concluded that pigeons do not discriminate well between components of second‐order schedules unless a unique exteroceptive cue is provided for each component. The relative discriminability of the components may account for the observed differences in initial‐component response rates between comparable brief‐stimulus, tandem, and chain schedules.
STIMULUS CHANGE AS A FACTOR IN RESPONSE MAINTENANCE WITH FREE FOOD AVAILABLE
Authors: Osborne Steve R. , Shelby Michael
Published: March 2006

Rats bar pressed for food on a reinforcement schedule in which every response was reinforced, even though a dish of pellets was present. Initially, auditory and visual stimuli accompanied response‐produced food presentation. With stimulus feedback as an added consequence of bar pressing, responding was maintained in the presence of free food; without stimulus feedback, responding decreased to a low level. Auditory feedback maintained slightly more responding than did visual feedback, and both together maintained more responding than did either separately. Almost no responding occurred when the only consequence of bar pressing was stimulus feedback. The data indicated conditioned and sensory reinforcement effects of response‐produced stimulus feedback.
SHORT‐COMPONENT MULTIPLE SCHEDULES: EFFECTS OF RELATIVE REINFORCEMENT DURATION1
Authors: Merigan William H. , Miller Jay S. , Gollub Lewis R.
Published: March 2006

Pigeons were exposed to multiple variable‐interval 2‐min variable‐interval 2‐min schedules of food presentation in which relative duration of food presentation was manipulated. When components alternated every 5 sec and were scheduled on separate response keys, relative response rates closely matched relative reinforcement duration in three of four pigeons. On the other hand, relative response rates were insensitive to relative reinforcement duration when components scheduled on a single response key alternated every 5 sec, and when components scheduled on separate response keys alternated every 2 min. Thus, both rapid alternation and spatial separation of components were necessary to produce approximate matching of relative responding to relative reinforcement duration. This finding contrasts with previous findings that only rapid component alternation is necessary for matching when relative rate of reinforcement is manipulated.
BEHAVIORAL CONTRAST IN THE PIGEON: A STUDY OF THE DURATION OF KEY PECKING MAINTAINED ON MULTIPLE SCHEDULES OF REINFORCEMENT1
Authors: Schwartz Barry , Hamilton Bruce , Silberberg Alan
Published: March 2006

Pecks on an operant key were reinforced on either multiple variable‐interval variable‐interval or multiple variable‐interval extinction schedules of reinforcement. The stimuli that signalled the multiple‐schedule components were located on a second key (signal key), and a changeover delay prevented reinforcement of signal key‐peck—operant key‐peck sequences. No behavioral contrast was observed on the operant key, and appreciable responding to the signal key occurred during the variable‐interval component of the multiple variable‐interval extinction procedure. Peck durations on the signal key were markedly shorter than peck durations on the operant key. Moreover, most responses on the signal key occurred just after the multiple‐schedule components changed. These data support an account of behavioral contrast in terms of the summation of pecks that are separately controlled by stimulus‐reinforcer and response‐reinforcer dependencies, and suggest that the stimulus‐reinforcer dependency is responsible primarily for local contrast. In addition, the data suggest that pecks that are controlled by these two dependencies may belong to topographically different classes.
MAINTENANCE OF BEHAVIOR CONTROLLING THE DURATION OF DISCRIMINATIVE STIMULI1
Authors: Leyland C. Mark , Honig Werner K.
Published: March 2006

The maintenance of a response controlling the duration of positive and negative discriminative stimuli in a multiple schedule was examined with respect to the possible consequences of the response: none, escape from the negative stimulus, production of the positive stimulus, and initiation of the reinforcement schedule associated with the latter. The last two seemed to be the major factors in producing and maintaining the response. Escape from the negative stimulus maintained it in most subjects, but only at a much lower level.
CONJUNCTIVE SCHEDULES OF REINFORCEMENT II: RESPONSE REQUIREMENTS AND STIMULUS EFFECTS1
Authors: Barrett James E.
Published: March 2006

Responding of three pigeons was maintained under conjunctive fixed‐ratio, fixed‐interval schedules where a key peck produced food after both schedule requirements were completed. The individual schedule requirements were then successively removed and reinstated with responding maintained under the following conditions: conjunctive fixed‐ratio, fixed‐time; fixed‐time; and fixed‐interval schedules. Patterns of responding changed in accord with the successive removal of the schedule requirements. Compared to the conjunctive fixed‐ratio, fixed‐interval schedule, pause duration increased and response rate decreased under conjunctive fixed‐ratio, fixed‐time schedules and under fixed‐time schedules alone. Overall mean rates of responding were highest and pause duration lowest under fixed‐interval schedules. When changes in the keylight colors were correlated with completion of the fixed‐ratio, the end of the fixed‐interval, or both of these conditions, the pattern of responding was modified and indicated a greater degree of control by the individual schedules. Although two birds showed large increases in interreinforcement time when they were initially exposed to the conjunctive schedule, when responding stabilized this measure was largely invariant for all birds across most schedule conditions.
A METHOD FOR THE OBJECTIVE STUDY OF TOOL‐USING BEHAVIOR
Authors: Powell Robert W. , Kelly William
Published: March 2006

Key pecking for food was shaped in four crows within a conventional operant‐conditioning test chamber. When pecking stabilized, a metal screen with openings 2.5 cm high by 1.0 cm wide, was placed over the response key, so that the crow could still see but could no longer peck the key. At the same time, several dozen wooden matchsticks, which could be used to operate the key, were placed in the test chamber. The crows made no use of these during 50 to 75 hr of exposure to this condition. Subsequently, the behavior of two crows was shaped so that they approached the matchsticks, picked one up in their beaks, approached the response key with the matchstick in their beak, and finally operated the response key by poking the matchstick through the screen. This shaping procedure was ineffective with the two other crows. However, these birds were successfully trained through positional fading of the tool. This involved suspending a metal rod from the ceiling so that it hung directly in front of the response key, and the crow had only to peck it to operate the key. Then, the rod was gradually lowered by lengthening its tether until it eventually rested on the floor of the test chamber. The principal advantage of this methodology is the automatic recording of the terminal (tool‐using) behavior under study.
PERSISTENCE OF ACQUIRED BEHAVIORAL CONTROL IN THE CONTEXT OF IMPRINTING1
Authors: Eiserer Leonard A. , Hoffman Howard S. , Klein Sandra H.
Published: March 2006

Newly hatched Khaki Campbell ducklings (Anas platyrhynchos domesticus) were exposed to a moving object that immediately suppressed distress vocalizations occurring in a novel environment. The static visual and auditory features of this object acquired the ability to suppress distress vocalizations after eight 20‐min sessions of exposure to the object in motion. The acquired suppressive properties of these features were found to persist throughout thirty 20‐min sessions given over 10 days. During these sessions, the ducklings were continually exposed to the static features in the absence of visual movement. In a second experiment, the ability of these features to serve as reinforcement for a pecking response was shown to persist for up to 56 hr. In one duckling, presentations of the static visual features did not maintain pecking behavior. However, it was shown that pecking responses could be re‐instated in this duckling by introducing novel stimuli to the environment.
BEHAVIORAL CONTRAST IN RATS WITH DIFFERENT REINFORCERS AND DIFFERENT RESPONSE TOPOGRAPHIES1
Authors: Beninger Richard J. , Kendall Stephen B.
Published: March 2006

Experiment I demonstrated positive behavioral contrast in rats when one of two qualitatively different reinforcers (milk and pellets) was removed from a component of a multiple schedule. The contrast effect was larger and more enduring when milk was removed. Experiment II showed that the rats spent more time on the side of a shuttle‐box on which milk was freely available than on the side on which pellets were freely available. Experiment III, a partial replication of Experiment I, failed to demonstrate the contrast effect of Experiment I. Experiment IV demonstrated contrast when two topographically distinct responses, nose‐key poking and lever pressing, were required in different components of a multiple schedule. These results extend the conditions that generate behavioral contrast in rats.