bluuebunny/crossref_metadata_2025 huggingface dataset:
RELATION BETWEEN LEVEL OF FOOD DEPRIVATION AND RATE OF SCHEDULE‐INDUCED ATTACK1
Authors: Dove L. Duane
Published: March 2006

The relation between food deprivation and schedule‐induced attack was investigated in four White Carneaux pigeons. Attack toward a mirror target was induced by a schedule of reinforcement in which 3‐sec food presentations occurred at alternate intervals of 15 and 120 sec (multiple fixed‐time 15‐sec fixed‐time 120‐sec schedule). A continuous tone was presented during the 15‐sec periods; it was absent during the 120‐sec periods. Each pigeon was tested at 65, 80, and 95% of its free‐feeding weight in ascending, descending, and ascending orders, respectively. Two relations were apparent; an inverse relation between body weight and rate of attack, and a tendency for rate of attack to increase during the experiment. Reduction or elimination of attack when the mirror was covered with brown paper for some sessions indicated that the results were due neither to changes in activity that might covary with weight nor to habituation to the experimental situation.
CHOICE AND THE RATE OF PUNISHMENT IN CONCURRENT SCHEDULES1
Authors: Deluty Marvin Z.
Published: March 2006

Rats' responses on two levers were reinforced according to independent random‐interval 1.5‐min food schedules. In addition, both lever presses were intermittently punished according to several concurrent random‐interval random‐interval shock schedules. For the left, the scheduled rate of punishment was kept constant according to a random‐interval 6‐min schedule. For the right, the rate of punishment varied. As the frequency of punishment for the right lever press increased, its rate decreased. The rate of the left punished lever press increased, however, even though its scheduled reinforcement rate and punishment rate remained unchanged.
THE ASSOCIATIVE RELATION UNDERLYING AUTOSHAPING IN THE PIGEON1
Authors: Woodruff Guy , Williams D. R.
Published: March 2006

Fifteen pigeons were exposed to either response‐independent or response‐dependent schedules of water reinforcement, whereby water was injected directly into the unrestrained pigeons' mandibles. Key‐contact responses were released by a lighted key correlated with water, but not by a lighted key uncorrelated with water. A negative response‐reinforcer contingency suppressed autoshaped key‐contact responses, resulting in responding directed away from the lighted key. In all pigeons, water injected directly into the mandibles elicited a consummatory fixed‐action pattern of “mumbling” and swallowing. The lighted key correlated with water released a broader set of both appetitive and consummatory responses: approach to the lighted key, “bowing”, “rooting”, “mumbling”, and swallowing. Key‐contact responses were “rooting” and “mumbling” motions of the beak on the surface of the key. Views of autoshaping based on stimulus substitution or stimulus surrogation do not fully explain the origin of autoshaped responses not previously elicited by the reinforcer. The present findings are consonant with views of conditioning that emphasize the large degree of biological pre‐organization in conditioned response patterns, and the importance of associative factors in the control of such patterns.
SCALING OF STIMULUS DURATION BY PIGEONS1
Authors: Stubbs D. Alan
Published: March 2006

Pigeons were presented with a series of key‐illumination time periods. During these periods two response keys were lit, one by white light and the other by red or green. White‐key responses changed the color on the other key and green‐ and red‐key responses intermittently produced food. Choice responses were reinforced at either of two intervals timed from the onset of the stimulus period. Food was scheduled for green responses during the shorter interval in some stimulus periods and food was scheduled for red‐key responses at the longer interval during alternate stimulus periods. The temporal location of food in the stimulus periods was varied across conditions. Across conditions, the pigeons responded on the green key until the time at which green‐key responses might be reinforced had passed; then, the probability of red‐key responses increased as the time approached at which red‐key responses might be reinforced. In all conditions, the pigeons, changed from green‐key to red‐key responses at the time that was an equal relative temporal distance from the two intervals where these responses were reinforced.
PUNISHMENT OF RESPONDING UNDER SCHEDULES OF STIMULUS‐SHOCK TERMINATION: EFFECTS OF d‐AMPHETAMINE AND PENTOBARBITAL1
Authors: Mckearney James W.
Published: March 2006

Responding maintained in squirrel monkeys under 5‐min fixed‐interval schedules of either food presentation or termination of a visual stimulus associated with electric‐shock delivery was suppressed by presenting an electric shock for every thirtieth response (punishment). In monkeys responding under the schedule of food presentation, d‐amphetamine sulfate only further decreased punished responding, and pentobarbital sodium markedly increased punished responding, as expected from previous reports. In monkeys responding under the schedule of stimulus‐shock termination, however, the effects of the two drugs were opposite: d‐amphetamine markedly increased punished responding, whereas pentobarbital only decreased responding. Thus, the effects of these drugs on punished responding were different depending on the type of event maintaining responding. These and previous results indicate that it may be misleading and inaccurate to speak of the effects of drugs on “punished responding” as though punishment were a unitary phenomenon. As with any behavior, the effects of drugs and other interventions on punished responding cannot be accurately characterized independently of the precise conditions under which the behavior occurs.
DIFFERENTIAL SAMPLE RESPONSE SCHEDULES IN THE ACQUISITION OF CONDITIONAL DISCRIMINATIONS BY PIGEONS1
Authors: Cohen Leila R. , Looney Thomas A. , Brady John H. , Aucella Arlene F.
Published: March 2006

Pigeons were trained on four matching‐to‐sample tasks with various schedule requirements in effect on the sample key. Differential sample‐schedule requirements (a differential‐reinforcement‐of‐low‐rates of 3 sec in the presence of one sample and a fixed‐ratio 16 in the presence of the other) produced rapid rates of acquisition that did not differ across tasks. Nondifferential sample‐schedule requirements (fixed‐ratio 1, fixed‐ratio 16 or a differential‐reinforcement‐of‐low‐rates of 3 sec in the presence of both samples) produced slower rates of acquisition, which depended on the difficulty of the discriminations between samples and between comparisons. Patterns of stimulus and position preferences were influenced both by the comparison stimuli in each task and by the sample‐schedule requirements. Detailed analyses of acquisition revealed frequent instances of complete differential sample control of comparison responding at intermediate levels of overall “accuracy”.
PRODUCING A CHANGE FROM COMPETITION TO SHARING: EFFECTS OF LARGE AND ADJUSTING RESPONSE REQUIREMENTS1
Authors: Olvera Dennis R. , Hake Don F.
Published: March 2006

Pairs of high‐school students matched‐to‐sample for money. On each trial, the first pair member to complete a fixed ratio of knob‐pulling responses could work the matching problem on that trial. Competition occurred when both pair members responded for the problem. Sharing occurred when only one pair member responded on each trial, and the subjects alternated trials. Hence, sharing requires less responding and still allows a moderate number of reinforcers for each subject. Recent research has shown that increasing the response requirement to the point that it may have aversive properties will produce a change from competition to sharing. A related variable is an adjusting schedule that adjusts the subjects' response requirements so that their abilities to take reinforcers are equal. In this way, subjects might learn that competition requires more responding but produces no more reinforcers. However, recent research also suggests that competition decreases over sessions without experimental manipulations. Because of this possibility of a time‐related variable, ratio size and an adjusting schedule were studied in a group design. Competition did decrease for all groups over sessions, but the large‐ratio groups switched from competition to sharing sooner than the low‐ratio groups. The adjusting schedule had a similar but smaller effect.
POSITIVE REINFORCEMENT AND THE ELIMINATION OF REINFORCED RESPONSES1
Authors: Zeiler Michael D.
Published: March 2006

Key pecking was maintained on a fixed‐interval schedule while either a differential‐reinforcement‐of‐not‐responding or a fixed‐time schedule was imposed simultaneously. The lower the time parameter of the not‐responding schedule, the lower was the response rate. Similar effects occurred with the fixed‐time schedule, if the pigeons had experience with reinforcement for not responding. Otherwise the effects were less orderly, to the extent that rate could reach maximum with the lowest‐valued fixed‐time schedule. The not‐responding and the response‐independent schedules had similar effects on rate in experienced pigeons only when the time parameter or nominal frequency of food presentation was considered. When considered in terms of obtained frequency of food presentation, reinforcement of not responding produced larger decrements in rate than did the fixed‐time schedule.
INTEGRATED DELAYS TO SHOCK AS NEGATIVE REINFORCEMENT1
Authors: Lewis Paul , Gardner Edward T. , Hutton Larrie
Published: March 2006

Rats were shocked at the rate of two per minute until they pressed a lever. In Experiment I, shocks were delivered at variable‐time intervals averaging 30 sec; in Experiment II, shocks were delivered at fixed‐time intervals of 30 sec. A response produced an alternate condition for a fixed‐time period. The shock frequency following a response, calculated over the whole alternate condition, was two per minute. The pattern of shocks in the alternate condition was controlled so that the first shock occurred at the same time as it would have occurred had the response not been emitted; the remaining shocks were delayed until near the end of the alternate condition. Bar pressing was acquired in both experiments. This finding is not explained by two‐factor theories of avoidance and is inconsistent with the notion that overall shock‐frequency reduction is necessary for negative reinforcement. The data imply that responding is determined by the integrated delays to each shock following a response versus the integrated delays to shock in the absence of a response.
LOCAL CONTRAST AND PAVLOVIAN INDUCTION1
Authors: Malone John C.
Published: March 2006

Two experiments examined the effects of number and similarity of stimuli on local contrast. In the first experiment, local contrast effects differed in magnitude as a function of the similarity among stimuli; greater positive local contrast appeared when stimuli were less similar, though this effect sometimes reversed for very dissimilar stimuli. In the second experiment, both positive and negative local contrast appeared transiently during the course of training a discrimination including two quite dissimilar stimuli. When two new stimuli were added, both effects reappeared in several cases. The effects remained when the discrimination was rendered more difficult by substituting a new stimulus very similar to one of the original pair. These and other data suggest that local contrast depends on the same factors that produce Pavlovian induction; in the absence of an alternative account, Pavlov's interpretation may be useful in suggesting further research that will help identify the mechanisms involved in both classical and operant discrimination learning.
A TEST OF THE REINFORCING PROPERTIES OF STIMULI CORRELATED WITH NON REINFORCEMENT1
Authors: Katz Harold N.
Published: March 2006

The information hypothesis of conditioned reinforcement predicts that a stimulus that “reduces uncertainty” about the outcome of a trial will acquire reinforcing properties, even when the stimulus reliably predicts nonreinforcement. Four pigeons' key pecks produced one of two 5‐sec stimuli with 0.50 probability according to a discriminated variable‐interval schedule. One stimulus was followed by reinforcement; a second stimulus was followed by blackout. To the same extent, therefore, both stimuli reduced uncertainty about the possibility that food would arrive at the termination of the schedule interval. When a second key in the chamber was lighted, each peck on it could produce the stimulus preceding reinforcement, the stimulus preceding nonreinforcement, a novel stimulus, or no stimulus, across separate conditions. The stimulus preceding food maintained responding at substantial levels on the second, stimulus‐producing, key. Such responding was not maintained by other stimuli. These data, replicated when the stimuli were reversed on the variable‐interval schedule, do not support the prediction that uncertainty‐reducing stimuli are necessarily conditioned reinforcers.
AUTOSHAPING, RANDOM CONTROL, AND OMISSION TRAINING IN THE RAT1
Authors: Locurto Charles , Terrace H. S. , Gibbon John
Published: March 2006

The role of the stimulus‐reinforcer contingency in the development and maintenance of lever contact responding was studied in hooded rats. In Experiment I, three groups of experimentally naive rats were trained either on autoshaping, omission training, or a random‐control procedure. Subjects trained by the autoshaping procedure responded more consistently than did either random‐control or omission‐trained subjects. The probability of at least one lever contact per trial was slightly higher in subjects trained by the omission procedure than by the random‐control procedure. However, these differences were not maintained during extended training, nor were they evident in total lever‐contact frequencies. When omission and random‐control subjects were switched to the autoshaping condition, lever contacts increased in all animals, but a pronounced retardation was observed in omission subjects relative to the random‐control subjects. In addition, subjects originally exposed to the random‐control procedure, and later switched to autoshaping, acquired more rapidly than naive subjects that were exposed only on the autoshaping procedure. In Experiment II, subjects originally trained by an autoshaping procedure were exposed either to an omission, a random‐control, or an extinction procedure. No differences were observed among the groups either in the rate at which lever contacts decreased or in the frequency of lever contacts at the end of training. These data implicate prior experience in the interpretation of omission‐training effects and suggest limitations in the influence of stimulus‐reinforcer relations in autoshaping.
CONJUNCTIVE SCHEDULES OF RESPONSE‐DEPENDENT AND RESPONSE‐INDEPENDENT REINFORCEMENT1
Authors: Zeiler Michael D.
Published: March 2006

Pigeons received food when they emitted the number of responses specified by a fixed‐ratio schedule, and the time specified by a fixed‐time schedule had elapsed. The order of meeting the response and time requirements was irrelevant. In different conditions, stimuli signalled completion of one, both, or neither requirement. Ratio size interacted with stimulus condition to determine performance. When a stimulus signalled the end of the fixed‐time period, under all ratios the birds tended to respond after the stimulus appeared. When stimuli followed both components, small ratios produced responding during the fixed‐time period, and other ratios resulted in responses after the time period had elapsed. With either no stimulus changes, or with a stimulus correlated with completion of the ratio alone, responding first increased and then decreased as the ratio increased. Low and high ratios produced stable response frequencies and patterns in successive intervals. Intermediate ratios resulted in two types of performance. Intervals with long initial pauses and few responses during the fixed‐time period were followed by intervals with short pauses and numerous responses and vice versa. The source of these dynamic effects was hypothesized to be number of responses per reinforcer in one condition and response‐reinforcer contiguity in the other.
INTERACTIONS IN MULTIPLE SCHEDULES: THE ROLE OF THE STIMULUS‐REINFORCER CONTINGENCY1
Authors: Spealman Roger D.
Published: March 2006

In Experiments I and II, pigeons were exposed to single‐key multiple schedules of response‐independent and ‐dependent food presentation. Components were correlated with different keylights. When the rate of food presentation in the first component exceeded that in the second component, the local rate of key pecking was relatively high at onset of the first component. Overall rate in that component varied inversely with component duration and the rate of food presentation in the second component. When responding was maintained in the second component, the local rate of key pecking was relatively low at onset of that component. Overall rate in the second component varied directly with component duration and the rate of food presentation in that component. In Experiment III, pigeons were exposed to a two‐key multiple schedule. Pecks on a constantly illuminated key produced food. Components were correlated with the color of a second key on which pecks had no scheduled consequences. The effects of component duration and rate of food presentation under the single‐key response‐dependent schedule were synthesized by combining response rates on each concurrently available key under the two‐key procedure. The results support an account of multiple‐schedule interactions in terms of the joint influence on responding of stimulus‐reinforcer and response‐reinforcer contingencies.
CHOICE AND THE DEPENDABILITY OF STIMULI THAT PREDICT SHOCK AND SAFETY1
Authors: Badia P. , Harsh J. , Coker C. C. , Abbott B.
Published: March 2006

This study assessed whether choosing a signalled shock condition over an unsignalled one is controlled by a stimulus that predicts the presence of shock (Experiment I), or by a stimulus that predicts the absence of shock (Experiment II). The dependability of these stimuli as predictors of either the presence or the absence of shock was parametrically varied over a wide range, and subjects (rats) were given an option to change from an unsignalled to a signalled condition. In the first experiment, all shocks were preceded by signals; however, the probability of a signal being followed by shock varied from 1.0 to 0.02. The data obtained indicate that the dependability of the signal as a predictor of shock is unimportant. Rats changed to the signalled condition when the signal was completely dependable (all signals followed by shock) and when the dependability of the signal was systematically degraded. In the second experiment, all signals were followed by shock; however, some shocks were not preceded by a signal. The data show that the dependability of a stimulus predicting the absence of shock is important in that, as dependability decreases, changing to the signalled condition also decreases.
LINE‐ORIENTATION GENERALIZATION FOLLOWING SIGNALLED‐REINFORCER TRAINING
Authors: Griffin Patrick , Stewart Donald J.
Published: March 2006

Three naive and three nonnaive pigeons key pecked for food on a multiple variable‐interval 1‐minute variable‐interval 1‐minute schedule with a black zero‐degree vertical line on a white surround associated with one component and a black line shifted 30 degrees to the right (+30 degree) associated with the other component. Subsequently, a signalled‐reinforcer procedure was introduced in the +30 degree component, i.e., whenever the reinforcer was available for the next response, the key changed to blank white. Following this training, the original unsignalled‐reinforcer condition was re‐instated. Line orientation generalization tests were given at the end of signalled‐reinforcer training and after the second unsignalled‐reinforcer condition. The signalled‐reinforcer procedure reduced response rate in the +30‐degree component in all subjects but facilitated responding during the zero‐degree component (behavioral contrast) for two of the naive subjects only. However, average generalization gradients following signalled‐reinforcer training indicated peak shift in two subjects and area shift in all five subjects that completed the experiment. There was no apparent relation between contrast and peak shift or degree of area shift. The data were interpreted as supporting the notion that the signalled‐reinforcer procedure segments a variable‐interval schedule into extinction and fixed ratio 1 segments.
FOOD AND INTRACRANIAL STIMULATION RESPONDING SUPPRESSED WITH REGULAR‐INTERVAL SHOCK
Authors: Schmidt Eugene , McCaleb Michael , Merrill H. Kent
Published: March 2006

Attenuation of conditioned suppression during intracranial stimulation was compared with that during food reinforcement. Response rates controlled by food and by brain stimulation were equalized on a multiple schedule by adjusting the stimulating current. When foot shock was delivered during timeout periods separating response components, responding for food was significantly more suppressed than responding for brain stimulation. When components were shortened from 10 to 2 minutes, responding maintained by either food or brain stimulation showed a similar temporal pattern of suppression preceding each shock, but responding in the component involving food remained significantly more suppressed. Explanations for the attenuated suppression during brain stimulation based on neural disruption, stimulus blocking, and analgesic properties were questioned. The increased responding during brain stimulation seemed to reflect greater response strength relative to food reinforced responding.
TRANSFER OF ODDITY‐FROM‐SAMPLE PERFORMANCE IN PIGEONS1
Authors: Urcuioli Peter J.
Published: March 2006

Four pigeons were trained on a modified three‐key oddity‐from‐sample task in which an observing response to the sample (center‐key) stimulus lighted a single comparison (side‐key) stimulus. If the comparison stimulus was different from the sample stimulus, a single peck to the lighted comparison was reinforced. If the comparison and sample stimuli were identical, the pigeons had to refrain from pecking the comparison for 4.6 seconds to terminate the matching comparison and to produce immediately a nonmatching comparison on the remaining side key. Each peck to the matching comparison reset the 4.6‐second delay interval. Three hues were used during acquisition. During tests for transfer of the oddity performance, two novel hues were substituted either individually or together for one or two of the original training hues. For three birds, latencies to novel nonmatching hues were identical to baseline nonmatching latencies. Latencies to novel matching hues were shorter than baseline matching latencies but were consistently longer than novel nonmatching latencies. These transfer data demonstrate that the pigeons learned the oddity concept.
SIGNALLED FREE‐OPERANT AVOIDANCE OF SHOCK BY PIGEONS PECKING A KEY1
Authors: de Moraes A. Bento Alves , Todorov João Claudio
Published: March 2006

Two pigeons were trained to peck a key under a free‐operant avoidance schedule. Then, changes in key color signalled the beginning (safe period) and the end (warning period) of the response‐shock interval, with a response required to change the key color. Finally, a change in key color signalled the warning period and either a response or a shock reinstated the safe stimulus. During signalled avoidance, response rate was higher during the warning stimulus than during the safe stimulus. More responding tended to occur in the warning stimulus when it was terminated by either a response or a shock than by only a response. In either procedure, response latency during the warning stimulus was a function of the duration of the warning stimulus. In general, response and shock rate were higher during unsignalled than during signalled avoidance. When the warning stimulus was brief, the results were similar to those of unsignalled avoidance. These results confirm previous findings with pigeons, are in general agreement with data provided by other species in studies of signalled avoidance, and thereby indicate the transituationality of the key‐pecking operant.
STUDIES OF OPERANT AND REFLEXIVE KEY PECKS IN THE PIGEON1
Authors: Schwartz Barry
Published: March 2006

The duration of pigeons' key pecks was studied in three experiments. Experiment I revealed that key pecks early in exposure to continuous reinforcement were of short duration, as were key pecks observed on an omission procedure in which pecks prevented food delivery. Key pecks later in exposure to continuous reinforcement, and those that occurred on positive automaintenance procedures, were of long duration. In Experiment II, pigeons were exposed to fixed‐interval and fixed‐ratio reinforcement schedules, and durations were recorded separately for each quarter of each interval or ratio. On fixed interval, durations were shorter in the first quarter of each interval than in subsequent quarters; on fixed ratio, durations were longer in the first quarter of the ratio than in subsequent quarters. These data parallel observations of concurrent operant responding and salivation in dogs. In Experiment III, pigeons were exposed to a discrete trial, differential‐reinforcement‐of‐low‐rate 6‐sec schedule. Durations of responses in the first 2 sec of the trial were substantially shorter than those of responses that occurred later. The data from all three experiments support the view that the pigeon's “key peck” actually consists of two subclasses of peck, one reflexive and one operant.
BEHAVIORAL ADAPTATION TO FIXED‐INTERVAL AND FIXED‐TIME FOOD DELIVERY IN GOLDEN HAMSTERS1
Authors: Anderson Merrill C. , Shettleworth Sara J.
Published: March 2006

Food‐deprived golden hamsters in a large enclosure received food every 30 sec contingent on lever pressing, or free while their behavior was continuously recorded in terms of an exhaustive classification of motor patterns. As with other species in other situations, behavior became organized into two main classes. One (terminal behaviors) increased in probability throughout interfood intervals; the other (interim behaviors) peaked earlier in interfood intervals. Which class an activity belonged to was independent of whether food was contingent on lever pressing. When food was omitted on some of the intervals (thwarting), the terminal activities began sooner in the next interval, and different interim activities changed in different ways. The interim activities did not appear to be schedule‐induced in the usual sense. Rather, the hamsters left the area of the feeder when food was not due and engaged in activities they would normally perform in the experimental environment.
MAGNITUDES OF SCORE DIFFERENCES PRODUCED WITHIN SESSIONS IN A COOPERATIVE EXCHANGE PROCEDURE1
Authors: Matthews Byron A.
Published: March 2006

Interest centered on maximal score differences produced within sessions during two‐party exchange. Subjects chose between earning money independently or through potentially higher‐paying exchange. In the exchange option, only one person could produce points for the other on a trial. Because each exchange response (“give”) required the giver to forego earning points independently, the larger the score difference produced (i.e., the further ahead in earnings the other person was put), the greater the reduction in the giver's earnings if the other person did not reciprocate. Results showed that scores were usually equal at the end of each session, and that subjects maintained close equality of scores throughout each session. When a response‐cost contingency that punished the alternation of giving was introduced, however, large within‐session score differences developed. These large differences continued to be produced after the response‐cost contingency was removed. Finally, when subjects were told that the session could end at any moment, score differences were sharply reduced, indicating that production of score differences remained under the control of discriminative stimuli associated with the likelihood of reciprocation. The study suggests that with appropriate procedures, an experimental analysis of behavioral phenomena associated with the concept of “trust” may be possible.
SOME IMPLICATIONS OF A RELATIONAL PRINCIPLE OF REINFORCEMENT1
Authors: Donahoe John W.
Published: March 2006

A formal statement of a relational principle of reinforcement is developed that makes contact with analyses of choice, interresponse‐time distributions, and stimulus control. Some implications for current theoretical and empirical work in the various areas are examined.
THE EFFECT OF REINFORCEMENT DIFFERENCES ON CHOICE AND RESPONSE DISTRIBUTION DURING STIMULUS COMPOUNDING1
Authors: Bushnell M. Catherine , Weiss Stanley J.
Published: March 2006

In Experiments I and II, rats were trained to respond on one lever during light and another during tone. The absence of tone and light controlled response cessation. In the multiple schedule of Experiment I, all reinforcements were received for responding in tone or light; in the chain schedule of Experiment II, all reinforcements were received in no tone + no light for not responding. Experiment I subjects, for which tone and light were associated with response and reinforcement increase, responded significantly more to tone‐plus‐light than to tone or light alone (additive summation). Experiment II subjects, for which tone and light were associated with response increase and reinforcement decrease, responded comparably to tone, light, and tone + light. Thus, additive summation was observed when stimulus‐response and stimulus‐reinforcer associations in tone and light were both positive, but not when they were conflicting. All subjects in both experiments responded predominantly on the light‐correlated lever during tone + light, even when light intensity was reduced in testing. Furthermore, when a light was presented to a subject engaged in tone‐associated responding, all subjects immediately switched the locus of responding to the light‐correlated lever. No change in locus occurred when a tone was presented to a subject engaged in light‐associated responding, irrespective of the stimulus‐reinforcer association conditioned to tone. The light‐lever preference in tone + light indicates that the heightened responding observed in Experiment I was not the summation of tone‐associated behavior with light‐associated behavior. Rather, it appears to be the result of a facilitation of one operant (light‐associated responding) by the reinforcement‐associated cue for the other.
CONDITIONAL DISCRIMINATION PERFORMANCE BY PIGEONS ON A RESPONSE‐INDEPENDENT PROCEDURE1
Authors: Looney Thomas A. , Cohen Leila R. , Brady John H. , Cohen Perrin S.
Published: March 2006

Pigeons were trained on a differential autoshaping procedure in which both components of two‐stimulus sequences predicted delivery or nondelivery of food. All birds acquired the conditional discrimination. When the subjects were exposed to an extinction procedure, the stimuli maintained conditional control as long as the birds continued to peck the key. When a delay interval was imposed between the two components of a stimulus sequence using a titration procedure, the stimuli maintained conditional control up to delay values of 7 to 10 sec. These data are consistent with the view that the controlling stimuli in conditional discrimination situations are compounds of stimulus elements.
DEMAND FOR FOOD ON FIXED‐RATIO SCHEDULES AS A FUNCTION OF THE QUALITY OF CONCURRENTLY AVAILABLE REINFORCEMENT1
Authors: Lea S. E. G. , Roper T. J.
Published: March 2006

Six rats lever pressed for food on concurrent fixed‐ratio schedules, in a two‐compartment chamber. In one compartment, mixed diet pellets were delivered on fixed‐ratio schedules of 1, 6, 11, and 16; in the other, either no food was delivered, or sucrose or mixed diet pellets were delivered on fixed‐ratio 8. The number of pellets obtained in the first compartment declined as a function of fixed‐ratio size in that compartment in all three conditions, but the decline was greatest overall with mixed diet pellets concurrently available in the other compartment, and least with no food concurrently available. The result is discussed in terms of economic demand theory, and is consistent with the prediction that elasticity of demand for a commodity (defined in operant terms as the ratio of the proportionate change in number of reinforcements per session to the proportionate change in fixed‐ratio size) is greater the more substitutable for that commodity are any concurrently available commodities.
PUNISHMENT OF AUTOSHAPED KEY‐PECK RESPONSES OF PIGEONS
Authors: Wesp Richard K. , Lattal Kennon A. , Poling Alan D.
Published: March 2006

The effects of different voltages of response‐dependent and response‐independent electric shock on the frequency of key‐peck responses engendered by an autoshaping procedure were studied. In Experiments I and II, each response produced a brief electric shock, and response frequency generally decreased more with higher‐voltage shock. Preshock frequencies of responding were generally recovered across successive sessions of relatively low‐voltage shock delivery but not at higher shock voltages. The effects of response‐dependent and response‐independent shock were compared in Experiment III by using a yoked‐control procedure in which each pigeon received each type of shock delivery at different times. Response‐dependent shock generally produced greater decreases in response frequency. In the final experiment, one response‐independent shock per autoshaping trial was scheduled. The number of auto shaped responses per trial was related to shock voltages. These results suggest that response‐dependent and response‐independent electric shock effectively decrease frequency of autoshaped responses.
SCHEDULE‐INDUCED BITING UNDER FIXED‐INTERVAL SCHEDULES OF FOOD OR ELECTRIC‐SHOCK PRESENTATION
Authors: DeWeese Jo
Published: March 2006

Squirrel monkeys pressed a lever under fixed‐interval schedules of food or of electric‐shock presentation. Both schedules induced repeated biting on a latex hose. Whether lever pressing was controlled by food or by electric shock, a pattern of decreasing hose biting and increasing lever pressing occurred within fixed‐interval cycles. As the fixed‐interval duration was increased from 6 to 600 sec, average rates of lever pressing decreased under both schedules. Average rates of hose biting first increased with increasing parameter value, reaching a maximum at values that varied from 60 to 337 sec in different monkeys, and then declined at higher values. d‐Amphetamine at appropriate doses increased overall rates of lever pressing maintained by food or by shock, but either did not affect or decreased overall rates of hose biting. When no timeout period occurred between fixed‐interval cycles, the monkeys bit most frequently immediately after food or electric shock was presented. When there was a timeout period, hose biting began shortly after the start of the fixed‐interval cycles, with little or no hose biting immediately after food or electric shock was presented. Most hose biting appeared to be schedule‐induced rather than food‐ or shock‐induced.
THE NATURE OF CONTROL BY SPOKEN WORDS OVER VISUAL STIMULUS SELECTION1
Authors: Dixon Lois S.
Published: March 2006

Eight retarded adolescents were trained to select one (a trained S+) of two visual stimuli in response to a spoken word (a trained word). Two different visual stimuli alternated randomly as the S‐. To determine if the spoken word was merely a temporal discriminative stimulus for when to respond, or if it also specified which visual stimulus to select, the subjects were given intermittent presentations of untrained (novel) spoken words. All subjects consistently selected the trained S+ in response to the trained spoken word and selected the previous S‐ in response to the untrained spoken words. It was hypothesized that the subjects were responding away from the trained S+ in response to untrained spoken words, and control by untrained spoken words would not be observed when the trained S+ was not present. The two visual S‐ stimuli selected on trials of untrained spoken words were presented simultaneously. The untrained spoken words presented on these trials no longer controlled stimulus selections for seven subjects. The results supported the hypothesis that previous control by spoken words was due to responding away from the trained S+ in response to untrained spoken words.
SELECTIVE PUNISHMENT EARLY AND LATE IN FIXED‐RATIO SCHEDULES OF FOOD REINFORCEMENT1
Authors: Dodd P. W. D. , Williams S. M. , Bissell M. L. , Weisman R. G.
Published: March 2006

Pigeons key pecked for grain on a fixed‐ratio 100 schedule; electric shocks occurred intermittently at the fifteenth or eighty‐fifth response in the ratio. In Experiment I, shock was at the fifteenth response for two birds, and at the eighty‐fifth response for two others, in every sixth, twelfth, or eighteenth ratio. Rate of responding decreased as frequency of shock increased, and the pattern of responding included an increased initial pause and low rates or pause‐run sequences that extended further into the ratio when shock was at the fifteenth response than when it was at the eighty‐fifth response. Shock early in the ratio engendered longer initial pauses than shock late in the ratio. In Experiment II, four birds responded on a two‐component multiple schedule in which shock occurred at the fifteenth response of the third ratio in the presence of a white keylight and at the eighty‐fifth response of the third ratio in the presence of a green keylight. The overall rates of responding decreased as shock intensity increased. All four birds responded differentially to the white and green keylights, but with a pattern that varied between birds. In general, punishment reduced the probability of responses that preceded it, regardless of the ordinal position of those responses. Both studies confirm that the probability of responding is reduced less by aversive stimuli produced late in a fixed‐ratio than by aversive stimuli produced early in a fixed‐ratio.
SPACED FOOD BUT NOT ELECTRICAL BRAIN STIMULATION INDUCES POLYDIPSIA AND AIR LICKING1
Authors: Ramer Donald G. , Wilkie Donald M.
Published: March 2006

An attempt was made to induce polydipsia in rats whose lever pressing was reinforced with food pellets or electrical brain stimulation. Nine food‐deprived, water‐sated rats drank water excessively during sessions in which food pellets were delivered. When brain stimulation was substituted for food, drinking immediately ceased. Delivering brain stimulation according to a variety of schedules, pairing brain stimulation with food reinforcement, and substituting an air stream for water, each failed to produce polydipsic licking. These results show that polydipsia is not induced by all reinforcers.
DRUG EFFECTS ON FIXED‐INTERVAL RESPONDING WITH PAUSE REQUIREMENTS FOR FOOD PRESENTATION1
Authors: Stitzer Maxine , McKearney James W.
Published: March 2006

In pigeons performing under a multiple schedule of food presentation, low key‐pecking rates (0.18 to 0.29 responses per second) were maintained during 3‐min fixed‐interval components toy requiring a 4‐, 5‐, or 6‐sec pause preceding the food‐delivery response (tandem DRL), while higher rates (0.70 to 1.37 responses per second) were maintained in alternate fixed‐interval components by requiring a pause of no more than 40 msec preceding the food‐delivery response (tandem DRH). Thus, reinforcement density was equal but overall response rates markedly different in the two schedule components. Pentobarbital (3, 10 mg/kg) had effects on overall rates of responding consistent with a rate‐dependency interpretation (low rates were increased while higher rates were decreased), but d‐amphetamine (0.03 to 3 mg/kg) either failed to increase low overall rates in the tandem DRL components or increased them only slightly. Effects of both drugs on local responding within the fixed‐intervals were always related in an orderly way to control response rate, but the extent of rate increases produced by d‐amphetamine was modified in some birds by pause requirements such that the drug increased comparable rates less when these occurred in the tandem DRL component than when they occurred in the tandem DRH components. Control rate is an important determinant of drug effects, independent of reinforcement density maintaining rates, and independent of environmental influences, such as response‐spacing requirements for food presentation, that can modify the extent of some drug‐produced rate changes.
RESPONSE AND TIME ALLOCATION IN CONCURRENT SECOND‐ORDER SCHEDULES1
Authors: Beautrais P. G. , Davison M. C.
Published: March 2006

Six pigeons were trained on two‐key concurrent variable‐interval schedules in which the required response was the completion of a fixed number of key pecks. When the required number of pecks was equal on the two keys, response‐ and time‐allocation ratios under‐matched obtained reinforcement rate ratios. A similar result was found when the required number of pecks was unequal, except that performance, measured in response terms, was biased to the shorter required number of pecks and was less sensitive to reinforcement‐rate changes. No such differences were found in the data on time spent responding. When the variable‐interval schedules were kept constant and the required numbers of pecks were systematically varied, response ratios changed inversely with the ratio of the required number of pecks, but time‐allocation ratios varied directly with the same independent variable. Thus, on response measures, pigeons “prefer” the schedule with the smaller peck requirement, but on time measures they “prefer” the schedule with the larger peck requirement. This finding is inconsistent with a commonsense notion of choice, which sees response and time‐allocation measures as equivalent.
ASSOCIATIVE INTERACTION: JOINT CONTROL OF KEY PECKING BY STIMULUS‐REINFORCER AND RESPONSE‐REINFORCER RELATIONSHIPS
Authors: Woodruff Guy , Conner Ned , Gamzu Elkan , Williams D. R.
Published: March 2006

The joint control of rate of key pecking in pigeons by stimulus‐reinforcer and response‐reinforcer relationships was studied in the context of a two‐component multiple schedule of reinforcement. Food presentation was always associated with one component and extinction with the other. The stimulus‐reinforcer relationship was manipulated by varying the relative durations of the two components. In the food‐presentation component, a fixed rate of reinforcement, independent of rate of responding, was generated by a schedule referred to as “T*”. One aspect of the response‐reinforcer relationship, contiguity, was manipulated by varying the percentage of delayed reinforcers. With the multiple T* extinction schedule, stimulus‐reinforcer and response‐reinforcer relationships could be varied independently of one another. Rate of key pecking was sensitive to manipulations of both relationships. However, significant differential effects due to either the stimulus‐reinforcer or response‐reinforcer relationship were obtained only when the other relationship was weak: stimulus‐reinforcer and response‐reinforcer relationships interacted in the joint control of responding.
DURATION AND RATE OF REINFORCEMENT AS DETERMINANTS OF CONCURRENT RESPONDING1
Authors: Keller John V. , Gollub Lewis R.
Published: March 2006

The duration and frequency of food presentation were varied in concurrent variable‐interval variable‐interval schedules of reinforcement. In the first experiment, in which pigeons were exposed to a succession of eight different schedules, neither relative duration nor relative frequency of reinforcement had as great an effect on response distribution as they have when they are manipulated separately. These results supported those previously reported by Todorov (1973) and Schneider (1973). In a second experiment, each of seven pigeons was exposed to only one concurrent schedule in which the frequency and/or duration of reinforcement differed on the two keys. Under these conditions, each pigeon's relative rate of response closely matched the relative total access to food that each schedule provided. This result suggests that previous failures to obtain matching may be due to factors such as an insufficient length of exposure to each schedule or to the pigeons' repeated exposure to different concurrent schedules.
FIXED‐RATIO DISCRIMINATION: EFFECTS OF INTERMITTENT REINFORCEMENT
Authors: Lydersen Tore
Published: March 2006

Four pigeons had discrimination training that required the choice of a left side‐key after completing a fixed‐ratio 10 on the center key, and a right side‐key choice after fixed‐ratio 20. Correct choices were reinforced on various fixed‐interval, fixed‐ratio, random‐interval, and random‐ratio schedules. When performance was examined across successive 15‐second intervals (fixed‐interval and fixed‐ratio schedules) accuracy was high in the first 15‐second interval, decreased in one or several of the next 15‐second intervals, and then increased again as reinforcement was approached. When performance was examined across correct trials on fixed‐interval and fixed‐ratio schedules, accuracy was lowest immediately after reinforcement, followed by a systematic increase in accuracy as the number of correct choices increased. These patterns were due primarily to errors on fixed‐ratio 20 trials. Systematic accuracy patterns did not occur on random‐interval or random‐ratio schedules. The results indicate that when choice patterns differed on fixed‐interval and fixed‐ratio schedules, the differences were due to the method of data analysis.
FIXED‐INTERVAL RESPONDING UNDER SECOND‐ORDER SCHEDULES OF FOOD PRESENTATION OR COCAINE INJECTION1
Authors: Kelleher R. T. , Goldberg S. R.
Published: March 2006

Squirrel monkeys operated a key under second‐order schedules in which every tenth completion of a 5‐minute fixed interval resulted in either presentation of food or intravenous injection of cocaine. When a 2‐second light was presented at the completion of the component fixed‐interval schedules, positively accelerated responding developed and was maintained in each component. Over a tenfold range of doses of cocaine (30 to 300 μ/kg/injection) and amounts of food (0.75 to 7.5 g/presentation), the second‐order schedule of cocaine injection maintained higher average rates of responding than the second‐order schedule of food presentation. Substituting saline for cocaine or eliminating food presentations decreased average rates of responding. When no stimulus change occurred at the completion of the first nine component fixed‐interval schedules, but the 2‐second light and food presentation or cocaine injection still occurred after the tenth component, only low and relatively constant rates of responding were maintained in each component. Patterns of responding characteristic of 5‐minute fixed‐interval schedules were maintained by the 2‐second light paired with either cocaine injection or food presentation, though the maximum frequency of cocaine injection or food presentation was less than once per 50 minutes.