bluuebunny/crossref_metadata_2025 huggingface dataset:
ATTENTION IN THE PIGEON: A REEVALUATION1
Authors: Wilkie Donald M. , Masson Michael E.
Published: March 2006

During training sessions, pigeons were successively exposed to compounds consisting of a white triangle on a red background and a white circle on a green background. Key pecking intermittently produced grain reinforcers in the presence of one form‐color compound. Once key pecking was confined to the compound associated with reinforcement, the elements—red, green, triangle, and circle—were presented during a test in which no reinforcement was available. Each bird pecked nearly exclusively in the presence of the color previously associated with reinforcement, a result that might be interpreted as indicating that the subjects had attended to color, but not form during training. Pecking was next reinforced when either the triangle or the circle was present. Pecking in the presence of the form previously associated with reinforcement was acquired more rapidly. This result suggests that the birds had learned about the forms during training, and that conclusions about attention based on the lack of differential pecking in the nonreinforcement test may not be appropriate.
EFFECTS OF A DELAY‐REINFORCEMENT PROCEDURE ON PERFORMANCE UNDER IRT > t SCHEDULES1
Authors: Gonzalez Fernando A. , Newlin Robert J.
Published: March 2006

Water‐deprived rats were studied under a compound schedule that prescribed that responses terminating interresponse times (IRTs) greater than a fixed value t1. (IRT > t1 component schedule) initiated a delay of reinforcement interval t2, at the end of which water was presented if the subject did not respond ( > t2 component schedule). If the subject responded before the t2 interval elapsed, the IRT > t1 component schedule was re‐initiated and water was not presented. The IRT > t1 and > t2 component schedules were not differentially correlated with distinctive stimuli. Rate of responding during the IRT > t1 component decreased as a function of the value of t2. The magnitude of the decreases in response rate appeared to be proportional to the subject's rate under the IRT > t schedule with no delay of reinforcement (t2 = 0 sec). The effects were independent of the parameter value of the IRT > t1 component schedule and of the rate of reinforcement. The results suggested that “efficiency” of performance under IRT > t schedules can be increased by appropriately arranging brief delays of reinforcement.
ERRATUM A COMPARISON OF THE KEY‐PECK AND TREADLE‐PRESS OPERANTS IN THE PIGEON: DIFFERENTIAL‐REINFORCEMENT‐OF‐LOW‐RATE SCHEDULE OF REINFORCEMENT1
Authors: Richardson W. Kirk , Clark David B.
Published: March 2006

Key pecking and treadle pressing in pigeons were compared under concurrent (key‐treadle) and single‐operant differential‐reinforcement‐of‐low‐rate schedules of food reinforcement ranging from 5 to 60 sec (concurrent procedure) or 5 to 120 sec (single‐operant procedure). Under both procedures, the two operants followed the same general law: decreasing response rate and reinforcement rate and increasing number of responses per reinforcement as a function of increasing schedule interval. High correlations were found between key pecking and treadle pressing for the measures of response rate, reinforcement rate, and responses per reinforcement. Regression equations allowed the prediction of treadle pressing from key pecking. More bursting occurred in responding to the key, and key pecking showed a more precise temporal discrimination than treadle pressing. A test for sequential dependencies between key and treadle responses showed significant dependencies not only under the concurrent procedure but also in data created artificially by merging key and treadle sequences from different pigeons under the concurrent procedure and from the same pigeon under the single‐operant procedure. It seems likely that the sequential dependencies found were due to the independent action of the schedule on each operant and that behavioral dependencies did not occur with the concurrent training procedure. The key‐peck operant does not appear to have any special qualities that preclude its use in discovering general laws of behavior, at least under the differential‐reinforcement‐of‐low‐rate schedule. The usefulness of the key peck in other situations requires direct experimental study.
SCHEDULE‐INDUCED DRINKING AS A FUNCTION OF INTERREINFORCEMENT INTERVAL IN THE RHESUS MONKEY1
Authors: Allen Joseph D. , Kenshalo Dan R.
Published: March 2006

Lever presses by two rhesus monkeys produced food pellets that were assigned by both an ascending and descending series of fixed‐interval schedules whose values varied between 1 and 512 sec. The amount of schedule‐induced drinking was bitonically related to interreinforcement interval, reaching a maximum at approximately 120 sec and declining at longer fixed intervals. The relation between water intake and interreinforcement interval was complexly related to two drinking measures: (1) the probability of drinking following a pellet and (2) the amount drunk per bout. Drinking rate was also bitonically related to interreinforcement interval.
EFFECTS OF ELECTRIC‐SHOCK DELIVERY ON SCHEDULE‐INDUCED WATER INTAKE: DELAY OF SHOCK, SHOCK INTENSITY, AND BODY‐WEIGHT LOSS
Authors: Hymowitz Norman
Published: March 2006

In each of four experiments, schedule‐induced water intake in the rat was studied under fixed‐time 40‐sec food delivery. Experiments I and II studied the temporal relationship between response‐independent electric‐shock delivery and licking. Shock was delivered under a variable‐time 60‐sec schedule. A lick‐dependent delay was imposed so that licking and shock delivery were systematically separated in time by a minimum of 1 to 15 sec. Over a wide range of shock intensities, the data failed to reveal a consistent delay‐of‐shock effect. Similar shock intensities led to similar reduction of water intake at each delay of shock interval. Experiments III and IV studied the effects of body‐weight loss on water intake during independent shock delivery. In Experiment III, shock was delivered under variable‐time 60‐sec with a minimum separation between shock and licking of 5 sec. In Experiment IV, shock was delivered under variable‐time 180‐sec. The minimum separation between shock and licking was 10 sec. In each study, the resistance of water intake to suppression by shock delivery increased as the degree of body‐weight loss increased. Schedule‐induced water intake was affected more by shock when the animal was maintained at 90% of free‐feeding weight than at 70%.
VARIABLES AFFECTING ESTABLISHMENT OF SCHEDULE‐INDUCED ATTACK ON PICTORIAL TARGETS IN WHITE KING PIGEONS1
Authors: Looney Thomas A. , Cohen Perrin S. , Yoburn Byron C.
Published: March 2006

White King pigeons exposed to food schedules before introduction of a colored photograph of a pigeon showed sustained schedule‐induced attack on that image; additional birds given an early introduction to both the photograph and the schedule subsequently attacked the image at lower rates. Other pigeons attacked a second photograph of a pigeon regardless of whether it was introduced early or late. The late‐introduction procedure was also effective in establishing attack on a projected image of a conspecific. The combined results showed that 14 of 17 White King pigeons given a late introduction to a pictorial target exhibited sustained attack against it and that a pigeon's initial reaction to a photograph of a conspecific when introduced early was a good predictor of subsequent schedule‐induced attack on it.
FACTORS INFLUENCING RESPONDING UNDER MULTIPLE SCHEDULES OF CONDITIONED AND UNCONDITIONED REINFORCEMENT
Authors: Cohen Steven L. , Lentz B. E.
Published: March 2006

Two experiments examined pigeons' responses under multiple schedules of conditioned and unconditioned reinforcement. In one component, responses produced food according to a fixed‐interval schedule; in a second component, responses produced brief stimuli according to a fixed‐ratio schedule. When brief‐stimulus presentations were paired with food in the first component, rates in the second component were usually higher than 10 responses per minute. When pairing in the first component was eliminated, responding continued to be maintained in the second component. Elimination of food presentation from the first component substantially decreased responding in the second component, even though the brief stimulus had not been paired with food. Experiment II demonstrated that response rate was affected by the duration of both the second component and the brief stimulus. The results suggest that three conditions are important in maintaining responding with brief‐stimulus presentations: (1) pairing the brief stimulus, at least initially, with food, (2) maintaining unconditioned reinforcement in one component, and (3) employing optimal brief‐stimulus and component durations.
FIXED VERSUS VARIABLE SEQUENCES OF FOOD AND STIMULUS PRESENTATION IN SECOND‐ORDER SCHEDULES1
Authors: Corfield‐Sumner P. K. , Blackman D. E.
Published: March 2006

Three pigeons were exposed to a second‐order schedule in which the behavior specified by a fixed‐interval component schedule was reinforced according to a ratio overall schedule. The completion of components not followed by food was signalled by a brief stimulus never paired with food. Food and the stimulus occurred in a random sequence or in fixed alternation, but the overall schedules (variable ratio 2 or fixed ratio 2) ensured that an equal number of food and brief‐stimulus presentations occurred in each session. The control exerted by the food and by the brief stimulus was measured by overall response rates, mean pauses, frequency distributions of pauses, and response patterning across components. In general, the stimulus controlled patterns of behavior more similar to those controlled by food when food and the stimulus occurred in a random sequence than when they occurred in fixed alternation.
FOOD DELIVERIES DURING THE PAUSE ON FIXED‐INTERVAL SCHEDULES1
Authors: Shull Richard L. , Guilkey Marilyn
Published: March 2006

Pigeons were trained on fixed‐interval schedules of food delivery. In Experiments I and II, the fixed interval was initiated by the previous fixed‐interval reinforcer; in Experiment III, the fixed interval was initiated by the first key peck following the preceding fixed‐interval reinforcer (a chain fixed‐ratio one, fixed‐interval schedule). During the postreinforcement pause, variable‐time schedules delivered food independent of any specific response. Rate of food delivery during the pause had only small effects on pause duration in Experiments I and II. In Experiment III, however, pause duration increased systematically with the rate of food delivery during the pause. These data suggest that the momentary proximity to reinforcement delivered via the fixed‐interval schedule exerts potent control over pause termination. Additional analysis revealed that pause termination was unaffected by the intermittent delivery of food during the pause. Such data suggest that the temporal control by fixed‐interval schedules is highly resistant to interference.
THE EFFECTS OF UNSIGNALLED DELAYED REINFORCEMENT1
Authors: Williams Ben A.
Published: March 2006

Pigeons' pecks were reinforced according to a variable‐interval schedule. A delay‐of‐reinforcement procedure was then added to the schedule, or a yoked‐control procedure was arranged where the reinforcers occurred independently of responding according to the same variable‐interval schedule. During the delay‐of‐reinforcement procedure, the first peck after a reinforcer was scheduled began a delay timer and the reinforcer was delivered at the end of the interval. No stimulus change signalled the delay interval and responses could occur during it, so that the obtained delays were often shorter than those scheduled. Responding under this procedure was highly variable but, in general, behavior was substantially reduced even with the shortest delay used, 3 sec. In addition, the rates maintained by delayed reinforcement were only slightly greater than those maintained by the yoked‐control procedure, suggesting that adventitious pairings of response and reinforcer were responsible for some of the maintenance of behavior that did occur. The results challenge recent conceptions of reinforcement as involving response‐reinforcer correlations and re‐emphasize the role of temporal proximity between response and reinforcer.
AUTOSHAPING AS A FUNCTION OF PRIOR FOOD PRESENTATIONS1
Authors: Downing Kevin , Neuringer Allen
Published: March 2006

Young chickens were given 1, 10, 100, or 1000 presentations of grain in a hopper. Subsequently, the key was illuminated before each presentation of grain to study autoshaping of the key‐peck response. The number of keylight‐grain pairings before a bird first pecked the lighted key was found to be a U‐shaped function of the number of prior food‐only presentations, with pecks occurring significantly sooner after 100 food‐only trials than after any of the other values. Two of five chicks at the 100‐trial value pecked on the first illumination of the key. Experiment II showed further that when a series of food‐only trials (no keylight) preceded keylight‐only trials (no food) 30% of the chicks pecked the illuminated key. Experiment III extended the generality of first‐trial pecking to pigeons. After preliminary training with food‐only, two of five pigeons pecked on the first illumination of a key. The results suggest a close relationship between autoshaping and pseudo‐conditioning.
REINFORCEMENT RATE AND INTERRESPONSE TIME DIFFERENTIATION1
Authors: Kuch Dennis O. , Platt John R.
Published: March 2006

Reinforcement rate and differential reinforcement of IRTs were independently manipulated to assess their relative contribution to the control of interresponse times (IRTs). Modified percentile reinforcement schedules (Platt, 1973) allowed control of reinforcement rate while longest or shortest IRTs were selectively reinforced. In the absence of differential IRT reinforcement, mean IRT decreased with increasing reinforcement rate. Compared to this small effect of reinforcement rate, reinforcement of long IRTs produced large changes in mean IRT at constant reinforcement rates. No interaction of reinforcement rate and IRT reinforcement was detected. The demonstration of large IRT changes in the absence of reinforcement‐rate changes indicates the precedence of IRT reinforcement over molar reinforcement‐rate correlations in the determination of IRTs in these procedures.
SHORT‐TERM MEMORY IN THE PIGEON: THE PREVIOUSLY REINFORCED RESPONSE1
Authors: Shimp Charles P.
Published: March 2006

Eighteen pigeons served in a discrete‐trials short‐term memory experiment in which the reinforcement probability for a peck on one of two keys depended on the response reinforced on the previous trial: either the probability of reinforcement on a trial was 0.8 for the same response reinforced on the previous trial and was 0.2 for the other response (Group A), or, it was 0 or 0.2 for the same response and 1.0 or 0.8 for the other response (Group B). A correction procedure ensured that over all trials reinforcement was distributed equally across the left and right keys. The optimal strategy was either a win‐stay, lose‐shift strategy (Group A) or a win‐shift, lose‐stay strategy (Group B). The retention interval, that is the intertrial interval, was varied. The average probability of choosing the optimal alternative reinforced 80% of the time was 0.96, 0.84, and 0.74 after delays of 2.5, 4.0, and 6.0 sec, respectively for Group A, and was 0.87, 0.81, and 0.55 after delays of 2.5, 4.0, and 6.0 sec, respectively, for Group B. This outcome is consistent with the view that behavior approximated the optimal response strategy but only to an extent permitted by a subject's short‐term memory for the cue correlated with reinforcement, that is, its own most‐recently reinforced response. More generally, this result is consistent with “molecular” analyses of operant behavior, but is inconsistent with traditional “molar” analyses holding that fundamental controlling relations may be discovered by routinely averaging over different local reinforcement contingencies. In the present experiment, the molar results were byproducts of local reinforcement contingencies involving an organism's own recent behavior.
EFFECTS OF CONCURRENT RESPONSE‐INDEPENDENT REINFORCEMENT ON FIXED‐INTERVAL SCHEDULE PERFORMANCE
Authors: Lattal Kennon A. , Bryan Anne J.
Published: March 2006

In three experiments, behavior maintained by fixed‐interval schedules changed when response‐independent reinforcement was delivered concurrently according to fixed‐ or variable‐time schedules. In Experiment I, a pattern of positively accelerated responding during fixed interval was changed to a linear pattern when response‐independent reinforcement occurred under a variable‐time schedule. Overall response rates (total responses/total time) decreased as the frequency of response‐independent reinforcement increased. Experiment II showed that the response‐rate changes in the first experiment were controlled by the response‐reinforcer relation, but the changes in patterns of responding were similar whether concurrently available reinforcement at varying times was response‐dependent or response‐independent. In the final experiment, the addition of response‐independent reinforcement at fixed times to a fixed‐interval schedule resulted in changes in both local and overall response rates and in the occurrence of positively accelerated responding between reinforcements. These results suggest that the temporal distribution of reinforcers determines response patterns and that both the response‐reinforcement dependency and the schedule of reinforcement determine overall response rates during concurrently scheduled response‐dependent and response‐independent reinforcement.
BEHAVIORAL CONTRAST AS A FUNCTION OF THE TEMPORAL LOCATION OF REINFORCEMENT1
Authors: Williams Ben A.
Published: March 2006

Pigeons were trained on a multiple variable‐interval variable‐interval schedule of reinforcement. One component was then changed to a variation of a fixed‐interval schedule in which the same rate of reinforcement was obtained as previously but the location of the reinforcer was fixed within the component. The effects of different temporal locations were compared. An increase in response rate for the unchanged variable‐interval component (behavioral contrast) occurred when the reinforcer was located in the middle or at the end of the FI component, but response suppression occurred when it was located at the beginning of the component. The pattern of results cannot be explained by any previous theories of contrast. The overall response rates, and the pattern of local rates within the components, were consistent with the hypothesis that the major determinant of the contrast effect was the transition to a lower reinforcement rate following the unchanged component.
SUCCESSIVE DISCRIMINATION TRAINING WITH EQUATED REINFORCEMENT FREQUENCIES: FAILURE TO OBTAIN BEHAVIORAL CONTRAST1
Authors: Boakes R. A. , Halliday M. S. , Mole J. S.
Published: March 2006

In two experiments, pigeons were trained on two‐component multiple schedules in which responding in one component (S1) was always maintained by a variable‐interval schedule. In Experiment I, low response rates were reinforced in the second (S2) component for six master subjects. This schedule was adjusted to equate reinforcement frequencies in the two components. These subjects were compared to yoked partners, for which reinforcement in the S2 component was made available on a variable‐interval schedule whose value was determined by the master subjects. A similar procedure was used in Experiment II, where the S2 schedule for master subjects made reinforcers contingent on the absence of responding. No evidence was found in either experiment for a behavioral contrast effect in the S1 component attributable to response reduction in the S2 component. A reliable contrast effect was obtained from a group of pigeons given extinction conditions in the S2 component, which was compared to a group maintained throughout on a multiple variable‐interval schedule. The results suggest that previous indications of behavioral contrast in similar situations were probably caused by uneven reinforcement distributions or reflect uncontrolled fluctuations in response rates.
BEHAVIORS OBSERVED DURING S‐ IN A SIMPLE DISCRIMINATION LEARNING TASK1
Authors: Rand Judith F.
Published: March 2006

Key pecking of pigeons was reinforced with food in the presence of a horizontal line and never reinforced in the presence of a vertical line. Highly stereotyped behaviors, as well as key pecking, were observed and recorded in the presence of both stimuli. Results showed that a high proportion of time spent in the presence of the horizontal line was occupied by key pecking, a high proportion of time in the presence of the vertical line was occupied by stereotyped nonkey‐pecking behaviors, and intermediate proportions of time spent in the presence of intermediate stimuli were occupied by each class of behavior during generalization tests. Similar running rates (number of key pecks divided by observed key‐pecking time) were obtained in the presence of all stimuli, indicating that changes in time rather than tempo accounted for the changes in overall rates of key pecking. An exception occurred in responding to the horizontal line as differential performance was developing. In addition to an increase in time spent key pecking, increased running rates occurred in seven of eight birds, suggesting that both time allocation and tempo play a role in behavioral contrast of overall rates of key pecking.
DEPENDENCY, TEMPORAL CONTIGUITY, AND RESPONSE‐INDEPENDENT REINFORCEMENT
Authors: Sizemore O. J. , Lattal Kennon A.
Published: March 2006

A comparison was made of the effects of variable‐interval, variable‐time, and tandem variable‐interval fixed‐time schedules on key‐peck responding of pigeons. The variable‐interval component of the tandem schedule retained the response‐reinforcement dependency; the fixed‐time component allowed the temporal proximity between responding and reinforcement to vary, constrained only by the duration of the fixed‐time interval. Response rates were highest during the variable‐interval and lowest during the variable‐time schedule. Intermediate response rates occurred during the tandem schedule. The results of a yoked control condition showed that the effects of the tandem schedule were not due simply to changes in reinforcement distribution or frequency. The results suggest that substantial reductions in responding occur when reinforcement is response‐dependent but not necessarily contiguous with the response required to produce reinforcement.
SOCIAL LEARNING BY FOLLOWING: AN ANALYSIS1
Authors: Bullock Daniel , Neuringer Allen
Published: March 2006

Learning by “following”, probably a common means by which behaviors are socially transmitted from adults to young in many species, was analyzed. Pigeons first learned to eat from a human hand. When the hand then approached an operant key and pecked it, the pigeons followed and quickly learned to do the same, thereby demonstrating social learning. When the hand only led the birds to the area of the key, without demonstrating the key‐peck response, the birds learned as rapidly as with a key‐peck demonstration. Birds also learned, but less reliably and more slowly, when they could observe the hand's responses but were constrained and unable to follow. “Following” was also shown to engender very rapid learning of a more complex, two‐member response chain.
RESPONSE SUMMATION TO A COMPOUND STIMULUS IN A CONTEXT OF CHOICE1
Authors: Millier P. J. , Beale I. L.
Published: March 2006

Key pecks by two groups of pigeons were reinforced on concurrent schedules. For group , pecks were reinforced during either a visual or an auditory stimulus; for group E, an additional, extinction component was available, during which both visual and auditory stimuli were absent. After training, both groups were given a compound test to measure preference among four stimuli, the three used in training plus a compound of the visual and auditory stimulus. Group E showed preference for the compound, emitting more pecks and spending more time in this stimulus than in other stimuli. Group showed no preference between the compound and visual stimulus, nor between the auditory stimulus and the absence of both stimuli, but preferred the former pair over the latter pair of stimuli.
MATCHING UNDER CONCURRENT FIXED‐RATIO VARIABLE‐INTERVAL SCHEDULES OF FOOD PRESENTATION1
Authors: Bacotti A. V.
Published: March 2006

Four pigeons were exposed to concurrent fixed‐ratio, variable‐interval schedules of food presentation. The fixed‐ratio requirement was either 25, 50, 75, or 100 responses, with the variable‐interval schedule parameter held constant at 4 minutes. A delay time was imposed between a changeover from one schedule to the other and subsequent food availability. The delay time was varied at each ratio requirement over four values; no delay, 0‐second delay, 1.5‐second delay, and 5.0‐second delay. As the fixed‐ratio requirement or the delay time increased, a greater proportion of the total responses and time spent responding occurred under the variable‐interval schedule relative to the proportion of food deliveries under that schedule. Neither relative overall response rate nor relative time spent responding equalled the relative frequency of food presentation, as would be predicted by a linear “matching” model. Rather, these data were described by power functions with slopes of approximately 1.0 and intercepts greater than 1.0. In the terms of Baum's (1974) analysis, these deviations from linear matching represent bias in favor of responding under the interval schedule. Bias, as reflected in the intercept of the power function, was greater for the ratio of time than the ratio of responses.
UNDERMATCHING: A REAPPRAISAL OF PERFORMANCE ON CONCURRENT VARIABLE‐INTERVAL SCHEDULES OF REINFORCEMENT1
Authors: Myers David L. , Myers Lawrence E.
Published: March 2006

The extant data for pigeons' performance on concurrent variable‐interval schedules were examined in detail. Least‐squares lines relating relative pecks and time to the corresponding relative reinforcements were obtained for four studies. The between‐study group slopes for time and pecks and five of seven within‐study group slopes from individual studies were less than 1.00. This suggested the generality that pigeons respond less to the richer reinforcement schedule than predicted by matching. For pecks, a nonparametric test for distribution of points also supported this concept of undermatching (to the richer reinforcement schedule). In addition, using mean squared error as the criterion, a cubic curve fit the peck proportion data better than any line or other polynomial. This indicates that the relation between peck and reinforcement proportions may be nonlinear.
POSITIVE CONTRAST, NEGATIVE INDUCTION, AND INHIBITORY STIMULUS CONTROL IN THE RAT1
Authors: Gutman Arthur
Published: March 2006

In Experiment I, 24 rats were trained on a multiple variable‐interval variable‐interval schedule with a doorlight and white noise serving as component cues. Two groups were then shifted to a multiple extinction variable‐interval schedule, and a third group was maintained on the multiple variable‐interval variable‐interval schedule. The multiple extinction variable‐interval condition produced positive contrast when either the light or noise signalled extinction, and both of these cues acquired inhibitory stimulus control as measured by a combined cue test. In Experiment II, the multiple variable‐interval variable‐interval condition was shifted to multiple extinction variable‐interval for one group, to multiple variable‐time variable‐interval for a second group, and was unchanged for the third group. The two experimental conditions produced identical patterns of response‐rate reduction in the altered component, but the multiple extinction variable‐interval condition produced positive contrast, whereas the multiple variable‐time variable‐interval condition did not. Subsequent combined cue and resistance to reinforcement tests revealed that the cue signalling extinction acquired stronger inhibitory stimulus control than the cue signalling variable time.
PIGEONS' PREFERENCES FOR STIMULUS INFORMATION: EFFECTS OF AMOUNT OF INFORMATION1
Authors: Green Leonard , Rachlin Howard
Published: March 2006

A concurrent‐chain procedure was used to study pigeons' preferences as a function of amount of information. Pigeons chose between two terminal links. Both terminal links ended in food reinforcement with probability (p) and in blackout with probability (1 — p). One terminal link (noninformative link) was signalled by a stimulus uncorrelated with either food or blackout. The other terminal link (informative link) was signalled by stimuli correlated with these outcomes. Amount of information conveyed by these stimuli was varied across conditions by changing the probability of reinforcement (p) and blackout (1 — p). The pigeons strongly preferred the informative link, and preferences were greater at p values above 0.50 than for their complements. The pigeons engaged in different behaviors during the stimulus periods, suggesting that the value of informative stimuli may be in their function as discriminative stimuli for interim activities and terminal responses.
EFFECT OF PUNISHMENT ON HUMAN VARIABLE‐INTERVAL PERFORMANCE
Authors: Bradshaw C. M. , Szabadi E. , Bevan P.
Published: March 2006

Three female human subjects pressed a button for monetary reinforcement in a range of variable‐interval schedules specifying different frequencies of reinforcement. On alternate days, responding was also punished (by subtracting money) according to a variable‐ratio 34 schedule. In the absence of punishment, rate of responding was an increasing negatively accelerated function of reinforcement frequency; the relationship between response rate and reinforcement frequency conformed to Herrnstein's equation. The effect of the punishment schedule was to suppress responding at all frequencies of reinforcement. This was reflected in a change in the values of both constants in Herrnstein's equation: the value of the theoretical maximum response‐rate parameter was reduced, while the parameter describing the reinforcement frequency corresponding to the half‐maximal response rate was increased.
CONTROL OF PIGEONS' PECKING BY TRACE STIMULI1
Authors: Wilkie Donald M. , Wilson C. Scott
Published: March 2006

In Experiment I, pigeons' pecking a white key was reinforced with grain when white was immediately preceded by a vertical white line on a green surround, but not by green alone. This procedure produced control of pecking by the line. Next, pecking white was reinforced after vertical line on green, but not after green alone or other orientations of the white line on green. The line‐tilt dimension initially did not control pecking, a result that showed that interdimensional (line versus no line) training does not always result in dimensional control. Line‐tilt control was eventually established but was accompanied by a decrease in interdimensional control. In Experiment II, interdimensional training, with or without a trace interval intervening between line on green or green alone and white, was followed by tests for line‐tilt control. While interdimensional control was unaffected by the trace interval, line‐tilt control tended to be less with the trace interval. This dissociation of interdimensional and dimensional control, as well as the failure of interdimensional training to produce dimensional control in Experiment I, suggests that the line stimulus is multidimensional.
THE CONDITIONED REINFORCEMENT OF REPEATED ACQUISITION1
Authors: Hursh Steven R.
Published: March 2006

Three monkeys were trained to emit a chain of three responses on three separate levers in a set of six levers to obtain food. The chain producing food (correct chain) was changed each day. During a trial, a press on any lever produced a feedback stimulus; a press on a correct lever produced an additional distinctive stimulus; the third correct press produced a food pellet. Test sessions in which either the food or the distinctive stimuli were removed were interspersed with baseline sessions. In tests without food presentations, the subjects acquired the correct chain rapidly, with a level of accuracy comparable to baseline. Removing the distinctive stimuli for either the first or second member of the correct chain greatly retarded acquisition of that member of the chain. Removing all distinctive stimuli often reduced accuracy throughout the chain to chance level, even though food was presented following each correct chain. These results were interpreted as evidence that the distinctive stimuli presented after correct responses functioned as conditioned reinforcers. Reductions in accuracy following an omitted distinctive stimulus indicated that they were also discriminative stimuli for correct responding in their presence.
EXTENDING SEQUENCE‐CLASS MEMBERSHIP WITH MATCHING TO SAMPLE1
Authors: Lazar Ronald
Published: March 2006

Three normal adults were first trained to point sequentially to each member of several pairs of visual stimuli. This baseline training established one class of stimuli to which subjects responded first, and another class of stimuli to which they responded second. Then, in a matching‐to‐sample procedure, baseline‐sequence stimuli served as samples and new visual stimuli served as comparisons. Subjects were trained to choose one group of new comparisons when the sample was a “first” stimulus from the sequence baseline, and to choose the other new comparison stimuli when the sample was a “second” from the sequence baseline. When the new stimuli were then presented as pairs in the posttest, two subjects pointed to them in sequences predictable on the basis of the stimulus‐class membership established during matching to sample. The failure of one subject to demonstrate sequential transfer was shown to be a consequence of the failure of the matching‐to‐sample procedure to establish stimulus classes. The production of sequences that were not directly trained suggested an empirical approach to the analysis of simple grammatical behavior.
TWO TYPES OF PIGEON KEY PECKING: SUPPRESSION OF LONG‐ BUT NOT SHORT‐DURATION KEY PECKS BY DURATION‐DEPENDENT SHOCK1
Authors: Schwartz Barry
Published: March 2006

The key pecking of eight pigeons was maintained on a variable‐interval 1‐minute schedule of food reinforcement. Sometimes, all responses between 35 and 50 milliseconds in duration produced a shock; sometimes, all responses between 10 and 25 milliseconds produced a shock; sometimes, shocks were produced by pecks without regard to duration (nondifferential punishment), and sometimes shocks were delivered independently of responding. Punishment of 35‐ to 50‐millisecond responses selectively suppressed those responses, while punishment of 10‐ to 25‐millisecond responses and nondifferential punishment suppressed responding overall but did not suppress responses of particular duration. Punishment of 35‐ to 50‐millisecond responses suppressed key pecking slightly less than did nondifferential punishment. Punishment of 10‐ to 25‐millisecond responses and response‐independent shock produced roughly equal amounts of suppression, substantially less than the other punishment procedures. The data support the view that there are at least two kinds of key peck, identifiable on the basis of duration, one of which (short duration) is insensitive to its consequences.
RATE AND TEMPORAL PATTERN OF KEY PECKING UNDER AUTOSHAPING AND OMISSION SCHEDULES OF REINFORCEMENT1
Authors: Deich James D. , Wasserman Edward A.
Published: March 2006

The role of response‐reinforcer contiguity on autoshaped key pecking in pigeons was studied by scheduling response‐dependent nonreinforcement at the beginning or the end of brief (8‐sec) discrete trials. Schedules that permitted chance conjunctions of key pecking and food sustained high rates of responding, whereas those that prevented the occurrence of key peck‐food intervals shorter than 4 sec sustained low response rates. In addition, selective reinforcement schedules supported accelerating or decelerating rates of responding within individual trials. These effects were traceable to response‐reinforcer (operant), but not stimulus‐reinforcer (respondent) factors.
STIMULUS GENERALIZATION FROM FEEDER TO RESPONSE KEY IN THE ACQUISITION OF AUTOSHAPED PECKING
Authors: Sperling Sally E. , Perkins Mark E. , Duncan Heather J.
Published: March 2006

During autoshaping, a 6‐second presentation of one stimulus and a variable time 30‐second presentation of a second stimulus alternated in appearance on a pigeon key. Grain always was delivered for 3 seconds at the end of the first stimulus interval. In the first experiment, autoshaped pecking of the stimulus preceding grain delivery began much sooner when that stimulus was a black vertical line on a white background and the other stimulus was green than when the opposite stimulus arrangement was used. Because these two stimuli differed in form, hue, brightness, and similarity in hue and brightness to the illumination of the raised feeder, three subsequent experiments examined whether the differential speed of autoshaping in the two groups was due to a feature‐positive, feature‐negative effect, a preference for brighter over darker stimuli, a simple preference for white over green, or stimulus generalization from the brightness or hue of the illuminated, raised feeder to the stimulus on the key preceding grain delivery. The data from these experiments showed that the first autoshaped key peck was most likely to be made to the stimulus of the same hue as that illuminating the feeder, regardless of whether that stimulus was positively or negatively associated with grain delivery. At least under some conditions, therefore, stimulus‐generalization mediated response transfer of pecking grain in the presence of the hue illuminating the feeder to pecking the key illuminated by a similar hue appears to account for the occurrence of autoshaped key pecking.
INCREASED REINFORCEMENT WHEN TIMEOUT FROM AVOIDANCE INCLUDES ACCESS TO A SAFE PLACE1
Authors: Baron Alan , DeWaard Richard J. , Lipson Joel
Published: March 2006

Three experiments investigated the reinforcing value of access to a safe place during timeout from an avoidance schedule. Rats were trained on conjoint schedules in which responding both postponed shock on a free‐operant avoidance schedule and produced periods of timeout on fixed‐ratio schedules. In some conditions, a shelf was inserted into the operant chamber during timeout, enabling subjects to get off the grid floor. The combination of timeout and shelf maintained substantially higher response rates than the baseline avoidance schedule with ratio requirements as high as 90 (Experiment I). Adding the shelf to timeouts in one component of multiple fixed‐ratio schedules of timeout resulted in higher response rates in the component where the shelf was included (Experiment II). When timeouts with and without the shelf were arranged on concurrent schedules, the shelf‐timeout combination was preferred, even when of shorter duration than timeout alone (Experiment III). In all three experiments, subjects climbed on the shelf, although all shocks were cancelled during timeout periods. The results could not be accounted for solely in terms of the reinforcing properties of changes in shock rates, but required an interpretation that ascribed conditioned reinforcing value to stimuli associated with such changes.
RESPONDING IN THE SQUIRREL MONKEY UNDER FIXED RATIO SCHEDULES OF STIMULUS TERMINATION1
Authors: Byrd L. D.
Published: March 2006

Key pressing was maintained under a fixed‐ratio schedule in which electric shock was scheduled for delivery at a fixed time (t seconds) after each stimulus onset, and every nth response terminated the stimulus and initiated a timeout from shock. Under this procedure, the higher the rate of responding, the briefer the duration of the stimulus presentation and the lower the frequency of shock delivery. The effects of several schedule parameters were studied to determine whether the maintenance of responding was dependent on an inverse relation between response rate and shock frequency. Shock rate and shock frequency were made independent of response rate by decreasing the value of t to 0.5 second and delivering shock only during the first presentation of the stimulus after a fixed time, including stimulus and timeout durations, had elapsed since the previous shock. The experiments showed that shock frequency and response rate are inversely related when t is of relatively long duration compared to the value of the fixed‐ratio parameter, but that a decrease in shock rate or frequency due to a high rate of responding is not necessary for the maintenance of responding under a fixed‐ratio schedule of stimulus termination.
THE EFFECTS OF TWO RESPONSE‐ELIMINATION PROCEDURES ON REINFORCED AND INDUCED AGGRESSION1
Authors: Flory Randall K. , Smith Eric L. P. , Ellis Barbara B.
Published: March 2006

Pecks against a stuffed pigeon were reinforced according to a fixed‐interval schedule for one group of pigeons and a variable‐interval schedule for a second group. Red and green stimulus lights were alternately illuminated. Subsequently, food deliveries no longer occurred during one color (extinction). In the presence of the other color, food was presented only when no attack occurred for 30 sec. When attack produced food, all pigeons generally exhibited characteristic fixed‐interval or variable‐interval response patterns. Two birds in each group frequently exhibited postreinforcement schedule‐induced aggression. Attack was reduced to low levels at approximately the same rate by extinction and differential reinforcement of other behavior. For birds that had previously exhibited schedule‐induced aggression, the initial reduction of attack during the second experimental phase was followed by induced attack immediately after food delivery in the differential‐reinforcement‐of‐other‐behavior component and upon onset of the extinction component. Either extinction or differential reinforcement of other behavior may eliminate reinforced aggression but may be relatively ineffective for reducing induced attack.
AN OPERANT ANALYSIS OF HUMAN ALTRUISTIC RESPONDING
Authors: Weiner Harold
Published: March 2006

Human altruistic responding (called give responding), which delivered a reinforcer to someone other than the responder, was compared to responding where the responder was the recipient of the reinforcer (called earn responding). The same type of response (button pressing), the same reinforcer (a point representing a penny), and the same reinforcer contingency (a 40‐response fixed‐ratio schedule) were used for both give and earn responding. Since points representing pennies were used to reinforce give and earn responding, responding for points not worth money was also assessed. Give, earn, and point responding were arranged as concurrent incompatible operants. Lowest rates were obtained for point responding. Compared to earn responding, give responding occurred at lower rates, was more susceptible to cessation when point responding was possible, extinguished more rapidly in the absence of money, and produced less responding during reconditioning compared to conditioning when reconditioning followed a period of nonreinforcement. Give responding was less when it reduced the giver's opportunity to earn. Finally, histories of getting reinforcement from others were shown to determine give responding.
SIGNALLED AND UNSIGNALLED PERCENTAGE REINFORCEMENT OF PERFORMANCE UNDER A CHAINED SCHEDULE1
Authors: Branch Marc N.
Published: March 2006

Pigeons were trained to peck a key under a chained fixed‐ratio 15 fixed‐interval 25‐sec schedule of food presentation. In Experiment 1, blocks of sessions in which 100%, 75%, 50%, and 25% of the sequences ended with food presentation were conducted. When food presentation was omitted, a timeout of equal duration replaced it. As the frequency of food presentation decreased so did the frequency of completing the chained schedule., In Experiment 2, 75%, 50%, or 25% of the sequences terminated with food presentation and outcomes were signalled, i.e., completion of the fixed ratio resulted in either a stimulus correlated with the fixed‐interval 25‐sec schedule or a stimulus correlated with extinction. As the frequency of food presentation decreased, the number of sequences completed per session increased for two pigeons and remained high for a third. In Experiments 3 and 4, assessments of the effects of signalling the outcome of the chained schedule were made with response‐independent presentation of events at the end of the sequence. Again, signalling the outcome of the chained schedule led to more chains being completed per session than did not signalling the outcome. Stimuli differentially paired with food presentation have powerful behavioral effects that may be attributed to the potency of these stimuli as conditioned reinforcers.
CONCURRENT SCHEDULES: A QUANTITATIVE RELATION BETWEEN CHANGEOVER BEHAVIOR AND ITS CONSEQUENCES
Authors: Stubbs D. Alan , Pliskoff Stanley S. , Reid Howard M.
Published: March 2006

Data from several published experiments on concurrent variable‐interval schedules were analyzed with respect to the effects of changeover delay on the time spent responding on a schedule before changing to an alternate schedule: i.e., the interchangeover time. Interchangeover time increases as the duration of the changeover delay increases, and the present analysis shows that a power function describes the relation. The power relation applied in spite of numerous differences in the experiments: different variable‐interval schedules for the concurrent pairs; equal or unequal reinforcement rates for the schedules of the concurrent pairs; different durations of the changeover delay; response‐dependent or response‐independent reinforcers; pigeons or rats as subjects; different reinforcers. A power function also described the data in experiments where the changeover incurred a timeout, where a fixed ratio was required to changeover, and also when asymmetrical changeover delays were used.
EFFECTS OF FIXED‐RATIO SAMPLE AND CHOICE RESPONSE REQUIREMENTS UPON ODDITY MATCHING1
Authors: Lydersen Tore , Perkins David , Chairez Herman
Published: March 2006

Three pigeons were trained on oddity matching in which either 1, 4, 8, 16, or 32 sample‐key observing responses were required to turn off the sample stimuli and turn on the comparison stimuli. Oddity accuracy increased when the observing‐response requirement was raised and decreased when the requirement was lowered. Next, while the observing requirement was maintained at one response, the number of responses required to the comparison stimuli was either 1, 4, 8, 16, or 32. Under these conditions, choice was defined as the comparison that first accumulated the required number of responses. In general, increasing the comparison‐response requirement decreased accuracy and lowering the comparison requirement increased accuracy. The fixed‐ratio observing requirements appeared to facilitate control by stimuli serving an instructional function.
ELECTRIC SHOCK PRODUCED DRINKING IN THE SQUIRREL MONKEY
Authors: Hutchinson R. R. , Emley G. S.
Published: March 2006

Squirrel monkeys were periodically exposed to brief electric tail shocks in a test environment containing a rubber hose, response lever, and a water spout. Shock delivery produced preshock lever pressing and postshock hose biting. Additionally, all subjects displayed licking responses following postshock biting‐attack episodes. Further experiments showed that licking was: (1) influenced by hours of water deprivation; (2) drinking behavior; (3) the direct result of shock delivery; and (4) developed spontaneously in naive subjects with or without opportunities for hose biting or lever pressing. Removing the opportunity to attack increased postshock drinking. A noxious environmental stimulus that causes aggression can also produce drinking.