摘要:

Twenty‐six infants, 3 to 23 months old, were trained on fixed‐interval schedules ranging from 10 s to 80 s. The operant response was touching an illuminated location on a touch‐sensitive screen, and 20 s of cartoon presentation was the reinforcer. The subjects were also trained in a six‐phase self‐control procedure in which the critical phases involved choice between 20 s of cartoon available after a 0.5‐s delay (impulsive choice) and 40 s of cartoon delayed for 40 s (self‐controlled choice). All the youngest children (3 to 5 months) showed long postreinforcement pauses on the fixed‐interval schedule, with most intervals involving the emission of a single, reinforced, response, and all made self‐controlled choices. Older subjects (9 to 23 months) either produced the same pattern as the younger ones on the fixed‐interval schedule (classified as pause‐sensitive subjects) or produced short pauses and higher steady response rates (classified as pause‐insensitive subjects). All pause‐sensitive subjects made self‐controlled choices in the self‐control condition, and all pause‐insensiti

ISSN:0022-5002    

DOI:10.1901/jeab.1993.60-239

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

Four experiments examined the relationship between rate of reinforcement and resistance to change in rats' and pigeons' responses under simple and multiple schedules of reinforcement. In Experiment 1, 28 rats responded under either simple fixed‐ratio, variable‐ratio, fixed‐interval, or variable‐interval schedules; in Experiment 2, 3 pigeons responded under simple fixed‐ratio schedules. Under each schedule, rate of reinforcement varied across four successive conditions. In Experiment 3, 14 rats responded under either a multiple fixed‐ratio schedule or a multiple fixed‐interval schedule, each with two components that differed in rate of reinforcement. In Experiment 4, 7 pigeons responded under either a multiple fixed‐ratio or a multiple fixed‐interval schedule, each with three components that also differed in rate of reinforcement. Under each condition of each experiment, resistance to change was studied by measuring schedule‐controlled performance under conditions with prefeeding, response‐independent food during the schedule or during timeouts that separated components of the multiple schedules, and by measuring behavior under extinction. There were no consistent differences between rats and pigeons. There was no direct relationship between rates of reinforcement and resistance to change when rates of reinforcement varied across successive conditions in the simple schedules. By comparison, in the multiple schedules there was a direct relationship between rates of reinforcement and resistance to change during most tests of resistance to change. The major exception was delivering response‐independent food during the schedule; this disrupted responding, but there was no direct relationship between rates of reinforcement and resistance to change in simple‐ or multiple‐schedule contexts. The data suggest that rate of reinforcement determines resistance to change in multiple schedules, but that this relationship does not

ISSN:0022-5002    

DOI:10.1901/jeab.1993.60-255

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

On fixed‐interval or response‐initiated delay schedules of reinforcement, the average pause following food presentation is proportional to the interfood interval. Moreover, when a number of intervals of different durations occur in a programmed cyclic series, postreinforcement pauses track the changes in interval value. What controls the duration of postreinforcement pauses under these conditions? Staddon, Wynne, and Higa (1991), in their linear waiting model, propose control by the preceding interfood interval. Another possibility is that delay to reinforcement, signaled by a key peck and/or stimulus change, determines the subsequent pause. The experiments reported here examined the role of these two possible time markers by studying the performance of pigeons under a chained cyclic fixed‐interval procedure. The data support the linear waiting model, but suggest that more than the immediately preceding interfood interval plays a role in temporal co

ISSN:0022-5002    

DOI:10.1901/jeab.1993.60-293

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

Six experiments were performed to explore the necessary and sufficient conditions for producing context specificity of discriminative operant performance in pigeons. In Experiment 1, pigeons learned a successive discrimination (red S+/blue S–) in two chambers that had a particular odor present and between which they were frequently switched. The birds subsequently learned the reversal (blue S+/red S–) in one of these chambers with a different odor present. When switched to the alternative chamber, although the odor and the reinforcement contingency were still appropriate to the reversal, performance appropriate to the original discrimination recurred in subjects for which the houselights were on during training and testing but not for those for which the houselights were off. This indicated the importance of visual contextual cues in producing context specificity. Experiment 2 showed that the frequent switching between boxes in initial training was of no consequence, presumably because the apparatus cues were highly salient to the subjects. Experiment 3 showed significantly less context specificity when odor cues were omitted. Experiment 4 showed that simply using a different reinforced stimulus in each phase of training was ineffective in producing context specificity. Experiment 5 showed that the generalization test procedure used in Experiment 4 was sensitive to context specificity when discrimination‐reversal training was used with different odors in the two training phases. Experiment 6 replicated the results of Experiment 4, but then showed that when different odors accompanied the two training phases, context specificity was obtained with the single‐stimulus paradigm. Thus in both single‐stimulus and discrimination‐reversal paradigms, redundant odor cues potentiated learning about app

ISSN:0022-5002    

DOI:10.1901/jeab.1993.60-313

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

Pigeons pecked keys for food reinforcers delivered by multiple variable‐interval 2‐min variable‐interval 2‐min schedules. Positive behavioral contrast was created by changing one component to extinction; negative contrast was achieved by changing one component to a variable‐interval 15‐s schedule. The duration of each component was varied independently of the other from 5 to 960 s. The size of positive contrast was greatest when the extinction component was 30 or 60 s long. It did not change significantly with changes in the duration of the variable‐interval 2‐min component. The absolute size of negative contrast decreased with increases in the duration of the variable‐interval 2‐min component. It did not change significantly with changes in the duration of the variable‐interval 15‐s component. These results show that the size of contrast is determined primarily by the duration of the component that provides the less favorable conditions of reinforcement. These results are not predic

ISSN:0022-5002    

DOI:10.1901/jeab.1993.60-331

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

The ability of stimuli correlated with successive periods in a fixed interfood interval to support a response that produced or removed them was examined using pigeons. The degree to which those correlated stimuli elicited directed key pecks was also obtained. Stimuli early in the interval functioned as negative reinforcers, and stimuli late in the interval functioned as positive reinforcers. Stimuli correlated with successively later portions of the second half of the interval supported successively higher rates of elicited pecking and, with the exception of the final stimulus, supported successively higher rates of stimulus production. Stimuli in successively earlier portions of the first half of the interval supported successively higher rates of correlated‐stimulus removal. This effect occurred in spite of the addition of a conjoint variable‐interval dependency for food. An ogive fit to the mean normalized response distributions resulted inr2s demonstrating that most of the variance in the temporal organization of the behavior was accounted for. The findings were taken to indicate that fixed interfood intervals establish bipolar cont

ISSN:0022-5002    

DOI:10.1901/jeab.1993.60-345

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

Peak deviation analysis is a quantitative technique for characterizing interresponse‐time distributions that result from training on differential‐reinforcement‐of‐low‐rate schedules of reinforcement. It compares each rat's obtained interresponse‐time distribution to the corresponding negative exponential distribution that would have occurred if the rat had emitted the same number of responses randomly in time, at the same rate. The comparison of the obtained distributions with corresponding negative exponential distributions provides the basis for computing three standardized metrics (burst ratio, peak location, and peak area) that quantitatively characterize the profile of the obtained interresponse‐time distributions. In Experiment 1 peak deviation analysis quantitatively described the difference between the interresponse‐time distributions of rats trained on variable‐interval 300‐s and differential‐reinforcement‐of‐low‐rate 72‐s schedules of reinforcement. In Experiment 2 peak deviation analysis differentiated between the effects of the psychomotor stimulantd‐amphetamine, the anxiolytic compound chlordiazepoxide, and the antidepressant desipramine. The results suggest that peak deviation analysis of interresponse‐time distributions may provide a useful behavioral assay system for ch

ISSN:0022-5002    

DOI:10.1901/jeab.1993.60-361

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

The present study compared the performance of 6 pigeons trained to detect luminance differences in two different signal‐detection procedures. Exposed to a three‐key array, the pigeons were trained to peck the left key when the brighter of two light intensities had been presented on the center key and to peck the right key when the dimmer of two light intensities had been presented on the center key. Procedure A was a standard signal‐detection procedure in which left/bright and right/dim responses produced food reinforcement and left/dim and right/bright responses produced periods of timeout. Procedure B was designed to simulate some of the contingencies operating in a prey‐detection situation. Left‐key responses produced reinforcement following the brighter center‐key stimulus and a period of timeout following the dimmer center‐key stimulus. Right‐key responses always produced a short period of timeout irrespective of the stimulus. Within each procedure, the duration of timeout arranged for false alarms (left/dim responses) was varied between 3 s and 120 s. Measures of accuracy and response bias were compared between the two procedures. The timeout manipulation produced systematic, but relatively small, changes in these measures when right/dim responses (i.e., correct rejections) produced reinforcement (Procedure A). Arranging timeout for right/dim responses in Procedure B produced greater variability in accuracy and response bias than did arranging reinforcement, but this variability was not related to timeout duration. Overall, discrimination accuracy was considerably higher when right/dim responses produced timeout than when they resulted in reinforcement, and accuracy was accompanied by a large bias toward the response associated with reinforcement. These results are consistent with a recently proposed model of s

ISSN:0022-5002    

DOI:10.1901/jeab.1993.60-387

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

Eight pigeons were trained on concurrent variable‐interval variable‐interval schedules with a minimum interchangeover time programmed as a consequence of changeovers. In Experiment 1 the reinforcement schedules remained constant while the minimum interchangeover time varied from 0 to 200 s. Relative response rates and relative time deviated from relative reinforcement rates toward indifference with long minimum interchangeover times. In Experiment 2 different reinforcement ratios were scheduled in successive experimental conditions with the minimum interchangeover time constant at 0, 2, 10, or 120 s. The exponent of the generalized matching equation was close to 1.0 when the minimum interchangeover time was 0 s (the typical procedure for concurrent schedules without a changeover delay) and decreased as that duration was increased. The data support the momentary maximizing theory and contradict molar maximizing theories and the melioration the

ISSN:0022-5002    

DOI:10.1901/jeab.1993.60-415

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

ISSN:0022-5002    

DOI:10.1901/jeab.1993.60-437

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY