bluuebunny/crossref_metadata_2025 huggingface dataset:
SECOND‐ORDER SCHEDULES: BRIEF SHOCK AT THE COMPLETION OF EACH COMPONENT1
Authors: Stubbs D. Alan , Silverman Philip J.
Published: March 2006

Pigeons worked on second‐order schedules in which completion of fixed‐interval component schedules was reinforced with food according to a variable‐interval schedule of reinforcement. The completion of each fixed‐interval component resulted in the presentation of a brief electric shock. In one condition (shock‐paired), the completion of every fixed‐interval component, including those that ended in food, resulted in the shock. In another condition (shock‐nonpaired), completion resulted in shock except for those components that ended in food. Shock presentations resulted in a positively accelerated rate within fixed‐interval components. This patterning within components was similar whether the shock was intermittently paired with food or not. Response rates tended to decrease as shock intensity increased. The characteristic fixed‐interval response pattern within components did not occur when shock presentations were omitted at the end of each component (tandem schedule). When shocks were scheduled but food was no longer presented (extinction) response rates declined to a near‐zero level. The performance under shock conditions is similar to that in other studies in which visual and auditory stimuli are presented at the completion of component schedules.
EFFECTS ON CONCURRENT PERFORMANCES OF A STIMULUS CORRELATED WITH REINFORCER AVAILABILITY1
Authors: Pliskoff Stanley S. , Green Donald
Published: March 2006

A multiple schedule was arranged in which each component consisted of two, concurrent variable‐interval schedules of reinforcement. A changeover‐key procedure was used, and the components of the multiple schedule were distinguished (initially) by the color of the changeover key. During one component of the multiple schedule, the availability of a reinforcer arranged by one of the variable‐interval schedules was marked by an exteroceptive stimulus, provided that that variable‐interval schedule was not at the time assigned to the main key. During the other component of the multiple schedule, no reinforcer‐correlated stimuli were ever presented. During the latter component of the multiple schedule, the distribution of responses and time for the concurrent variable‐interval schedules suggested control by the distribution of reinforcements. During the former component, most main‐key responses were emitted on the key in the presence of which reinforcer‐correlated stimuli were presented. Changeover rate in the presence of that key color was depressed. The discriminative control over the changeover was easily established and was reversible.
AGGRESSION AS A REINFORCER: OPERANT BEHAVIOR IN THE MOUSE‐KILLING RAT1
Authors: Van Hemel Paul E.
Published: March 2006

Two experiments examined mouse killing as a reinforcer of key pressing by rats that killed mice. In Experiment I, mouse‐killing rats performed the key‐pressing response when each press was reinforced with presentation of a mouse. Offered a choice between a key that yielded presentation of mice and one that did not, the rats preferred the key that yielded mice. When the contingency was reversed, the rats preferred the other key and continued to kill mice. In Experiment II, mouse‐killing rats that did not kill rat pups performed a key‐pressing response reinforced with presentation of mice on a variable‐interval schedule. In tests for responding reinforced on that schedule with presentation of normal mice, anesthetized mice, dead mice, or rat pups, these rats that killed mice but not rat pups exhibited a decline in response rate when rat pups were the reinforcer. Altering the condition of the mice did not significantly affect performance.
CONCURRENT PERFORMANCES: RATE AND ACCURACY OF FREE‐OPERANT ODDITY RESPONDING1
Authors: Catania A. Charles , Dobson Ricardo
Published: March 2006

In pigeon's oddity performances, maintained by variable‐interval reinforcement of pecks on the odd key of three keys in a triangular array, accuracy and response rate varied inversely with the rate of variable‐interval reinforcement scheduled concurrently for pecks on a fourth, spatially isolated key. But when variable‐interval and extinction components alternated in a multiple schedule for pecks on the spatially isolated key, oddity accuracy was greater during variable‐interval components than during extinction components. Oddity response rate was not affected systematically by the alternating components. Changeovers between the oddity keys and the spatially isolated key were frequent during variable‐interval components; responding occurred almost exclusively on the oddity keys during extinction components. This difference in performance during the two components was eliminated by arranging stimulus‐correlated variable‐interval reinforcement in the multiple schedule on the spatially isolated key: a stimulus was presented in the variable‐interval components only when reinforcement became available, thereby reducing responding on this key to near‐zero levels in both components while maintaining the variable‐interval reinforcement. The effect of the multiple‐schedule components on oddity accuracy was not altered, however, and thus apparently depended directly on concurrent reinforcement and not on differential sequential properties of concurrent responding during the two components.
AVOIDANCE RESPONSE RATES DURING A PRE‐FOOD STIMULUS IN MONKEYS1
Authors: Henton Wendon W.
Published: March 2006

Free‐operant avoidance responding was maintained by a shock avoidance schedule in three monkeys. The frequency of avoidance responses during a stimulus terminated by response‐independent food pellet presentation was dependent upon the method of pellet delivery. Avoidance rates were relatively increased when food retrieval responses followed pellet delivery. Avoidance rates were decreased when retrieval responses preceded pellet delivery.
CONDITIONED SUPPRESSION OF AN AVOIDANCE RESPONSE BY A STIMULUS PAIRED WITH FOOD
Authors: Davis Hank , Kreuter Charles
Published: March 2006

Three food‐deprived Long‐Evans rats were exposed to a non‐discriminated shock avoidance procedure. Superimposed upon this operant avoidance baseline were periodic presentations of a conditioned stimulus that was paired with food, the unconditioned stimulus. These pairings resulted in increases in the rate of shock over that recorded when the conditioned stimulus was not present. A traditional suppression ratio failed to reveal any differential effect of the conditioned stimulus on the overall rate of avoidance responding, although all subjects showed a consistent pattern of pausing and postshock response bursts during presentations of the conditioned stimulus. When food was withheld during a final extinction phase, the conditioned stimulus ceased to occasion increases in shock rates and disruptive postshock response bursts were eliminated. An analysis of conditioned suppression procedures is proposed that stresses not only operant‐Pavlovian or appetitive‐aversive incompatibility, but also the manner in which the baseline schedule of reinforcement affects operant behavior changes that are elicited by the superimposed Pavlovian procedure.
CHARACTERISTICS AND RESPONSE‐DISPLACEMENT EFFECTS OF SHOCK‐GENERATED RESPONDING DURING NEGATIVE REINFORCEMENT PROCEDURES: PRE‐SHOCK RESPONDING AND POST‐SHOCK AGGRESSIVE RESPONDING1
Authors: Hake D. F. , Campbell R. L.
Published: March 2006

Bar‐pressing (Experiment I) or key‐pressing (Experiments II and III) responses of monkeys were reinforced according to a fixed‐interval schedule of negative reinforcement: the first response after a fixed interval of time terminated regularly spaced shocks for a fixed time designated as the reinforcement period. During extinction, shocks continued during the reinforcement period. That there were two types of responding generated by shock alone was indicated by (1) the level of responding maintained during extinction relative to conditions without shock, (2) the stability of two between‐shock response patterns across reinforcement and extinction conditions, and (3) the development of these two between‐shock patterns without a history of reinforcement. Subjects developed either a pre‐shock or a post‐shock response pattern when only the bar was available. However, when both a bite tube, an operandum requiring an aggressive topography, and a recessed key, an operandum that did not require an aggressive topography, were provided, the post‐shock pattern was observed in tube biting and the pre‐shock pattern was observed in key pressing. Removal of the bite tube produced post‐shock key responding similar to that observed when only the bar was available. The displacement of post‐shock, aggression‐motivated responding confirmed the confounding effect of shock‐generated responding in negative reinforcement procedures, and suggests that the use of concurrent response alternatives would reduce such confounding.
THE INFLUENCE OF ULTRAVIOLET RADIATION ON THE PIGEON'S COLOR DISCRIMINATION1
Authors: Wright Anthony A.
Published: March 2006

Two experiments demonstrated the pigeon's sensitivity to ultraviolet light. In Experiment I, pigeons' responses were reinforced on a multiple schedule with a variable‐interval reinforcement schedule in one component and extinction in the other component. Response rates were quite different in the two components where the 520‐nm stimuli signalling each component differed only in that one of them contained a 366‐nm ultraviolet component. In Experiment II, pigeons were trained to peck one side key when two halves of a split field were of different wavelength and to peck another side key when they were of the same wavelength. Initially, field halves contained both “visible” and ultraviolet components of energy. Discrimination performance improved when the ultraviolet component was removed from one field half. It was argued that the critical change in the stimulus was a color change, rather than a brightness one, or a fluorescence of structures in the pigeon's eye.
MAINTENANCE AND SUPPRESSION OF RESPONDING UNDER SCHEDULES OF ELECTRIC SHOCK PRESENTATION1
Authors: McKearney James W.
Published: March 2006

In squirrel monkeys previously trained under a continuous avoidance schedule, characteristic patterns of responding were maintained under a 3‐min variable‐interval schedule of shock presentation (response‐produced shock). Responding in the presence of a periodically presented stimulus, the termination of which coincided with the delivery of a response‐independent electric shock (Estes‐Skinner procedure), was not reliably affected. When shocks followed every response during certain signalled portions of the session, and were presented under the variable‐interval schedule during the rest of the session (multiple 1‐response fixed‐ratio, 3‐min variable‐interval schedule of shock presentation), responding was suppressed during the fixed‐ratio component and maintained during the variable‐interval component. Environmental consequences do not have immutable properties, and may either support or suppress behavior, depending on the schedule of presentation.
VARIABLE LOCATION OF PUNISHMENT IN A RESPONSE SEQUENCE1
Authors: Dardano J. F.
Published: March 2006

Key pecking of pigeons under a fixed‐ratio 100, grain reinforcer schedule was followed by electric shock occurring once in each sequence of 100 responses with the shocked response varying irregularly in successive sequences. Under this shock schedule, a localized suppression of responding in a response sequence was not correlated with the probability of shock at different points in the sequence. High shock levels increased the duration of post‐reinforcement pauses and suppressed responding during the first half of the response sequence. This suppression often persisted after the shocked response when shock occurred early in the sequence. The shock schedule did not produce a consistent suppressing effect on responding during the last half of the response sequence.
SOME EFFECTS OF PUNISHMENT UPON UNPUNISHED RESPONDING1
Authors: Dunham Philip J.
Published: March 2006

Animals permitted free access to a running wheel and drinking tube increased the amount of running when drinking was punished with electric shock. Additional experiments demonstrated that the simple presence or absence of a drinking tube (or running wheel) was a sufficient condition to observe a decrease or an increase in the alternative response. A quantitative analysis of these interactions observed between the incompatible running and drinking responses suggested that each response occupied a constant proportion of the time available for it. These results question an interpretation of the increase in unpunished alternative responding based upon its avoidance properties.
POSITIVE INTERACTION (INDUCTION) IN MULTIPLE VARIABLE‐INTERVAL, DIFFERENTIAL‐REINFORCEMENT‐OF‐HIGH‐RATE SCHEDULES1
Authors: Hemmes Nancy S. , Eckerman David A.
Published: March 2006

The effect of increases in the rate of responding in one component of a multiple schedule upon the rate of responding in a second component was investigated. Pigeons were exposed to a multiple schedule where both components were initially variable‐interval schedules having the same parameter value. After rate of key pecking stabilized, one component was changed to a schedule that differentially reinforced high rates of responding. Rate of reinforcement in this varied component was adjusted to remain equal to rate of reinforcement in the constant (variable‐interval) component. Four of five pigeons showed a maintained increase in rate of responding during both the constant and varied components, even though rates of reinforcement did not change.
TWO TEMPORAL PARAMETERS OF FOOD POSTPONEMENT1
Authors: Smith James B. , Clark Fogle C.
Published: March 2006

Rats were trained to press a lever under schedules of food postponement. In the absence of lever presses, food was delivered periodically (food‐food interval). Responses initiated a second interval (response‐food interval) that was reset by each additional response. Performance was first studied at different response‐food intervals with the food‐food interval fixed at 30 or 60 sec, or 10 min. Response‐food intervals were examined in ascending order and then recovery was studied at shorter intervals. Finally, the food‐food interval was manipulated with response‐food interval fixed at 30 sec. At food‐food intervals of 30 and 60 sec, responding first increased and then decreased as the response‐food interval increased. At the 10‐min food‐food interval, responding decreased with increasing response‐food interval. In general, very low rates of responding occurred when the response‐food interval was 60 sec or more and when it equalled or exceeded the food‐food interval. However, responding was maintained in one animal when the food‐food interval was decreased from 120 to 15 sec with the response‐food interval at 30 sec. Results, in terms of several dependent variables, are compared with data on shock avoidance. Effects of response‐independent and response‐produced food and shock are discussed.
CONDITIONED SUPPRESSION WITH EXTINCTION AS THE SIGNALLED STIMULUS1
Authors: Holmes Paul W.
Published: March 2006

The key pecking of pigeons that was maintained by a 60‐sec random‐interval schedule of food reinforcement was suppressed during a variable‐duration warning stimulus that signalled a 5‐min extinction period. The onset of the extinction period immediately followed the termination of the warning signal and was independent of the subject's responses. All subjects eventually showed nearly complete suppression of responding during the warning stimulus.
RESPONSE‐REINFORCER INDEPENDENCE AND CONVENTIONAL EXTINCTION AFTER FIXED‐INTERVAL AND VARIABLE‐INTERVAL SCHEDULES1
Authors: Lattal Kennon A.
Published: March 2006

After training three albino rats to bar press during a multiple fixed‐interval variable‐interval schedule, the response‐reinforcer dependency was simultaneously removed from both components, converting the schedule to multiple fixed‐time variable‐time. Response rates were reduced in both components under these conditions but the fixed‐time schedule maintained relatively higher response rates with each rat. After reinstating the response‐reinforcer dependency in both components, responding was conventionally extinguished by rendering the pellet dispenser inoperative. Responding rapidly decreased to near‐zero levels. Differences in fixed and variable‐time schedules in sustaining behavior are discussed in terms of differences in response rates at the time of reinforcer delivery. Similarities and differences between conventional extinction and schedules delivering response‐independent reinforcers are also discussed.
UNSIGNALLED AVOIDANCE IN A SHUTTLEBOX: A RAPID ACQUISITION, HIGH‐EFFICIENCY PARADIGM
Authors: Riess Dave , Farrar Charles H.
Published: March 2006

Detailed descriptive data are provided on the free‐operant avoidance behavior of rats in a shuttlebox during both acquisition and terminal performance. Initially, eighteen 21‐min acquisition sessions were given. Each hurdle‐cross postponed the next shock 20 sec (response‐shock interval) and shocks were scheduled every 5 sec (shock‐shock interval) in the absence of a response. All eight subjects avoided over 70% of the shocks due (12/min) in Session 1. Maximum response rates were reached by the third session and declined slowly while shock rates continued to drop slowly through Session 15. Three subjects were run an additional five months with a response‐shock interval of 20 sec and their terminal response rates were all under five responses per minute and shock rates were 0.07 per minute. Interresponse time distributions for terminal performance showed that over 95% of all responding by all three subjects occurred in the last half of the response‐shock interval.
EFFECTS OF ALTERNATIVE REINFORCEMENT: DOES THE SOURCE MATTER?1
Authors: Rachlin Howard , Baum William M.
Published: March 2006

In a chamber with a single response key, pigeon's key pecks were reinforced with food according to a variable‐interval schedule. In addition, extra reinforcements occurred concurrently according to an independent schedule. In one condition, availability of the extra reinforcements was signalled by a change in key color from white to red. The extra reinforcements occurred after a peck on the red key. In a second condition, the extra reinforcements were unsignalled and occurred only after a 2‐sec pause in pecking for one group of subjects and were unsignalled and occurred freely as scheduled for another group of subjects. In the first two conditions, duration of reinforcement was varied. A third condition duplicated the second but varied rate rather than duration of reinforcement. The rate of pecking varied inversely with the amount of extra reinforcement per unit time according to the same function, regardless of the condition regulating occurrence of the extra reinforcements, and regardless of whether or not a 2‐sec pause was required for their occurrence. The shape of this function was predicted by Herrnstein's (1970) matching law.
TIME LIMITS FOR COMPLETING FIXED RATIOS. II. STIMULUS SPECIFICITY1
Authors: Zeiler Michael D.
Published: March 2006

Pigeons were exposed to two stimuli that were each correlated with the same fixed‐ratio schedule. During one stimulus, the ratio had to be completed in more than a specified time for food to be presented. During the other, the ratio had to be completed in less than a specified time. Failures to meet the time criterion produced a timeout and reset the ratio. Treating the entire behavioral sequence generated by a fixed‐ratio schedule as a unitary response and scheduling differential reinforcement with respect to the duration of the sequence produced effects comparable to those observed previously with individual responses. The times taken to complete the ratios conformed to the time criteria under both stimulus conditions. Similar effects have been observed with differential reinforcement of the duration of individual responses and in experiments specifying running speed criteria under discrete trial conditions.
REINFORCEMENT VALUES OF VISUAL PATTERNS COMPARED THROUGH CONCURRENT PERFORMANCES1
Authors: Berlyne D. E.
Published: March 2006

Use of concurrent variable‐interval performances confirms that more‐complex visual patterns have greater reinforcement value for human subjects than less‐complex patterns. The findings tally with verbal evaluative ratings and with results of previous experiments using a discrete‐trial binary‐choice technique.
SHOCK‐INDUCED AGGRESSION AS A FUNCTION OF PRIOR EXPERIENCE WITH AVOIDANCE, FIGHTING, OR UNAVOIDABLE SHOCK1
Authors: Powell D. A. , Francis M. J. , Francis J. , Schneiderman N.
Published: March 2006

Rats were trained in shock‐induced aggression, free operant avoidance, or were presented with unavoidable shocks. Fighting in response to shock was subsequently measured by intermatching individual animals that had received the three training procedures. The fighting probabilities of animals with histories of avoidance and dominant animals with histories of fighting were higher than the fighting probabilities of non‐dominant fighting rats or rats with a history of unavoidable shocks. Animals with higher fighting probabilities disrupted avoidance baselines more than animals with lower fighting probabilities. Control experiments suggested that fighting decrements produced by administration of prior grid‐shock were due to the acquisition of behaviors incompatible with aggression.
A CLASSIFICATION AND REVIEW OF COOPERATION PROCEDURES1
Authors: Hake Don F. , Vukelich Ron
Published: March 2006

The definition of cooperation allows many procedural variations, as revealed by examination of the cooperation literature which includes procedures differing so greatly that it is surprising that all of them are considered under the same topic. This paper attempts to provide a framework for organizing that literature by (1) indicating some procedural dimensions along which cooperation procedures can be classified, (2) classifying and reviewing briefly the research at the extremes of these procedural dimensions, and (3) indicating the behavioral effects that are necessary to demonstrate control by the various cooperation procedures.
RECOGNITION BY THE PIGEON OF STIMULI VARYING IN TWO DIMENSIONS1
Authors: Blough Donald S.
Published: March 2006

Pigeons served in four experiments, each of which involved about 44,000 discrete 1.2‐sec trials under steady‐state conditions. The first experiment scaled a short segment of the visual wavelength continuum; this dimension was then combined in a conditional discrimination with each of three others; time after reinforcement, tone frequency, and line tilt. In the two‐stimulus experiments, the birds' responses were reinforced in the presence of only one stimulus combination: “582 nm” together with “2 min after reinforcement”, “3990 Hz”, or “vertical line”. Many other stimulus combinations also appeared equally often and went without reinforcement. The wavelength stimuli conformed to an equal‐interval scale, and per cent response was generally linear with wavelength, when scaled on cumulative normal coordinates. The components of the compound stimulus were found to interact in a multiplicative fashion; when one component differed greatly from its reinforcement value, changes in the other component had relatively little effect. For the “time”‐“wavelength” compound, this interaction appeared to be modified by the effects of set or attention. Certain response latency data are reported, and other combination rules are discussed.
TRANSITIVITY AS A PROPERTY OF CHOICE1
Authors: Navarick Douglas J. , Fantino Edmund
Published: March 2006

Pigeons' pecks in the presence of two concurrently available initial‐link stimuli occasionally produced one of two stimuli associated with mutually exclusive terminal links. Pecks during either terminal link produced food according to aperiodic (variable‐interval and variable‐ratio) or periodic (fixed‐interval and fixed‐ratio) schedules of reinforcement. Aperiodic and periodic schedules to which the pigeons were indifferent, in the sense that these schedules maintained equal responding in the initial links, often yielded different preferences in separate choice tests with a third schedule. Conversely, aperiodic and periodic schedules that were equally preferred to a third schedule often failed to generate indifference. These intransitivities imply that (1) aperiodic and periodic schedules are not functionally equivalent in their effects upon choice, and (2) efforts to find a simple method for transforming aperiodic schedules into their periodic equivalents will fail.
CONTROL OF A CONTINUOUS RESPONSE DIMENSION BY A CONTINUOUS STIMULUS DIMENSION1
Authors: Wildemann Donald G. , Holland James G.
Published: March 2006

Pigeons were trained to respond to stimuli from a continuous stimulus dimension (tonal frequency) with response values from a continuous response dimension. Both the number of points of correspondence and problem difficulty were varied. After training, subjects were tested with stimulus values intermediate to those trained. During these test tones, subjects emitted only those response values reinforced during training. The study suggested that if there are fast and efficient methods to obtain control of a continuous response dimension by a continuous stimulus dimension, these methods must depend on factors other than simple generalization.
DURATION DISCRIMINATION: EFFECTS OF PROBABILITY OF STIMULUS PRESENTATION
Authors: Elsmore Timothy F.
Published: March 2006

Monkeys initiated a stimulus by pressing on the center of three levers and the stimulus terminated independently of behavior 60, 80, 90, or 100 sec later. Presses on the right lever were reinforced with food following the three briefer durations, and presses on the left lever, following the 100‐sec duration. Incorrect responses produced a 10‐sec timeout. Probability of presenting the 100‐sec duration was manipulated in the range from 0.25 to 0.75, with the probabilities of the briefer durations remaining equal and summing to one minus the probability of the 100‐sec duration. Percentage of responses on either side lever was functionally related to both the probability of presenting the 100‐sec stimulus and to stimulus duration. An analysis of the data based on the theory of signal detection resulted in operating characteristics that were linear when plotted on normal‐normal coordinates. The percentage of responses on either lever approximated the optimal values for maximizing reinforcement probability in each condition of the experiment.
THE DEVELOPMENT OF FIXED‐RATIO PERFORMANCE UNDER THE INFLUENCE OF RIBONUCLEIC ACID1
Authors: Gott C. Thomas , Weiss Bernard
Published: March 2006

The transition from fixed‐ratio 1 performance (every response reinforced) to fixed‐ratio 30 performance (every thirtieth response reinforced) was studied in nine pigeons. These were divided into three treatment groups given daily oral doses of saline, or 250 mg/kg/day or 500 mg/kg/day of yeast ribonucleic acid. Detailed computer‐assisted analyses of how fixed‐ratio behavior develops revealed the following typical sequence. After the transition, the first few ratios typically were emitted without long interresponse times within the ratio. Steady responding then ceased, and numerous long interresponse times occurred, with no systematic relationship to ordinal position within the ratio. Gradually, a new pattern evolved, characterized by a consistently long post‐reinforcement time, a border region of the next few interresponse times within which the mean interresponse time monotonically decreased, and short interresponse times within the last 80% of the ratio. Long interresponse times were eliminated from this last section of the ratio without regard to proximity to reinforcement. Various analytical procedures suggested that the final pattern can be conceived, in part, as the shaping of a reliable response topography. The group of three pigeons given 250 mg/kg/day of yeast ribonucleic acid responded at higher rates than the saline and 500 mg/kg/day groups. The latter group, in contrast to the saline and lower dose groups, which continued to increase their rates, reached a rate asymptote very early.
RESPONSE PATTERNING ON AN AVOIDANCE SCHEDULE AS A FUNCTION OF TIME‐CORRELATED STIMULI1
Authors: Grabowski John , Thompson Travis
Published: March 2006

Control of avoidance response patterning by time‐correlated stimuli was studied in rhesus monkeys. At several shock‐shock = response‐shock intervals, the intervals were divided into 8, 4, or 2 time segments by correlating, respectively, 1, 2, or 4 discrete lights of an eight‐light display with each successive segment. A further condition examined response patterning when the avoidance interval was not segmented: all eight lights of the display were lit throughout the interval. Reversal of the order in which the lights were lit in sequence was also examined. Generally, increasing the number of lights lit at one time (decreasing the number of signalled time segments) increased response rates and shifted interresponse time distributions to the left. When the lights were lit one at a time, signalling eight discrete time segments of the interval, response rates were consistently low.
REDUCTION OF INTRASPECIES AGGRESSION IN RATS BY POSITIVE REINFORCEMENT OF INCOMPATIBLE BEHAVIORS1
Authors: Baisinger Joy , Roberts Carl L.
Published: March 2006

Fighting responses were elicited by response‐independent shocks delivered to pairs of rats. Food pellets were presented following different non‐fighting responses to shock: some pairs of rats received pellets dependent upon a specific non‐fighting response to shock; others received pellets dependent upon any non‐fighting response to shock; and control pairs never received pellets. The mean probability of an elicited aggressive response to shock was reduced to 0.2 by food reinforcement for a specific non‐fighting response, and to 0.5 by food reinforcement for any kind of non‐fighting response. These values contrasted with the 0.8 probability of elicited aggression when pairs of rats received no food reinforcement. Consistent findings were obtained when treatment conditions were changed for individual pairs of rats.
COMBINED‐STIMULUS CONTROL AS A FUNCTION OF THE RESPONSE RATE CONTROLLED BY THE ABSENCE OF THE SINGLE STIMULI1
Authors: Wiltz Robert A.
Published: March 2006

Rat's bar‐press responses were maintained at moderate rates during separate presentations of light and tone by separate but concurrent variable‐interval schedules of food and shock presentation. The relative response rate maintained during light‐out‐no‐tone was alternated in four successive phases: in Phases 1 and 3 responding was maintained at a higher rate than that during light and tone alone by a variable‐interval food schedule, while in Phases 2 and 4 responding was reduced to a lower rate by a differential‐reinforcement‐of‐other‐behavior food schedule. In test presentations of light, tone and a light‐plus‐tone combination, administered at the end of each phase, the proportion of responses emitted during light‐plus‐tone was an inverse function of the relative response rate controlled by light‐out‐no‐tone, indicating that the relative training response rate controlled by the absence of the single stimuli determined the control exerted by the combined stimuli. Different relative response rates maintained in training may also be partly responsible for previously observed differences in the form of generalization gradients following the establishment of multi‐stimulus control.
A TEST OF THE NEGATIVE DISCRIMINATIVE STIMULUS AS A REINFORCER OF OBSERVING
Authors: Dinsmoor James A. , Browne Michael P. , Lawrence Charles E.
Published: March 2006

Five pigeons were used to test the hypothesis that the source of reinforcement for observing behavior is the information that it provides concerning the schedule of primary reinforcement. On a variable‐interval schedule, pecking the left‐hand key produced a 30‐sec display of such information. During this 30‐sec period, when pecking the right‐hand key was reinforced on a random‐interval schedule, both keys were green; when no reinforcement was scheduled (extinction) both keys were red. Later, this baseline procedure, in which both red and green were available, was replaced for blocks of sessions by procedures in which either (a) the red was eliminated and only the green could be produced; or (b) the green was eliminated and only the red could be produced. The results were that green maintained rates of pecking on the left key that were as high or higher than when both colors were available and that red maintained no responding. It was concluded that the reinforcing value of a stimulus depends on the positive or negative direction of its correlation with primary reinforcement, rather than upon the amount of information that it conveys.
COMPARISONS BETWEEN VARIABLE‐INTERVAL AND FIXED‐INTERVAL SCHEDULES OF ELECTRIC SHOCK DELIVERY
Authors: Hymowitz Norman
Published: March 2006

Responding maintained in rats under a variable‐interval 35‐sec food schedule was suppressed more by 60‐sec and 240‐sec fixed‐interval schedules of shock delivery than by 60‐sec and 240‐sec variable‐interval schedules of shock delivery. When the delivery of shock was preceded by a 5‐sec visual stimulus, little overall response suppression was found with either fixed‐interval or variable‐interval schedules. In a third experiment, the percentage of occasions on which a cue preceded each shock delivery was varied from 0% to 100%. For the fixed‐interval shock condition, the most suppression occurred with the 0% treatment, the least with 100%, and an intermediate amount with the 50% treatment. For the variable‐interval groups, the most suppression occurred in the 50% condition, the least in the 100% group, and an intermediate amount with 0%.
BEHAVIORAL ASSESSMENT OF PAIN DETECTION AND TOLERANCE IN MONKEYS1
Authors: Manning Alexander A. , Vierck Charles J.
Published: March 2006

Cebus albifrons monkeys received electrical stimulation of the hindlimbs over a wide range of intensities. On trials signalled by a blue light, the animals were permitted to escape shock by pressing a disc, or shock was terminated after 8 sec (free escape). Escape force (disc pressure) was found to increase as stimulation intensity increased well beyond escape threshold, while shock duration curves reached plateau at the mid‐range of intensities. The shock duration curves generated by free escape responses should be comparable to pain detection functions obtained by similar operations in humans, and the curves were stable over months of testing, as is generally found in pain‐detection studies. On trials signalled by a red light, the animals received intense tail shock immediately after escape responses (punished escape), or, if they endured leg shock for 8 sec without escaping, then they could avoid tail shock with a panel press. The shock duration curves generated by punished escape responses should be comparable to pain tolerance functions as defined for human subjects, and the escape thresholds were considerably higher on red‐light trials. As in human studies, the tolerance curves were not stable over repeated testing sessions, and some feature of the paradigm forced a progression toward extremely high levels of tolerance.
AN ANALYSIS OF RESPONSE AND TIME MATCHING TO REINFORCEMENT IN CONCURRENT RATIO‐INTERVAL SCHEDULES1
Authors: LaBounty Charles E. , Reynolds G. S.
Published: March 2006

Key pecks by six pigeons were reinforced on concurrent fixed‐interval fixed‐ratio schedules. The value of the fixed‐interval was held constant at 4 min while the fixed‐ratio varied from 25 to 450 responses. All of the pigeons responded on, with pecks reinforced under, both of the schedules over most of the concurrent pairings, and four of the six distributed responses between the schedules such that matching was obtained between the proportions of responses and reinforcements. Previous studies using concurrent variable‐interval schedules have shown that when response‐reinforcement matching occurs, a comparable match of time to reinforcement proportions is obtained. In the present study, time devoted to each response alternative was measured from the first response on that alternative to a subsequent response on the other alternative. Using that measure, large differences existed in the local rates of responding on the two schedules, and a time‐reinforcement match was not produced. These results indicate that in a situation where response‐reinforcement and time‐reinforcement matching are incompatible, the measurement of response proportions is the better means of evaluating the effects of reinforcement.
CONTRAST EFFECTS IN MAINTAINED GENERALIZATION GRADIENTS1
Authors: Malone John C. , Staddon J. E. R.
Published: March 2006

In Experiment I, pigeons were given equal reinforcement (variable‐interval 1‐min) for responding during randomized presentations of eight line‐orientation stimuli. Then, only responding in the vertical orientation was reinforced. Stable generalization gradients soon formed and persistent behavioral and local (transient) contrast effects appeared. Local contrast effects were not a function of relative reinforcement frequency or of any other variable known to produce contrast. Instead, they were related to average response rates associated with each stimulus. Experiment II showed that local contrast effects represent increases and decreases in response rates relative to baseline responding, and that these effects are relative; a given stimulus might enhance responding during a subsequent presentation of one stimulus, but depress responding when followed by another. These data indicate that discrimination learning is not adequately described as the acquisition of excitatory properties by some stimuli and inhibitory properties by others. A more adequate account implies that stimuli exert both excitatory and inhibitory effects related to their value.
NONDISCRIMINATED AVOIDANCE OF SHOCK BY PIGEONS PECKING A KEY1
Authors: Ferrari Elenice A. , Todorov João Claudio , Graeff Frederico Guilherme
Published: March 2006

Four pigeons were trained to avoid shock by pecking a key on a free‐operant avoidance schedule in which no exteroceptive stimulus signalled impending shock. Response rate was an inverse function of response‐shock interval when shock‐shock interval was held constant at 2 sec and response‐shock intervals varied from 5 to 40 sec. Amphetamine increased response rates in two subjects and reserpine markedly reduced responding in one.
APPLICATION OF BOWER'S ONE‐ELEMENT MODEL TO PAIRED‐ASSOCIATE LEARNING BY PIGEONS
Authors: Rodewald H. Keith
Published: March 2006

Bower's (1961) all‐or‐none model of human paired‐associate learning was applied to individual data supplied by three pigeons. When the center one of three keys was illuminated with red light or with three white dots in a vertical array on a black ground, pecking on the left key was reinforced. When the center key was lighted green or with a horizontal array of three white dots on a black ground, pecking on the right key was reinforced. The left and right keys were illuminated with white light. The task was considered to be analogous to learning a paired‐associate list of four pairs involving four stimulus items and two response items. The model was evaluated by comparing the following model predictions with values obtained from each animal: trials‐to‐criterion, standard deviation of trials‐to‐criterion, standard deviation of errors‐to‐criterion, mean error runs, mean error runs of lengths one to four, and autocorrelations of errors of lags one to three. Most of the predictions based upon the model were in close agreement with the obtained data.
ASSOCIATIVE FACTORS UNDERLYING THE PIGEON'S KEY PECKING IN AUTO‐SHAPING PROCEDURES1
Authors: Gamzu Elkan R. , Williams David R.
Published: March 2006

Key pecking in pigeons can be engendered by associating response‐independent food presentations with illumination of a key. Specific pairings of key and food are not necessary for this phenomenon. Differential positive association between key and food (defined in terms of relative densities of reinforcement), however, is necessary and sufficient to produce and maintain key pecking. Thus, the occurrence of key pecking in auto‐shaping can be considered to depend on associative processes similar to classical conditioning. Consequently, auto‐shaped pecking can be virtually eliminated by the addition of food presentations in the intertrial interval, thus removing the association between key and food. Initial exposure to random reinforcement, or reinforcement only in the absence of the key, results in lower rates of pecking in subsequent auto‐shaping procedures.
PUP RETRIEVING AS A REINFORCER IN NULLIPAROUS MICE1
Authors: Hemel Susan B. Van
Published: March 2006

Six nulliparous female mice were trained to bar press with bar pressing reinforced by the opportunity to retrieve pups to the nest. Then, responses on one bar produced the opportunity to retrieve pups, while responses on a second bar produced sensory contact with non‐retrievable pups, presented behind a screen door. All subjects emitted more responses on the bar yielding retrievable pups. When the bar‐pup contingency was reversed, five subjects learned to press the opposite bar for retrievable pups. The sixth subject showed extinction of responding on the bar that had previously yielded retrievable pups, but failed to press the other bar. A major portion of the reinforcing value of pup presentation resulted from the opportunity to perform the behavior of pup retrieving. This finding supports theoretical formulations which state that the performance of species‐typical consummatory behaviors should have reinforcing properties.
EFFECTS OF PUNISHING ELEMENTS OF A SIMPLE INSTRUMENTAL‐CONSUMMATORY RESPONSE CHAIN1
Authors: Myer James S.
Published: March 2006

Rats were trained to press a lever, with every response reinforced with water. After responding was established, nine rats were administered a brief shock after each lever press, and nine others were shocked after drinking. The two procedures resulted in similar suppression of responding, and examination of the latency data when responding was partially suppressed indicated that under both conditions response suppression was due primarily to an increase in the latency of the instrumental response, rather than to pausing between the instrumental and consummatory responses. Thus, punishment following either the instrumental or consummatory component of the simple response sequence reduced the number of sequences initiated, rather than selectively suppressing the punished behavior.
SYNTHETIC VARIABLE‐INTERVAL SCHEDULES OF REINFORCEMENT1
Authors: Shimp Charles P.
Published: March 2006

Three pigeons pecked for food on a synthetic variable‐interval schedule of reinforcement that had two independent parts: a variable‐interval schedule that arranged a distribution of interreinforcement intervals, and a device that randomly assigned each reinforcement to one of 10 classes of interresponse times. The frequencies of reinforcement for the 10 classes of interresponse times were systematically varied, while the overall frequency of reinforcement was held within a comparatively narrow range. The 10 classes extended either from 0.1 to 0.6 sec in 0.05‐sec intervals, or from 1.0 to 6.0 sec in 0.5‐sec intervals. In the former case, some control by reinforcement was obtained, but it was weak and no simple relationships were discernible. In the latter case, the relative frequency of an interresponse time was a generally increasing function of its relative frequency of reinforcement, and two simple controlling relationships were found. First, the function relating interresponse times per opportunity to reinforcements per opportunity was, over a restricted range, approximately linear with a slope of unity. Second, when all 10 classes of interresponse times were reinforced equally often, the relative frequency of an interresponse time approximately equalled the relative reciprocal of its length.
CHOICE BETWEEN CONCURRENT SCHEDULES1
Authors: Menlove Ronald L. , Moffitt Marilynne , Shimp Charles P.
Published: March 2006

Six pigeons pecked for food in a three‐key experiment. A subject at any time could choose the left or right key and receive reinforcement according to one two‐key concurrent variable‐interval variable‐interval schedule of reinforcement, or it could peck the center key. A peck on the center key arranged the complementary two‐key concurrent variable‐interval variable‐interval schedule on the left and right keys. The two different two‐key concurrent schedules arranged reinforcements concurrently and were signalled by two different colors of key lights. Choice behavior in the presence of a given color conformed to the usual relationship in two‐key concurrent schedules: the relative frequency of responding on a key approximately equalled the relative frequency of reinforcement on that key. Preference for a two‐key concurrent schedule, which was equivalent to preference for a color, was measured by the percentage of all responses on the left and right keys in the presence of that color: this percentage approximately equalled the percentage of all reinforcements that were delivered in the presence of that color. Thus, choice between concurrent schedules conforms approximately to the same relationship as does choice between alternatives in a single concurrent schedule.
SHARED ATTENTION IN PIGEONS1
Authors: Maki William S. , Leith Charles R.
Published: March 2006

Two pigeons performed a three‐key matching‐to‐sample task. The comparison (side key) stimuli were either solid colors or white lines. The sample (center key) stimuli were either compounds (white lines on colored grounds) or elements (white lines on black grounds on some trials, and solid colors on other trials). Sample stimuli were presented for nine sample stimulus durations ranging between 0.04 and 5.00 sec. Within each daily session, both compound and element samples were presented at each sample duration in a random sequence. Compound samples controlled matching responses less effectively than did element samples at all sample stimulus durations.
EFFECTS OF STIMULUS CONTROL AND DEPRIVATION UPON DISCRIMINATIVE RESPONDING1
Authors: Powell Robert W.
Published: March 2006

Discriminative responding in pigeons was studied under multiple variable‐interval extinction schedules in which extinction was correlated with either a tone or a white keylight. The two procedures resulted in weak and strong stimulus control, respectively. In the first experiment, there was no interaction between schedule components when stimulus control was strong and reinforcement was omitted under the previously reinforced component, However, there was marked induction between components when stimulus control was weak and responding was extinguished under the previously reinforced component. In the second experiment, hours of food deprivation was varied under two levels of stimulus control. Deprivation mainly influenced response rates under the extinction stimulus, with greater absolute rate increases occurring the lower the existing level of stimulus control. Increases in responding during the extinction stimulus were four times as great from 24 to 72 hours of deprivation as from 24 to 48 hours under conditions of both high and low stimulus control.
INSIDE THE BLACK BOX, WITH APOLOGIES TO PANDORA. A REVIEW OF ULRIC NEISSER'S COGNITIVE PSYCHOLOGY1
Authors: Salzinger Kurt
Published: March 2006

It behooves us, as good citizens of the science of psychology, to shirk no area of psychology as long as we can apply scientific method to it. The research in cognitive psychology is certainly interesting, on the whole well executed, and very challenging. It is well within the scope of a behavioristic approach. It merely awaits more attention from behaviorists.