摘要:

Undergraduate students' presses on left and right buttons occasionally made available points exchangeable for money. Blue lights over the buttons were correlated with multiple random‐ratio random‐interval components; usually, the random‐ratio schedule was assigned to the left button and the random‐interval to the right. During interruptions on the multiple schedule, students filled out sentence‐completion guess sheets (e.g.,The way to earn points with the left button is to…). For different groups, guesses were shaped with differential points also worth money (e.g., successive approximations to “press fast” for the left button), or were instructed (e.g.,Write “press slowly” for the left button), or were simply collected. Control of rate of pressing by guesses was examined in individual cases by reversing shaped or instructed guesses, by instructing pressing rates, and/or by reversing multiple‐schedule contingencies. Shaped guesses produced guess‐consistent pressing even when guessed rates opposed those characteristic of the contingencies (e.g., slow random‐ratio and fast random‐interval rates), whereas guesses and rates of pressing rarely corresponded after unsuccessful shaping of guesses or when guessing had no differential consequences. Instructed guesses and pressing were inconsistently related. In other words, when verbal responses were shaped (contingency‐governed), they controlled nonverbal responding. When they were instructed (rule‐governed), their control of nonverbal responding was inconsistent: the verbal behavior sometimes controlled, sometimes was controlled by, and sometimes was indepe

ISSN:0022-5002    

DOI:10.1901/jeab.1982.38-233

出版商:Blackwell Publishing Ltd    

年代:1982

数据来源: WILEY

摘要:

Pigeons were exposed to stimuli correlated with the presence or absence of a variable‐interval 60‐second schedule of reinforcement only while they depressed a crossbar or “perch.” In the first experiment, the stimuli were different tilts of a line displayed on the key. When the difference in brightness between the line and the background (salience) was maximal, seven of eight birds acquired the discrimination, but when the difference was reduced by 50%, only one succeeded. In the second experiment, wavelength of chamber illumination served as the relevant dimension. Neither experiment showed a large effect attributable to the magnitude of the difference (disparity) between the positive and the negative stimulus. Individual differences in time spent observing were positively correlated with level of discrimination in the presence of the stimuli. All birds produced the positive stimulus for a greater proportion of the available time than they did the negative stimulus. This may be the mechanism that provides selective reinforcement of observing. Finally, the formation of a discrimination was analyzed in terms of changes in the proportion of time spent in contact with the discriminative

ISSN:0022-5002    

DOI:10.1901/jeab.1982.38-249

出版商:Blackwell Publishing Ltd    

年代:1982

数据来源: WILEY

摘要:

Pigeons acquired a conditional discrimination in an autoshaping procedure in which certain stimulus combinations (form plus color) were followed by food, whereas others were not followed by food. Although the discrimination normally was acquired quickly, it was completely prevented when the color elements of the stimulus compounds were presented during the intertrial intervals preceding the trials in which both stimulus elements were available. This failure of discrimination was then prevented by having the colors serve as houselights rather than being localized on the response key and by pretraining procedures in which the colors were utilized in simpler discriminations. The results suggest that stimulus salience plays a critical role in determining whether conditional discriminations will be acquired, as the effects of all of the different operations could be understood in terms of increasing or decreasing the salience of the color elements, above or below some threshold value.

ISSN:0022-5002    

DOI:10.1901/jeab.1982.38-265

出版商:Blackwell Publishing Ltd    

年代:1982

数据来源: WILEY

摘要:

The results of a number of recent studies suggest that acquisition of autoshaped key pecking in pigeons is affected by the similarity of the grain‐hopper stimulus and response‐key stimulus. In Experiment 1 this hypothesis was tested by training independent groups of pigeons to key peck under six different hopper‐stimulus and key‐stimulus similarity conditions, and three procedures containing either immediate reinforcement, variable delay of reinforcement, or omission of reinforcement for key pecking. Number of trials to acquisition was found to be related to the similarity variable. Maintained responding was affected by the response‐reinforcer contingency. This effect was found both within and between subjects. Under two of the contingencies (automaintenance and omission), maintained responding continued to be affected by the similarity of the hopper stimulus and key stimulus. In Experiment 2 pigeons were given omission training with a hopper light on or off. Both acquisition and maintenance of key pecking were facilitated by the presence of the hopper light. The present findings suggest that much of the responding reported in various automatic shaping and training procedures may reflect the effects of key stimulus/food stimulus s

ISSN:0022-5002    

DOI:10.1901/jeab.1982.38-281

出版商:Blackwell Publishing Ltd    

年代:1982

数据来源: WILEY

摘要:

In a series of three experiments, groups of food‐deprived and water‐deprived rats were given pairings of a retractable lever (CS+) with response‐independent deliveries of either solid or liquid reinforcers. In Experiment 1 food‐deprived rats given a solid‐pellet reinforcer differentially tended to sniff, paw, mouth, and bite the CS+lever more often than a lever that was not paired with food (CS−), whereas food‐deprived rats given a liquid reinforcer tended to differentially sniff, paw, and lick the CS+lever. 23½‐hour water‐deprived rats given liquid reinforcers showed very little CS+contact. In Experiment 2 increasing the severity of water deprivation from 23½ to 47½ hours significantly increased CS+contact. In Experiment 3, subjects that were simultaneously food and water deprived and given a water reinforcer failed to exhibit differential CS+contact, but subjects that were simultaneously food and water deprived and given a food reinforcer did acquire differential CS+‐contact behavior. These results suggest that (a) even under a single motivational state the nature of signal‐centered behavior can be determined by type of reinforcer, (b) although water reinforcement produces less signal contact than food reinforcement, this can be facilitated with more severe water‐deprivation levels, and (c) high CS‐contact rates using food reinforcement are not simply a product of reductions in body

ISSN:0022-5002    

DOI:10.1901/jeab.1982.38-291

出版商:Blackwell Publishing Ltd    

年代:1982

数据来源: WILEY

摘要:

In a discrete‐trial symbolic matching‐to‐sample procedure, pigeons' left‐key responses were reinforced following presentation of one center‐key sample, and right‐key responses were reinforced following presentation of another. Recallability was measured by the difference between log ratios of left to right responses following each sample. In Experiment 1, samples were successively presented same or different wavelengths in the relational discrimination, or individual wavelengths in the single discrimination. The rate at which recallability decreased with increasing delay since sample presentation was the same for single and relational discriminations, but the initial level of performance differed, indicating that the relational discrimination was more difficult. In Experiment 2, recall functions for easy and difficult discriminations between individual wavelengths also differed in levels of initial performance but not in rate of decrement of recallability over time. Recall for stimuli differing in complexity may therefore reflect differences in discrimination

ISSN:0022-5002    

DOI:10.1901/jeab.1982.38-305

出版商:Blackwell Publishing Ltd    

年代:1982

数据来源: WILEY

摘要:

Relative reinforcer duration was varied in concurrent schedules with a fixed‐ratio four changeover requirement. The schedule in effect after each reinforcer was randomly chosen. For all three pigeons, relative response rates overmatched relative reinforcer durations. Time allocation was less extreme and, on the average, matched relative reinforcer duration. In a subsequent manipulation, the level of preference was shown to depend on the size of the changeover requirement. These results are similar to those from related unequal reinforcement‐frequency procedu

ISSN:0022-5002    

DOI:10.1901/jeab.1982.38-313

出版商:Blackwell Publishing Ltd    

年代:1982

数据来源: WILEY

摘要:

The relative immediacy of reinforcement in concurrent‐chain schedules was varied while the relative reduction in the overall average time to reinforcement associated with terminal‐link entry was held constant. For each of four pigeons, choice did not vary with relative immediacy of reinforcement. Subsequently, choice by the same subjects was shown to be sensitive to relative reduction in average time to reinforcem

ISSN:0022-5002    

DOI:10.1901/jeab.1982.38-321

出版商:Blackwell Publishing Ltd    

年代:1982

数据来源: WILEY

摘要:

Although concurrent schedules may arrange reinforcers irregularly, relatively large numbers of reinforcers are obtained when an animal changes from one schedule to the other. This paper proposes a quantitative relation that predicts the proportion of reinforcers obtained when an animal is working on a schedule and the proportion when the animal changes over to a schedule. Basically the relation states that the number of reinforcers obtained while an animal works on a schedule varies directly with the relative amount of time spent working on that schedule; and the number of reinforcers obtained when an animal changes to a schedule varies directly with the relative amount of time spent on the alternate schedule. An important aspect of this relation is that when relative reinforcement rates are less than .50, more reinforcers are obtained just after an animal changes to a schedule than at all other times when this schedule is engaged. Data obtained both from a stat‐bird and a live pigeon were in close agreement with the quantitative predictions. The relation between changing over and reinforcement held across several procedural changes that included changes in relative reinforcement rate, changes from independent to interdependent scheduling procedures, and changes in the variable‐interval reinforcement distributions. The results are discussed in terms of the effects of the local distribution of reinforcement on responding. The local reinforcement distribution can affect local response rates and affects the resulting matching relation. This arrangement has implications for explanations of cho

ISSN:0022-5002    

DOI:10.1901/jeab.1982.38-327

出版商:Blackwell Publishing Ltd    

年代:1982

数据来源: WILEY

摘要:

Data from recent studies employing concurrent variable‐interval schedules are reviewed. Subject species employed in different experiments have included rats, pigeons, and humans, and reinforcers have varied from food and shock avoidance to points exchangeable for money. Undermatching (a greater preference for the schedule of the concurrent pair that delivers the lower rate of reinforcement than the Matching Law predicts) has been preponderant in recent studies, irrespective of whether behavior has been measured in terms of response ratios or time allocation, with the possible exception of data produced by human subjects. Little difference in the degree of undermatching exhibited by response and time measures has been found, except in the results from a single laboratory, in which time‐allocation measures have tended to undermatch less than response measures. Procedural features, such as type of manipulandum used and changeover delay, seem to have little effect on the degree of undermatching exhibited, but asymmetrical response manipulanda (such as lever and key) for the different concurrent schedules, or other asymmetries in the experimental situation, show up clearly in bias measures, in a manner consistent with previous analy

ISSN:0022-5002    

DOI:10.1901/jeab.1982.38-339

出版商:Blackwell Publishing Ltd    

年代:1982

数据来源: WILEY