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1.
Pigeons were trained on a multiple schedule in which separate concurrent schedules were presented in the two components of the schedule. During one component, concurrent variable-interval 40-sec variableinterval 80-sec schedules operated. In the second component, concurrent variable-interval 40-sec variableinterval 20-sec schedules operated. After stable baseline performance was obtained in both components, extinction probe choice tests were presented to assess preference between the variable-interval 40-sec schedules from the two components. The variable-interval 40-sec schedule paired with the variableinterval 80-sec schedule was preferred over the variable-interval 40-sec schedule paired with the variableinterval 20-sec schedule. The subjects were also exposed to several resistance-to-change manipulations: (1) prefeeding prior to the experimental session, (2) a free-food schedule added to timeout periods separating components, and (3) extinction. The results indicated that preference and resistance to change do not necessarily covary. 相似文献
2.
Four pigeons were exposed to several nonindependent concurrent variable-interval schedules of reinforcement. One schedule component required a keypecking response; the other component required a treadlepressing response. The birds matched the ratio of their behavior (as measured by responses and time) between the two topographically different responses to the ratio of reinforcement in those two components. When additional foods not contingent on a keypeck or treadle-press were then added, the birds matched time spent in the components to total rates of food delivered in those components; response matching was somewhat disrupted. The matching law, developed under concurrent variable-interval schedules requiring similar responses, can thus account for choice behavior involving topographically different responses. 相似文献
3.
Guy Woodruff 《Learning & behavior》1979,7(3):339-346
Groups of pigeons were exposed to multiple variable-interval variable-interval and multiple variable-interval extinction schedules of either food or water reinforcement for keypecking. Discriminative stimuli associated with component schedules were located either on the operant key or on a second “signal” key. When the stimuli were projected on the operant key, positive contrast appeared during discrimination conditions with either food or water as the reinforcer. When the stimuli were projected on the signal key, overall responding to the operant and signal keys showed contrast with food, but negative induction with water as the reinforcer. In the latter condition, the signal for the variable-interval shcedule of water reinforcement elicited a variety of water-related behavior, only some of which was directed at the signal. Thus, the type of reward and location of discriminative stimuli interacted to determine the presence or absence of behavioral contrast effects. In large part, these results support and extend the autoshaping view of contrast. 相似文献
4.
Sated rats, previously trained to leverpress for H2O reinforcement on continuous or variable-interval (10-sec or 60-sec) schedules, were given NaCl injections and tested for leverpressing. Under all schedules, responding was an inverted U function of NaCl concentration (0.15M to 3.0M). However, NaCl thirst produced relatively little change in behavior under the VI 60-sec schedule. 相似文献
5.
Eight White King pigeons were exposed to various two-component arrangements of concurrently available variable-interval reinforcement schedules. Line orientation stimuli associated with each component differed by 45,15, or 0 deg for different subjects. Relative responding matched relative reinforcement with 45 deg separation, while undermatching resulted with 15 deg separation and extreme undermatching resulted with 0 deg separation. Since obtained relative reinforcement indicated contact with the contingencies in all conditions of line orientation disparity, it is concluded that stimulus disparity between components of concurrently available reinforcement schedules is an important determinant of response distribution between components. 相似文献
6.
James D. Dougan Valeri A. Farmer-Dougan Frances K. McSweeney 《Learning & behavior》1989,17(2):247-255
The effects of reinforcement rate on behavioral contrast were examined in pigeons and rats. Each species was exposed to a series of 12 multiple variable-interval schedules, divided into four 3-schedule series. Each series consisted of a standard contrast manipulation, and baseline schedules provided a different rate of reinforcement in each of the series. The functions relating reinforcement rate to the magnitude of contrast were different across species. Rats showed a U-shaped function, with reliable contrast occurring only at high reinforcement rates. Pigeons showed an inverted U-shaped function, with contrast occurring on all schedules except the schedule providing the lowest rate of reinforcement. Pigeons discriminated between schedule components better than rats did, although differences in discrimination were probably not responsible for the differences in contrast. The results suggest that behavioral contrast in rats may be a different phenomenon from behavioral contrast in pigeons. The results cannot be explained by current theories, which view contrast as the product of a single general process. 相似文献
7.
Six rats were placed on concurrent variable-interval variable-interval schedules with a 15-sec changeover delay (COD). The variable-interval schedules were varied such that the COD comprised between 25% and 100% of the average interreinforcement interval of the more favorable alternative. The obtained reinforcement rate and the rate of changing from one schedule to the other were compared to predictions of Houston and McNamara’s (1981) optimality model of concurrent choice. The pattern of behavioral allocation was consistent with the predictions of the model, although none of the animals was able to achieve optimal performance on any of the presented schedules. Observed behavior reliably tracked optimal behavior in that the ratio of obtained reinforcers to the optimum predicted by Houston and McNamara did not vary as the underlying schedule parameters was changed. 相似文献
8.
Frances K. McSweeney 《Learning & behavior》1978,6(4):444-450
Four pigeons pecked keys and pressed treadles for food reinforcers delivered by several variable-interval schedules of reinforcement. Then the subjects responded on several concurrent schedules. Keypecking produced reinforcers in one component, and treadle-pressing produced reinforcers in the other. The changeover delay, which prevented reinforcement after all switches from one response to the other, was 0, 5, or 20 sec long. An equation proposed by Kerrnstein (1970) described the rates of treadle-pressing and keypecking emitted during the variable-interval schedules. The k parameter of this equation was larger for keypecking than for treadle-pressing. The R0 parameters were not systematically different for the two responses. The rates of keypecking and treadle-pressing emitted during the components of the concurrent schedules correlated with, but were not equal to, the rates of responding predicted by Herrnstein’s equation and the subject’s simple schedule responding. The ratios of the rates of responding emitted during, and the ratios of the time spent responding on, the components of the concurrent schedules conformed to an equation proposed by Baum (1974), but not to Herrnstein’s equation. 相似文献
9.
Ralph W. Richards 《Learning & behavior》1978,6(3):286-289
Pigeons were trained on a multiple variable-interval 5-min variable-interval 5-min schedule and then shifted to either a multiple variable-interval 1-min variable-interval 5-min or a multiple variable-interval 30-sec variable-interval 5-min schedule. A generalization test was subsequently administered along the dimension containing the stimulus associated with the variable-interval 5-min component. The generalization gradients for subjects that received multiple variable-interval 1-min variable-interval 5-min training were not consistent in shape. However, an incremental gradient was obtained from each subject that received multiple variable-interval 30-sec variable-interval 5-min training. Thus, a sufficiently large reduction in merely the relative frequency of reinforcement during a stimulus resulted in that stimulus’ acquiring inhibitory control over responding. 相似文献
10.
Eight pigeons chose between pairs of different sizes and delays of reinforcement scheduled according to nonindependent concurrent variable-interval variable-interval schedules. The results were best described by the generalized matching law, where the relative effects of amount and delay on preference are independent and multiplicative. Order of presentation of the conditions had a significant effect on preference that was best represented in the model by a modification of the bias parameter. 相似文献
11.
Pamela G. Real 《Learning & behavior》1983,11(2):255-265
Pigeons responded to concurrent variable-interval variable-interval schedules of food reinforcement. Interchangeover times and reinforcements were recorded in intact time series during acquisition following several schedule-density manipulations. Probability of a changeover, while constant as a function of time since the previous changeover, was found to be a nonmonotonically increasing function of time since reinforcement. Autocorrelation analyses of intact time series revealed the presence of statistically significant sequential dependencies in the time series during acquisition, but not during asymptotic performance. Lag transformations of actual interchangeover times revealed inhomogeneities in the time series not shown in the autocorrelations or in the overall distribution of interchangeover times. 相似文献
12.
Animals exposed to schedules of partial reinforcement are typically more resistant to extinction than are animals trained with continuous reinforcement. This is the partial reinforcement effect (PRE). Animals experienced with both partial and continuous schedules are often more persistent on the continuous schedule, yielding a reversed PRE. Both conventional and reversed PREs have been elusive with classical conditioning paradigms. The present experiment attempted to demonstrate between- and within-subject PREs using 50% and 100% autoshaping schedules. Presence or absence of a PRE depended on the behavioral measures used. Marked terminal group differences in acquisition produced a between-subjects PRE with absolute response levels but not with rate-of-change measures. Within subjects, only choice trial comparisons were sensitive enough to differentiate the two schedules. Acquisition data were inconsistent with most of the classical conditioning PRE literature, but consistent with results reported in the autoshaping literature. These discrepancies may reflect the operant-classical interaction in autoshaping. 相似文献
13.
Four pigeons pecked for food reinforcement on variable interval 1-min schedules and on the variable-interval 1-min components of multiple, concurrent, and pseudoconcurrent schedules. The pseudoconcurrent schedule provided only one schedule of reinforcement; but, any reinforcer could be collected by responding on either of two keys. The rate of responding generated by the variable interval schedule was not greater than the rates of responding generated by the components of the complex schedules. But, the rate of reinforcement obtained from the variable interval schedule was greater than the rates of reinforcement obtained from the components of the multiple schedule. These results may contradict the equation proposed by Herrnstein (1970). The equation predicts that the rate of responding generated by a schedule of reinforcement will be greater when the schedule appears alone, than when it appears as one component of a complex schedule. 相似文献
14.
Terry W. Belke 《Learning & behavior》1992,20(4):401-406
Four pigeons were exposed to multiple schedules with concurrent variable interval (VI) components and then tested for preference transfer. Half of the pigeons were trained on a multiple concurrent VI 20-sec, VI 40-sec/cuncurrent VI 4G-sec5 VI 80-sec schedule. The remaining pigeons were trained on a multiple concurrent VI 80-sec, VI 40-sec/concurrent VI 40-sec, VI 20-sec schedule-After stability criteria for time and response proportions were simultaneously met, four preference transfer tests were conducted with the stimuli associated with the VI 40-sec schedules. During the transfer tests, each pigeon allocated a greater proportion of responses (M=0,79) and time (M=0.82) to the stimulus associated with the VI 40-sec schedule that was paired with the VI 80-sec schedule than lo the VI 40-sec schedule stimulus paired with the VI 20-sec schedule. Absolute reinforcement rates on the two VI 40 sec schedules were approximately equal and unlikely to account for the observed preference. Nor was the preference consistent with the differences in local reinforcement rates associated with the two stimuli. Instead, the results were interpreted in terms of the differential value that stimuli acquire as a function of previous pairings with alternative schedules of reinforcement. 相似文献
15.
Pigeons’ choice responding on 10-sec interpolated probes was studied after baseline training on multiple variable-interval variable-interval schedules of food reinforcement. Unreinforced choice following training with three different relative reinforcement rates (Experiment 1), with a 3-ply multiple schedule (Experiment 2), and with three different relative reinforcement durations (Experiment 3) was examined. Least squares lines were fit to choice relative response rate and schedule relative response rate as functions of training relative reinforcement rate; choice slope was significantly greater than schedule slope in all three experiments. This result is counter to the prediction of Herrnstein’s (1970) theory that these slopes should not differ. Luce’s (1959) theory also failed to account for the data. It was concluded that choice responding was controlled by both approach to the stimulus associated with the smaller mean interreinforcer interval or the longer duration, and avoidance of the other stimulus. 相似文献
16.
Pigeons’ responses on an operant key were reinforced according to either multiple variable-interval variable-interval or multiple variable-interval extinction schedules. The multiple-schedule components were signaled by line-tilt stimuli on a second key (signal key). Signal-key responses never produced reinforcement, and operant-key responses were not reinforced if they followed within 1 sec of a signal-key response. Behavioral contrast was not observed on the operant key, although there was a small, but reliable, increase in signal-key responding in the variable-interval component of the multiple variable-interval extinction condition. Generalization tests were interspersed between sessions of multiple variable-interval extinction training. Generalization gradients along the line-tilt dimension exhibited peak shift for both operant-key and signal-key responding following intradimensional (line tilt) discrimination training. Line-tilt generalization gradients following interdimensional discrimination did not exhibit peak shift. Gradients following intradimensional discrimination were sharper than gradients following interdimensional discrimination for both operant-key and signal-key responding. It was concluded that dimensional stimulus control of topographically tagged responding maintained by the stimulusreinforcer relation parallels that maintained by the response-reinforcer relation. 相似文献
17.
James Allison 《Learning & behavior》1980,8(2):185-192
The conservation model was generalized to the variable-interval schedule by incorporating the concept of unscheduled instrumental responses, those which occur in the time before the next setup is due. Thirsty rats responded in constant-duration sessions on two 7-sec schedules that required one leverpress for 25 and 50 licks at a water tube and on a 14-sec 25-lick schedule. In accordance with the model, total licks decreased linearly as total presses increased, and the schedules facilitated leverpressing and suppressed licking relative to paired baseline levels of responding. While the matching model also gave a satisfactory fit to instrumental responding under the schedules, its two constants, representing asymptotic rate of responding and extraneous reinforcement, had anomalous values which led the model to predict that response rate would decrease as the rate of reinforcement increased, directly opposing its prediction for the constant-consumption experiments of its previous tests. 相似文献
18.
Stanley J. Weiss 《Learning & behavior》1977,5(4):421-429
Multiple schedules established stimulus-reinforcer (S-SR) associations on baselines in which equal response rates and patterning were maintained in all components. Subsequently, stimuli associated with an increase in reinforcement but no change in ongoing response rate were compounded. For one experimental group, free-operant avoidance (FOA) was programmed in tone and in light while variable-interval (VI) food reinforcement was effective in their simultaneous absence (T + L). The opposite stimulus-schedule combinations were programmed for the other. Both groups remained in their VI components 85% of the session on schedule preference tests, and on a stimulus compounding test emitted approximately 1.5 times as many responses to tone-plus-light (T + L) as to tone or light alone. This is the first report of additive summation to combined discriminative stimuli associated with only an increase in reinforcement. Nondifferentially trained controls who had the same contingency effective in tone, light, and T + L-VI or FOA—showed neither preference among schedule components or summation during stimulus compounding, indicating that nonassociative stimulus factors made no contribution to either resultant in the experimental animals. Evidence supporting an algebraic combination of response and reinforcement associations is presented, and functional similarities between transfer-of-control studies and the stimulus compounding tests of the experimental groups in the present experiment are discussed. 相似文献
19.
Pigeons’ preference between fixed-interval and variable-interval schedules was examined using a concurrent-chains procedure. Responses to two concurrently available keys in the initial links of the concurrent chains occasionally produced terminal links where further responses were reinforced under either a fixed- or variable-interval schedule. In previous studies, preferences for the variable schedule with such a procedure have been interpreted as reflecting atemporal scaling process that heavily weights the shorter intervals in the variable schedule. The present experiment examined whetherpredictability, i.e., the presence of external stimuli correlated with the reinforcement interval, might also influence preference in such situations. When the two intervals in a variable schedule were made predictable by being associated with different key colors, preference for that schedule increased. This increase was reliable but small in magnitude and transient when initial-link responses only occasionally produced terminal links; it was large in magnitude when only one response in the initial link was required to produce the appropriate terminal-link schedule. The results suggest that preference between fixed and variable schedules may be influenced both by temporal scaling and to a lesser extent by predictability of the reinforcement intervals. 相似文献
20.
Frans van Haaren 《Learning & behavior》1981,9(3):425-431
The effects of changeover delays of fixed or variable duration on concurrent variable-interval performance in pigeons were investigated in a series of three experiments. Experiment 1 compared the effects of a fixed, variable, or variable signaled changeover delay on interchangeover times and responding during and after the changeover delay. The duration of the changeover delays was systematically varied in Experiment 2, and the relative reinforcement frequencies were manipulated in Experiment 3. Interchangeover times were found to be shorter when changeover delays of variable duration were compared with those of fixed duration. Changeover delays of fixed duration produced higher response rates during the changeover delay than after the changeover delay had elapsed; changeover delays of variable duration produced such differences to a lesser extent. It was concluded that the changeover delay in concurrent variable-interval schedules of reinforcement functionally acts as a delay period to the next opportunity for reinforcement, possibly serving as a conditioned reinforcer for the behavior preceding it (the interchangeover time) and as a discriminative stimulus for the behavior in its presence (response rates during the delay). 相似文献