bluuebunny/crossref_metadata_2025 huggingface dataset:
EFFECTS OF CYCLE LENGTH ON PERFORMANCE ON A TEMPORALLY DEFINED AVOIDANCE SCHEDULE1
Authors: Dunn Michael E. , Foster William S. , Hurwitz Harry M. B.
Published: March 2006

Three rats were trained on a temporally defined avoidance schedule logically similar to a fixed‐interval, limited‐hold positive reinforcement schedule. This avoidance schedule was composed of time periods during which responses had no scheduled consequences alternating with time periods during which a response precluded shock. As with fixed‐interval length and response rate on positive reinforcement schedules, an inverse relationship was obtained between the length of the no‐consequence interval and response rate during the no‐consequence interval. An inverse relationship was also obtained between the length of the no‐consequence interval and the per cent of shocks avoided. A rate increase within the no‐consequence interval, similar to that typically produced by fixed‐interval positive reinforcement procedures, was displayed by one of the rats where the no‐consequence interval was at intermediate values and frequency of shock was relatively high. The introduction of a discriminative stimulus correlated with the avoidance interval produced typical discriminated avoidance behavior as well as alterations in temporal patterning of responses during the no‐consequence interval in the two rats exposed to this procedure. These alterations in temporal patterning disappeared when the discriminative stimulus was removed. The results were consonant with those reported in the literature involving food reinforcement and fixed‐interval, limited‐hold schedules.
STIMULUS CONTROL OF SKIN RESISTANCE RESPONSES ON AN ESCAPE‐AVOIDANCE SCHEDULE1
Authors: Greene William A. , Sutor Linda T.
Published: March 2006

The effects of discrimination and avoidance training on the skin resistance response were studied in eight humans. Responses occurring during one stimulus delayed the interruption of music for 30 sec; responses during a second stimulus either had no effect or interrupted the music for 15 sec. The results showed stimulus control in all subjects and an increased discrimination between the first one‐half and last one‐half of the sessions for seven of the eight subjects.
CONDITIONED SUPPRESSION OF AN AVOIDANCE RESPONSE1
Authors: Hurwitz H. M. B. , Roberts A. E.
Published: March 2006

A signal followed by shock was presented at irregular intervals during a free‐operant avoidance schedule. The effects of this procedure were studied in terms of the rate of unavoided shock in the presence and absence of the signal and the rate of response before and during the signal. Three shock intensities were employed. Response enhancement as well as response suppression were observed; irrespective of changes in responding, shock rates substantially increased during signalled periods compared to non‐signalled periods. Shock rates in non‐signalled periods were generally higher than during training.
SECOND‐ORDER SCHEDULES AND THE PROBLEM OF CONDITIONED REINFORCEMENT
Authors: Stubbs D. Alan
Published: March 2006

Thirteen pigeons were exposed to a variety of second‐order schedules in which responding under a component schedule was reinforced according to a schedule of reinforcement. Under different conditions, completion of each component resulted in either (1) the brief presentation of a stimulus also present during reinforcement (pairing operation), (2) the brief presentation of a stimulus not present during reinforcement (nonpairing operation), or (3) no brief stimulus presentation (tandem). Brief‐stimulus presentations engendered a pattern of responding within components similar to that engendered by food. Patterning was observed when fixed‐interval and fixed‐ratio components were maintained under fixed‐ and variable‐ratio and fixed‐ and variable‐interval schedules. There were no apparent differences in performance under pairing and nonpairing conditions in any study. The properties of the stimuli presented in brief‐stimulus operations produced different effects on response patterning. In one study, similar effects on performance were found whether brief‐stimulus presentations were response‐produced or delivered independently of responding. Response patterning did not occur when the component schedule under which a nonpaired stimulus was produced occurred independently of the food schedule. The results suggest a reevaluation of the role of conditioned reinforcement in second‐order schedule performance. The similarity of behavior under pairing and nonpairing operations is consistent with two hypotheses: (1) the major effect is due to the discriminative properties of the brief stimulus; (2) the scheduling operation under which the paired or nonpaired stimulus is presented can establish it as a reinforcer.
RESPONDING IN THE PIGEON UNDER CHAINED SCHEDULES OF FOOD PRESENTATION: THE REPETITION OF A STIMULUS DURING ALTERNATE COMPONENTS1
Authors: Byrd Larry D.
Published: March 2006

Key pecking in the pigeon was maintained under chained schedules in which the completion of one schedule component initiated the next component, and food was presented upon completion of a sequence of components. Under the chained schedules studied, a particular key color appeared during more than one component, and different key colors appeared during the other components. When seven 1‐min fixed‐interval components comprised a chained schedule and the response key was the same color during the first, third, fifth, and terminal components, patterns of positively accelerated responding were maintained during all but the first two components of each sequence. In general, response rates were always lowest during the first one or two components and highest during the terminal component when as few as three and as many as eight components comprised a schedule. Increasing the number of components from three to eight showed that response rate during a component increased when it was no longer one of the initial two components of the schedule, even though its temporal relation to food presentation had not changed. Finally, when seven components comprised a schedule and the response key was one color during the first, third, and fifth and a different color during the last component, response rates were low during the first five components and high during the last two components preceding food presentation.
EFFECT OF PROXIMITY OF ELEMENTS ON THE FEATURE‐POSITIVE EFFECT1
Authors: Sainsbury R. S.
Published: March 2006

Eight groups of pigeons were trained to discriminate between two stimulus displays that could be differentiated only by a single distinctive feature on one of the displays. For half of the pigeons, responses to displays containing the distinctive feature were reinforced (feature‐positive), and for the remaining pigeons responses to displays without the distinctive feature were reinforced (feature‐negative). The pigeons were further grouped so that half were presented displays in which the distinctive feature was in close proximity to other features (compact displays) and half were presented displays in which the features were not close together (distributed displays). Pigeons in the feature‐positive groups localized responses on the distinctive feature of the displays and seldom responded to displays without the distinctive feature. Pigeons in the distributed feature‐negative groups localized responses on features common to the two displays and did not learn the discrimination. Compacting the displays facilitated discrimination performance for the subjects in the feature‐negative condition. Tests carried out in extinction indicated that responding in the compact feature‐negative group was largely controlled by pattern rather than by the individual elements on the display.
DISCRIMINATION OF COMPOUND STIMULI INVOLVING THE PRESENCE OR ABSENCE OF A DISTINCTIVE VISUAL FEATURE1
Authors: Farthing G. William
Published: March 2006

Pigeons learned a free operant, go/no‐go discrimination between stimuli produced by rapid alternation of different features on the response key. The 0° –B compound consisted of a vertical black line on a white background (the 0° feature) alternated with a blank white field (the B feature), with successive 0.75‐sec feature on periods separated by 0.20‐sec dark periods. Pecks at the alternating 0° and B features were recorded separately. When pecks at the 0°–B compound were reinforced and pecks at the B—B stimulus (repeated brief presentations of the B feature) were extinguished, the birds pecked more at the 0° feature than at the B feature in the 0°–B compound; subsequently, decremental line‐tilt generalization gradients were obtained. When pecks at B—B were reinforced and pecks at 0°–B were extinguished, the rate of pecking at the 0° feature decreased to a low level much more rapidly than did the rate of pecking at the B feature in the 0°–B compound; incremental line‐tilt gradients were obtained. Following training with pecks at 0°–B reinforced and pecks at 0°–0° extinguished, incremental line‐tilt gradients were obtained, whereas the gradients were decremental following training with 0°–0° reinforced and 0°–B extinguished.
OVERT ACTIVITY DURING CONDITIONED SUPPRESSION: A SEARCH FOR PUNISHMENT ARTIFACTS1
Authors: Hoffman Howard S. , Barrett James
Published: March 2006

Pigeons, previously trained to peck a key (using food as the reinforcer), were permitted unlimited access to food and, concurrently, key pecking was allowed to go unreinforced until all pecking ceased. A tone ending with electrical shock was then repeatedly presented in an effort to establish the tone as a potentially suppressing stimulus. When key pecking was later reestablished, tone presentation (without shock) sharply reduced the rate of pecks. At selected points throughout the experiment, special observation procedures supplemented the recordings of key pecks and provided detailed fine‐grain protocols of the birds' overt movements during the periods before, during, and after tone presentations. Results indicated that neither punishment of key pecks nor punishment of other overt movements was a necessary precursor to the conditioned suppression observed in the final stage. As such, the findings support interpretations of conditioned suppression that characterize the phenomenon as reflecting a conditioned emotional reaction that either directly or indirectly inhibits overt activity.
SHOCK‐INDUCED THREAT AND BITING BY THE TURTLE1
Authors: Fraser David , Spigel Irwin M.
Published: March 2006

Shock‐induced biting and threat by the male painted turtle (Chrysemys picta marginata) were studied in three experiments. When restrained facing each other, the turtles threatened and bit other turtles in response to electric shock. Shock alone caused turtles to threaten an unshocked turtle; the movements of a shocked turtle were sufficient to cause an unshocked but restrained turtle to threaten. When the turtles were free to move, they avoided an encounter when shocked, even reversing a strong position preference in order to do so.
EFFECTS OF PAIRING STIMULI WITH REINFORCEMENT ON MULTIPLE SCHEDULE PERFORMANCE OF CHILDREN
Authors: Birnbrauer J. S.
Published: March 2006

A nonsense word was paired with reinforcement to determine if pairing affected emission of a response that produced the word in the signalled absence of reinforcement. Children were trained on a multiple schedule that consisted of a reinforcement component, conditioned reinforcement component, and control component, each set of contingencies being signalled by a different colored light. In the primary reinforcement component, lever presses produced reinforcers which, in some phases, were paired with a word. In the other two components, lever presses were not reinforced and a button was made accessible. Button presses in the conditioned reinforcement component produced the word to be (or being) paired, e.g., “yafeh”, while button presses in the control component produced another word, e.g., “grunch”. Button pressing increased when one of the words was being paired and decreased when pairing was discontinued, but directly related rate changes occurred also in the control component. The order of components was shown to be a contributing variable.
AVOIDANCE OF RISK AS A DETERMINANT OF COOPERATION
Authors: Schmitt David R. , Marwell Gerald
Published: March 2006

Pairs of subjects could either cooperate or respond on a lower paying individual task. Whenever both subjects chose to cooperate, either subject could make a response that took $1.00 of the other's earnings. In Exp. I, a stimulus signalled when a “take” response had been made. Either subject could avoid the loss by switching to the individual task within 5 sec after the stimulus appeared. Rates of cooperation were high when losses could be avoided but decreased again when the avoidance condition was removed. In Exp. II, a response prevented “takes” from occurring for a specified time interval after the response. This procedure also maintained cooperation. When each avoidance response subtracted from earnings, both avoidance responding and cooperation were eliminated.
THE REINFORCEMENT OF FOUR INTERRESPONSE TIMES IN A TWO‐ALTERNATIVE SITUATION1
Authors: Shimp Charles P.
Published: March 2006

Pigeons pecked for food in a two‐key procedure. A concurrent variable‐interval variable‐interval schedule of reinforcement for two classes of interresponse times was arranged on each key. A visual stimulus set the occasion for potential reinforcement of the four operant classes: shorter and longer interresponse times on left and right keys. In Exp. I, the relative frequency of respones on a key equalled the relative frequency of reinforcement on that key. In Exp. II, the relative frequency of an interresponse time equalled the relative reciprocal of its length. In Exp. III, the relative frequency of an interresponse time was a monotonically increasing function of its relative frequency of reinforcement. These functions relating the relative frequency of an interresponse time to its relative length and to its relative frequency of reinforcement were the same as if there had been no second key. Also, the distribution of responses between keys was independent of the relative frequency of an interresponse time on either key. Experiment IV replicated Exp. I except that choices between keys were controlled by a stimulus that signalled the availability of reinforcement on the right key. A comparison of Exp. I and IV suggested that the relative frequency of an interresponse time on one key generally was independent of behavior on the other key, but that the number of responses per minute on a key did depend on behavior on the other key.
TEMPORAL TRACKING ON CYCLIC‐INTERVAL REINFORCEMENT SCHEDULES1
Authors: Innis Nancy K. , Staddon J. E. R.
Published: March 2006

Pigeons were exposed to four cycles per session of a schedule in which the duration of successive interreinforcement intervals differed by t‐sec. A cycle was composed of seven increasing and seven decreasing intervals, from 2t to 8t sec in length. In Exp. 1, postreinforcement pause tracked interval duration on five cyclic schedules, with values of t ranging from 2 to 40 sec. Tracking was better at shorter t values, and when discriminative stimuli signalled increasing and decreasing parts of the cycle. Pooled data for the whole experiment showed postreinforcement pause to bear a power function relationship to interval length, with a smaller exponent than the comparable function for fixed‐interval schedules. Tests in a second experiment showed that pigeons trained on an arithmetic progression could also track schedules in which successive intervals followed either a logarithmic or a geometric progression, although tracking was more stable in the logarithmic case.
BEHAVIORAL CONTRAST AND RESPONSE INDEPENDENT REINFORCEMENT1
Authors: Halliday M. S. , Boakes R. A.
Published: March 2006

Four pigeons received pre‐training that included presentation of the reinforcer independently of behavior and then baseline training on a variable‐interval schedule of reinforcement. With the introduction of a multiple schedule, in which the first stimulus was associated with a response contingent and a second stimulus with a response independent, 1‐min variable‐interval schedule, a reduction in response rate was obtained in the second component, which was not accompanied by a behavioral contrast effect in the first component. A further three pigeons were given the same pre‐training and baseline training before the introduction of an otherwise identical multiple schedule, in which no reinforcement occured in the second component. Behavioral contrast was obtained from all three subjects. The results indicated that under conditions of constant reinforcement density a reduction in responding is not a sufficient condition for the occurrence of behavioral contrast.
CONCURRENT PERFORMANCES: EFFECT OF PUNISHMENT CONTINGENT ON THE SWITCHING RESPONSE1
Authors: Todorov Joao Claudio
Published: March 2006

Pigeons' key‐pecking responses were maintained under concurrently available variable‐interval schedules of reinforcement. Responses in the presence of two different key‐colors were reinforced on two independent and concurrent variable‐interval schedules of food reinforcement, each associated with one of the key colors (red or green). Pecks at a second key (changeover key), always white, would alternate the colors on the main key. In Exp. 1 and 2, electric shock of 50 msec duration followed immediately after changeovers. The proportion of responses in the presence of the color associated with the higher frequency of reinforcements per hour was a direct function of shock intensity contingent on changeovers. When both schedules provided equal number of reinforcements per hour, there was no systematic effect of shock intensity on response distribution. In Exp. 3, a timeout period was contingent on changeovers, and response distribution was a function of timeout length.
CONCURRENT SCHEDULES OF REINFORCEMENT: EFFECTS OF GRADUAL AND ABRUPT INCREASES IN CHANGEOVER DELAY1
Authors: Allison Tom S. , Lloyd Kenneth E.
Published: March 2006

Pigeons' pecks were maintained on concurrent variable‐interval 1‐min variable‐interval 3‐min schedules of reinforcement, with a changeover delay of 2 sec. When changeover delay was increased successively to 5.0, 7.5, and 12.5 sec (Exp. I) the actual relative rate of reinforcement for the variable‐interval 3‐min key decreased progressively for two birds, abruptly for two other birds, and the subjects devoted proportionately less of their time and responding to that key. However, the relative performance measures (relative time and relative responding) approximated the actual relative rate of reinforcement, with a maximum discrepancy of 11%, over all changeover delay values investigated. Experiment II attempted to lengthen response‐run durations on the variable‐interval 3‐min key so that they were long enough to meet the changeover delay requirement at each new changeover delay value, by progressively increasing the changeover delay by 0.5‐sec increments. With this procedure the actual relative rate of reinforcement approximated more closely the scheduled relative rate as changeover delay increased. As in Exp. I, relative performance measures approximated the actual relative reinforcement rate (maximum discrepancy 17%).
CHANGEOVER BEHAVIOR UNDER PAIRS OF FIXED‐RATIO AND VARIABLE‐RATIO SCHEDULES OF REINFORCEMENT1
Authors: Shull Richard L. , Pliskoff Stanley S.
Published: March 2006

Three pigeons were studied under a pair of equal fixed‐ratio schedules and a pair of equal variable‐ratio schedules. Each pair was arranged as independent, concurrent schedules and also in a non‐independent relation where each peck in a schedule counted toward the response requirement of both schedules. The non‐independent pair of variable‐ratio schedules maintained much higher changeover rates than any of the other three arrangements. Thus, two factors seemed necessary for generating high changeover rates. Responding on a schedule had to count toward the response requirement of both schedules, and the component schedules had to be variable. These data are consistent with the hypothesis that changeovers are at least partly controlled by the probability of reinforcement following a changeover.
CONTROL OF RESPONDING BY STIMULUS DURATION1
Authors: Elsmore Timothy F.
Published: March 2006

Pigeons were trained on a procedure in which the key was white for 30 sec, alternating with periods of darkness, or timeout. In a nondifferential training procedure, timeout duration was held constant at either 9 or 21 sec for different animals, and pecks on the white key were reinforced on a variable‐interval 36‐sec schedule. After 30 sessions an extinction generalization test was conducted where the duration of the timeout was varied from 3 to 27 sec. This test showed no differences in responding following timeouts of different durations. In a differential training procedure, timeout durations of either 9 or 21 sec were randomly scheduled for each animal. The variable‐internal schedule was in effect following the same timeout duration as in the prior nondifferential procedure. No pecks were reinforced after the other timeout duration. In 40 sessions, differences in response rates following the two durations gradually developed. A maintained generalization procedure was then imposed in which timeout durations were varied from 3 to 27 sec, with the variable‐interval schedule in effect following only the same duration as in the previous procedures. The first maintained generalization session showed that the prior differential training had established control of the animals' behavior by the timeout duration. In continued training on the maintained generalization procedure, control by the timeout duration decreased.
STIMULUS CONTROL DURING CONDITIONAL DISCRIMINATION1
Authors: Yarczower Matthew
Published: March 2006

Pigeons were used to assess stimulus control during the development of a conditional discrimination. The training consisted of three stages. In Stage 1, key pecks were reinforced in the presence of a white line tilted 40° to the right of vertical on a green background and non‐reinforced when the same line appeared on a red background. In Stage 2, key pecks were reinforced when a white vertical line appeared on a red background and were non‐reinforced in the presence of a 40° slanted line on a red background. In Stage 3, key pecks were reinforced in the presence of the green background regardless of the line tilt, but were differentially reinforced in the presence of the red background (as in Stage 2). Generalization tests were conducted after each stage of training and consisted of five white lines on backgrounds that were green, red, or dark. The effects of the differential reinforcement contingencies on control by line orientation were restricted to the condition in which the red light appeared and resulted in behavioral control that could be characterized as: if red, pay closer attention to line tilt than if not red.
EVIDENCE OF INTERACTION BETWEEN DEPRIVATION EFFECTS AND STIMULUS CONTROL
Authors: Powell Robert W.
Published: March 2006

Discriminative responding in pigeons was studied under multiple variable‐interval extinction and variable‐ratio extinction schedules, as deprivation was varied. Generally, the greater the accuracy of discrimination that developed during training, the smaller the effect of deprivation upon subsequent performance. This was true both in terms of changes in response rates, and in the relationship between response rates during food reinforcement and extinction. When discrimination was inaccurate, increases in deprivation resulted in disproportionate increases in responding during extinction, as compared to increases during food reinforcement components of the schedule. The results suggest that as stimulus control (accuracy) of responding increases, discriminative performance becomes less and less susceptible to influence by deprivation.
EFFECTS OF MONOCHROMATIC REARING ON SPECTRAL DISCRIMINATION LEARNING AND THE PEAK SHIFT IN CHICKS1
Authors: Rudolph Robert L. , Honig Werner K.
Published: March 2006

Chicks were hatched and raised in white or monochromatic sodium (589 nm) light. They were trained on a 590 (+) vs. 580 (‐) nm successive discrimination. The combined results of two experiments indicated that rearing illumination did not affect discrimination acquisition. All subjects given generalization tests after discrimination training exhibited peak shifts that were equivalent for the two rearing conditions. The peak shifts exhibited by the monochromatically reared subjects represent maximum responding to stimuli they had not previously seen. This result further confirms the notion that behavioral control by the spectral dimension in birds is organized independently of differential early experience on that dimension.
SOME EFFECTS OF RESPONSE‐DEPENDENT CLOCK STIMULI IN A FIXED‐INTERVAL SCHEDULE1
Authors: Kendall Stephen B.
Published: March 2006

Two experiments studied the effects of brief response‐dependent clock stimuli in fixed‐interval schedules of reinforcement. In the first experiment, two pigeons were exposed to a fixed‐interval schedule. Two conditions were compared. In both conditions each peck on the key produced a brief stimulus. In one condition, pecks produced a different stimulus in successive sixths of the interval. This was the clock condition. In the other condition, the same stimulus was produced throughout the interval. Response rates were lower and the pause after reinforcement was longer in the clock condition. In the second experiment, a two‐key optional clock procedure was used. Responding on the clock key produced one of three stimuli correlated with the three successive minutes of a fixed‐interval schedule. A response on the other key produced grain at the end of the 3 min. When the final stimulus was removed from the situation and pecking produced nothing during the third minute, responding to the clock key declined to a very low rate. When the first two stimuli were removed and the third one replaced, responding to the clock key was resumed.
FIXED‐INTERVAL BEHAVIOR: EFFECTS OF PERCENTAGE REINFORCEMENT1
Authors: Zeiler Michael D.
Published: March 2006

The percentage of fixed intervals terminating with food presentation was varied parametrically. Intervals that did not end with food were terminated by a stimulus uncorrected with food presentation (a timeout stimulus). In Experiment I, the pigeons' response rates were an inverted U‐shaped function of the percentage of food presentations: decreasing the percentage from 100% to 90%, 70%, or 50% produced an increase in response rates; lower percentages decreased the rates. The patterns of responding in the 100% condition differed from those of the other conditions. In Experiment II, the chamber was darkened after food presentations and timeouts. Response rate was directly related to the percentage of food presentations: decreasing the percentage decreased the response rate. Characteristic fixed‐interval patterns of responding were maintained as long as there were occasional food presentations; pausing followed by positively‐accelerated responding occurred in percentage conditions ranging from 7% to 100%. The ability to maintain fixed‐interval performance with percentage reinforcement suggested that the behavioral sequences occurring in each interval may operate as unitary responses.
CHANGING THE RESPONSE UNIT FROM A SINGLE PECK TO A FIXED NUMBER OF PECKS IN FIXED‐INTERVAL SCHEDULES1
Authors: Shull Richard L. , Guilkey Marilyn , Witty William
Published: March 2006

Each of three pigeons was studied first under a standard fixed‐interval schedule. With the fixed interval held constant, the schedule was changed to a second‐order schedule in which the response unit was the behavior on a small fixed‐ratio schedule (first a fixed‐ratio 10 and then a fixed‐ratio 20 schedule). That is, every completion of the fixed‐ratio schedule produced a 0.7‐sec darkening of the key and reset the response count to zero for the next ratio. The first fixed‐ratio completed after the fixed‐interval schedule elapsed produced the 0.7‐sec blackout followed immediately by food. These manipulations were carried out under two different fixed‐interval durations for each bird ranging from 3 min to 12 min. The standard fixed‐interval schedules produced the typical pause after reinforcement followed by responding at a moderate rate until the next reinforcement. The second‐order schedules also engendered a pause after reinforcement, but responding occurred in bursts separated by brief pauses after each blackout. For a particular fixed‐interval duration, post‐reinforcement pauses increased slightly as the number of pecks in the response unit increased despite large differences in the rate and pattern of key pecking. Post‐reinforcement pause increased with the fixed‐interval duration under all response units. These data confirm that the allocation of time between pausing and responding is relatively independent of the rate and topography of responding after the pause.
TIMEOUT AND CONCURRENT FIXED‐RATIO SCHEDULES WITH HUMAN SUBJECTS1
Authors: Striefel Sebastian
Published: March 2006

Human subjects given choices among 10 different pairs of concurrent fixed‐ratio schedules preferred the smaller ratio. After a preference had been determined, timeout of increasing duration followed the completion of the preferred schedule. The larger the fixed‐ratio difference, the longer the timeout necessary to produce the shift to the previously nonpreferred ratio. Responses by two of three subjects were unaffected by changes from response‐dependent to response‐independent pay.
SCHEDULE CONTROL OF THE VOCAL BEHAVIOR OF CEBUS MONKEYS1
Authors: Leander J. David , Milan Michael A. , Jasper Kathleen B. , Heaton Kathleen L.
Published: March 2006

The vocal behavior of three Cebus monkeys was maintained by fixed‐ratio schedules of response dependent reinforcement at values between fixed‐ratio 1 and fixed‐ratio 15. In one monkey that was exposed to variable‐interval, fixed‐interval, and conjunctive fixed‐ratio fixed‐interval schedules of reinforcement, vocal responding occurred at a low rate, but schedule‐appropriate patterns were maintained. The rates and patterns of responding engendered indicated that the vocal operant can be brought under schedule control in the monkey by the use of response‐dependent reinforcement.
COMPOUNDING DISCRIMINATIVE STIMULI CONTROLLING FREE‐OPERANT AVOIDANCE1
Authors: Emurian Henry H. , Weiss Stanley J.
Published: March 2006

The performances of three rats were stabilized on a multiple schedule that maintained responding by a free‐operant avoidance schedule during independent presentations of tone and light. The simultaneous absence of these stimuli signalled shock‐free periods and controlled response cessation. Subsequently, test sessions were administered consisting of independent presentations of each stimulus and these stimuli compounded (tone‐plus‐light). During an extinction test, additive summation was observed to the compounded stimuli, i.e., more responses were emitted to the compound than to either tone or light. During a series of 28 maintenance‐test sessions in which the shock schedule remained operative, the compounded stimuli produced a generally enhanced response rate and fewer pauses terminating with shock than either single stimulus condition. These results extend the generality of free‐operant additive summation to responding maintained by aversive control. In addition, a comparison of the present study with previous experiments reporting additive summation of positively reinforced responding indicates that similar variables—rate and aversive differences between training stimulus conditions—should be considered in accounting for response distributions during stimulus compounding when responding is controlled by either positive or negative contingencies.
CONDITIONED SUPPRESSION OF FREE‐OPERANT AVOIDANCE
Authors: Bryant Rodney C.
Published: March 2006

The responses of white rats were maintained on an unsignalled free‐operant avoidance schedule. Superimposed on the avoidance schedule was a blinking white light followed immediately by response‐independent electric shock. Duration of the light stimulus was either 1 or 3 min. Avoidable shock was 1.5 mA; response‐independent shock was 7.5 mA. Suppression of responding during the light stimulus (both durations) developed over sessions. Responding immediately following the response‐independent light‐shock sequence was neither suppressed nor accelerated. The similarity is noted between the present result and findings of “positive conditioned suppression”.
PREFERENCE FOR LOCUS OF PUNISHMENT IN A RESPONSE SEQUENCE1
Authors: Dardano J. F.
Published: March 2006

Food‐deprived pigeons pecked a key under a schedule in which grain was made available after the seventieth peck. In each sequence of 70 responses, either the first, middle, or final response was followed by electric shock. Before the first response of each sequence, each response on a second key changed the color of the food key and the schedule of shock that was correlated with the food key color. Each pigeon preferred a schedule of shock, in that each of the three shock schedules did not occur equally often. The preferred shock schedule and the strength of the preference varied among the pigeons. The overall rate of responding by a pigeon under a given shock schedule was directly related to the pigeon's relative preference for that schedule, except when shock after the first response in the sequence was the most preferred schedule.
ENHANCEMENT OF PROGRESSIVE‐RATIO PERFORMANCE BY CHLORDIAZEPOXIDE AND PHENOBARBITAL1
Authors: Thompson Donald M.
Published: March 2006

The key pecking of two pigeons was reinforced with food on a progressive‐ratio schedule, which required an increasing number of responses for each successive reinforcement: 8, 16, 24, 32, etc. When the subject failed to complete the next ratio in the sequence within 60 min, the session terminated. The number of responses in the final completed ratio was defined as the “breaking point”. After the breaking point had stabilized (60 sessions), it served as a baseline to assess the effects of varying doses (5 to 80 mg/kg) of chlordiazepoxide and phenobarbital, administered intramuscularly 30 min before the sessions. Both drugs increased the breaking point. The dose‐effect curves were inverted U‐shaped, with maximum enhancement of performance occurring at 20 mg/kg for chlordiazepoxide and at 40 mg/kg for phenobarbital. A comparable enhancement was not obtained during a non‐drug “probe” session, which was conducted after the subjects' body weights had been temporarily reduced from 80% to 70% of their free‐feeding weights. The drug‐induced enhancement of breaking point was related to the initial values of the performance and may represent a reduction in the aversiveness of the schedule.
SOME EFFECTS OF INTERREINFORCEMENT TIME UPON CHOICE1
Authors: Fantino Edmund , Duncan Barbara
Published: March 2006

Pigeons' responses were reinforced on two identical and concurrently available chain variable‐interval‐schedules. Unlike the typical concurrent chains procedure, both links were operative throughout, thus producing three types of concurrency: (1) concurrent initial links; (2) concurrent initial and terminal links; (3) concurrent terminal links. Choice proportions in each of these three states suggested that the pigeons were sensitive to momentary likelihoods of reinforcement: choice proportions for a schedule were higher when the schedule had been operative for some time, resulting in a higher probability of reinforcement. The study also showed that the relative rates of responding did not match the relative rates of reinforcement in any of the three states of concurrency. Instead, the choice proportions in both the concurrent initial and in the concurrent terminal links were intermediate between the scheduled and the obtained relative rates of reinforcement, while the choice proportions for a terminal link concurrent with an initial link consistently overmatched the relative interreinforcement times (and were typically 1.00). These data indicate that an accurate characterization of choice may not be obtained by considering only the relative interreinforcement interval where one interreinforcement interval is segmented into a chain. Instead, the organism's choice for a schedule will be substantially lowered by the chaining operation.
UNDERWATER AUDIOGRAM OF THE CALIFORNIA SEA LION BY THE CONDITIONED VOCALIZATION TECHNIQUE1
Authors: Schusterman Ronald J. , Balliet Richard F. , Nixon James
Published: March 2006

Conditioning techniques were developed demonstrating that pure tone frequencies under water can exert nearly perfect control over the underwater click vocalizations of the California sea lion (Zalophus californianus). Conditioned vocalizations proved to be a reliable way of obtaining underwater sound detection thresholds in Zalophus at 13 different frequencies, covering a frequency range of 250 to 64,000 Hz. The audiogram generated by these threshold measurements suggests that under water, the range of maximal sensitivity for Zalophus lies between one and 28 kHz with best sensitivity at 16 kHz. Between 28 and 36 kHz there is a loss in sensitivity of 60 dB/octave. However, with relatively intense acoustic signals (> 38 dB re 1 μb underwater), Zalophus will respond to frequencies at least as high as 192 kHz. These results are compared with the underwater hearing of other marine mammals.
THE ROLE OF THE RESPONSE‐REINFORCER CONTINGENCY IN NEGATIVE AUTOMAINTENANCE1
Authors: Schwartz Barry , Williams David R.
Published: March 2006

When a response key is briefly illuminated before a grain reinforcer is presented, key pecking is reliably developed and maintained in pigeons, even if pecking prevents reinforcement (negative automaintenance). This experiment demonstrated that pigeons are sensitive to a negative response‐reinforcer contingency, even though it does not eliminate responding. Within individual pigeons, two kinds of trials were compared: red key trials, in which reinforcement was negatively contingent on responding, and white key trials, in which reinforcement was unrelated to responding. Reinforcement frequency in non‐contingent trials was yoked to the obtained reinforcement frequency in negatively contingent trials. All eight pigeons pecked substantially more on the non‐contingent key than on the negative key, and preferred the non‐contingent key to the negative key on occasional “choice” trials where both were presented together. When the stimuli correlated with the two conditions were reversed, the pigeons' behavior also shifted. These response differences are taken as evidence that pigeons are sensitive to the negative response‐reinforcer contingency.
CONDITIONING OF A FREE OPERANT IN OCTOPUS CYANEUS GRAY1
Authors: Crancher Pamela , King M. G. , Bennett Adrienne , Montgomery R. B.
Published: March 2006

Operant conditioning was studied in six specimens of Octopus cyaneus Gray. An “arm‐out‐of‐water” operant, in which the octopus inserted an arm up a feeding‐tube breaking the water surface, proved susceptible to reinforcement schedules. An apparatus was developed that provided automated reinforcement and recording. Performance was studied under continuous reinforcement, fixed‐ratio and variable‐ratio schedules, and extinction conditions.
PROBABILITY LEARNING AS A FUNCTION OF MOMENTARY REINFORCEMENT PROBABILITY1
Authors: Williams Ben A.
Published: March 2006

Pigeons were trained on a probability learning task where the overall reinforcement probability was 0.50 for each response alternative but where the momentary reinforcement probability differed and depended upon the outcome of the preceding trial. In all cases, the maximum reinforcement occurred with a “win‐stay, lose‐shift” response pattern. When both position and color were relevant cues, the optimal response pattern was learned when the reinforcement probability for repeating the just‐reinforced response was 0.80 but not when the probability was 0.65. When only color was relevant, learning occurred much more slowly, and only for subjects trained on large fixed ratio requirements.
PERFORMANCE IN CONCURRENT INTERVAL SCHEDULES1
Authors: Trevett A. J. , Davison M. C. , Williams R. J.
Published: March 2006

Four pigeons were trained under concurrent variable‐interval variable‐interval and fixed‐interval variable‐interval schedules in a two‐key situation. Both response allocation and time allocation to the two schedules were measured when various reinforcement rates were arranged on each key. All animals showed an approximately constant proportional preference for the variable‐interval schedule over the fixed‐interval schedule. These results support Schneider's (1969) analysis of fixed‐interval schedule performance.
INVERSE RELATION BETWEEN CHOICE AND LOCAL RESPONSE RATE WITH A SCHEDULE OF RESPONSE‐PRODUCED BLACKOUTS1
Authors: Arnett Faye Bush
Published: March 2006

Pigeons were exposed to a two‐key concurrent chains schedule in which identical frequencies and distributions of food presentations generated different response rates in the terminal links. An inverse relation between local rate of response in the terminal links and relative frequency of response in the initial links was observed. The high response rate was produced in one terminal link by a second‐order schedule in which responding produced brief blackouts of the response key. Responding under the same schedule in the other terminal link did not produce blackouts. Under initial training and after spatial reversal of the terminal‐link schedules, two of three pigeons had lower relative frequencies of response in the initial member of the chain with the higher terminal link response rate. The third pigeon showed no change in preference at reversal.
REINFORCEMENT DELAY: SOME EFFECTS ON BEHAVIORAL CONTRAST1
Authors: Richards Ralph W.
Published: March 2006

Thirty five White Carneaux pigeons first received 20 sessions of non‐delayed reinforcement according to a multiple variable‐interval 1‐min variable‐interval 1‐min schedule. For the remaining 15 sessions, subjects were assigned to one of five groups, with seven subjects per group. Four of these groups involved reinforcement according to the same multiple schedule as before, but reinforcement during one of the components was delayed for either 2.5, 5, 10, or 120 sec. The schedule for the fifth group was changed to multiple variable‐interval 1‐min extinction schedule of reinforcement. While some subjects in all groups showed behavioral contrast, it occurred more consistently in the groups involving extinction or the longer delays of reinforcement. Groups involving the various durations of delayed reinforcement or even extinction during the altered component did not, however, show a statistically significant difference in the amount of behavioral contrast. It was suggested that neither a reduction in reinforcement frequency nor response rate during the altered component is necessary to the production of behavioral contrast.
SCHEDULE‐INDUCED LICKING DURING MULTIPLE SCHEDULES1
Authors: Jacquet Yasuko Filby
Published: March 2006

Schedule‐induced polydipsia was studied in rats bar pressing under two‐component multiple schedules of food reinforcement. The first component of the multiple schedule was a variable‐interval 1‐min schedule throughout the experiment. The schedule comprising the second component was varied over blocks of sessions in terms of rate and magnitude of reinforcement, and was either variable‐interval 3‐min (one pellet), variable‐interval 3‐min (three pellets), variable‐interval 1‐min (one pellet), or extinction. Water intake per session varied with the rate of reinforcement in the schedule comprising the second component and was highest when the schedule was variable‐interval 1‐min. Both bar‐pressing behavior and licking behavior showed behavioral interactions between the two components of the multiple schedules. With magnitude of reinforcement held constant, a matching relationship was observed between lick rate and reinforcement rate; the relative frequency of licks in the constant component matched the relative frequency of reinforcement in that component. Bar pressing, however, showed only a moderate degree of relativity matching. During the schedule‐induced licking, a burst of licking followed each delivery of a pellet (post‐prandial drinking). The duration of these bursts of licking was observed to be a function of the inter‐reinforcement interval.
COMPONENT DURATION AND RELATIVE RESPONSE RATES IN MULTIPLE SCHEDULES1
Authors: Todorov João Claudio
Published: March 2006

Pigeons were trained on a multiple variable‐interval 30‐sec, variable‐interval 90‐sec schedule with each component presented alternately for an equal (on the average) duration. This average duration of exposure to each component was varied from 5 to 300 sec. The main concern was with rate of response in the variable‐interval 30‐sec component relative to rate of response in the variable‐interval 90‐sec component. In all cases, rate of response was higher in the variable‐interval 30 sec component, but the discrepancy in the rate produced by the two schedules tended to be greatest when the duration of component presentation was brief. The mean proportion of responses emitted during the variable‐interval 30‐sec component (responses in variable‐interval 30‐sec component divided by total responses) varied from about 0.60 to 0.71, where 0.75 would be expected on the basis of a matching rule, and 0.59 was that obtained by Lander and Irwin (1968). These results are in agreement with data reported by Shimp and Wheatley (1971) from a similar experiment.
THREE‐CONFIGURATION MATCHING‐TO‐SAMPLE IN THE PIGEON1
Authors: Kamil Alan C. , Sacks Robert A.
Published: March 2006

Pigeons were trained on a zero‐delay matching‐to‐sample procedure during which only three of the four possible stimulus configurations were presented. Subsequently, all birds were exposed to all four configurations as a transfer test. A high degree of negative transfer from the three training configurations was obtained in Experiment 1. The results of Experiment 2 indicated that three‐configuration training produced differential position‐preference effects. During the transfer test, responding after one sample stimulus was apparently based on position, while responding after the other sample was based on color.
THE MATCHING LAW
Authors: Killeen Peter
Published: March 2006

The matching law may be viewed either as an empirical generalization, and therby subject to disproof, or as part of a system of equations used to define the utility (“value”) of a reinforcer. In the latter case it is tautologous, and not subject to disproof within the defining context. A failure to obtain matching will most often be a signal that the independent variables have not been properly scaled. If, however, the proper transformations have been made on the independent variables, and matching is not obtained, the experimental paradigm may be outside the purview of the matching law. At that point, reinterpretations or revisions of the law are called for. The theoretical matching law is but one of many possible ways to define utility, and it may eventually be rejected in favor of a more useful definition.
FIXED‐INTERVAL LIMITED‐HOLD AVOIDANCE WITH AND WITHOUT SIGNALLED REINFORCEMENT1
Authors: Black R. E. , Walters Gary C. , Webster C. D.
Published: March 2006

Rats trained to lever press on a fixed‐interval limited‐hold avoidance schedule maintained a pattern of responding similiar to that maintained by fixed‐interval limited‐hold schedules of positive reinforcement. But this positively accelerated pattern of behavior was maintained only when the occurrence of reinforcement was signalled by the presentation of a brief flash of light. This result suggests that the discriminative function of the reinforcer in avoidance is less pronounced than the discriminative function of the reinforcer in escape or positive reinforcement. It also suggests that the distinction between positive reinforcement and avoidance is not superfluous. Although the schedule of reinforcement is an important variable in determining the pattern of behavior, other variables, such as the nature (i.e., stimulus presentation, termination, or omission) of the reinforcer, are also potent determinants of behavior.