bluuebunny/crossref_metadata_2025 huggingface dataset:
EFFECTS OF FOOD DEPRIVATION AND REINFORCEMENT MAGNITUDE ON CONDITIONED SUPPRESSION
Authors: Leslie Julian C.
Published: March 2006

In Experiment I, the responding of rats lever pressing on a variable‐interval schedule for sucrose solution was partially suppressed by a variable duration conditioned stimulus followed by shock. When food deprivation was increased, response rates during and before the conditioned stimulus increased monotonically. Varying the concentration of sucrose across blocks of sessions or from session to session in a semi‐random sequence had little effect on response rates either before or during the conditioned stimulus. With a fixed sequence of increasing concentrations across a five‐session block, increased concentration produced much more rapid increases in response rates before than during the conditioned stimulus. In Experiment II, rats were presented with the same sequence of increasing concentrations across a five‐session block. When tested at 80% body weight, response rates increased rapidly as concentration increased, but at 100%, body‐weight rates increased only slightly. The effect of a change in body weight in Experiment II thus mimicked the effect of the conditioned stimulus in the latter part of Experiment I. These findings support the view that the effect of a pre‐aversive conditioned stimulus is similar to that of a change in food deprivation, but unlike that of a change in reinforcement magnitude.
PARAMETERS AFFECTING THE MAINTENANCE OF NEGATIVELY REINFORCED KEY PECKING1
Authors: Gardner Edward T. , Lewis Paul
Published: March 2006

Three negative reinforcement experiments employing a key‐peck response are described. In Experiment I, pigeons shocked on the average of twice per minute (imposed condition) could produce, by pecking a key, an alternate condition with correlated stimuli. Delayed shocks were added, across sessions, to the alternate condition until pecking stopped. Two of three pigeons continued to peck despite a 100% increase in shock frequency. In Experiment II, pigeons were shocked in the imposed condition four times per minute. The postresponse delay to shock was held constant by delivering, in the alternate condition, the next shock, or the next two, three, or four shocks from the imposed‐condition shock schedule. All three subjects continued to peck with no change in delay to the first two postresponse shocks but with a 75% reduction in shock frequency. In Experiment III, a response produced an immediate shock followed by a shock‐free period. Three of four subjects continued to respond despite reduced delay to shock. Delay‐to‐shock or shock‐frequency reduction was sufficient to maintain key pecking, but neither was necessary. The conditions that negatively reinforce the pigeon's key peck were similar to conditions that negatively reinforce the rat's bar press.
SHORT‐TERM MEMORY IN THE PIGEON: DELAYED‐PAIR‐COMPARISON PROCEDURES AND SOME RESULTS1
Authors: Shimp Charles P. , Moffitt Marilynne
Published: March 2006

A discrete‐trials, delayed‐pair‐comparison procedure was developed to study visual short‐term memory for tilted lines. In four experiments, pigeons' responses on left or right keys were reinforced with food depending on whether a comparison stimulus was or was not the same as a standard stimulus presented earlier in the same trial. In Experiment I, recall was an increasing function of the exposure time of the to‐be‐remembered stimulus and was a decreasing function of the retention interval. In Experiment II, retroactive interference was investigated: recall was poorer after a retention interval during which was presented either a tilted line or contextual stimuli in the form of the illuminated experimental chamber. In Experiment III, a subject was required to engage, throughout the retention interval, in one or the other of two different behaviors, depending on which of two stimuli a subject was to remember. This mnemonic strategy vastly improved recall after 15‐ and 20‐second retention intervals. In Experiment IV, the opposite end of the performance continuum was studied: by combining the effects of a larger stimulus set and the effects of what presumably was an increased memory load, performance was reduced to approximately chance levels after retention intervals shorter than 1 second.
YOKED VARIABLE‐RATIO AND VARIABLE‐INTERVAL RESPONDING IN PIGEONS1
Authors: Catania A. Charles , Matthews T. James , Silverman Phillip J. , Yohalem Rona
Published: March 2006

Pigeons' key pecks were maintained by variable‐ratio or variable‐interval schedules of food reinforcement. For pairs of pigeons in one group, variable‐ratio reinforcement was arranged for one pigeon's pecks; for the second pigeon, reinforcement was arranged according to a variable‐interval schedule yoked to the interreinforcement times produced by the first pigeon. For pairs of pigeons in another group, variable‐interval reinforcement was arranged for one pigeon's pecks; for the second pigeon, reinforcement was arranged according to a variable‐ratio schedule yoked to the interreinforcement responses produced by the first pigeon. For each pair, the yoking procedure was maintained for four or five consecutive sessions of 50 reinforcements each. In more than three‐quarters of the pairs, variable‐ratio response rates were higher than variable‐interval rates within two sessions; in all cases, the rate difference developed within four sessions.
ON THE ROLE OF “MEMORY” IN THE ANALYSIS OF BEHAVIOR
Authors: Branch Marc N.
Published: March 2006

Shimp's (1976) recent paper on memory and the structure of behavior is discussed, as is the concept of memory itself. Radical behaviorism is distinguished from associationism, and behavioral accounts of experiments on short‐term and long‐term memory are provided. Unobservable theoretical quantities, such as rate of response, are distinguished from theoretical constructs such as memory. The logical inconsistency involved in the use of short‐term memory as a “theoretical primitive” in the definition of units of behavior is explicated, and an alternative strategy for identifying units of behavior is presented. It is argued that the experimental analysis of behavior has ignored processes usually considered as memorial because many of the phenomena are irreversible. Methods for the study of transitions in single subjects should be developed more fully. Possible pitfalls associated with subscription to the term memory are listed, and it is concluded that the concept is neither required nor helpful in the analysis of behavior.
SPECIES DIFFERENCES IN TEMPORAL CONTROL OF BEHAVIOR
Authors: Lowe C. Fergus , Harzem Peter
Published: March 2006

Temporal control of rats' and pigeons' responding was analyzed and compared in detail on fixed‐interval and fixed‐time schedules with parameters of 30, 60, and 120 seconds. On fixed‐time schedules, rats' responding decreased greatly or ceased, whereas pigeons continued to respond, especially on low schedule values. The running rate of responses (calculated by excluding the postreinforcement pause) was related to the duration of the preceding postreinforcement pause for rats but not for pigeons. Changes in response rate in successive segments of the interval were best described by normal curves. The relationship between midpoints of the normal curves and schedule value was a power function, with an exponent of less than one for pigeons but greater than one for rats. These differences could be explained in terms of a basic difference between the key‐peck and lever‐press responses, the two being differently affected by the response‐eliciting properties of food.
CONDITIONING OF WITHIN‐TRIAL PATTERNS OF KEY PECKING IN PIGEONS1
Authors: Wasserman Edward A.
Published: March 2006

The possibility of conditioning systematic patterns of responding during brief discrete trials was studied by requiring hungry pigeons to key peck and then pause or to pause and then key peck in order to gain access to food. These schedules were highly effective in promoting decelerated and accelerated rates of responding, respectively, within individual trials; indeed, performance was quite similar to that observed when explicit external stimuli were correlated with “peck” and “pause” portions of the daily trials. Finally, schedules of reinforcement that did not selectively reinforce peck‐pause or pause‐peck patterns neither generated these patterns nor maintained them at the previous high levels. The results, therefore, confirm Shimp's (1976) proposal that organized groupings of discrete responses may function as operants—even in the absence of strict response‐reinforcer contiguity.
ORIENTATION AND LEVER RESPONDING IN AUDITORY DISCRIMINATIONS IN SQUIRREL MONKEYS1
Authors: Harrison J. M. , Briggs R. M.
Published: March 2006

Head orientation during auditory discriminations was studied in squirrel monkeys using a two‐lever trial‐by‐trial procedure. Animals were studied using auditory discriminations based on the position of the sound and on the spectral content differences between a pure tone and a noise. After the percentage of correct responses reached asymptote, head orientation was measured using videotape recordings. Orientation occurred on virtually every trial and was under the control of the position of the sound under all conditions. Lever responding was controlled by the same parameters of the sound under some conditions, and by different parameters in others. Orientation and lever responding were correlated (a lever response could be predicted from the direction of orientation) when both responses were under the control of the same parameter of the sound. The two responses were uncorrected when they were controlled by different parameters of the sound. Orientation and lever responding were not functionally related.
CONTROL OF RESPONDING BY LOCATION OF AUDITORY STIMULI: ADJACENCY OF SOUND AND RESPONSE1
Authors: Harrison J. M. , Iversen S. D. , Pratt S. R.
Published: March 2006

Four rhesus monkeys were trained to respond on one key when a one‐second noise burst was presented through one speaker and to respond on a second key when the noise burst was presented through a second speaker. The acquisition of stimulus control was studied under three conditions, in each of which the relationship between the sound source and the response‐key positions varied: an adjacent condition in which the noise burst was presented through the key and a response on this key was reinforced; a reversed‐adjacent condition in which the noise burst was presented through one key and responding on the other key was reinforced; and a nonadjacent condition in which responding on the key nearer the sound was reinforced. Under adjacent conditions, stimulus control developed within one or two sessions. Under reversed and nonadjacent conditions, 10 sessions were required for the development of control. The asymptote of correct responding was the same under each condition in all animals.
MULTIPLE AND CONCURRENT SCHEDULE PERFORMANCE: INDEPENDENCE FROM CONCURRENT AND SUCCESSIVE SCHEDULE CONTEXTS
Authors: Lobb Brenda , Davison M. C.
Published: March 2006

Six pigeons were trained on multiple variable‐interval schedules and performance was measured in the presence or absence of another variable‐interval schedule (the common schedule) arranged concurrently with both components. Manipulations included varying the rate of reinforcement on the common schedule, leaving the common schedule unchanged while the components of the multiple schedule were varied, varying the multiple schedule components in the absence of the common schedule, and varying one component of the multiple schedule while the other component and the common schedule were unchanged. The normal rate‐increasing and rate‐decreasing effects of reinforcement rate increase were found, except that changing one multiple schedule component did not affect the response rate in the successively available common schedule component. Both concurrent and multiple schedule performance undermatched obtained reinforcement‐rate ratios, but the degree of undermatching in multiple schedules was reliably greater. Allocation of responses between multiple schedule components was unaffected by the concurrent availability of reinforcement, and allocation of responses between concurrent schedules was unaffected by the successive availability of different reinforcement rates.
PUNISHMENT‐SPECIFIC EFFECTS OF PENTOBARBITAL: DEPENDENCY ON THE TYPE OF PUNISHER1
Authors: Branch Marc N. , Nicholson Gayle , Dworkin Steven I.
Published: March 2006

Pigeons were trained to peck a key under a multiple random‐interval 1‐minute, random‐interval 6‐minute schedule of food presentation. Subsequently, over three phases, additions were made during the random‐interval 1‐minute component as follows: pecks during the component occasionally were punished by timeout presentation (Phase 1), timeouts were presented independently of responding during the component (Phase 2), pecks during the component occasionally were punished by electric‐shock presentation (Phase 3). In Phases 1 and 3, response‐dependent timeout and shock suppressed responding and established equivalent rates in both components of the multiple schedule. Intermediate doses of pentobarbital increased responding suppressed by electric‐shock punishment but had little or no effect on responding suppressed by timeout punishment. Response‐independent presentation of timeouts did not result in suppression of responding (thus showing that response‐dependent timeout acted as a punisher), and pentobarbital did not reliably increase unpunished responding. Pentobarbital's selective “punishment‐attenuating” properties depend on the nature of the punisher.
INTERLOCKING SCHEDULES: THE RELATIONSHIP BETWEEN RESPONSE AND TIME REQUIREMENTS1
Authors: Rider David P.
Published: March 2006

Rats were exposed to an interlocking fixed‐ratio 150 fixed‐interval 5‐minute schedule of food reinforcement and then to yoked variable‐ratio schedules in which individual ratios corresponded exactly to the ratios of responses to reinforcement obtained on the interlocking schedule. After additional training with the interlocking schedule, the rats were exposed to yoked variable‐interval schedules in which intervals corresponded to the intervals between successive reinforcements obtained on the second interlocking schedule. Response rates were highest in the yoked VR condition and lowest in the yoked VI, while intermediate rates characterized the interlocking schedule. Break‐run patterns of responding were generated by the interlocking schedule for all subjects, while both the yoked VR and VI schedules produced comparatively stable local rates of responding. These results indicate that responding is sensitive to the interlocking schedule's inverse relationship between reinforcement frequency and responses per reinforcement.
STIMULUS‐ AND RESPONSE‐REINFORCER CONTINGENCIES IN AUTOSHAPING, OPERANT, CLASSICAL, AND OMISSION TRAINING PROCEDURES IN RATS
Authors: Atnip Gilbert W.
Published: March 2006

Separate groups of rats received 500 trials of lever‐press training under autoshaping (food delivery followed 10‐second lever presentations, or occurred immediately following a response); operant conditioning (responding was necessary for food delivery); and classical conditioning (food followed lever presentations regardless of responding). Each group then received 500 trials on an omission procedure in which food was omitted on trials with a response. Another group received 1000 trials on the omission procedure, and a fifth group, random control, received 1000 uncorrelated presentations of lever and food. The autoshaping, operant, and classical groups reached high response levels by the end of initial training. Acquisition was fastest in the autoshaping group. Responding remained consistently low in the control group. The omission group responded at a level between the control group and the other three groups. During omission training, responding in these three groups declined to the omission‐group level. During omission training, the rats continued contacting the lever frequently after lever pressing had declined. Response maintenance under omission training seems not to require topographic similarity between the response and reinforcer‐elicited consummatory behaviors.
FIXED‐INTERVAL MATCHING‐TO‐SAMPLE: INTERMATCHING TIME AND INTERMATCHING ERROR RUNS1
Authors: Nelson Thomas D.
Published: March 2006

Four pigeons were trained on a matching‐to‐sample task in which reinforcers followed either the first matching response (fixed interval) or the fifth matching response (tandem fixed‐interval fixed‐ratio) that occurred 80 seconds or longer after the last reinforcement. Relative frequency distributions of the matching‐to‐sample responses that concluded intermatching times and runs of mismatches (intermatching error runs) were computed for the final matching responses directly followed by grain access and also for the three matching responses immediately preceding the final match. Comparison of these two distributions showed that the fixed‐interval schedule arranged for the preferential reinforcement of matches concluding relatively extended intermatching times and runs of mismatches. Differences in matching accuracy and rate during the fixed interval, compared to the tandem fixed‐interval fixed‐ratio, suggested that reinforcers following matches concluding various intermatching times and runs of mismatches influenced the rate and accuracy of the last few matches before grain access, but did not control rate and accuracy throughout the entire fixed‐interval period.
A STUDY OF MISBEHAVIOR: TOKEN REINFORCEMENT IN THE RAT1
Authors: Boakes R. A. , Poli M. , Lockwood M. J. , Goodall G.
Published: March 2006

The purpose of this research was to investigate the phenomenon of misbehavior described by Breland and Breland (1961). Rats were trained to obtain ball‐bearings and drop them in a hole for food or water reinforcers. In confirmation of the Brelands' observation, many subjects were slow to deliver the balls, and frequently attempted to chew them before they were dropped. A series of four experiments, in which the same rats were used throughout, showed that delivery times tended to be longer with food than with water, and that these times increased when nylon balls were substituted. The effect of motivational level was investigated by varying both deprivation and amount of prefeeding; no effect on delivery time was detected, although other measures of performance were affected by motivational factors. Similar results were obtained in a final experiment that employed a new set of naive subjects. The studies demonstrated that misbehavior can be studied in an experimental situation, and the results supported an analysis in terms of competition between stimulus‐reinforcer and response‐reinforcer contingencies. The question of why such effects have not been reported in previous token reinforcer studies was unanswered.
HISTOLOGICAL DATA: HOLLARD AND DAVISON (1971)
Authors: Hollard Valerie , Davison M. C.
Published: March 2006

As Mogenson and Cioé (1977) have assumed that our electrodes aimed at the ectostriatum (Hollard and Davison, 1971) were actually located there, we feel that a presentation of the histological data is necessary. Following termination of further experiments (Hollard, 1974) the pigeons, numbered 93, 95, and 119, were sacrificed and perfused with saline followed by 10% formalin. Sections, 50 microns thick, were cut on a freezing microtome. Prints were made by mounting each unstained section of a microscope slide and placing them in a standard photographic enlarger. The electrode tips of Pigeons 93 and 119 were located in the paleostriatal complex. The sections of Pigeon 95 were damaged and precise localization was not possible. Further work in this laboratory has also found that, using the same coordinates, electrode tips tend to fall in the paleostriatum, rather than in the more dorsal ectostriatum at which they are aimed. The paleostriatal placements tended to sustain self‐stimulation, whereas others located in the ectostriatum sustained relatively low or unstable rates.
BEHAVIORAL CONTRAST AS DIFFERENTIAL TIME ALLOCATION
Authors: White K. Geoffrey
Published: March 2006

In Experiment I, hooded rats were exposed to multiple variable‐interval schedules of reinforcement in which manipulanda and reinforcement magazines at opposite ends of the experimental chamber were associated with the different components. Time allocated to each component was measured by recording the time spent by the subject in the appropriate half of the chamber. Positive behavioral contrast was observed for the comparison between multiple variable‐interval 30‐second variable‐interval 30‐second and multiple variable‐interval 30‐second variable‐interval 90‐second conditions for both response frequency and time allocation measures, but not for mean local response rate (response frequency per time allocated to a component). In Experiment II, rats were exposed to multiple variable‐time schedules in which reinforcement was response independent. Time allocated to each component was measured for two conditions, multiple variable‐time 30‐second variable‐time 30‐second and multiple variable‐time 30‐second variable‐time 90‐second. Positive behavioral contrast of time allocation was exhibited. The results indicated that time allocation was differentially sensitive to changes in reinforcement probability, and that behavioral contrast may result from the differential allocation of time to the different components of the multiple schedule.
EFFECT OF VARIABLE‐INTERVAL PUNISHMENT ON THE BEHAVIOR OF HUMANS IN VARIABLE‐INTERVAL SCHEDULES OF MONETARY REINFORCEMENT1
Authors: Bradshaw C. M. , Szabadi E. , Bevan P.
Published: March 2006

One male and three female human subjects pressed a button for monetary reinforcement under a range of variable‐interval schedules specifying different frequencies of reinforcement. On alternate days, responding was also punished (by subtraction of money) according to a variable‐interval 170‐second schedule. In the absence of punishment, the rate of responding was an increasing negatively accelerated function of reinforcement frequency, as predicted by Herrnstein's equation. The effect of the punishment schedule was to suppress responding under lower frequencies of reinforcement; responding under higher reinforcement frequencies was much less affected. This was reflected in an increase in the value of KH (the constant expressing the reinforcement frequency corresponding to the half‐maximal response rate), whereas there was no significant change in the value of Rmax (the constant expressing the maximum response rate). Previous results had shown that variable‐ratio punishment resulted in a change in the values of both constants (Bradshaw, Szabadi, and Bevan, 1977). The results of the present study were consistent with the concept that the suppressive effects of punishment on responding depend on the nature of the punishment schedule.
CHOICE PERFORMANCE IN SEVERAL CONCURRENT KEY‐PECK TREADLE‐PRESS REINFORCEMENT SCHEDULES1
Authors: Wheatley Kimbal L. , Engberg Larry A.
Published: March 2006

Five pigeons were exposed to several concurrent variable‐interval food reinforcement schedules. For three subjects, one component of the schedule required a key‐pecking response, the other a treadle‐pressing response. For the other two subjects, both schedule components required treadle‐pressing responses. The relative probability of reinforcement associated with the manipulanda was varied from 0 to 1.0 in 13 experimental conditions for the Key‐Treadle subjects and nine conditions for the Treadle‐Treadle subjects. The results indicated that the logarithms of relative time spent responding, and the logarithms of relative number of responses emitted on a manipulandum, approximated direct linear functions of logarithms of the relative frequencies of reinforcement associated with that manipulandum. No systematic bias in favor of time spent key pecking over time spent treadle pressing was apparent for the Key‐Treadle subjects. All subjects exhibited undermatching, in that the ratios of time and response allocation at the alternatives systematically differed from the ratios of reinforcers obtained from the alternatives in the direction of indifference. Key pecking appeared to have no special link to food beyond treadle pressing or what would be expected on the basis of the reinforcement dependencies alone.
TIME‐ALLOCATION MATCHING BETWEEN PUNISHING SITUATIONS1
Authors: Deluty Marvin Z. , Church Russell M.
Published: March 2006

In the presence and absence of white noise, response‐independent aversive events were delivered to rats according to several variable‐time electric‐shock schedules. The animals could switch from the noise component to the no‐noise component and vice versa by making a single lever‐press response. If the schedule in one component was not in operation when the animal was in the other component, the proportion of time allocated to one component equalled or matched the proportion of obtained punishers in the other component. If both schedules were always in operation, minimizing tended to occur: the animals allocated almost all of their time to the component having the lower shock rate. An analysis of these results, in terms of the expected time until an aversive event, is presented.
TIME‐DEPENDENT CHANGES IN CONDITIONED SUPPRESSION
Authors: Howard R. C. , Rilling Mark
Published: March 2006

Time‐dependent changes in a response following aversive conditioning were investigated using a conditioned suppression procedure in a within‐subjects design. Four groups of pigeons received Pavlovian conditioning “off the baseline”, immediately followed by an operant task. During the Pavlovian phase, two groups received a forward pairing of a tone with shock, one group received a backward pairing, and one group received a truly random pairing. One of the forward pairing groups also received a delay between the Pavlovian and operant phases. For all groups, key pecking was reinforced on a variable‐interval schedule during the operant phase. Testing sessions were identical to training sessions, except that the tone used during Pavlovian conditioning was presented either 0, 15, 30, 45, of 60 minutes after the operant phase began. Testing sessions in which the Pavlovian phase was omitted were also included. The results showed suppression to change as a function of the retention interval, with maximum suppression occurring at intermediate intervals. This U‐shaped function was obtained for 11 of the 12 pigeons in the forward‐pairing groups and for three of the five in the truly random group. Pigeons in the background pairing group did not show changes in suppression as a function of the retention interval.
CONSERVATION, CHOICE, AND THE CONCURRENT FIXED‐RATIO SCHEDULE
Authors: Shapiro Neil , Allison James
Published: March 2006

Five rats got all of their water in daily 60‐minute sessions. Two levers and a water spout were freely available throughout baseline sessions. Contingency sessions offered a choice between two alternative fixed‐ratio components, in the form of a choice between the two levers. Each component required a specified number of lever presses for access to the spout, and then a specified number of licks for another choice between components. Given the observed relative frequency, the absolute frequency of selecting each component was predicted accurately by assuming that the subject conserved between baseline and contingency the total amount of a dimension attributable to lever pressing and licking. Several quantitative models for predicting relative frequency were examined. The best of these assumed that the subject would show a nonexclusive preference for the component requiring fewer lever presses.
CONSTRUCTION OF EQUAL‐HUE DISCRIMINABILITY SCALES FOR THE PIGEON1
Authors: Wright Anthony A.
Published: March 2006

Equal‐hue discriminability steps for the pigeon are shown as tabular entries that can be summed or interpolated to produce sequences of equal discriminability steps of various step size. Equal‐hue discriminability sequences can be constructed where the number of stimuli and spectral range are specified, or where an interval in one spectral region is to be equated to an interval in another spectral region.
LEVER ATTACKING AND PRESSING AS A FUNCTION OF CONDITIONING AND EXTINGUISHING A LEVER‐PRESS AVOIDANCE RESPONSE IN RATS1
Authors: Pear Joseph J. , Hemingway Michael J. , Keizer Peter
Published: March 2006

Six experimental rats were conditioned to press one of two available levers to avoid shock. The levers registered bites as well as presses. For four of these rats, shock was contingent on lever bites when a specified time period had elapsed after the previous shock. An extinction period, in which only periodic noncontingent shocks were presented, followed avoidance training. Six yoked‐control rats received the same sequence of shocks as did the corresponding experimental rats in both the conditioning and extinction phases. All six experimental rats repeatedly bit the avoidance lever. Four bit it more than the nonavoidance lever during conditioning, and five bit it more during extinction. Five of the six experimental rats consistently bit the levers many more times during each session than did their respective control rats, suggesting that avoidance conditioning facilitated lever biting. Rates of lever biting and pressing by all of the experimental rats and by some of the control rats were highest immediately following shock throughout both phases. During later portions of the intervals following shock, characteristic effects of conditioning and extinction were observed. This finding suggests that extinction of avoidance behavior by unavoidable shock presentations can be demonstrated more readily when shock‐elicited responding is extricated from the data.
ACUTE AND CHRONIC EFFECTS OF COCAINE ON EXTINCTION‐INDUCED AGGRESSION1
Authors: Moore Mitchell S. , Thompson Donald M.
Published: March 2006

Pigeons worked individually in a chamber containing a response key and a mirror. Pecking on the key was controlled by a multiple schedule in which a brief period of continuous food reinforcement alternated with a 5‐minute period of extinction. Under baseline conditions, aggressive behavior (responding on the mirror) occurred at the onset of each extinction period. In Experiment I (acute drug administration), the aggressive behavior was decreased by doses of cocaine that had little or no effect on key pecking. Such food‐reinforced responding was disrupted, however, by higher doses of cocaine. An attempt to mimic the disruptive drug effects by a prefeeding manipulation was unsuccessful. In Experiment II (chronic drug administration), some tolerance developed to the disruptive effects of cocaine on the food‐reinforced responding, except at the highest dose tested. There was no clear‐cut indication of tolerance to the initial effect of cocaine on the aggressive behavior at any dose.
SPECIES DIFFERENCES IN TEMPORAL CONTROL OF BEHAVIOR II: HUMAN PERFORMANCE1
Authors: Lowe C. Fergus , Harzem Peter , Bagshaw Michael
Published: March 2006

Human subjects responded on two panels. A differential‐reinforcement‐of‐low‐rate schedule with a limited‐hold contingency operated on Panel A. In Condition 1, responses on Panel B produced a stimulus on the panel that signalled whether reinforcement was available on Panel A. In Condition 2, responses on Panel B briefly illuminated a digital clock. In both conditions, performance on Panel A was very efficient; with few exceptions, Panel A was pressed only when reinforcement was available. Thus, in effect, a fixed‐interval schedule operated on Panel B. In Condition 1, a “break‐and‐run” response pattern occurred on Panel B; with increasing temporal parameters, the duration of the postreinforcement pause on Panel B increased linearly while overall response rate and running rate (calculated by excluding the postreinforcement pauses) remained approximately constant. In Condition 2, the response pattern on Panel B was scalloped; the postreinforcement pause was a negatively accelerated increasing function of schedule value, while overall response rate and running rate were negatively accelerated decreasing functions of schedule value. The performance of subjects in Condition 2, but not in Condition 1, was highly sensitive to the contingencies in operation, and resembled that of other species on the fixed‐interval schedule.
THE SYMMETRICAL LAW OF EFFECT AND THE MATCHING RELATION IN CHOICE BEHAVIOR1
Authors: Farley Joseph , Fantino Edmund
Published: March 2006

In a concurrent‐chains procedure, pigeons chose between outcomes that differed in the rate of response‐independent delivery of food and electric shocks. The application of functional measurement techniques confirmed the matching relation—between choice and rate of reinforcement value—for two of three pigeons. Scale values of the outcomes were extracted for the two birds that conformed to matching, and the value of a single occurrence of shock per minute—in terms of negative food units—was estimated. A second experiment with concurrent chains provided a test of these parameter estimates. The close correspondence between predicted and obtained choice behavior found in Experiment II indicated that the estimates of outcome value were indeed reliable. Both experiments together support the contention that the effects on choice behavior of positive and aversive stimuli appear to be equal, though opposite in sign.
BEHAVIOR SIMULTANEOUSLY MAINTAINED BY BOTH PRESENTATION AND TERMINATION OF NOXIOUS STIMULI1
Authors: Barrett James E. , Spealman Roger D.
Published: March 2006

Lever pressing by two squirrel monkeys was maintained under a 3‐minute variable‐interval schedule of response‐produced electric‐shock presentation. At the same time, responding on a second lever was maintained under a 3‐minute fixed‐interval schedule of termination of the shock‐presentation schedule and shock‐correlated stimuli. Under the termination schedule, the first response after a 3‐minute period produced a 1‐minute timeout, during which no events occurred and responding had no scheduled consequence. Relatively high and constant rates of responding were maintained on the lever where responding produced shock. Lower rates and positively accelerated patterns of responding occurred on the lever where responding terminated the shock schedule. Thus, responding was simultaneously maintained by presentation of an event and by termination of a stimulus associated with that event. Rates and patterns of responding on each lever were reversed when the schedules arranged on each lever were reversed on two occasions. When shock intensity was increased from 0 to 10 mA, responding maintained both by presentation of shock and by termination of the shock schedule increased, but responding maintained by shock presentation increased to a greater extent. Positive and negative reinforcement, usually regarded as separate behavioral processes involving different events, can coexist when behavior is controlled by different contingencies involving the same event.
d‐AMPHETAMINE AND FIXED‐INTERVAL PERFORMANCE: EFFECTS OF OPERANT HISTORY
Authors: Urbain Cathleen , Poling Alan , Millam James , Thompson Travis
Published: March 2006

Sixteen rats were initially exposed for 50 sessions to either a fixed‐ratio 40 or an interresponse‐time‐greater‐than‐11‐second food reinforcement schedule, then shifted to a fixed‐interval 15‐second food reinforcement schedule. Animals with fixed‐ratio 40 histories lever pressed at much higher rates under the fixed‐interval schedule than did animals with interresponse‐time‐greater‐than‐11‐second histories. This difference persisted across 93 sessions of fixed‐interval exposure. The effects of d‐amphetamine were assessed after 15 and 59 sessions of fixed‐interval exposure. On both occasions, the low‐rate responding of animals with interresponse‐time‐greater‐than‐11‐second histories was typically increased by all doses of the drug, while the high‐rate responding of animals with fixed‐ratio 40 histories was typically decreased by all doses of the drug. These results suggest that control response rate under the fixed‐interval schedule, which may be affected by a history of responding under another schedule, is the primary determinant of the relative effects of d‐amphetamine.
CONDITIONED REINFORCEMENT AND DISCRIMINATION IN SECOND‐ORDER SCHEDULES
Authors: Rose Jed E. , Fantino Edmund
Published: March 2006

Pigeons were exposed to multiple second‐order schedules in which responding on the “main key” was reinforced according to either a variable‐interval or fixed‐interval schedule by production of a brief stimulus on the “brief‐stimulus key”. A response was required to the brief stimulus during its fourth (final) presentation to produce food; responses to the earlier brief stimuli indicated the extent to which the final brief stimulus was discriminated from preceding ones. Main‐key response rates were higher in early components of paired brief‐stimulus schedules, in which each brief stimulus was the same as that paired with reinforcement, than in comparable unpaired brief‐stimulus or tandem schedules. Poor discrimination occurred between paired brief stimuli (Experiment I). When chain stimuli on the main key induced a discrimination between the first two and second two brief stimuli, the response‐rate enhancement in the paired brief‐stimulus schedule persisted (Experiment II). Rate enhancement diminished when the initial link of the chain included the first three components (Experiment IV). Eliminating the contingency between responding and brief‐stimulus production also diminished rate enhancement (Experiment III). The results show that the discriminative and conditioned reinforcing effects of food‐paired brief stimuli may be selectively manipulated and suggest that the reinforcing effects are modulated by other reinforcers in the situation.
TIME ALLOCATION IN CONCURRENT SCHEDULES: THE EFFECT OF SIGNALLED REINFORCEMENT1
Authors: Marcucella Henry , Margolius Garry
Published: March 2006

The responses of five pigeons were reinforced on concurrent variable‐interval variable‐interval reinforcement schedules in which changeover key responses changed the stimulus and reinforcement schedules associated with the food key. While the reinforcement availability in one component remained unchanged throughout the experiment, the reinforcement availability in the other component was, during several conditions, signalled by the onset of an additional discriminative stimulus. During unsignalled conditions, both the relative frequency of responding and the relative time spent in each component approximated the obtained relative reinforcement frequency in each component. The effect of signalling reinforcer availability in one component was to (1) reduce responding in the signalled component to near‐zero levels, and (2) increase the relative time in the unsignalled component, without a corresponding increase in the obtained relative reinforcement frequency. The magnitude of the increase in relative time in the unsignalled component decreased as the overall frequency of reinforcement increased. This deviation in the matching relation between relative time and the obtained relative reinforcement frequency was eliminated if the overall reinforcement frequency was increased before the signal was introduced and then, without removing the signal, gradually reduced.
NEGATIVE BEHAVIORAL CONTRAST ON MULTIPLE TREADLE‐PRESS SCHEDULES
Authors: McSweeney F. K.
Published: March 2006

Eight pigeons pressed treadles for food reinforcers delivered by several multiple variable‐interval schedules. The rate of reinforcement for responding during one component schedule was held constant at 30 reinforcers per hour. The rate of reinforcement for responding during the other component varied from 0 to 120 or 240 reinforcers per hour. The schedules were presented in different orders for different subjects. The rate of responding emitted during the variable component schedule varied directly with the rate of reinforcement it provided. The rate of responding during the constant component did not increase consistently when the rate of reinforcement obtained from the variable component decreased from 30 to 0 reinforcers per hr. The rate of responding emitted during the constant component decreased when the rate of reinforcement obtained from the variable component increased from 30 reinforcers per hour to a higher rate. That is, negative but not positive behavioral contrast occurred. The failure to find positive contrast is consistent with one of the predictions of the additive theories of behavioral contrast. Finding negative contrast has ambiguous implications for the additive theories.
SCHEDULE‐INDUCED POLYDIPSIA IN RATS LIVING IN AN OPERANT ENVIRONMENT
Authors: Petersen Michael R. , Lyon David O.
Published: March 2006

The effect of variations in interreinforcement interval on the temporal and distributional relation between feeding and drinking was continuously monitored. Rats were housed continuously in an operant chamber in which water was freely available, but lever pressing was required to obtain food (45‐mg pellets). Initially, pellets were delivered on a fixed‐ratio 1 schedule of reinforcement, which was followed by testing on response‐initiated fixed‐interval 15‐, 30‐, and 60‐second schedules. The total number of discrete, daily meals (a period in which several pellets were earned in succession) was slightly higher during the fixed‐interval schedules than during the fixed‐ratio 1, but there was no systematic effect of fixed‐interval length on meal frequency. Total water consumption, in contrast, increased dramatically as the interval was lengthened: both subjects consumed two to three times as much water on the fixed‐interval 60‐second schedule as on the fixed‐ratio 1. The increased water consumption was the result of an alteration in the distribution of drinking relative to eating. During the fixed‐ratio 1 condition, drinking occurred infrequently following individual food pellets and represented the smallest percentage of total drinking; drinking occurred predominantly just before or after a meal. As the fixed interval was lengthened, however, the frequency of postpellet drinking gradually increased and eventually comprised the largest proportion of daily drinking.
THE ROLE OF PHYSICAL IDENTITY OF THE SAMPLE AND CORRECT COMPARISON STIMULUS IN MATCHING‐TO‐SAMPLE PARADIGMS1
Authors: Santi Angelo
Published: March 2006

Pigeons were trained in a higher‐order conditional discrimination paradigm to assess the role of physical identity in a within‐subjects design. A line orientation which was superimposed on all response keys signalled whether a response to the matching color or a response to the nonmatching color was correct. Following training under this paradigm, stimulus control gradients were obtained by varying the angularity of the lines. Orderly gradients of stimulus control were obtained and no bias toward or away from the physically identical comparison stimulus was observed. The data were interpreted as indicating that the pigeons acquired a discrimination for each specific stimulus configuration or a set of specific stimulus‐response chains based on compound stimuli in which physical identity played no special role.
EFFECTS OF ERROR AND ERRORLESS DISCRIMINATION ACQUISITION ON REVERSAL LEARNNG
Authors: Robinson P. W. , Storm R. H.
Published: March 2006

The effectiveness of trial‐and‐error, graded‐choice, and verbal‐instruction procedures on the acquisition and maintenance of a two‐choice simultaneous color discrimination in an intradimensional double‐reversal learning situation was studied using 18 first‐grade children. After acquiring a red‐green discrimination during one 70‐trial session, the discriminative roles of the stimuli were reversed for 30 trials, followed by a second reversal for 30 trials. Children in the graded‐choice and verbal‐instruction groups acquired and maintained the discriminations with fewer errors than children who learned by trial and error. The importance of the results in terms of two‐stage discrimination learning theories is pointed out and similarities between errorless learning and overtraining are discussed.
ATTENTIONAL CHANGES DURING DISCRIMINATION LEARNING BY RETARDED CHILDREN1
Authors: Singh N. N. , Beale I. L.
Published: March 2006

Eight moderately retarded children were trained on a simultaneous two‐choice discrimination problem and a series of discrimination‐shift problems. The procedure required the subjects to perform overt observing responses to produce elements of the discriminative stimuli, making it possible to measure directly changes in attention to different aspects of stimuli during learning. The patterns of change in observing responses were generally in line with descriptions of attentional changes derived from two‐process theories of discrimination learning; for example, the frequency of irrelevant observing responses was high during the presolution period during extradimensional shifts but was low during intradimensional shifts. Contrary to current theories, extradimensional shifts caused an immediate increase in irrelevant observing responses, and intradimensional shifts usually caused an increase in relevant observing responses. Subjects responded to later shift problems by initially increasing both relevant and irrelevant observing responses, then withholding irrelevant observing responses.
BEYOND THE RELATIONAL PRINCIPLE OF REINFORCEMENT1
Authors: Allison James
Published: March 2006

Behavior under baseline conditions in which the contingency is absent can shed some light on the individual's performance under a schedule, but is insufficient as a basis for prediction of performance. This insufficiency of the baseline data runs counter to a recent formalization of the relational principle of reinforcement (Donahoe, 1977). A more satisfactory predictive model must incorporate not only the baseline level of the instrumental response and that of the contingent response, but also the schedule requirements, the character of each response in relation to the other, and the behavior required in simply switching from each to the other.
COMPLEX LEARNING AND INFORMATION PROCESSING BY PIGEONS: A CRITICAL ANALYSIS
Authors: Carter David E. , Werner Thomas J.
Published: March 2006

Three models of conditional discrimination learning by pigeons are described: stimulus configuration learning, the multiple‐rule model, and concept learning. A review of the literature reveals that true concept learning is not characteristic of the behavior of pigeons in matching‐to‐sample, oddity‐from‐sample, or symbolic matching studies. Instead, pigeons learn a set of sample‐specific SD rules. Transfer of the discrimination to novel stimuli, at least along the hue dimension, is predicted by a “coding hypothesis”, which holds that pigeons make a unique, but usually unobserved response, R1, to each sample, and that the comparison stimulus chosen depends on which R1 was emitted in the presence of the sample. Convincing evidence is found that pigeons do code sample hues, but there is little evidence that allows one to infer that the “coding event” must have behavioral properties. Parameters of the conditional discrimination paradigm are identified, and it is shown that by appropriate parametric manipulation, a variety of analogous tasks may be generated for both human and animal subjects. The tasks make possible the comparative study of complex learning, attention, memory, and information processing, with the added advantage that behavior processes may be compared systematically across tasks.
MATCHING IN CONCURRENT VARIABLE‐INTERVAL AVOIDANCE SCHEDULES
Authors: Logue A. W. , de Villiers Peter A.
Published: March 2006

After pretraining with multiple variable‐interval avoidance schedules, two rats were exposed to a series of concurrent variable‐interval avoidance schedules. Responses on two levers cancelled delivery of electric shocks arranged according to two independent variable‐interval schedules. The ratio of responses and time spent on the two levers approximately matched the ratio of shocks avoided on each. Matching to the number of shocks received was not obtained. Concurrent variable‐interval avoidance can therefore be added to the group of positive and negative reinforcement schedules that can be expressed in the quantitative framework of the matching law.