bluuebunny/crossref_metadata_2025 huggingface dataset:
HUNGER AND CONTRAST IN A MULTIPLE SCHEDULE1
Authors: Herrnstein R. J. , Loveland Donald H.
Published: March 2006

Pigeons working for food on a multiple variable‐interval 1‐min—variable‐interval 4‐min schedule were subjected to variations in body weight, presumably causing changes in hunger. The proportion of responses in each component approached and eventually reached the proportion of reinforcements as body weight increased. This effect follows from the matching‐law interpretation of contrast in multiple schedules.
A DETAILED ANALYSIS OF THE EFFECTS OF d‐AMPHETAMINE ON BEHAVIOR UNDER FIXED‐INTERVAL SCHEDULES1
Authors: Branch Marc N. , Gollub Lewis R.
Published: March 2006

Pigeons were exposed to fixed‐interval schedules of food reinforcement with durations of 300 sec, 100 sec, or 40 sec. A range of doses of d‐amphetamine was administered to each pigeon, and the resulting behavior was analyzed at several levels of detail. Average rates in different portions of the intervals predicted the magnitude of the drug's effect, but a finer analysis showed that average rates did not adequately characterize the behavior in some parts of the intervals. The probability of responding in different parts of an interval without drug was also a good predictor of the magnitude of the effect of d‐amphetamine, and at the same time was more descriptive of the interval‐to‐interval performance. Analyses of the control performance indicated that responding in individual intervals could be described as consisting of two parts: a very low, or zero, rate at the beginning of the interval followed by an abrupt transition to a slightly, but reliably, positively accelerated rate maintained until reinforcement.
CONTINGENCY SPACES AND MEASURES IN CLASSICAL AND INSTRUMENTAL CONDITIONING1
Authors: Gibbon John , Berryman Robert , Thompson Robert L.
Published: March 2006

The contingency between conditional and unconditional stimuli in classical conditioning paradigms, and between responses and consequences in instrumental conditioning paradigms, is analyzed. The results are represented in two‐ and three‐dimensional spaces in which points correspond to procedures, or procedures and outcomes. Traditional statistical and psychological measures of association are applied to data in classical conditioning. Root mean square contingency, ø, is proposed as a measure of contingency characterizing classical conditioning effects at asymptote. In instrumental training procedures, traditional measures of association are inappropriate, since one degree of freedom—response probability—is yielded to the subject. Further analysis of instrumental contingencies yields a surprising result. The well established “Matching Law” in free‐operant concurrent schedules subsumes the “Probability Matching” finding of mathematical learning theory, and both are equivalent to zero contingency between responses and consequences.
GENERALIZATION OF FREE‐OPERANT AVOIDANCE BEHAVIOR IN PIGEONS1
Authors: Klein Marty , Rilling Mark
Published: March 2006

Three groups of four pigeons, trained to press a treadle on a free‐operant avoidance schedule, were given auditory discrimination training. Alternating 2‐min components of avoidance and no shock were paired with either a tone or white noise. The pigeons were subsequently given two types of generalization tests, with and without avoidable shocks scheduled. Two of the groups, trained interdimensionally, produced excitatory and inhibitory generalization gradients along the tone frequency dimension. A predicted post‐discrimination gradient was computed from the algebraic summation of these gradients of excitation and inhibition. The predicted gradient was compared with the actual post‐discrimination gradient obtained from the third group of pigeons that had been given intradimensional discrimination training on the tone frequency dimension. The predicted postdiscrimination gradient agreed in shape with the empirical postdiscrimination gradient. The results in general support Spence's (1937) gradient interaction theory.
BEHAVIOR UNDER LARGE VALUES OF THE DIFFERENTIAL‐REINFORCEMENT‐OF‐LOW‐RATE SCHEDULE1
Authors: Richardson W. Kirk , Loughead Tomas E.
Published: March 2006

Pigeons pecked a key and rats pressed a lever for food reinforcement under large values of the differential‐reinforcement‐of‐low‐rate schedule. Each subject was tested under 10 different schedule values ranging from 1 to 45 min and was exposed to each schedule value at least twice. The mean interresponse time and mean interreinforcement time increased with the schedule value according to power functions. Response‐probability functions were computed for schedule values below 20 min and showed an increase in response probability as a function of time since the last response in most cases. Mean responses per reinforcer increased as a function of schedule value for the rats, but decreased as a function of schedule value for the pigeons. The proportion of responses with interresponse times shorter than 1 sec were an increasing function of schedule value for the pigeons, but did not vary as a function of schedule value for the rats.
PREFERENCE FOR SIGNALLED REINFORCEMENT1
Authors: Lewis Paul , Lewin Lewis , Muehleisen Penny , Stoyak Michael
Published: March 2006

Key pecking was reinforced on a two‐component multiple schedule. A variable‐interval schedule controlled reinforcement in both components. During one component, access to reinforcement was preceded by a tone; Final Acceptance in the other component, a standard unsignalled schedule was in effect. After performance stabilized, subjects were given a choice between the signalled and unsignalled schedules. They were placed in the chamber with the unsignalled schedule in effect on the right key. A single response on the left, or changeover, key produced the signalled schedule for 1 min. Both pigeons in Experiment I pecked the changeover key at a rate sufficient to remain under the signalled schedule for over 90% of the session. Removing and reintroducing the tone demonstrated that the changeover‐key responses were due to the occurrence of the tone. In Experiment II, when pecking the changeover key produced the unsignalled schedule, pecking the changeover key declined. The results may be explained either in terms of Hendry's information hypothesis or as escape from an intermittent positive reinforcement schedule.
TWO UNLIKE PATTERNS OF RANDOM‐RATIO RESPONDING ASSOCIATED WITH DIFFERENT EATING HABITS IN RHESUS MONKEYS1
Authors: Kelly Dennis D.
Published: March 2006

Four rhesus monkeys were exposed to an identical series of schedules that specified a uniform probability of reinforcement for every response. As probability was lowered slowly in 10 steps of 20 sessions each from 1.0 through 0.01, two distinct patterns of responding emerged. Two subjects showed high, pause‐free response rates that increased with each successive reduction in reinforcement probability. The other two showed consistent post‐reinforcement pausing at all probabilities, including 1.0, and substantially lower response rates that peaked at the moderate probability values of 0.04 and 0.03. This low‐rate pattern was found to be correlated with a pre‐experimental preference in the two subjects for mouthing and chewing food pellets one at a time, while the former high‐rate, pause‐free pattern was linked to a long‐standing habit of “pouch feeding” in the other monkeys. These idiosyncratic collateral behaviors that differentiated the schedule performances appeared neither superstitious in origin, nor useful in the case of the low‐rate monkeys.
EFFECTS OF RESPONSE‐DEPENDENT AND INDEPENDENT ELECTRIC SHOCK ON SCHEDULE‐INDUCED POLYDIPSIA
Authors: Hymowitz Norman , Freed Earl X.
Published: March 2006

In Experiment I, lever pressing by rats was maintained by the delivery of food pellets under a 45‐sec fixed‐interval schedule. Fixed‐time 180‐sec and fixed‐interval 180‐sec schedules of shock delivery were systematically superimposed on the baseline food schedule to study effects on schedule‐induced water intake. Response‐dependent shock had little, if any, effect on water intake, whereas shocks independent of lever pressing attenuated fluid intake. In Experiment 2, rats received food pellets under a fixed‐time 60‐sec schedule. Electric shock delivered concurrently under a variable‐time 180‐sec schedule, but never while the animal was licking or within 5 sec after licking terminated, led to similar attenuation of water intake. These findings suggest that schedule‐induced polydipsia is sensitive to differences in the functional properties of response‐independent and dependent electric shock.
A YOKED‐CHAMBER COMPARISON OF CONCURRENT AND MULTIPLE SCHEDULES: THE RELATIONSHIP BETWEEN COMPONENT DURATION AND RESPONDING1
Authors: Silberberg Alan , Schrot John
Published: March 2006

Two experimental chambers were electrically connected so that the component selected by a pigeon confronting concurrent variable‐interval schedules in one chamber could be successively presented as a multiple schedule to a second pigeon in the other chamber. Component duration was regulated by the use of a changeover delay, the value of which was systematically varied between 0 and 30 sec. It was found that the relative local response rates on the preferred key (absolute response rate to that component divided by the sum of the absolute response rates during both components) tended to increase with increasing component durations for the birds in the concurrent chamber, but decreased for the birds in the multiple chamber. These data support the interpretation that there are fundamental differences in the mode of responding to multiple and concurrent schedules. Based on these findings, it was concluded that previous demonstrations of matching on multiple schedules do not establish that response allocation is controlled by a process equivalent to that found on choice paradigms. It now appears that matching on multiple (but not concurrent) schedules is a consequence of selecting short component durations. The implications of these data for Herrnstein's (1970) and Rachlin's (1973) formulations of the relationship between multiple and concurrent schedules are examined.
ON TWO TYPES OF DEVIATION FROM THE MATCHING LAW: BIAS AND UNDERMATCHING1
Authors: Baum William M.
Published: March 2006

Data on choice generally conform closely to an equation of the form: log(B1/B2) = a log(r1/r2) + log k, where B1 and B2 are the frequencies of responding at Alternatives 1 and 2, r1 and r2 are the obtained reinforcement from Alternatives 1 and 2, and a and k are empirical constants. When a and k equal one, this equation is equivalent to the matching relation: B1/B2 = r1/r2. Two types of deviation from matching can occur with this formulation: a and k not equal to one. In some experiments, a systematically falls short of one. This deviation is undermatching. The reasons for undermatching are obscure at present. Some evidence suggests, however, that factors favoring discrimination also favor matching. Matching (a = 1) may represent the norm in choice when discrimination is maximal. When k differs from one, its magnitude indicates the degree of bias in choice. The generalized matching law predicts that bias should take this form (adding a constant proportion of responding to the favored alternative). Data from a variety of experiments indicate that it generally does.
EFFECTS OF RANDOM REINFORCEMENT SEQUENCES1
Authors: Morgan M. J.
Published: March 2006

Rats were exposed to a random sequence of reinforcement on two levers, such that there was no way to predict from the previous reinforcement which lever would deliver reinforcement next. The rats showed a tendency to repeat the choice that had just produced reinforcement, despite the absence of an overall contingency that differentially reinforced such repetition. However, this tendency decreased with continued exposure to the schedule. Runs of successive reinforcements on a lever increased the probability of pressing that lever, but only slightly, and only in the earlier phases of training. The more quickly a press was made after reinforcement the more likely it was to be on the lever that had delivered that reinforcement. Repetition of choice followed by reinforcement should be viewed as a naturally occurring behavior in the rat, but not necessarily as a behavior that will continue without differential reinforcement of repetition.
ERRORLESS DISCRIMINATION ESTABLISHED BY DIFFERENTIAL AUTOSHAPING1
Authors: Wilkie Donald M. , Ramer Donald G.
Published: March 2006

In Experiment I, pigeons exposed to a differential autoshaping procedure pecked a key in the presence of the stimulus associated with reinforcement but did not peck, or pecked infrequently, in the presence of the stimulus associated with nonreinforcement. In Experiment II, pigeons were exposed to a differential autoshaping procedure in which one stimulus was associated with reinforcement and two stimuli were associated with nonreinforcement. The birds initially responded in the presence of one stimulus associated with nonreinforcement but never responded in the presence of the second stimulus associated with nonreinforcement. They were subsequently exposed to an autoshaping procedure in which reinforcement followed both these stimuli. The number of stimulus‐reinforcement pairings required to establish pecking in the presence of the stimulus during which responses had not previously occurred suggested that such stimuli are inhibitory. These findings have implications for autoshaping, errorless discrimination, inhibition, and theories of discrimination byproducts.
AUTOSHAPING: FURTHER STUDY OF “NEGATIVE AUTOMAINTENANCE”1
Authors: Woodard William T. , Ballinger John C. , Bitterman M. E.
Published: March 2006

The key pecking of pigeons was autoshaped to three key colors paired with food in discrete trials. Then, the effects of three different color‐correlated contingencies were compared: reward (presentation of food contingent on pecking), omission (presentation of food prevented by pecking), and extinction (no food). Two measures of performance were used: initial response (the number of trials with each color on which at least one peck was made) and multiple response (the total number of pecks per trial). In general, the reward color produced more pecking than the omission color, the omission color more than the extinction color, and the extinction color more than on blank trials with an unlighted key, although (relative to reward) omission produced a higher level of initial than of multiple responding. These results point clearly to the importance of stimulus‐reinforcer continguity in the control of pecking.
DIFFERENTIAL AUTOSHAPING TO COMMON AND DISTINCTIVE ELEMENTS OF POSITIVE AND NEGATIVE DISCRIMINATIVE STIMULI1
Authors: Wasserman Edward A. , Anderson Patricia A.
Published: March 2006

The learning by hungry pigeons of a discrimination between two successively presented compound visual stimuli was investigated using a two‐key autoshaping procedure. Common and distinctive stimulus elements were simultaneously presented on separate keys and either followed by food delivery, S+, or not, S—. The subjects acquired both between‐trial and within‐trial discriminations. On S+ trials, pigeons pecked the distinctive stimulus more than the common stimulus; before responding ceased on S— trials, they pecked the common stimulus more than the distinctive one. Mastery of the within‐display discrimination during S+ trials preceded mastery of the between‐trials discrimination. These findings extend the Jenkins‐Sainsbury analysis of discriminations based upon a single distinguishing feature to discriminations in which common and distinctive elements are associated with both the positive and negative discriminative stimuli. The similarity of these findings to other effects found in autoshaping—approach to signals that forecast reinforcement and withdrawal from signals that forecast nonreinforcement—is also discussed.
SHORT‐TERM MEMORY IN THE PIGEON: STIMULUS‐RESPONSE ASSOCIATIONS1
Authors: Shimp Charles P. , Moffitt Marilynne
Published: March 2006

Three pigeons pecked for food in two experiments in which each trial consisted of two phases: a study and a test phase. The study phase in Experiment i consisted of two stimulus‐response pairs presented successively. Each pair consisted of the illumination of a left or right key (the stimulus) and a peck on the lighted side key (the response). The study phase in Experiment ii consisted of three such pairs presented successively. a retention interval, varied between 0.1 and 4.0 sec, separated the study phase from the test phase. The test phase of a trial began with the illumination of the center key by one of two (Experiment i) or three (Experiment ii) colors. This color was the same as the stimulus element of one of the pairs in the study phase. a reinforcer was presented if a subject then emitted the response element of the indicated stimulus‐response pair. The results provide information on the conditions that enable a pigeon to remember the responses most recently emitted in the presence of various stimuli. The results suggest an account of the maintenance of behavior that is temporally noncontiguous with reinforcement.
ALL‐OR‐NONE ACQUISITION IN MATCHING‐TO‐SAMPLE AND A TEST OF TWO MODELS
Authors: Rodewald H. Keith
Published: March 2006

Three pigeons learned to match three colors in a matching‐to‐sample procedure. The sample hue was presented on the center one of three keys, and the comparison hues were presented on the side keys. Forty responses on the center key produced the stimuli on the side keys and left the sample on the center key. A single response on the correct side key produced 3‐sec access to grain, which was followed by a 25‐sec intertrial interval. A correction procedure was employed when an error was committed. Before attaining asymptotic levels, there was no evidence of learning, responses were independent of the preceding response, and distributions of errors in four‐trial blocks were binomial. Distributions of error runs, runs of various lengths, autocorrelations of errors of several lags, alternations of correct responses and errors, etc., were shown to fit Bower's (1961) all‐or‐none model better than a gradual learning model of Bush and Sternberg (1959). A transfer test employing a novel color showed only transitory degradation of performance.
EFFECTS OF REINFORCEMENT MAGNITUDE ON INTERVAL AND RATIO SCHEDULES1
Authors: Lowe C. Fergus , Davey Graham C. L. , Harzem Peter
Published: March 2006

Rats' lever pressing was studied on three schedules of reinforcement: fixed interval, response‐initiated fixed interval, and fixed ratio. In testing, concentration of the milk reinforcer was varied within each session. On all schedules, duration of the postreinforcement pause was an increasing function of the concentration of the preceding reinforcer. The running rate (response rate calculated by excluding the postreinforcement pauses) increased linearly as a function of the preceding magnitude of reinforcement on fixed interval, showed slight increases for two of the three animals on response‐initiated fixed interval, and did not change systematically on fixed ratio. In all cases, the overall response rate either declined or showed no effect of concentration. The major effect of increasing the reinforcement magnitude was in determining the duration of the following postreinforcement pause, and changes in the response rate reflected this main effect.
CONJUNCTIVE SCHEDULES OF REINFORCEMENT I: RATE‐DEPENDENT EFFECTS OF PENTOBARBITAL AND d‐AMPHETAMINE1
Authors: Barrett James E.
Published: March 2006

Key pecking of pigeons was maintained under conjunctive schedules of food presentation in which both a fixed‐interval and a fixed‐ratio schedule had to be completed before a peck produced food. For two pigeons, pecks on a single key completed both schedule requirements (fixed‐interval 3‐min, fixed‐ratio 50 for one bird, fixed‐interval 5‐min, fixed‐ratio 50 for the second). For two other pigeons, each requirement was scheduled on a separate key. On the two‐key schedule, a peck after 5 min on the key scheduling the fixed‐interval requirement produced food if at least 10 pecks had occurred on the ratio key (conjunctive fixed‐interval 5‐min, fixed‐ratio 10). When each requirement was scheduled on a separate key, response rates on the fixed‐ratio key were generally higher in the early portion of the interval and declined as the interval progressed; responding on the fixed‐interval key, once initiated, typically remained at a constant rate throughout the interval. Responding under the single‐key schedule was characterized by a high rate early in the interval; this then changed to a lower rate that continued until a peck produced food. For all pigeons, increases in response rates with pentobarbital and d‐amphetamine were inversely related to the control rate of responding. When equivalent rates on each key of the two‐key schedule were compared, both drugs increased rates on the fixed‐ratio key less. Although the effects of both drugs were rate dependent, each drug differentially modified the pattern of responding under the single‐key schedule.
MATCHING AND CONTRAST ON SEVERAL CONCURRENT TREADLE‐PRESS SCHEDULES
Authors: McSweeney Frances K.
Published: March 2006

Four White King pigeons pressed treadles for food reinforcement on several concurrent variable‐interval variable‐interval schedules. The rate of reinforcement available for responding in one of the two component schedules was held constant at 30 reinforcers per hour. The rate of reinforcement available for responding in the other was varied from 120 to 60 to 15, and then to 30 reinforcers per hour. The relative rate of responding in each component schedule equalled the relative rate of reinforcement that the component provided. And, behavioral contrast, defined as an inverse relationship between the rate of responding in the constant component and the rate of reinforcement obtained by responding in the other component, occurred for all schedules.
ECCENTRIC STIMULI ON MULTIPLE FIXED‐INTERVAL SCHEDULES1
Authors: Kello John E. , Innis Nancy K. , Staddon J. E. R.
Published: March 2006

The effects of presenting a different (“eccentric”) stimulus for one interval during either or both components of a cyclic multiple fixed‐interval fixed‐interval schedule, with 12 short and four long intervals per cycle, were studied in three experiments. Eccentric stimuli in the short‐interval component reliably produced a persistent, substantial elevation in key‐peck rate. The effect appears to depend on schedule context and an initial “disinhibiting” effect of the eccentric stimulus.
LOCAL PATTERNS OF RESPONDING MAINTAINED BY CONCURRENT AND MULTIPLE SCHEDULES1
Authors: Menlove Ronald L.
Published: March 2006

Local patterns of responding were studied when pigeons pecked for food in concurrent variable‐interval schedules (Experiment I) and in multiple variable‐interval schedules (Experiment II). In Experiment I, similarities in the distribution of interresponse times on the two keys provided further evidence that responding on concurrent schedules is determined more by allocation of time than by changes in local pattern of responding. Relative responding in local intervals since a preceding reinforcement showed consistent deviations from matching between relative responding and relative reinforcement in various postreinforcement intervals. Response rates in local intervals since a preceding changeover showed that rate of responding is not the same on both keys in all postchangeover intervals. The relative amount of time consumed by interchangeover times of a given duration approximately matched relative frequency of reinforced interchangeover times of that duration. However, computer simulation showed that this matching was probably a necessary artifact of concurrent schedules. In Experiment II, when component durations were 180 sec, the relationship between distribution of interresponse times and rate of reinforcement in the component showed that responding was determined by local pattern of responding in the components. Since responding on concurrent schedules appears to be determined by time allocation, this result would establish a behavioral difference between multiple and concurrent schedules. However, when component durations were 5 sec, local pattern of responding in a component (defined by interresponse times) was less important in determining responding than was amount of time spent responding in a component (defined by latencies). In fact, with 5‐sec component durations, the relative amount of time spent responding in a component approximately matched relative frequency of reinforcement in the component. Thus, as component durations in multiple schedules decrease, multiple schedules become more like concurrent schedules, in the sense that responding is affected by allocation of time rather than by local pattern of responding.
ON THE MINIMAL CONDITIONS FOR THE DEVELOPMENT OF A PEAK‐SHIFT AND INHIBITORY STIMULUS CONTROL1
Authors: Rosen Andrea Penkower , Terrace H. S.
Published: March 2006

Failures to obtain a peak‐shift and inhibitory stimulus control following massed extinction in the presence of intra‐ and interdimensional stimuli confirm earlier results reported by Honig, Thomas, and Guttman (1959) and by Weisman and Palmer (1969). Peak‐shifts and inhibitory stimulus control were observed when any of the following procedures intervened for 3 min between massed extinction and generalization testing: (1) S+ presented, responding reinforced; (2) S+ presented, responding not reinforced; or, (3) noncontingent food presented in the presence of a dark key. Behavioral contrast was shown not to be a necessary antecedent for the occurrence of peak‐shift or inhibitory stimulus control.
EFFECTS OF PREVIOUS HOUSING CONDITIONS ON SHOCK‐INDUCED AGGRESSION1
Authors: Creer Thomas L.
Published: March 2006

This study investigated shock‐induced aggression as a function of housing rats in single or communal cages for varying periods of time before testing. Rates of fighting were unaffected by housing conditions when rats spent seven or 14 days in either of these settings before testing. Placing rats in these settings for 21 or 28 days before testing, however, did affect rates of fighting. Communal caging of subjects for 28 days before testing was particularly deleterious to shock‐induced aggression. How rats are housed outside the experimental chamber is a variable affecting shock‐induced aggression and should be considered both in designing future studies and as a topic for future investigation.
THE EFFECT OF TIMEOUT ON PERFORMANCE ON A VARIABLE‐INTERVAL SCHEDULE OF ELECTRIC‐SHOCK PRESENTATION1
Authors: Eubanks James L. , Killeen Peter , Hamilton Bruce , Wald Bruce A.
Published: March 2006

Responding was maintained in squirrel monkeys under variable‐interval schedules of electric shock presentation when a period of timeout followed each response‐dependent shock. Response rate decreased when timeout duration was decreased, and responding ceased when timeout was eliminated. These results indicate that under certain conditions, a shock‐free period following each response‐produced shock is necessary to maintain responding.
SOME EFFECTS OF RESPONSE‐INDEPENDENT REINFORCEMENT ON AUDITORY GENERALIZATION GRADIENTS
Authors: Huff Ronald C. , Sherman J. E. , Cohn Marion
Published: March 2006

Two groups of six rats received discrimination training with two auditory stimuli differing in intensity. During one stimulus, the schedule was variable interval; during the other, it was either variable time or extinction. Both the variable time and extinction schedules resulted in differential rates of responding in the presence of the two stimuli. Extinction resulted in an earlier and more stable difference. Stimulus generalization gradients obtained along the noise‐intensity dimension revealed peak shift with both procedures. In addition, a secondary peak to stimuli in between the two training stimuli occurred with the variable‐time schedule.
SECOND‐ORDER SCHEDULES OF TOKEN REINFORCEMENT: EFFECTS OF VARYING THE SCHEDULE OF FOOD PRESENTATION1
Authors: Malagodi E. F. , Webbe Frank M. , Waddell Thomas R.
Published: March 2006

In the initial link of a complex schedule, one discriminative stimulus was presented and lever pressing produced tokens on fixed‐ratio schedules. In the terminal link, signalled by a second discriminative stimulus, deposits of the tokens produced food. With two rats, the terminal link was presented after each sixth component schedule of token reinforcement was completed. With the other two rats, the terminal link was presented following the first component schedule completed after a fixed interval. During the terminal link, each token deposit initially produced food. The schedule of food presentation was subsequently increased such that an increasing number of token deposits in the terminal link was required for each food presentation. Rates of lever pressing in the initial link were inversely related to the schedule of food presentation in the terminal link. These results are similar to those of experiments that have varied schedules of food presentation in chained schedules. Rates and patterns of responding controlled throughout the initial link were more similar to those ordinarily controlled by second‐order brief‐stimulus schedules than to those controlled by comparable extended chained schedules.
THE BLOCKING OF REINFORCEMENT CONTROL1
Authors: Williams Ben A.
Published: March 2006

Two experiments were conducted to extend the blocking effect to the reinforcement of a response. A delayed reinforcement contingency was presented to subjects with or without a previously pretrained response available during the delay interval. The interpolated response had no scheduled effect on delivery of the reinforcer, but its availability reduced strengthening of the initial response, which completely extinguished for some subjects. The results were interpreted as support for blocking as a fundamental principle of behavior, and as evidence against the principle of reinforcement being stated solely in terms of temporal proximity between response and reinforcer.
EFFECTS OF d‐AMPHETAMINE, CHLORPROMAZINE, AND CHLORDIAZEPOXIDE ON INTERCURRENT BEHAVIOR DURING SPACED‐RESPONDING SCHEDULES1
Authors: Smith James B. , Clark Fogle C.
Published: March 2006

Effects of d‐amphetamine, chlorpromazine, and chlordiazepoxide on lever pressing under direct control of spaced‐responding schedules were compared with effects on intercurrent drinking and wheel running in the rat. Drug effects on lever pressing were systematically related to dose and were consistent for all animals; drug effects on intercurrent behavior were generally different for each animal. In the case of lever presses, increasing doses of d‐amphetamine first increased and then decreased response rate, increasing doses of chlorpromazine produced graded decreases in response rate, and doses of chlordiazepoxide up to 40 mg/kg produced no effect on response rate. These data are discussed in context with the concept of schedule control, and it is suggested that the behavioral pharmacology of intercurrent behavior be explored as a useful procedure in the experimental analysis of intercurrent behavior.
MOLECULAR CONTINGENCIES: REINFORCEMENT PROBABILITY1
Authors: Hale John M. , Shimp Charles P.
Published: March 2006

Pigeons obtained food by responding in a discrete‐trials two‐choice probability‐learning experiment involving temporal stimuli. A given response alternative, a left‐ or right‐key peck, had 11 associated reinforcement probabilities within each session. Reinforcement probability for a choice was an increasing or a decreasing function of the time interval immediately preceding the choice. The 11 equiprobable temporal stimuli ranged from 1 to 11 sec in 1‐sec classes. Preference tended to deviate from probability matching in the direction of maximizing; i.e., the percentage of choices of the preferred response alternative tended to exceed the probability of reinforcement for that alternative. This result was qualitatively consistent with probability‐learning experiments using visual stimuli. The result is consistent with a molecular analysis of operant behavior and poses a difficulty for molar theories holding that local variations in reinforcement probability may safely be disregarded in the analysis of behavior maintained by operant paradigms.
DIFFERENTIAL REINFORCEMENT AND SIGNAL DETECTION1
Authors: Nevin John A. , Olson Karen , Mandell Charlotte , Yarensky Peter
Published: March 2006

Reinforcement was introduced for responses normally treated as errors in signal‐detection procedures. The first experiment used a standard two‐response discrete‐trial procedure with no reinforcement for errors. Results showed that rats altered their response biases but maintained constant sensitivity to visual signals when reinforcement probabilities varied, and that their sensitivity depended on the physical difference between signals, in accordance with the predictions of signal‐detection theory. Experiment II, with rats, and Experiment III, with pigeons, demonstrated that sensitivity decreased in this procedure when reinforcement was scheduled for errors with the signals held constant, despite independence of overall number of reinforcers and sensitivity. Experiment IV, with rats, replicated the decrease in sensitivity in a continuous procedure employing only one response. The decrements in sensitivity were similar across Experiments II, III, and IV, and accorded well with earlier research. Thus, contrary to a fundamental assumption of signal‐detection theory, estimates of sensitivity are not always invariant with respect to the outcomes of responding, but depend on relative reinforcement of correct responses.
RESPONSE PREFERENCES OF MONKEYS (MACACA MULATTA) WITHIN WAVELENGTH AND LINE‐TILT DIMENSIONS
Authors: Sahgal Arjun , Pratt S. Roderick , Iversen Susan D.
Published: March 2006

Four rhesus monkeys were tested for preferences within the wavelength and line‐tilt dimensions. In the case of wavelength, the response panel was back‐illuminated by light of one of the following wavelengths, presented in a random manner: 470, 525, 580, and 635 nm. Similarly, the line‐tilt dimension was studied, by presenting a 5 cm by 0.3 cm black bar tilted at 0, 30, 60, or 90 degrees. No preferences were found within this latter dimension; in contrast, marked wavelength preferences existed, the order of preference being 470 (most preferred), 525, 580, and 635 nm (least preferred). These response preferences were resistant to behavioral manipulation; the number of responses to blue and to red in extinction was about equal when red was used as the training stimulus, but vastly different following training on blue. These results indicate that such response preferences must be taken into account in the design of a wide variety of experiments.
SOME VARIABLES AFFECTING RATE OF KEY PECKING DURING RESPONSE‐INDEPENDENT PROCEDURES (AUTOSHAPING)1
Authors: Perkins Charles C. , Beavers William O. , Hancock Robert A. , Hemmendinger Patricia C. , Hemmendinger Dennis , Ricci John A.
Published: March 2006

Rate of key pecking by pigeons subjected to response‐independent procedures in which a stimulus on the response key preceded food presentation was investigated in eight experiments. Color and shape of the stimulus, duration of the stimulus, probability of food following the stimulus, duration of the intertrial interval, and duration of food presentation were varied separately and in combination. All variables studied, except color and shape of the stimulus, had a reliable effect on pecking rate, but some variables had stronger effects than others. Rapid key pecking may be obtained with a variety of response‐independent procedures, as well as by response‐dependent reinforcement. The results of experiments in which food is both dependent on key pecking and correlated with stimulus conditions are not representative of simple operant effects. Key pecking is an ideal response for studying the simultaneous operation of response‐reinforcer and stimulus‐reinforcer effects.
EFFECTS OF HALOPERIDOL ON SCHEDULE‐INDUCED POLYDIPSIA1
Authors: Keehn J. D. , Coulson G. E. , Klieb J.
Published: March 2006

In dose‐related amounts, the drug haloperidol attenuated schedule‐induced drinking by rats prefed with 0.01‐mg drug added to 0, 25, 50, 75 or all of 100 Noyes 45‐mg pellets. Drug pellets also induced less drinking than did regular Noyes pellets by rats that obtained these pellets at 1‐min intervals by bar pressing. Haloperidol also reduced bar pressing and, temporarily, rate of reinforcement. The results appeared not to be due to a general sedative effect of haloperidol but to its selective power to reduce angiotensin‐induced drinking. Thus, schedule‐induced drinking, which is abnormal in not causing satiation, is controllable by a drug that interferes with the renin‐angiotensin hormone system thought to regulate normal drinking.
DISCRIMINATIVE PROPERTIES OF BRIEFLY PRESENTED STIMULI
Authors: Cohen Steven L. , Stubbs D. Alan
Published: March 2006

In Experiment I, pigeons' responses produced food according to a fixed‐interval schedule while responses on the key also produced brief stimuli according to a variable‐interval schedule. Each brief stimulus reset the fixed interval. Thus, a brief stimulus occurred irregularly but a fixed minimum time separated the occurrence of food from a brief stimulus. Pauses followed brief stimuli and were followed by an accelerated response rate until another brief stimulus or food occurred. In Experiment II, four control procedures were examined. (1) Brief‐stimulus presentations were omitted, producing a loss of response patterning. (2) A second‐order schedule was studied with fixed‐interval components. This schedule produced patterning following brief stimuli similar in kind and degree to that found in Experiment I. (3) A conjoint schedule was arranged in which food was no longer separated from the stimulus by a fixed time; pauses following the stimulus no longer resulted. (4) A brief food reinforcer replaced the brief visual stimulus, resulting in a constant response rate with no pausing following the brief food stimulus. The results suggest that the brief‐stimulus effects were due to discriminative functions produced by the fixed temporal relation separating the stimulus from food.
CONJUNCTIVE SCHEDULES OF REINFORCEMENT: III. A FIXED‐INTERVAL ADJUSTING FIXED‐RATIO SCHEDULE1
Authors: Barrett James E.
Published: March 2006

Key pecking of three pigeons was studied under a conjunctive schedule that specified both a fixed‐interval and an adjusting fixed‐ratio requirement. The fixed‐interval schedule was 6 min for one pigeon and 3 min for the other two. The size of the ratio requirement was determined within each cycle of the fixed interval by the duration of the pause before responding began. The fixed‐ratio value was at maximum at the start of each fixed interval and decreased linearly until the first response occurred (adjusting fixed‐ratio schedule). A peck produced food when the number of responses remaining on the fixed‐ratio schedule was completed and when the fixed interval had elapsed. If no response occurred during the interval, the fixed‐ratio requirement decreased to one and a single response after the interval elapsed produced food. The initial value of the adjusting fixed‐ratio schedule was studied over a range of 0 to 900. Increases in the adjusting fixed‐ratio schedule to about 300 responses increased both pause duration and running response rate and also modified the pattern of responding from that obtained under the fixed‐interval schedule. Higher values of the adjusting fixed ratio generally decreased pause duration and running response rate and also disrupted responding. Interreinforcement time under the conjunctive schedule was increased substantially when the adjusting fixed‐ratio size exceeded 300 responses.
RESPONDING UNDER POSITIVE AND NEGATIVE RESPONSE CONTINGENCIES IN PIGEONS AND CROWS
Authors: Powell Robert W. , Kelly William
Published: March 2006

Four crows were trained to key peck for food. Then, they were exposed to a positive response contingency that required them to peck the key when it was illuminated briefly (the trial) in order to receive food. This procedure resulted in consistent within‐trial pecking. When the contingency changed so that food was presented at the end of a trial when no response occurred, but the trial terminated immediately and food was omitted when a response occurred (negative response contingency), responding decreased markedly. Eight pigeons were studied under the same change in contingencies. These birds varied in their response histories from naive to having several years' experience. The previously naive pigeons also showed rapid declines in responding under the negative contingency; the responding of the birds with extended training histories declined much more slowly. Eventually, however, six of the eight pigeons showed little or no responding under the negative contingency, while they responded consistently when re‐exposed to the positive contingency. These findings question the power and the generality of the negative auto‐maintenance phenomenon.
EFFECTS OF SIGNALS PRECEDING AND FOLLOWING SHOCK ON BASELINE RESPONDING DURING A CONDITIONED‐SUPPRESSION PROCEDURE1
Authors: Davis Hank , Memmott John , Hurwitz Harry M. B.
Published: March 2006

Long‐Evans rats were exposed to a succession of conditioned‐suppression procedures involving pairings of (1) signal‐shock, (2) shock‐signal, and (3) a signal‐shock‐signal sequence in which first and second signals were at first physically identical. Traditional suppression of food‐reinforced responding was obtained under the signal‐shock arrangement, and exposure to the shock‐signal sequence resulted in conditioned enhancement of responding during the signal. The signal‐shock‐signal condition reliably suppressed responding during the first signal, but produced no differential effect on response rate during the second signal. Baseline responding was least changed from preshock rates under the signal‐shock‐signal procedure, but baseline rate was considerably reduced under the signal‐shock and shock‐signal arrangements, the latter yielding most substantial reductions. a second experiment indicated that the magnitude and direction of changes in baseline responding reported in Experiment I were not confined to cases in which the first and second signals in the signal‐shock‐signal arrangement were physically identical. It is suggested that the major effects of the conditioned‐suppression procedure on response rate might not be confined to presentations of the signal.
EFFECTS ON RESPONDING OF MIXED AND MULTIPLE SCHEDULES OF SIGNALLED AND UNSIGNALLED RESPONSE‐DEPENDENT ELECTRIC‐SHOCK DELIVERY1
Authors: Hymowitz Norman
Published: March 2006

Responding in two rats was maintained under mixed and multiple variable‐interval 35‐sec variable‐interval 35‐sec food delivery schedules. Similar rates and patterns of responding occurred in each component of the two schedules. Mixed and multiple variable‐interval 65‐sec variable‐interval 65‐sec schedules of response‐dependent shock delivery were superimposed on the mixed and multiple baseline food schedules, respectively. In one component, a 5‐sec stimulus was presented on the average of once every 65 sec. Offset of the stimulus arranged that the next response would produce shock. In the other component, no stimulus was presented during the 5‐sec period. The mixed schedule of signalled and unsignalled dependent shock delivery yielded similar degrees of response suppression in each component, but the multiple schedule of shock delivery revealed differential degrees of response suppression. Considerably more suppression occurred in the component not associated with the preshock stimulus, thus implicating the discriminative functions of the correlated stimulus.
A TEMPORAL PARAMETER INFLUENCING CHOICE BETWEEN SIGNALLED AND UNSIGNALLED SHOCK SCHEDULES1
Authors: Harsh John , Badia Pietro
Published: March 2006

The present study investigated whether choice of a signalled variable‐time shock schedule over an unsignalled one was influenced by the average intershock interval. Eight rats were given a choice between signalled and unsignalled shock schedules in a series of conditions with average intershock intervals of 510, 270, 150, 90, 60, and 45 sec. Each test condition was preceded by a training‐baseline condition, and schedule values were arranged in an ascending (four subjects) or descending (four subjects) order. Choice of the signalled conditions was directly related to the average intershock interval of the variable‐time schedule for six of the eight subjects. The per cent of time in the signalled condition was highest when the average intershock interval was 150 sec or longer and lowest when the average intershock interval was 45 sec. The findings were interpreted as being due to changes in the safety features of the signalled schedule, rather than to changes in the average intershock interval per se.
SOME EFFECTS OF d‐AMPHETAMINE AND PENTOBARBITAL ON PERFORMANCE UNDER A LONG FIXED‐INTERVAL SCHEDULE1
Authors: McMillan D. E. , Healey M. L.
Published: March 2006

The effects of d‐amphetamine and pentobarbital were studied on performance during 3‐hr sessions under fixed‐interval 60‐min schedules of food presentation. Low doses of d‐amphetamine increased rates of responding and higher doses decreased rates of responding, both during the entire 3‐hr session and during each of the individual fixed intervals. Pentobarbital produced little effect on rates of responding averaged over the 3‐hr session, but it decreased rates during the first fixed interval and increased them during the second and third fixed intervals. The effects of d‐amphetamine were shown to be dependent on the control rate of responding, as has been shown with shorter fixed‐interval values. Analysis of d‐amphetamine effects in terms of the point at which the probability of responding is greater than zero was not descriptive of overall fixed‐interval performance.
SHORT‐TERM MEMORY IN THE PIGEON: RELATIVE RECENCY1
Authors: Shimp Charles P.
Published: March 2006

Three pigeons pecked for food in an experiment in which each trial consisted of two phases. The first phase consisted of a pattern of three successively illuminated, randomly selected left or right keys. A subject was required to peck each of the lighted keys as they appeared. Thus, in the first phase, a subject emitted a pattern of three left‐ or right‐key pecks. Over trials, all eight possible patterns appeared. A time interval separated the first phase from the second phase, which began with presentation of a randomly selected one of three cues. A reinforcer was delivered in the second phase if a subject pecked the side key that had appeared in the first phase in an ordinal position corresponding to the cue presented in the second phase. That is, the three cues probed a pigeon's memory for the side key it had pecked first, second, or third, in the first phase of a trial. The results show that a pigeon can remember for more than 4 sec the order in which it has just seen and pecked two lighted keys: a pigeon can remember the temporal organization or pattern of events in its recent environment. Consequently, the functional stimulus present when a reinforcer is delivered may include a subject's short‐term memory for the temporal organization of recent events, such as the pattern of its own recent behavior. This possibility is consistent with a molecular analysis of operant behavior focusing on local patterns of behavior.