bluuebunny/crossref_metadata_2025 huggingface dataset:
RESPONSE RATE UNDER VARYING FREQUENCY OF NON‐CONTINGENT REINFORCEMENT1
Authors: Lachter G. D. , Cole B. K. , Schoenfeld W. N.
Published: March 2006

Two White Carneaux hen pigeons were exposed to a 60‐sec random‐interval baseline procedure. Six different exteroceptive stimuli were successively correlated, within a single session, with blocks of 10 reinforcement presentations. Following this training, a non‐contingent reinforcement procedure was instated with inter‐reinforcement intervals of 5, 15, 30, 60, 120, and 240 sec. Within a single session, each non‐contingent frequency was correlated with one of the previously presented discriminative stimuli. After an initial increase in the rate of responding as the result of a high density of non‐contingent reinforcements, the rate declined as exposure to each non‐contingent frequency was prolonged.
DIFFERENTIAL REINFORCEMENT OF OTHER BEHAVIOR (DRO): A YOKED‐CONTROL COMPARISON1
Authors: Davis Jennifer , Bitterman M. E.
Published: March 2006

After training to press a lever on a variable‐interval 30‐sec schedule, one group of rats was shifted to a differential‐reinforcement‐of‐other‐behavior 10‐sec schedule, while a second group was shifted to a noncontingent yoked‐control schedule that provided the same frequency and distribution of reinforcement. Then, both groups were extensively retrained on the variable‐interval schedule, after which the first group was shifted to a series of differential‐reinforcement‐of‐other‐behavior 30‐sec sessions alternating daily with variable‐interval 30‐sec sessions, while the second group was treated like the first on variable‐interval days and yoked with the first as before on differential‐reinforcement‐of‐other‐behavior days. In both phases, response‐decrement was more rapid and more marked in the differential‐reinforcement‐of‐other‐behavior animals than in the controls. The difference was due, at least in large measure, to sustainment of response in the control animals by adventitious reinforcement. All the differential‐reinforcement‐of‐other‐behavior animals developed “other” behavior—the same distinctive pattern of waiting at the foodcup—but there was no direct evidence that it contributed in any way to the decrement in lever pressing.
ON THE TAUTOLOGY OF THE MATCHING LAW1
Authors: Rachlin Howard
Published: March 2006

The generalized matching law, that organisms divide their time between alternatives in proportion to the value of the reinforcement consequent on the choice, is derivable from the assumption that an organism choosing between alternatives is under no constraints except those the contingencies of reinforcement impose. Hence, the law is not subject to empirical test. Its value lies in its simple codification of assumptions underlying choice experiments.
A MODEL FOR CHOICE IN SIMPLE CONCURRENT AND CONCURRENT‐CHAINS SCHEDULES1
Authors: Squires Nancy , Fantino Edmund
Published: March 2006

Pigeons' responses in the presence of two concurrently available (initial‐link) stimuli produced one of two different (terminal‐link) stimuli. Entrance into the mutually exclusive terminal links was arranged by different and independent variable‐interval schedules for each key, while responses during the mutually exclusive terminal‐link stimuli produced a single food reinforcement according to identical and independent variable‐interval schedules. The pigeons emitted more initial‐link responses on the key with the shorter average inter‐reinforcement interval in the initial link. This difference in initial‐link response rates varied directly with the difference between the average inter‐reinforcement intervals of the initial‐link schedules and decreased when the initial‐link schedule with the longer average interreinforcement interval was followed by several consecutive food reinforcements on the variable‐interval schedule in the terminal link on that key. These results are incompatible with previous formulations of choice behavior with the concurrent‐chains procedure. A modified formulation with a multiplier for the overall rate of primary reinforcement obtained on each key provides a better description of choice. In addition, the new formulation applies to behavior in simple (concurrent) choice situations, an advantage not achieved by previous formulations.
REINFORCEMENT SCHEDULES: THE ROLE OF RESPONSES PRECEDING THE ONE THAT PRODUCES THE REINFORCER1
Authors: Catania A. Charles
Published: March 2006

In a two‐key pigeon chamber, variable‐interval reinforcement was scheduled for a specified number of pecks, emitted either on a single key or in a particular sequence on the two keys. Although the distribution of pecks between the two keys was affected by whether pecks were required on one or on both keys, the total pecks emitted was not; the change from a one‐key to a two‐key requirement simply moved some pecks from one key to the other. Thus, each peck preceding the one that produced the reinforcer contributed independently to the subsequent rate of responding; the contribution of a particular peck in the sequence was determined by the time between its emission and the delivery of the reinforcer (delay of reinforcement), and was identified by the proportion of pecks moved from one key to the other when the response requirement at that point in the sequence was moved from one key to the other.
AVOIDANCE OF TIMEOUT FROM RESPONSE‐INDEPENDENT REINFORCEMENT1
Authors: D'Andrea Thomas
Published: March 2006

Responses on a lever by rats postponed scheduled timeouts, or periods during which the delivery of response‐independent food was withheld. The effects of a number of experimental variables were examined and the conclusions drawn are that the functional relations describing free‐operant avoidance of timeout from response‐independent reinforcement are similar to those for avoidance of electric shock and that both phenomena are sensitive to the same parametric manipulations. Results suggest that high frequency of food delivery in timein maintains a higher rate of timeout avoidance than low frequency. The evidence argues against an interpretation in terms of adventitious food‐reinforcement of the timeout avoidance response. Finally, the effects of scheduling timeouts independently of responding and of omitting timeouts confirm the view that timeouts can be aversive and may act as punishment for responding.
OPERANTS1
Authors: Schick Karl
Published: March 2006

The definition of an operant as a response class each of whose members possesses the property upon which reinforcement is contingent is not broad enough to cover the units that are supposed in Skinner's accounts of extinction, superstition, and transfer of learning. A broader definition is suggested. Finally, properties defining operants are discussed.
PREFERENCE FOR QUALITATIVELY DIFFERENT REINFORCERS1
Authors: Hollard Valerie , Davison M. C.
Published: March 2006

Three pigeons were studied under two‐key concurrent variable‐interval schedules with food as the reinforcer on one key and ectostriatal brain stimulation as the reinforcer on the other. Brain‐stimulation parameters were kept constant while the rate of food reinforcement availability was varied. The results showed that qualitatively different reinforcers could be handled in the same theoretical framework that applies when choice is between different rates, immediacies, and amounts of a single reinforcer.
ELIMINATING BEHAVIOR WITH REINFORCEMENT1
Authors: Zeiler Michael D.
Published: March 2006

Responding produced food according to a fixed‐ratio schedule while the prevailing key‐color alternated between red and blue. Stimulus durations were varied until a period was found that maintained equal rates of responding in the presence of both colors. Then, food presentation was discontinued in the presence of one stimulus and made dependent on not responding in the presence of the other. Food presentation dependent on not responding reduced the rate of responding faster than did extinction. Spontaneous recovery occurred only during the stimulus correlated with extinction.
CONDITIONED SUPPRESSION OF BAR‐PRESSING BEHAVIOR BY STIMULI ASSOCIATED WITH DRUGS1
Authors: Cameron Oliver G. , Appel James B.
Published: March 2006

Ten naive male albino rats were trained to press a bar under a variable‐interval 30‐sec schedule with water as the reinforcer in two experiments. This behavior was disrupted by chlorpromazine in Experiment I (two rats) and by lysergic acid diethylamide (LSD) in both Experiment I (two rats) and Experiment II (six rats). The administration of the drug was paired with an originally neutral white light. After several pairings with either drug, the light also depressed behavior. When the light was no longer paired with drug, the depression effect extinguished much faster than is usually observed in conditioned suppression studies.
COMMITMENT, CHOICE AND SELF‐CONTROL1
Authors: Rachlin Howard , Green Leonard
Published: March 2006

When offered a choice (Choice Y) between a small immediate reward (2‐sec exposure to grain) and a large reward (4‐sec exposure to grain) delayed by 4 sec, pigeons invariably preferred the small, immediate reward. However, when offered a choice (Choice X) between a delay of T seconds followed by Choice Y and a delay of T seconds followed by restriction to the large delayed reward only, the pigeon's choice depended on T. When T was small, the pigeons chose the alternative leading to Choice Y (and then chose the small, immediate reward). When T was large, the pigeons chose the alternative leading to the large delayed reward only. The reversal of preference as T increases is predicted by several recent models for choice between various amounts and delays of reward. The preference for the large delayed alternative with long durations of T parallels everyday instances of advance commitment to a given course of action. Such commitment may be seen as a prototype for self‐control.
PREFERENCE FOR MIXED‐INTERVAL VERSUS FIXED‐INTERVAL SCHEDULES: NUMBER OF COMPONENT INTERVALS1
Authors: Davison M. C.
Published: March 2006

Six pigeons were trained under a concurrent chains procedure so that preference for fixed‐interval versus mixed‐interval schedules with varying numbers of component intervals could be examined. The smallest and largest intervals in the terminal links were the same value as those used by Davison (1969). Relative choice in all cases approximated the relative means of the squares of the harmonic intervals to reinforcement in the terminal links, and no effect of number of component intervals was demonstrated. Mixed‐interval versus fixed‐interval choice could not be predicted from extant data on fixed‐interval versus fixed‐interval choice.
PERFORMANCE IN MULTIPLE FIXED‐INTERVAL SCHEDULES1
Authors: Barron Beverley , Davison M. C.
Published: March 2006

The performances of five pigeons were studied under a variety of multiple fixed‐interval schedules in which both component duration and reinforcement rate were varied. The three series of experimental conditions were: (a) when the ratio of component durations equalled the reciprocal of the ratio of component reinforcement rates; (b) when the component durations were equal; and (c) when the ratio of component durations equalled the ratio of component reinforcement rates. Relative response rates were related to relative reinforcement rates in the same manner as in multiple variable‐interval schedules, but no effect of component duration was found.
SCHEDULE‐INDUCED ESCAPE FROM FIXED‐INTERVAL REINFORCEMENT1
Authors: Brown Thomas G. , Flory Randall K.
Published: March 2006

Pigeons trained to peck one of two keys for food were exposed to an ascending and descending series of fixed‐interval values. A response on the second key produced an escape period consisting of a visual stimulus change. During escape periods, the fixed‐interval timer continued to operate and even if it timed out, a response on the food key would not operate the feeder unless preceded by an escape‐key response that terminated the escape condition. As the fixed‐interval schedule was increased logarithmically through six values from 30 to 960 sec, the percentage of session time spent in escape as well as the frequency, duration, and rate of escape increased to a maximum and then decreased. One subject did not develop escape behavior to any significant degree. For all pigeons, escapes usually occurred after, rather than before, reinforcement.
AVERSIVE ASPECTS OF A FIXED‐INTERVAL SCHEDULE OF FOOD REINFORCEMENT1
Authors: Richards Ralph W. , Rilling Mark
Published: March 2006

The key pecking of pigeons was reinforced according to a fixed‐interval schedule of reinforcement. The pigeons were also given the opportunity to attack a restrained target pigeon. The attack rates during the sessions of fixed‐interval reinforcement were higher than during the operant level sessions in four of the five pigeons. Most attack occurred during the post‐reinforcement pause in key pecking. It was suggested that a fixed‐interval schedule of positive reinforcement possesses aversive properties, the most aversive of which are located during the post‐reinforcement pause.
AVOIDANCE RESPONDING AS A FUNCTION OF STIMULUS DURATION AND RELATION TO FREE SHOCK1
Authors: Shimoff Eliot
Published: March 2006

Response‐independent pairings of a tone and a brief shock were superimposed on uncued avoidance responding in four groups of rhesus monkeys. For one group, tone presentations were immediately followed by an unavoidable electric shock; for the remaining groups, gaps of 5, 20, and 80 sec intervened between tone termination and shock delivery. These temporal values subsume paradigms usually treated as discrete procedures; the conditioned emotional response procedure (0‐sec gap between tone and shock), trace procedure (5‐sec gap) and safety‐signal training (80‐sec gap). Within each group, tone durations of 10, 20, 40, and 80 sec were examined. A response pattern marked by maximum response rate in the initial 5 sec of the tone followed by deceleration before shock was observed when shock immediately followed the tone, but not when gaps were interposed between the tone and shock. Response rates in the first 5 sec of the tone were a function of both tone duration and duration of the gap. When the gap was 0 to 5 sec, initial response rates were highest in longer duration tones; this relationship between tone duration and initial tone response rate was not observed for longer gaps.
THE RELATIVE AVERSIVENESS OF SIGNALLED VS UNSIGNALLED ESCAPABLE AND INESCAPABLE SHOCK
Authors: Badia Pietro , Culbertson Stuart
Published: March 2006

In the first study, subjects escaped shock by pressing on a lever under an unsignalled condition. By pressing a different lever they changed the condition to signalled escape for three minute periods. The second study used the changeover procedure to study inescapable‐unavoidable shock. Seven rats were used in each study. All subjects in both studies changed over from unsignalled to signalled conditions. Once contact with the signal condition was made, subjects responded to remain in that condition. The three different extinction conditions showed that the correlated stimulus without the signal had greater control over responding than the signal without the correlated stimulus. An analysis based upon shock and shock‐free periods was presented.
DETECTION OF INCREMENTS IN NOISE INTENSITY BY MONKEYS1
Authors: Clopton Ben M.
Published: March 2006

Monkeys were trained to detect 100‐msec increments in the intensity of continuous white noise. A response on one of two bars was reinforced with some probability if it conformed to the presence or absence of the increment on that trial. Stimulus parameters of background intensity, increment size, and probability of increment presentation were varied, and response probabilities and latencies were recorded. The task was analogous to the “yes‐no” task used in human psychophysics. Data analysis within the context of signal‐detection theory revealed response biasing toward one bar or the other to be related to the probability of increment presentation, whereas sensitivity depended on the combination of increment size and background noise intensity. Weber's law was found to hold for a large range of background intensities in that the sensitivity to relative intensity increments varied little. Performance was compared to that of an ideal observer that uses samples of the envelope of the noise waveform on which to base its responses.
VARIABLE‐TIME REINFORCEMENT IN MULTIPLE AND CONCURRENT SCHEDULES1
Authors: Wilkie Donald M.
Published: March 2006

Experiment I examined the role of a reduced rate of responding in the occurrence of behavioral contrast. Four rats and a pigeon were exposed to a two‐component multiple schedule in which one component was always a variable‐interval schedule. The second component was, at different times, either a variable‐time schedule in which food was delivered independently of responding, or extinction. Both extinction and the variable‐time schedule reduced the rate of responding in the second component. Behavioral contrast was observed, however, only when extinction was scheduled in the second component. Experiment II examined preference, as measured by time allocation in concurrent schedules for a variable‐interval schedule relative to a variable‐time schedule. Two rats displayed a lack of preference between the two schedules. The results of these experiments support a preference interpretation of behavioral contrast, which holds that behavioral contrast is the result of the introduction of a less‐preferred condition in one component of a multiple schedule.
INTERMITTENT REINFORCEMENT OF AN INTERRESPONSE TIME1
Authors: Wilkie Donald M. , Pear Joseph J.
Published: March 2006

Rats were exposed to schedules in which reinforcement was contingent upon the emission of a 1.0‐ to 2.0‐sec interresponse time. The rate of emission and the temporal distribution of this interresponse time was recorded. Several different contingencies between the emission of the interresponse time and reinforcement were examined. Both the rate of emission and the temporal distribution of the 1.0‐ to 2.0‐sec interresponse time varied as a function of the schedule on which it was reinforced. This finding, which suggests that an interresponse time behaves as other operants, has implications for the analysis of conventional reinforcement schedules in terms of the differential reinforcement of interresponse times.
SUSTAINED BEHAVIORAL CONTRAST IN CHILDREN1
Authors: Waite Wenden W. , Osborne J. Grayson
Published: March 2006

Children were exposed to a multiple schedule involving equal variable‐interval schedules in each of two components and a multiple schedule involving a variable‐interval schedule in one component and an extinction schedule in the other. Response rates were equal in both components when each involved a variable‐interval schedule. Response rates differed in the two components of the multiple variable‐interval extinction schedule. Response rates were higher in the variable‐interval schedule when the accompanying schedule was extinction than when it was variable interval. The increase in response rate in the variable‐interval component, simultaneous with the decrease in response rate in the extinction component, illustrated sustained behavioral contrast, and was the first evidence of this phenomenon in children.
RESPONDING IN THE SQUIRREL MONKEY UNDER SECOND‐ORDER SCHEDULES OF SHOCK DELIVERY1
Authors: Byrd Larry D.
Published: March 2006

Lever‐pressing responses were maintained in the squirrel monkey when the only consequence of responding was the delivery of a response‐produced electric shock, or alternatively, a brief visual stimulus that was occasionally followed by an electric shock. When shock was produced by the first response occurring after 8 min (8‐min fixed‐interval schedule), a period of no responding at the beginning of the interval was followed by a gradual increase in response rate during the interval. Similar rates and patterns of responding were maintained when a 1‐sec visual stimulus was produced by the first response occurring after 8 min and shock delivery followed the brief stimulus. Subsequently, patterns of positively accelerated responding were engendered during individual fixed‐interval components when the first response occurring after 4 min produced a 1‐sec visual stimulus and shock delivery followed the second, and later the fourth, presentation of the 1‐sec stimulus. When the duration of the brief stimulus was varied over a 100‐fold range from 0.1 to 10.0 sec (1) mean response rates decreased monotonically as stimulus duration increased, and (2) patterns of positively accelerated responding were least variable and response rates during the initial part of each 4‐min interval were lowest at a stimulus duration of 1 sec.
FOOD‐AVOIDANCE IN HUNGRY PIGEONS, AND OTHER PERPLEXITIES1
Authors: Herrnstein R. J. , Loveland D. H.
Published: March 2006

Twenty‐three pigeons were subjected to a series of procedures in which the key‐peck's effects ranged from immediate, differential food reinforcement, through delayed reinforcement, the production of stimulus changes with and without probable secondary reinforcement, the prevention of food presentation (“food‐avoidance”), to extinction. Neither primary nor secondary food reinforcement appeared to be essential for the maintenance or acquisition of key pecking. The food‐avoidance contingency failed to suppress responding in any subject. Only complete extinction, when pecking produced neither food nor stimulus changes, eliminated all pecking for most subjects. A combination of stimulus‐change reinforcement and food reinforcement appeared to account for the results, but only if it could be assumed that the presence of food in a procedure enhanced the reinforcing power of stimulus change, whether or not the food was also dependent upon responding. Such an interaction between reinforcers may be involved in the phenomenon of auto‐shaping.
THE EFFECT OF DISCRIMINATION TRAINING ON RESPONSES TO A NEW STIMULUS
Authors: Anger Kathleen , Anger Douglas
Published: March 2006

Most previous research on the effect of the duration of preceding discrimination training on responding to a new stimulus has measured the responding during extinction. To reduce effects originating in the extinction procedure itself, the present study assessed the effect of discrimination training on responses to a new negative stimulus added during continued discrimination training. Pigeons were given a new negative stimulus (blue key) after 0, 1, 3, or 9 days of discrimination training with a yellow key as the positive stimulus, and both a green key and a red key as negative. Fewer responses were made to the blue key when it was introduced after nine days of discrimination training than after less discrimination training. That effect of long discrimination training agrees with reported results from extinction tests. However, the effect of briefer discrimination training in the present study differed from reported results with extinction testing. It appears that testing during continued discrimination training eliminates a distortion present in extinction tests of the effect of discrimination training on responding to a new stimulus.
RESPONDING MAINTAINED BY THE OPPORTUNITY TO ATTACK DURING AN INTERVAL FOOD REINFORCEMENT SCHEDULE1
Authors: Cherek D. R. , Thompson T. , Heistad G. T.
Published: March 2006

Pigeons responded in a two‐key situation. Responses on the right key (food key) were reinforced with food presentation on a response‐initiated fixed‐interval schedule, (i.e., first response after a fixed period of time was reinforced); responses on the left key (target key) were reinforced on a fixed‐ratio schedule (i.e., every nth response was reinforced) with the presentation of a target bird that could be attacked. When the interval value of the food reinforcement schedule was varied from 1 min to 5 min, both the rate of attack responding on the target bird and the rate of responding on the target key were a function of the interval value. Responding on the target key was not maintained by the stimulus change associated with target availability, and was successively extinguished and reconditioned by removing and returning the target bird to the restraining box. When food was delivered independently of behavior, responding on the target key either remained unchanged or decreased, but was not eliminated. Responding on the target key was not maintained in the absence of an intermittent schedule of food presentation.
RATS' LEVER‐PRESS DURATIONS AS PSYCHOPHYSICAL JUDGMENTS OF TIME1
Authors: Platt John R. , Kuch Dennis O. , Bitgood Stephen C.
Published: March 2006

Hungry rats received food following lever‐press durations exceeding a minimum value, which ranged from 0 to 6.4 sec. When no intertrial intervals separated successive presses, modal press durations remained at very short values as the minimum value required for food was increased. This was particularly true immediately after a food presentation. When an 8‐sec intertrial interval followed each lever release, modal press durations were always at or beyond the minimum value required for food, and outcome of the preceding press had no effect on press duration. Possible reasons for the effects of intertrial intervals included punishment of short presses, increased delay of reinforcement of short presses, and reduced density of reinforcement. In addition, functions relating discrete‐trials lever‐press duration to minimum duration required for food were found to be qualitatively and quantitatively similar to the power functions recently proposed by Catania (1970) for interresponse time and response latency. This similarity was taken as support for a general psychophysical law of temporal judgments.
RESPONDING UNDER CHAINED AND TANDEM FIXED‐RATIO SCHEDULES
Authors: Jwaideh Alice R.
Published: March 2006

The role of stimuli in chained fixed‐ratio schedules of reinforcement was examined. At various ratio values, responding on schedules consisting of three or five equal components, with a different colored light in each component (“block counter”) was compared with responding on tandem or simple fixed‐ratio schedules having the same color present throughout the entire ratio. At all ratio values except the smallest, the chain stimuli resulted in longer pauses after reinforcement. The magnitude of this effect became greater as the size of the ratio was increased. Post‐reinforcement pause durations were longer under five‐component schedules than under three‐component schedules. Running rates in the first component were lower on the chained schedules than on the tandem schedules; on both kinds of schedule, rates were lower in the first component than in the rest of the ratio. When the sequence of stimuli was reversed, the duration of the post‐reinforcement pause dropped markedly and the running rate in the initial component increased, but these effects gradually disappeared after the first reversal session. When the final chain stimulus was substituted for the first component stimulus but continued to appear in the final chain component as well, the pause duration dropped and remained at this lower level during subsequent sessions.
SELF‐INHIBITING EFFECTS OF REINFORCEMENT1
Authors: Catania A. Charles
Published: March 2006

The reinforcers produced by one response reduce the rate of other, concurrently reinforced responses. An analysis of the logical and empirical implications of the relation indicates that one reinforcer must have this effect on responses maintained by other reinforcers even when all reinforcers are produced by the same class of responses. A quantitative expression of the relation leads to a formulation, mathematically equivalent to Herrnstein's (1970), in which the rate of a reinforced response is a joint function of (1) an excitatory effect of the reinforcers produced by that class of responses, and (2) an inhibitory effect of the total reinforcers produced both by that class and by other classes of responses.
THE MAINTENANCE OF KEY PECKING BY STIMULUS‐CONTINGENT AND RESPONSE‐INDEPENDENT FOOD PRESENTATION
Authors: Gamzu Elkan , Schwartz Barry
Published: March 2006

Three naive pigeons were exposed to a series of two‐component multiple schedules of response‐independent food presentation. The component schedules were sometimes identical (non‐differential procedures) and sometimes different (differential procedures). High rates of key pecking were maintained in all the differential procedures, and pecking decreased substantially in non‐differential procedures, even when the frequency of food presentation in non‐differential procedures was higher than in differential procedures. It is suggested that the high rates of key pecking were maintained not by adventitious response‐reinforcer contingencies, but by differential contingencies between the stimulus (keylight) and food. The role of such contingencies in the phenomenon of behavioral contrast is discussed.
REDUNDANT INFORMATION IN AN OBSERVING‐RESPONSE PROCEDURE1
Authors: Kendall Stephen B.
Published: March 2006

In three observing‐response experiments relevant to the information hypothesis of conditioned reinforcement, the basic procedure was one in which an observing response produced one stimulus on trials that terminated in non‐contingent reinforcement and another stimulus on trials that terminated in a brief timeout. In Experiment I, the observing response consisted of a single peck or a short fixed‐ratio schedule (FR 3 or FR 6), depending on the type of trial. If the single peck produced the negative stimulus and the fixed ratio produced the positive stimulus, observing responses were maintained. If the single peck produced the positive stimulus and the fixed‐ratio produced the negative stimulus, observing responses were not maintained on negative trials. In the second experiment, the response key was either white or dark at the beginning of a trial, indicating whether it was a positive or negative trial. Observing responses continued to be maintained on positive trials but not on negative trials. In Experiment III, only positive or negative trials were scheduled for several sessions. Observing responses extinguished regardless of whether positive or negative trials were scheduled. The results do not support the hypothesis that making the stimuli produced by observing responses redundant will reduce observing responses.
THE CORRELATION‐BASED LAW OF EFFECT1
Authors: Baum William M.
Published: March 2006

It is commonly understood that the interactions between an organism and its environment constitute a feedback system. This implies that instrumental behavior should be viewed as a continuous exchange between the organism and the environment. It follows that orderly relations between behavior and environment should emerge at the level of aggregate flow in time, rather than momentary events. These notions require a simple, but fundamental, change in the law of effect: from a law based on contiguity of events to a law based on correlation between events. Much recent research and argument favors such a change. If the correlation‐based law of effect is accepted, it favors measures and units of analysis that transcend momentary events, extending through time. One can measure all consequences on a common scale, called value. One can define a unit of analysis called the behavioral situation, which circumscribes a set of values. These concepts allow redefinition of reinforcement and punishment, and clarification of their relation to discriminative stimuli.
OBSERVING STIMULUS SOURCES THAT SIGNAL FOOD OR NO FOOD1
Authors: Jenkins H. M. , Boakes R. A.
Published: March 2006

Pigeons were given a choice between observing a stimulus source that was uncorrelated with food or one that was informative. The informative source was either positive, in which a stimulus change signalled food, or negative, in which change signalled no food. If observing is supported by the reduction of uncertainty, the negative as well as the positive source should be preferred to the uncorrelated source. On the other hand, if observing requires support by conditioned reinforcement, the negative source should not be preferred to the uncorrelated source. Two keys served as stimulus sources in a discrete trial procedure. The keys were lighted together, remained on for a variable length of time, and went off together. A key could change color 1 sec before going off. In the uncorrelated source, the change occurred equally often on trials ending with or without food. In the positive information source, the change occurred only on food trials, whereas in the negative information source, it occurred only on no‐food trials. All stimulus changes and food delivery were response independent. As measured by orientation and autoshaped pecking, the positive information source was preferred to the uncorrelated source. However, the uncorrelated source was preferred to the negative information source. The latter result does not support the view that observing behavior is reinforced by the reduction of uncertainty. The positive and negative information sources reduced uncertainty equally but only the positive source provided a signal that could act as a conditioned reinforcer by virtue of its relation to food.
ALTERING THE PROPORTION OF COMPONENTS IN A MIXED FIXED‐RATIO SCHEDULE1
Authors: Crossman E. K. , Silverman L. T.
Published: March 2006

Pigeons were trained under a schedule consisting of a number of fixed‐ratio 100 components followed by a single fixed‐ratio 10 component. The proportion of fixed‐ratio 100 to fixed‐ratio 10 components was varied according to several ascending and descending series within the range of 99:1 to 1:1. When this proportion was reduced to about 20:1 and below, the pause following each fixed‐ratio 100 gradually decreased in length. Primes, a burst of responses at the start of the fixed‐ratio 100 component, increased in frequency, and then decreased when the proportion became extremely low. Also, when the relative frequency of fixed‐ratio 10 components was very high, primes were seldom observed in the first fixed‐ratio 100 component following a fixed‐ratio 10 component, but were distributed evenly throughout the remaining fixed‐ratio 100 components.
CONTROLS FOR AND CONSTRAINTS ON AUTO‐SHAPING
Authors: Bilbrey John , Winokur Stephen
Published: March 2006

Auto‐shaping the pigeon's key‐peck response was examined as a respondent conditioning procedure with the use of Rescorla's truly‐random control procedure. In the first experiment, pigeons received presentations of brief light on the response key and brief presentations of food where the light and the food were independently presented. All birds failed to key peck after many light and food presentations, but explicit pairing of the light and food rapidly conditioned pecking to the light. Experiment 2 showed that even when an independent light/food presentation schedule was reduced to variable‐time 30 sec, additional naive birds would not key peck and only one bird pecked when the schedules were variable‐time 15 sec. A third experiment examined an explicit‐unpairing control procedure, where the light and food were not only presented on independent schedules but were also separated by a minimum time, and found that auto‐shaping did not occur. A fourth experiment investigated a number of control procedures and found them ineffective. A fifth experiment investigated the effects of a physical separation of the locus of the response key and the food dispenser, and a sixth experiment investigated using a tone in place of the light. It was concluded that pecking is generated by auto‐shaping procedures only when an intermittently presented keylight is regularly paired with food.
VISUAL ACUITY IN THE PIGEON II: EFFECTS OF TARGET DISTANCE AND RETINAL LESIONS1
Authors: Blough Patricia M.
Published: March 2006

Visual acuity thresholds for grating targets were determined for three pigeons at target distances ranging from 13 to 73 cm. These measurements were made both while the birds were wearing goggles restricting vision to the frontal field of view and when vision was unrestricted. Using a slightly different method, performance was also compared for target distances of 6 and 13 cm while the goggles were in place. For a second group of three pigeons, acuity data were obtained before and after laser lesions of the retina's foveal region. The findings suggested that acuity was relatively poor for targets at the intermediate distances and that it improved as distance both increased and decreased from these intermediate values. The acuity improvement with increasing distance did not occur, however, when the birds were wearing frontal goggles. The data appear to be consistent with Catania's 1964 suggestion that the pigeon has separate frontal and lateral visual systems that differ in their refractive characteristics. Foveal lesions did not appear to affect acuity for distant targets, and it was concluded that, while the fovea serves the lateral field of view, its presence is not necessary to the static acuity characteristics of this system.
CONCURRENT SCHEDULE CONTROL OF HUMAN VISUAL TARGET FIXATIONS1
Authors: Rosenberger Peter B.
Published: March 2006

Operant conditioning techniques were applied to the study of how target fixations are controlled by the probability of signal occurrence. In a standard vigilance setting, gaze at three illuminable volt meters was monitored by a Mackworth television eye camera with automatic recording capability. Gaze at a given meter produced illumination of the meter, and signals (deflections of the needle on the meter) were scheduled as intermittent consequences of this response. Target fixations were thus placed under the control of concurrent variable‐ratio, differential‐reinforcement‐of‐low‐rate, and fixed‐interval schedules in normal adult volunteers.
EFFECTS OF STIMULUS DURATION ON OBSERVING BEHAVIOR MAINTAINED BY DIFFERENTIAL REINFORCEMENT MAGNITUDE1
Authors: Auge Robert J.
Published: March 2006

Pigeons made observing responses for stimuli signalling the availability of either 10‐sec or 2‐sec access to grain on fixed‐interval 1‐min schedules. If observing responses did not occur, food‐producing responses occurred to a stimulus common to both reinforcement magnitudes. When the stimuli remained on for the duration of the components and signalled differential reinforcement magnitudes, observing responses were maintained; however, when the stimuli remained on for 10 sec, observing responses decreased markedly. In addition, it was shown that the occasional presentation of the stimulus signalling 10‐sec access to grain was necessary for the maintenance of observing behavior. A control condition demonstrated that when all the available stimuli signalled 6‐sec access to grain, observing responses declined. Taken together, the results demonstrated that the occasional presentation of the stimulus that remained on for the duration of the component and signalled the larger reinforcement magnitude was necessary for the maintenance of observing behavior.
A LOCAL‐RATE‐OF‐RESPONSE AND INTERRESPONSE‐TIME ANALYSIS OF BEHAVIORAL CONTRAST1
Authors: Arnett Faye Bush
Published: March 2006

Three pigeons were exposed to a two‐component multiple schedule in which a variable‐interval 3‐min schedule was always in effect in one component. The schedule in the other component was either variable‐interval 3‐min or extinction in alternate blocks of sessions. When the schedule was changed from multiple variable‐interval 3‐min variable‐interval 3‐min to multiple variable‐interval 3‐min extinction in the second and fourth phases of the experiment, overall response rates in the unchanged variable‐interval 3‐min component increased in two pigeons. Response rate declined when the schedule was changed to multiple variable‐interval 3‐min variable‐interval 3‐min again. Correlated with increases in overall response rate in the unchanged component were increases in local response rates at the beginning of the unchanged component and immediately after food presentation. Local rates 40 sec after food presentation did not increase greatly in the presence of the multiple variable‐interval 3‐min extinction schedule. An interresponse time analysis of three local rate samples showed small increases in the relative frequency of short‐duration interresponse times at the beginning of the unchanged component and immediately after food presentation. Neither the postreinforcement pause nor the latency to the first response in the unchanged component changed systematically.
FAILURE TO OBTAIN POSITIVE CONTRAST WHEN PIGEONS PRESS A BAR1
Authors: Westbrook R. F.
Published: March 2006

In Experiment 1, two groups of pigeons were exposed to multiple variable‐interval 1‐min variable‐interval 1‐min schedules of reinforcement. The required response was a key peck for one group, and a foot press of a bar for the other. When the procedure was shifted to multiple variable‐interval 1‐min extinction, positive contrast occurred with pigeons that key pecked, whereas negative induction occurred with those that bar pressed. Moreover, the absence of contrast could not be ascribed to the lack of inhibition, since negative generalization gradients after bar press training were U‐shaped in Experiment 2. The results are discussed in terms of possible relationships between positive contrast and the phenomenon of autoshaping.
EXTINCTION‐INDUCED AGGRESSION DURING ERRORLESS DISCRIMINATION LEARNING1
Authors: Rilling Mark , Caplan Harry J.
Published: March 2006

Pigeons were trained to discriminate without errors between a green light and a dark key. The key‐pecking response was reinforced in the presence of green, and extinction was in effect in the presence of the dark key. The duration of the dark key was gradually increased during the first few sessions of conditioning. The opportunity to attack a restrained target pigeon was also present. During discrimination training, the rate of attack in the presence of the dark key was higher for each animal than the operant level, even though most of the animals acquired the discrimination without errors. Furthermore, the rate of attack did not decrease during 45 sessions of discrimination training. Attack also occurred in the presence of the green stimulus, although to a lesser extent than during extinction. Reinforcement during green is a determinant of attack during extinction because removal of reinforcement virtually eliminated attack during extinction.
LONG‐TERM PREREWARD SUPPRESSION IN MONKEYS UNACCOMPANIED BY CARDIOVASCULAR CONDITIONING1
Authors: Kelly Dennis D.
Published: March 2006

In Experiment I, a 3‐min tone that preceded a free pellet of food suppressed variable‐interval performances maintained by the same type of pellets, but failed to elicit conditioned changes in the heart rates and blood pressures of two rhesus monkeys. Initially severe, the prereward suppression became temporally discriminated to progressively later portions of the tone, and was maintained at an attenuated level for over four months. The suppression was apparently not caused by interfering autonomic respondents, nor was it superstitiously conditioned, since 21 of the initial 25 tone‐food pairings took place outside of baseline sessions. In Experiment II, a 1‐min light, paired with four free pellets of food, suppressed the variable‐interval responding of a second pair of similarly trained monkeys. An interresponse‐time analysis showed that in one subject, mild prereward suppression of responding developed through two stages. On early trials, response rate slowed by 10% throughout the prefood interval. On later trials, the animal suppressed by pausing for a like portion of the interval, most often near the end, but otherwise responded normally during the prefood signal.
AN OBJECTIVE TECHNIQUE FOR RECORDING SHOCK‐INDUCED AGGRESSION IN UNRESTRAINED PAIRS OF RATS1
Authors: Selekman Warren , Meehan Edward
Published: March 2006

Pairs of rats received grid shock in a conical enclosure. Each shock elicited the stereotyped fighting posture. An omnidirectional pole, which was always between the rats, was accidentally operated whenever the rats fought. The number of pole hits, and the number of observed fight bouts, increased with current intensity. The number of pole hits served as a reliable and objective measure of shock‐induced fighting in rats.
STIMULUS CONTROL OF HEART RATE BY AUDITORY FREQUENCY AND AUDITORY PATTERN IN PIGEONS1
Authors: Delius Juan D. , Tarpy Roger M.
Published: March 2006

A new method was used to investigate auditory discrimination in pigeons. Basically, the method involves the repeated presentation of one stimulus preceding the single presentation of a different stimulus that is followed by shock. Stimulus control is assessed by the increase in heart rate that accompanies the presentation of the second stimulus. In Experiment 1, the efficiency of the method was explored by determining the frequency difference thresholds of pigeons at 500, 1000, 2000, and 4000 Hz. Weber fractions comparable to those reported in an earlier study using the conditioned suppression method were obtained. Experiment 2 demonstrated that, contrary to results of earlier studies, auditory temporal patterns can exercise differential stimulus control in pigeons. One stimulus consisted of the presentation (once per second) of a 1000‐Hz pure tone of 150 msec duration followed by a 2000‐Hz pure tone of equal duration; the other was the same except for the reversed order of the frequency components. Results indicated that the frequency pattern and not the loudness pattern of the stimuli was the cue controlling heart‐rate changes.
CHOICE BEHAVIOR ON DISCRETE TRIALS: A DEMONSTRATION OF THE OCCURRENCE OF A RESPONSE STRATEGY1
Authors: Silberberg Alan , Williams David R.
Published: March 2006

Three pairs of pigeons were trained to peck at two keys presented simultaneoulsy in discrete trials with intertrial intervals of 1, 22, or 120 sec. Left‐key responses incremented the probability of reinforcement for the first right‐key response and, conversely, right‐key responses incremented the probability of reinforcement for the first left‐key response. In terms of relative response rates, it was found that all birds' choices were described by a momentary maximizing strategy, but this fact was not reflected in the detailed sequential statistics for birds with the longer (22 or 120 sec) intertrial intervals. It was hypothesized that choice behavior, in general, may be accurately described by a momentary maximizing sequence, but that prior failures to demonstrate this were due to “errors” in executing the momentary maximizing sequence. These misappropriated responses, which are hypothesized to be randomly distributed among the responses defining the momentary maximizing sequence, caused successive choices to appear to be statistically independent when, in fact, they were not.
A FUNCTIONAL ANALYSIS OF CHAINED FIXED‐INTERVAL SCHEDULE PERFORMANCE1
Authors: Davison M. C.
Published: March 2006

Three pigeons were trained on two‐link chained fixed‐interval fixed‐interval schedules. Numbers of responses, time spent responding, and the total time spent in each component were measured. The data were analyzed according to the matching law for multiple and concurrent schedules. In most conditions, the ratio of response rates in the two links was a constant proportion of the ratio that would be predicted in a multiple schedule with the same components. Data on pauses during the interval schedules showed that, in most conditions, the pause duration was a linear function of the interval length, and greater in the initial link than in the terminal link. The experiment thus demonstrated a quantitative functional analysis of performance on a chained schedule.