bluuebunny/crossref_metadata_2025 huggingface dataset:
CONCURRENT SECOND‐ORDER SCHEDULES OF REINFORCEMENT1
Authors: Cohen Steven L.
Published: March 2006

Responses on one key (the main key) of a two‐key chamber produced food according to a second‐order variable‐interval schedule with fixed‐interval schedule components. A response on a second key (the changeover key) alternated colors on the main key and provided a second independent second‐order variable‐interval schedule with fixed‐interval components. The fixed‐interval component on one variable‐interval schedule was held constant at 8 sec, while the fixed interval on the other variable‐interval schedule was varied from 0 to 32 sec. Under some conditions, a brief stimulus terminated each fixed interval and generated fixed‐interval patterns; in other conditions, the brief stimulus was omitted. Relative response rate and relative time deviated substantially from scheduled relative reinforcement rate and, to a lesser extent, from obtained relative reinforcement rate under both brief‐stimulus and no‐stimulus conditions. Matching was observed with equal components on both schedules; with unequal components, increasingly greater proportions of time and responses than the matching relation would predict were spent on the variable‐interval schedule containing the shorter component. Preference for the shorter fixed interval was typically more extreme under brief‐stimulus than under no‐stimulus schedules. The results limit the extension of the matching relation typically observed under simple concurrent variable‐interval schedules to concurrent second‐order variable‐interval schedules.
TIME ALLOCATION ON CONCURRENT SCHEDULES WITH ASYMMETRICAL RESPONSE REQUIREMENTS1
Authors: Bauman Richard A. , Shull Richard L. , Brownstein Aaron J.
Published: March 2006

Pigeons were trained on concurrent schedules in which key pecking was required by both schedules (concurrent variable‐interval variable‐interval schedules) and on concurrent schedules in which key pecking was required by only one of the schedules (concurrent variable‐interval variable‐time schedules). The distribution of reinforcements was systematically varied with both types of concurrent schedules. The distribution of time between the schedules depended on the reinforcement distribution and was independent of the symmetry of the response requirement. The relation between time and reinforcement distributions appears to be invariant over a wide range of manipulations of responding maintained by concurrent schedules.
EVIDENCE FOR THE INNATE BASIS OF THE HUE DIMENSION IN THE DUCKLING1
Authors: Terrace H. S.
Published: March 2006

Different groups of ducklings reared under sodium monochromatic light (589 nanometers) and under white light were trained to discriminate between the stimulus correlated with reinforcement (589 nanometers), and the stimulus correlated with extinction, whose value was either 570 or 610 nanometers. The peaks of subsequently obtained gradients of wavelength generalization of both groups were displaced away from the stimulus correlated with extinction. The peaks of the groups trained not to respond to 570 nanometers were located at 600 nanometers. The peaks of the groups trained not to respond to 610 nanometers were located at 580 nanometers. These results (in agreement with earlier data of Rudolph and Honig, 1972) suggest that ducklings have an innate basis for ordering stimuli of different wavelengths along the hue dimension.
NEAR‐FIELD VISUAL ACUITY OF PIGEONS: EFFECTS OF HEAD LOCATION AND STIMULUS LUMINANCE
Authors: Hodos William , Leibowitz Rosalind W. , Bonbright James C.
Published: March 2006

Two pigeons were trained to discriminate a grating stimulus from a blank stimulus of equivalent luminance in a three‐key chamber. The stimuli and blanks were presented behind a transparent center key. The procedure was a conditional discrimination in which pecks on the left key were reinforced if the blank had been present behind the center key and pecks on the right key were reinforced if the grating had been present behind the center key. The spatial frequency of the stimuli was varied in each session from four to 29.5 lines per millimeter in accordance with a variation of the method of constant stimuli. The number of lines per millimeter that the subjects could discriminate at threshold was determined from psychometric functions. Data were collected at five values of stimulus luminance ranging from −0.07 to 3.29 log cd/m2. The distance from the stimulus to the anterior nodal point of the eye, which was determined from measurements taken from high‐speed motion‐picture photographs of three additional pigeons and published intraocular measurements, was 62.0 mm. This distance and the grating detection thresholds were used to calculate the visual acuity of the birds at each level of luminance. Acuity improved with increasing luminance to a peak value of 0.52, which corresponds to a visual angle of 1.92 min, at a luminance of 2.33 log cd/m2. Further increase in luminance produced a small decline in acuity.
SOME CONDITIONS AFFECTING THE CHOICE TO COOPERATE OR COMPETE1
Authors: Schmitt David R.
Published: March 2006

Three experiments investigated conditions affecting the choice to cooperate or compete. Experiment i compared the effects first of an individual activity, then of a competitive task as an alternative to cooperation. For both comparisons, subjects could earn more by cooperating. Choice of competition, but not individual activity, was found to depend on the task choice contingencies. Competition predominated when both subjects could compete if either or both chose competition. Previously competitive pairs cooperated when both subjects could cooperate if either or both chose cooperation. Experiment ii investigated the effects of differences in magnitude of the reinforcers for cooperating or competing. Choice between the two alternatives was manipulated in all pairs by varying reinforcer difference. Competition was chosen over cooperation only within the limits within which competition was potentially profitable. Experiment iii replicated the findings of Experiment ii using triads. Subjects in triads, however, were more likely to withdraw from the experiment. Thus, the data for pairs and triads suggest an orderly relation between reinforcer difference for cooperating or competing and task choice. Motivation of subjects to maximize relative gain by competing can be overridden by moderate reinforcer differences favoring cooperation.
PROCEDURAL ANTECEDENTS OF BEHAVIORAL CONTRAST: A RE‐EXAMINATION OF ERRORLESS LEARNING1
Authors: Kodera Thomas L. , Rilling Mark
Published: March 2006

Behavioral contrast reliably occurred in pigeons following errorless discrimination training, contrary to Terrace's (1963) observations. In the main experiment, a 60‐sec green keylight, associated with a variable‐interval 30‐sec schedule of reinforcement alternated with a 60‐sec period of extinction when the key was dark. Such aspects of the discrimination training procedure as: (1) the amount of prior nondifferential exposure to the positive stimulus before the discrimination was instituted, and (2) the rapidity with which the negative stimulus was introduced (whether progressively or abruptly) directly influenced the amount of behavioral contrast produced. This occurred independently of the number of errors made by a pigeon during acquisition of the discrimination. In a series of control experiments, substitution of a red keylight for the dark key during extinction resulted in greater behavioral contrast, while an increase to 3 min in the duration of the green keylight associated with reinforcement attenuated the behavioral contrast effect.
THE EFFECTS OF A COOPERATION CONTINGENCY ON BEHAVIOR IN A CONTINUOUS THREE‐PERSON ENVIRONMENT1
Authors: Emurian Henry H. , Emurian Cleeve S. , Bigelow George E. , Brady Joseph V.
Published: March 2006

Five groups of three subjects resided for 10 or 15 days within a continuously programmed environment. Subjects followed a programmatic arrangement of required and optional private and social activities that determined the individual and group baseline behaviors into which experimental operations were introduced and withdrawn. A cooperation condition was in effect when all three subjects were required to select simultaneous access to a group area before it became available for use. A noncooperation condition was in effect when access to a group area could be selected by individual subjects, without regard to the other subjects' selections. For all groups, the effects of these two conditions on individual and group behaviors were investigated in reversal designs where several successive days occurred under each condition. Groups 1, 4, and 5 had the noncooperation condition interposed between cooperation conditions. Groups 2 and 3 had the cooperation condition interposed between noncooperation conditions. Durations of triadic activities, per cent of time in triadic activities, intercom use, and intersubject program synchronization were greater during cooperation conditions than during noncooperation conditions. These data show that a cooperation contingency within the behavioral program affected both social behavior and the collateral individual behavior necessary to execute the cooperation response.
RELATIVE REINFORCER MAGNITUDE UNDER A NONINDEPENDENT CONCURRENT SCHEDULE OF COCAINE REINFORCEMENT IN RHESUS MONKEYS1
Authors: Llewellyn Mark E. , Iglauer Carol , Woods James H.
Published: March 2006

Lever pressing by three rhesus monkeys was maintained under a two‐lever concurrent schedule of cocaine reinforcement. Responding on one lever (constant‐dose lever) produced a constant dose of 0.05 or 0.1 mg/kg/injection arranged according to a variable‐interval 1‐min schedule. Responding on the other lever (variable‐dose lever) produced a comparison dose of cocaine (0.013 to 0.8 mg/kg/injection), also under a variable‐interval 1‐min schedule. The two variable‐interval schedules were made nonindependent by arranging that the assignment of a reinforcer by one schedule inactivated the second schedule until the assigned reinforcer had been obtained. This modification ensured that the two cocaine doses were obtained with approximately equal frequency, regardless of the distribution of the subject's responding. Preference, indicated by relative response frequency on the variable‐dose lever, was almost always for the larger of the doses and was a monotonic function of the comparison dose, except at the highest doses. Preferences at the highest comparison doses may have resulted from the low overall response rates exhibited at these doses. Relative response frequencies on the variable‐dose lever roughly matched relative reinforcer magnitude (mg/kg/injection available on the variable‐dose lever divided by the sum of mg/kg/injections available on each lever).
MATCHING IN A NETWORK1
Authors: Herrnstein R. J. , Loveland Donald H.
Published: March 2006

Pigeons were given practice choosing between pairs of alternatives yielding different frequencies of reinforcement. Four individual alternatives were set into four pairwise choices. Averaged over subjects, the distribution of responses in each choice approximated matching. The four individual alternatives were then presented, two by two, in two pairwise choices for which there had been no initial practice. No further reinforcement was given during the tests with the new pairs. Transfer to the two test pairs deviated systematically from matching in most cases by exaggerating the preference for the alternative that had had the higher frequency of reinforcement.
BEHAVIOR CHANGES DURING REPEATED EIGHT‐DAY EXTINCTIONS1
Authors: Anger Douglas , Anger Kathleen
Published: March 2006

Pigeons were given repeated two‐day conditionings alternating with eight‐day extinctions using a trial procedure. One group had different key colors during each of the first five conditioning‐extinction pairs; another group had the same key color throughout. Total extinction responses of both groups were quite constant over successive extinctions. This finding differs from the rapid declines found in most previous studies with bar‐press and key‐peck responses. The difference probably was due to our longer extinctions, because responses early in each extinction did decrease. However, that decrease was neutralized by increases in responses late in each extinction. The two opposite changes indicate the influence of two different factors during repeated extinctions, with neither factor having much stimulus specificity. The reduction of early responses may result from feeding changes confounded with extinction. The increase in later extinction responses may result from a decrease in the effect of unreinforced responses after their repeated occurrence.
ELICITED RESPONDING TO SIGNALS FOR REINFORCEMENT: THE EFFECTS OF OVERALL VERSUS LOCAL CHANGES IN REINFORCEMENT PROBABILITY1
Authors: Williams Ben A.
Published: March 2006

Pigeons were studied on a three‐component multiple schedule where all reinforcement was independent of responding. Two components were cued by different keylights and were associated with different rates of reinforcement. The third was always a no‐key period associated with extinction. After a few sessions, pecking was elicited by the keylights signalling the reinforcement and continued to be maintained indefinitely. The duration and sequence of the three components were varied to determine if the primary controlling variable was differences in the overall probability of reinforcement, or if it was the immediate change in reinforcement signalled by the onset and/or offset of the stimulus. Both variables were found to control behavior. When 30‐sec components were used, the primary controlling variable was the overall probability of reinforcement, but when 3‐min components were used, overall probability had little effect. Control by local changes in reinforcement also occurred, although the type of local control varied both across subjects and experimental conditions. Some behaviors were controlled more by the change in reinforcement signalled by the onset of the stimulus, while others were controlled more by the change signalled by the offset of the stimulus.
TIME‐BASED AND COUNT‐BASED MEASUREMENT OF PREFERENCE1
Authors: Baum William M.
Published: March 2006

Rats' pressing on two levers was reinforced according to two independent variable‐interval schedules that were varied during the experiment. Since the levers were connected directly to the programming equipment, bypassing the standard pulseformers, reinforcement could occur while a lever was held down. Although the time a lever was pressed might, therefore, have varied independently of number of presses, these two measures covaried substantially, because the average duration of the presses remained roughly constant. This rough invariance may have resulted from the rats' tendency to make bursts of brief presses (i.e., to jiggle the levers), even though the contingencies encouraged holding. When duration did vary, presses on the two levers tended to vary together. As a result, relative time spent pressing corresponded closely to relative number of presses. Both of these measures conformed well to the matching law. Absolute behavioral frequency at a lever, measured either way, varied directly with proportion of reinforcement for that lever, in accordance with the generalized version of the matching law. Number of presses seemed, on balance, to be a slightly more reliable measure than pressing time. The substantial interchangeability may prove more significant than the slight disparity, however, because it supports the notion that all behavior can be measured on a common scale of time.
THE EFFECT OF REARING ENVIRONMENTS ON THE CONTRAFREELOADING PHENOMENON IN RATS1
Authors: Coburn Janet F. , Tarte Robert D.
Published: March 2006

Eight naive rats were reared in enriched or impoverished environments for 39 days after weaning and then lived in operant chambers, in which they could obtain food pellets freely or by lever pressing, for 25 or 30 days. The animals raised in an impoverished environment acquired the bar‐press response quickly when placed in the operant chambers and maintained a preference for obtaining food via bar pressing. Animals raised in an enriched environment did not learn to lever press, as demonstrated by low levels of responding and the lack of bar pressing when free food was subsequently removed. It was concluded that restricting animals' postweaning environments facilitated learning in a choice situation, probably because of increased activity levels. The results are interpreted in relation to previous studies on rearing environments and on contrafreeloading.
THE STAGES OF ACQUISITION IN STIMULUS FADING1
Authors: Fields Lanny , Bruno Vincent , Keller Kenneth
Published: March 2006

Pigeons were exposed to a stimulus fading procedure in which control of responding was transferred from red and black stimuli to lines of different angular orientation. After superimposing one line on the red stimulus and the other line on the black stimulus, the intensity of the lines was gradually increased and that of the red stimulus was gradually reduced. Probes consisting of red and line stimuli presented separately were used during the course of fading to assess control exerted by each element of the compound. As the lines were faded in, they did not acquire control of responding. As red was faded out, control of responding was acquired first by the lower intensity red stimuli in combination with the line stimulus, and finally by the angular orientation of the lines. Probes also determined the point at which the line stimuli, presented alone, would maintain a high degree of stimulus control. The results demonstrated that new stimuli in fading acquire dimensional control of responding in two sequential stages. Acquisition of stimulus control in fading was explained in terms of attenuation of stimulus blocking.
MATCHING‐BASED HEDONIC SCALING IN THE PIGEON
Authors: Miller H. L.
Published: March 2006

Four slightly hungry pigeons chose between pairs of grains in a Findley concurrent choice procedure. For Condition I, choice involved hemp versus buckwheat; for Condition II, wheat versus buckwheat; and for Condition III, hemp versus wheat. In all conditions, frequency of reinforcement was arranged according to concurrent variable‐interval variable‐interval schedules. On the assumption that subjects matched their behavior and time distributions to those of reinforcer value, the choice functions obtained in Conditions I and II were transformed to yield estimates of values of hemp and wheat relative to buckwheat. These, in turn, provided predictions about behavior and time allocation in Condition III. In general, the predicted outcomes were close to those actually obtained. The results evidence the effectiveness of matching‐based hedonic scales in the prediction of choice between qualitatively different reinforcers.
EFFECTS OF PROMAZINE, CHLORPROMAZINE, d‐AMPHETAMINE, AND PENTOBARBITAL ON TREADLE PRESSING BY PIGEONS UNDER A SIGNALLED SHOCK‐POSTPONEMENT SCHEDULE1
Authors: Leander J. David
Published: March 2006

The effects of promazine on treadle pressing to postpone the presentation of electric shock were studied in three pigeons. The effects of chlorpromazine, d‐amphetamine, and pentobarbital were studied in two of these pigeons. Each treadle press postponed electric shock for 20 sec and presentation of a preshock stimulus for 14 sec. Selected doses of both promazine and chlorpromazine increased the rates of treadle pressing in all birds. The response‐rate increases produced by promazine and chlorpromazine were due to increased conditional probabilities of treadle pressing both before and during the preshock stimulus. d‐Amphetamine (1 and 3 mg/kg) slightly increased responding in one of the birds, but not to the extent that promazine or chlorpromazine did. In the other bird, the 10 mg/kg dose of d‐amphetamine increased shock rate but did not change response rate. Some doses of d‐amphetamine increased the conditional probabilities of responding both in the absence of the preshock signal and during the preshock signal in both birds. Pentobarbital only decreased response rates and increased shock rates.
THE EFFECTS OF d‐AMPHETAMINE ON THE TEMPORAL CONTROL OF OPERANT RESPONDING IN RATS DURING A PRESHOCK STIMULUS
Authors: Sanger D. J. , Blackman D. E.
Published: March 2006

The operant behavior of six rats was maintained by a random‐interval schedule of reinforcement. Three‐minute periods of noise were superimposed on this behavior, each period ending with the delivery of an unavoidable shock. Overall rates of responding were generally lower during the periods of noise than in its absence (conditioned suppression). These suppressed response rates also exhibited temporal patterning, with responding becoming less frequent as each noise period progressed. The effects of d‐amphetamine on this behavioral baseline were then assessed. In four animals the relative response rates during the noise and in its absence suggested that the drug produced a dose‐related decrease in the amount of conditioned suppression. However, this effect was often due to a decrease in the rates of responding in the absence of the preshock stimulus, rather than to an increase in response rates during the stimulus. Temporal patterning in response rates during the preshock stimulus was abolished, an effect that was interpreted in terms of rate‐dependent effects of d‐amphetamine. This study thus extends rate‐dependent analyses of the effects of amphetamines to the patterns of operant behavior that occur during a preshock stimulus, and which have been discussed in terms of the disrupting effects of anxiety on operant behavior.
FORCE AND RATE RELATIONS IN RESPONDING DURING VARIABLE‐INTERVAL REINFORCEMENT1
Authors: Mintz Donald E. , Samuels Richard M. , Barber Ned G.
Published: March 2006

Four rats responded on one‐minute variable‐interval schedules with several variations in peak‐force of response required for food reinforcement. Measures of peak force and rate were taken for the responses, which were the downward exertions of force against a static force‐transducing operandum. The analysis distinguished responses, a generic class of measured behavior, from criterion responses, an operationally specified subclass required for reinforcement. Absolute rate of response showed no systematic change, but the rate of responses meeting a newly required criterion of peak‐force invariably increased through changes in the absolute rate of response, the relative‐frequency distributions of peak force, or some combination of both. The relative frequency of responses meeting an elevated force criterion during variable‐interval reinforcement exceeded that maintained with the same criterion with continuous reinforcement. The requirement of more effortful responding for reinforcement does not necessarily reduce response rate. Conformity of the behavior to the requirement for reinforcement is the salient effect.
QUANTITATIVE STUDIES OF REINFORCEMENT RELATIVITY1
Authors: Mazur James E.
Published: March 2006

Three experiments examined an application of the matching law to the area of reinforcement relativity. In Experiment I, rats ran in a wheel and drank a sucrose solution. Equations derived from the matching law made fairly accurate predictions of the amounts of time spent running and drinking when licks and wheel revolutions had to occur in fixed proportions. In Experiment II, rats were required to spend four times as much time drinking as running, but the absolute durations of the cycles of drinking and running were varied. Except for the shortest cycle size tested, durations were close to those predicted. Experiments III investigated a tendency for obtained durations of running and drinking to be slightly longer than predicted. Simply shortening the periods when these behaviors were available increased their values. It was concluded that the matching law equations provided reasonably accurate predictions in some experiments, but changes in motivation set the limits of such accuracy.
THE MATCHING LAW IN AND WITHIN GROUPS OF RATS1
Authors: Graft D. A. , Lea S. E. G. , Whitworth T. L.
Published: March 2006

In each of the two experiments, a group of five rats lived in a complex maze containing four small single‐lever operant chambers. In two of these chambers, food was available on variable‐interval schedules of reinforcement. In Experiment I, nine combinations of variable intervals were used, and the aggregate lever‐pressing rates (by the five rats together) were studied. The log ratio of the rates in the two chambers was linearly related to the log ratio of the reinforcement rates in them; this is an instance of Herrnstein's matching law, as generalized by Baum. Summing over the two food chambers, food consumption decreased, and response output increased, as the time required to earn each pellet increased. In Experiment II, the behavior of individual rats was observed by time‐sampling on selected days, while different variable‐interval schedules were arranged in the two chambers where food was available. Individual lever‐pressing rates for the rats were obtained, and their median bore the same “matching” relationship to the reinforcement rates as the group aggregate in Experiment I. There were differences between the rats in their distribution of time and responses between the two food chambers; these differences were correlated with differences in the proportions of reinforcements the rats obtained from each chamber.
ELIMINATION OF REINFORCED BEHAVIOR: INTERMITTENT SCHEDULES OF NOT‐RESPONDING1
Authors: Zeiler Michael D.
Published: March 2006

Pigeons' key pecking resulted in food according to either a variable‐ratio or a variable‐interval schedule. At the same time, food was available for not pecking for a specified time. The required time of not‐pecking was segmented into not‐responding units, and these units were followed by food according to a fixed‐ratio schedule. Both unit duration and the number required were varied. In general, the shorter the time unit or the smaller the ratio, the lower was response rate. When total required not‐responding time was constant, but changes in unit duration and the number required altered how the total was achieved, shorter units produced lower rates. Other conditions involved substitution of food delivered independent of responding for the not‐responding schedule. With low and moderate total times to food presentation, the not‐responding schedule produced lower rates; with the longest times, the response‐independent schedule generated less responding. When considered in terms of relative frequency of food presentation available from a source other than pecking, the not‐responding schedule reduced rate more effectively than did the response‐independent schedule. Comparisons with other research suggested that food presented dependent on not responding compared favorably with punishment as a procedure for reducing response rate. Transient effects differed. Although punishment temporarily depresses rate when first imposed and temporarily enhances it when first removed, food given for not responding quickly generated steady‐state rates.
TIME LIMITS FOR COMPLETING FIXED RATIOS. IV. COMPONENTS OF THE RATIO1
Authors: DeCasper Anthony J. , Zeiler Michael D.
Published: March 2006

Pigeons received food after completing a fixed ratio if the temporal properties of responding exceeded minimum duration requirements. In one set of conditions, a minimum time had to elapse before the first response of the ratio (the initial pause). In another set, the minimum duration was the time between the first and last response of the ratio. Obtained times increased as a power function of required times in both conditions. The power function resembled that occurring in experiments involving temporal differentiation of individual responses, interresponse times, latencies, and entire fixed‐ratio sequences. Moreover, in all of these experiments individual performances could be described as a function of the base duration (the duration occurring in the absence of temporal requirements) and the specific time requirement. Control conditions indicated that the effects resulted from temporal requirements and not from reinforcer intermittency.
GENERAL ATTENTIVENESS EFFECTS OF DISCRIMINATIVE TRAINING
Authors: DePaulo Peter , DeWald Louise , Yarczower Matthew
Published: March 2006

Using a design that permitted the simultaneous assessment of intra‐, inter‐, and extradimensional effects of discriminative training, the generality of discriminative effects that have been said to reflect increases in “general attentiveness” was assessed. Pigeons received either discriminative training with two stimuli correlated with reinforcement and one stimulus correlated with nonreinforcement, or nondifferential reinforcement (control) training. One positive stimulus was part of an intradimensional task and the other was not. After training, generalization tests were conducted to assess stimulus control along several dimensions. Discriminative training resulted in increased control along dimensions of the positive stimulus involved in the intradimensional task, but not along any dimensions of the other positive stimulus. The results suggested that discriminative training leads to increases in attention that are neither so general as suggested by the “general attentiveness” view nor so specific as to be revealed solely by intradimensional effects.
POLYDIPSIA INDUCED IN RATS BY SECOND‐ORDER SCHEDULES OF REINFORCEMENT1
Authors: Corfield‐Sumner P. K. , Blackman D. E. , Stainer G.
Published: March 2006

Three rats were exposed to a second‐order schedule in which fixed‐interval components ended either with food or with a brief stimulus that was never paired with food. Food and the brief stimulus occurred in a random sequence (variable‐ratio 2 overall schedule). Another three rats were exposed to a similar second‐order schedule, the only difference being that the food or the stimulus was presented independently of operant behavior (fixed‐time components). The three rats exposed to the fixed‐interval components licked at a water spout after each food presentation. These rats also licked in the intervals after the brief stimulus. Although the discriminative properties of food and of the brief stimulus were identical in relation to subsequent reinforcement, licking after the stimulus was less than after food. The three rats exposed to the second‐order schedules with fixed‐time components also licked at the water spout after food, but these rats did not lick consistently after brief stimulus presentations.
AUDITORY STIMULUS CONTROL IN PIGEONS: JENKINS AND HARRISON (1960) REVISITED1
Authors: Rudolph Robert L. , Van Houten Ronald
Published: March 2006

Pigeons were trained to peck a key in the presence of a 1000‐Hz tone on a variable‐interval one‐minute schedule of reinforcement. One group was trained with an illuminated key; the other was trained in a totally dark chamber. During a generalization test on tonal frequency, subjects trained and tested with the key illuminated produced rather shallow gradients around the training value; subjects trained and tested in the dark produced steeper generalization gradients. These data replicate Jenkins and Harrison's (1960) finding that tone acquires relatively little control over responding and demonstrate that this absence of control is a function of the presence of the keylight.
UNINSTRUCTED HUMAN REPONDING: SENSITIVITY TO RATIO AND INTERVAL CONTINGENCIES1
Authors: Matthews Byron A. , Shimoff Eliot , Catania A. Charles , Sagvolden Terje
Published: March 2006

College students' presses on a telegraph key were occasionally reinforced by light onsets in the presence of which button presses (consummatory responses) produced points later exchangeable for money. One student's key presses were reinforced according to a variable‐ratio schedule; key presses of another student in a separate room were reinforced according to a variable‐interval schedule yoked to the interreinforcement intervals produced by the first student. Instructions described the operation of the reinforcement button, but did not mention the telegraph key; instead, key pressing was established by shaping. Performances were comparable to those of infrahuman organisms: variable‐ratio key‐pressing rates were higher than yoked variable‐interval rates. With some yoked pairs, schedule effects occurred so rapidly that rate reversals produced by schedule reversals were demonstrable within one session. But sensitivity to these contingencies was not reliably obtained with other pairs for whom an experimenter demonstrated key pressing or for whom the reinforcer included automatic point deliveries instead of points produced by button presses. A second experiment with uninstructed responding demonstrated sensitivity to fixed‐interval contingencies. These findings clarify prior failures to demonstrate human sensitivity to schedule contingencies: human responding is maximally sensitive to these contingencies when instructions are minimized and the reinforcer requires a consummatory response.
ON HERRNSTEIN'S EQUATION AND RELATED FORMS
Authors: Staddon J. E. R.
Published: March 2006

In 1970, Herrnstein proposed a simple equation to describe the relation between response and reinforcement rates on interval schedules. Its empirical basis is firm, but its theoretical foundation is still uncertain. Two approaches to the derivation of Herrnstein's equation are discussed. It can be derived as the equilibrium solution to a process model equivalent to familiar linear‐operator learning models. Modifications of this approach yield competing power‐function formulations. The equation can also be derived from the assumption that response strength is proportional to reinforcement rate, given that there is a ceiling on response rate. The proportional relation can, in turn, be derived from a threshold assumption equivalent to Shimp's “momentary maximizing”. This derivation implies that the two parameters of Herrnstein's equation should be correlated, and may explain its special utility in application to internal schedules.
ANTECEDENTS TO FECHNER'S LAW: THE ASTRONOMERS J. HERSCHEL, W. R. DAWES, AND N. R. POGSON
Authors: Pliskoff Stanley S.
Published: March 2006

The history of the stellar magnitude scale is briefly traced from the second century B.c. until the middle of the nineteenth century. It becomes clear that astronomers formulated “Fechner's Law” by about 1850. While Fechner is credited with the grander view of things, the contention is made that the astronomers John Herschel, W. R. Dawes, and N. R. Pogson have not been given their due by historians of psychology.
SCHEDULES OF FOOD POSTPONEMENT. II. MAINTENANCE OF BEHAVIOR BY FOOD POSTPONEMENT AND EFFECTS OF THE SCHEDULE PARAMETER
Authors: Clark Fogle C. , Smith James B.
Published: March 2006

In Experiment I, food‐deprived, feeder‐trained squirrel monkeys pressed a lever to postpone brief electric shocks (Response‐Shock/Shock‐Shock interval=30 seconds). Forty‐one three‐hour sessions of shock postponement were followed by 120 sessions of concurrent shock and food postponement. The shock schedule was unchanged and the food schedule was Response‐food interval‐20 seconds, Food‐food interval 10 seconds. After concurrent shock and food postponement, the shock schedule was discontinued and 40 sessions of food postponement ensued, followed by 53 sessions of extinction. After extinction, food postponement was resumed for 11 sessions. Stable responding with low food rates was maintained under food‐postponement after the concurrent schedule. Responding decreased to low levels under extinction and recovered immediately to previous levels when the food‐postponement schedule was re‐instated. In Experiment II, a parameter of the food‐postponement schedule was studied sequentially. Using the same subjects, the Response‐food‐Food‐food interval was manipulated from four seconds to 80 seconds with several orders of presentation. Relations of response rates and food rates to the parameter were similar to those seen under shock postponement. Exposure to very short postponement times (four seconds), resulting in very high food rates, decreased but did not abolish subsequent responding at longer postponement times. Results are discussed from the point of view that reinforcing functions of stimuli consequent on responding depend on a prior history of scheduled contact with those stimuli.
SUPPRESSION OF ETHANOL‐REINFORCED LEVER PRESSING BY DELAYING FOOD AVAILABILITY
Authors: Poling Alan , Thompson Travis
Published: March 2006

When food was initially available to rats under a fixed‐interval 26‐second schedule and each liquid‐reinforced lever press delayed food availability 8 seconds, suppression of liquid‐reinforced lever pressing and liquid consumption occurred when the liquid presented was 4, 8, 16, 32, and 0% ethanol. Suppression did not occur in yoked‐control animals, which received food coincidentally with experimental animals but were not directly exposed to the delay dependency. After exposure to the food schedule, each ethanol solution served as a reinforcer in the absence of food presentation. Delaying food availability for increasingly long periods (8 to 2048 seconds) suppressed ethanol‐reinforced lever pressing and consumption relative to baseline levels, with the maximum decrease being below the level maintained in the absence of food. However, degree of suppression did not increase monotonically with delay length. Liquid‐reinforced performance of yoked‐control animals indicated that suppression did not result from changes in the sequencing of food presentation alone.
A MOLECULAR ANALYSIS OF MULTIPLE SCHEDULE INTERACTIONS: NEGATIVE CONTRAST1
Authors: Marcucella Henry , MacDonall James S.
Published: March 2006

The present experiments investigated the relationship between changes in the relative reinforced interresponse‐time distributions and the occurrence of positive and negative contrast in multiple variable‐interval—variable‐interval and multiple variable‐interval— extinction schedules of reinforcement. Experiment I demonstrated that changes in the interresponse‐time distributions were consistently correlated with response‐rate changes referred to as positive and negative contrast. Corresponding changes in the reinforced interresponse‐time distributions suggested that negative contrast resulted as an inductive effect of selectively reinforcing long interresponse times in the altered component at the moment the baseline schedule was reintroduced. Experiment II demonstrated that the magnitude of the negative‐contrast effect could be significantly decreased if the altered component schedule was modified in order to prevent the reinforcement of these interresponse times during the first few sessions of baseline recovery. The results supported a proposal that interresponse time—reinforcer relations may act as amplifiers or attenuators of negative contrast.
THE ROLE OF PRELIMINARY MAGAZINE TRAINING IN ACQUISITION OF THE AUTOSHAPED KEY PECK1
Authors: Davol G. H. , Steinhauer G. D. , Lee A.
Published: March 2006

A series of experiments tested the hypothesis that initial key pecks in the autoshaping procedure are generalized pecks at the illuminated grain hopper. Experiment I found that autoshaping readily occurred when the chamber was continuously illuminated by a house‐light. In Experiment II, pigeons given magazine training and autoshaping with an un‐lighted grain hopper failed to autoshape in 200 trials. Acquisition of autoshaped key pecking was retarded in Experiment III when stimulus control by the magazine light was reduced. In the fourth study, pigeons were given magazine training with either a red or white magazine light and then given autoshaping with concurrently presented red and white keys. For all pigeons in this experiment, the first key peck occurred on the key of the same color as that pigeon's magazine light. The results of these experiments were interpreted as supporting an account of autoshaping that identifies initial key pecks as arising due to generalization of pecking at the lighted grain hopper to pecking at the lighted key.
DISCRIMINATIVE FUNCTIONS OF SCHEDULE STIMULI AND MEMORY: A COMBINATION OF SCHEDULE AND CHOICE PROCEDURES
Authors: Stubbs D. Alan , Vautin Susan J. , Reid Howard M. , Delehanty Denis L.
Published: March 2006

Pigeons responded under a combination brief‐stimulus schedule and choice procedure. Normally, a fixed‐interval schedule was in effect, where completion randomly produced either a brief stimulus or food. Intermittently, this schedule was interrupted by a choice arrangement. Two choice keys were lit, either a short or a long time since a prior event (food or stimulus). One choice response produced food if the time had been short, and the alternate response produced food if the time had been long. Across conditions, the duration of the fixed‐interval schedule was varied, the stimuli that comprised the brief‐stimulus operation were changed, and the stimuli were presented as paired and nonpaired with food. The focus of the study was the control of both schedule performance and choice responding across conditions. The results showed that choice accuracy was correlated with the degree of fixed‐interval curvature, the response pattern of a pause followed by a gradually accelerated rate. As fixed‐interval schedule duration was increased, both the degree of fixed‐interval curvature and choice accuracy decreased. The particular brief stimulus used affected schedule and choice performance, with a more salient stimulus producing a greater degree of curvature and higher accuracy. Pairing and nonpairing operations produced striking differences in performance with the less salient brief stimulus, but not with the more salient stimulus. The results suggest that brief‐stimulus schedule performance may be conceptualized in the context of memory research.
STABILITY CRITERIA
Authors: Killeen Peter R.
Published: March 2006

Three approaches to the determination of behavioral stability were examined. In the first, a learning curve was fit to acquisition data (from Cumming and Schoenfeld, 1960), and the “experiment” stopped when the data approached sufficiently close to the theoretical asymptote. In the second, the data were analyzed for variability and linear and quadratic trend. In the third, the experiment was stopped when the magnitude of the daily changes in the data fell below a criterion. Accuracy was measured as deviation between the average value of the dependent variable when the experiment was stopped, and the average value over the last 100 sessions. The first approach was most accurate, but at the cost of requiring the most sessions and being the most difficult to apply. Both the second and third approaches provided acceptable criteria with a reasonable cost‐accuracy tradeoff. The second approach permits a continuous adjustment of the criteria to accommodate the variability intrinsic in the experimental paradigm. The third, nomothetic, approach also takes into account the decreasing marginal utility of extended training sessions.
ACCELERATION AND SUPPRESSION OF RATS' RESPONDING TO AVOID FOOT SHOCK AND TAIL SHOCK1
Authors: Barbaree H. E. , Weisman R. G.
Published: March 2006

Signalled response‐independent shocks were superimposed on rats' wheel‐turn responding to avoid shock administered to their feet through a grid floor or to their tails through fixed electrodes. In Experiment I, a tone paired with response‐independent foot shock increased responding in three of four rats; a tone paired with tail shock increased responding in only one of four rats and suppressed responding in two rats. In Experiment II, a tone presented randomly with respect to response‐independent shock had no reliable effect on responding to avoid foot shock or tail shock. In Experiment III, tail shock and foot shock were compared in a within‐subject design while the temporal pattern of responding during conditioned stimuli was recorded. Responding during the conditioned stimulus preceding foot shock was characterized by initial suppression of responding at tone onset, followed by increased responding just before response‐independent shock. Responding was suppressed throughout the conditioned stimulus preceding tail shock. Foot shock elicited bursts of responding, but tail shock did not.
STIMULUS‐REINFORCER CONTINGENCIES AND LOCAL BEHAVIORAL CONTRAST1
Authors: Schwartz Barry
Published: March 2006

Four pigeons were exposed to a series of multiple schedules of variable‐interval reinforcement in which pecks were required on one key (operant key) and components were signalled on a second key (signal key). Four additional pigeons experienced identical conditions, except that a yoking procedure delivered food on variable‐time schedules, with no key pecks required. One of the components of the multiple schedule was constant throughout the experiment as a variable‐interval (or variable‐time) 30‐second schedule. Operant‐key responding during the constant component was uniform throughout the component, uninfluenced by changes in the duration of the variable component, and only slightly influenced by changes in reinforcement frequency correlated with the variable component. By comparison, signal‐key response rate during the constant component was highest at the onset of the component, was higher when the variable component was 60‐sec long than when it was 1‐sec long, and was higher when no reinforcement occurred in the variable component than when reinforcement was scheduled in the variable component. These characteristics of signal‐key pecking matched characteristics of local positive behavioral contrast. These data are taken to support the “additivity theory” of behavioral contrast and to suggest that Pavlovian stimulus‐reinforcer relations contribute primarily to the phenomenon of local positive contrast.
EFFECTS OF A PAIRING CONTINGENCY ON BEHAVIOR IN A THREE‐PERSON PROGRAMMED ENVIRONMENT
Authors: Emurian Henry H. , Emurian Cleeve S. , Brady Joseph V.
Published: March 2006

Four groups of three subjects resided for 10 days within a continuously programmed environment. Subjects followed a behavioral program of contingently scheduled activities that determined individual and social behaviors. A triadic condition was in effect when all three subjects were required to select simultaneous access to a group area before it became available for a social episode. A dyadic condition was in effect when access to a group area was permitted to any combination of two, and only two, subjects. The effects of these two conditions on individual and social behaviors were studied in reversal designs with several successive days devoted to each condition. Results showed that durations of social activities and synchronization of individual activities were greater during triadic conditions than during dyadic conditions. Under both conditions, wake‐sleep cycles departed from a typical day‐night rhythm for most subjects. Instances when subjects did not respond to each others' attempts to initiate conversations using the intercom were generally more frequent during dyadic than triadic conditions. Physical distance during triadic social episodes was found to be related to sociability levels during dyadic conditions.