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1.
In this investigation, which employed rats in a runway, discriminative responding consisted of faster running on the reinforced than on the nonreinforced trials of either the 4NR or R4N schedule, both schedules containing fixed, repeated sequences of nonreinforced and reinforced trials. Under the 4NR schedule, four nonreinforced trials preceded a reinforced trial each day, and under the R4N schedule, a reinforced trial was followed by four nonreinforced trials each day. The major finding obtained was that under the 4NR schedule, discriminative responding was improved very substantially by a shift to extinction. Rats maintained on the 4NR schedule did not show improved discriminative responding, nor did discriminative responding improve in extinction following training under either the R4N schedule or a schedule of consistent reinforcement. Latent discrimination learning was defined as discriminative responding which fails to reflect adequately the amount of discrimination learning accomplished. The present findings demonstrate latent discrimination learning for regular schedules of partial reinforcement, something already demonstrated for brightness differential conditioning and possibly DRL schedules, as well.  相似文献   

2.
Four groups of 10 rats each were given six acquisition trials (Phase 1) under continuous reinforcement (CR), partial reinforcement (PR), constant delay (CD), or partial delay of reinforcement (PD) conditions. In Phase 2, all Ss were given 18 nonreinforced trials, followed by 12 continuously reinforced trials in Phase 3. In Phase 4, all Ss were given 12 more extinction trials. A constant 24-h ITI was observed throughout the experiment. A strong partial reinforcement extinction effect (PREE) was obtained in both Phases 2 and 4. Only a temporary partial delay of reinforcement effect (PDRE) was observed, which was restricted to the first nine trials of the first extinction phase. No constant delay of reinforcement effect (CDRE) was observed in either extinction phase. The results were discussed in terms of both frustration and sequential theories.  相似文献   

3.
Three experiments investigated the effects of magnitude and schedule of reinforcement and level of training in instrumental escape learning at a 24-h intertriai interval. In Experiment I, two magnitudes of reinforcement were factorially combined with two schedules of reinforcement (CRF and PRF). Under PRF, large reward produced greater resistance to extinction than did small reward, while the reverse was true under CRF. In Experiment II, two levels of acquisition training were factorially combined with three schedules of reinforcement (CRF, single-alternation, and nonalternated PRF). Patterned running was observed late in acquisition in the single-alternation extended-training condition. Resistance to extinction was greater for the nonalternated PRF condition than for the single-alternation condition following extended acquisition, and the reverse was true following limited acquisition. Experiment III confirmed the extinction findings of Experiment II. The results of all three experiments supported an analysis of escape learning at spaced trials in terms of Capaldi’s (1967) sequential theory.  相似文献   

4.
In two differential conditioning experiments, groups of 10 rats each differed with respect to average reward and schedule of reward received in S+. Nonreward (N) occurred on all S? trials. In both experiments, extinction of responding to S? (resistance to discrimination) was extensively regulated by reward sequence and was largely independent of average reward. In Experiment 1, resistance to discrimination was a function of transitions from N to rewarded (R) trials (N-R transitions). In Experiment 2, resistance to discrimination was increased by large reward on the R trial of N-R transitions and decreased by large reward on the R trial of R-N transitions. These schedule effects on resistance to discrimination parallel the effects of comparable schedules on resistance to extinction following partial reinforcement. The results are discussed in terms of sequential theory, reinforcement level theory, and their implications for various schedule manipulations that have previously shown S? behavior to be inversely related to average reward in S+.  相似文献   

5.
The acquisition and extinction of locomotor responses of rats in a straight alley were examined for groups trained under escape, partial-avoidance, and avoidance procedures. During acquisition, one group (escape) received a 0-sec delay between being dropped into the alley and the onset of shock; two groups (partial avoidance) had 0.5- and 1-sec delays; and two groups (avoidance) had delays of 2 and 4 sec. On the final day of acquisition, the partial-avoidance rats displayed higher running speeds than either the escape- or avoidance-trained animals. The 4-sec avoidance group was consistently slower than all other groups. Speeds for all groups decreased during extinction, with rate of decline showing some relation to terminal acquisition level. Relative group performance levels proved to be consistent with a simple arithmetic model based on the assumption that changes in running speeds affect the aversiveness of the situation by altering US duration, CS duration, and effective US length.  相似文献   

6.
Learning & Behavior - Four fish were trained under several values of a differential reinforcement of low rates schedule. Overall rate of responding decreased as the delay period increased....  相似文献   

7.
When extinction is delayed very long, the superior resistance to extinction of the random schedule group relative to the alternating schedule group disappears (partial reinforcement delayed extinction effect, PRDE). Two experiments assessed the effects of reinforcement/nonreinforcement on Trial 1 on the PRDE. Following extended partial reinforcement acquisition training in a runway, rats received extinction training after a short (1-day) or long (23-day) retention interval. The schedules used in Experiment 1 were: a single-alternation (SA) schedule beginning each day with a rewarded (r) trial, for Group r-SA; an SA schedule beginning with a nonrewarded (n) trial, for Group n-SA; and a random (Rd) schedule, for Group Rd. The schedules and group names used in Experiment 2 were r-SA, Rd, and r-Rd. The results were that (1) rats given r-SA schedules yielded considerable resistance under delayed extinction, (2) those given Rd and r-Rd schedules showed a decline in resistance to extinction over a long retention interval, (3) those given the n-SA schedule showed relatively low resistance at both retention intervals, although retention deficit was not greater than in the case of the Rd schedule, and thus, (4) the PRDE was found in both experiments, although only weakly in Experiment 1. The results indicated that a regularly alternating reward pattern was a more important determinant than was type of reward on Trial 1 for the PRDE. The PRDE due to differential retention deficits among schedules is discussed on the basis of dual-process associative sequential mechanisms and cognitive rule-encoding mechanisms.  相似文献   

8.
A series of experiments used food-deprived pigeons to examine several parameters of reinforcement omission in an attempt to control changes of keypeck response measures on a subsequent schedule. In Experiments 1 and 2, the pigeons were tested with a multiple fixed-ratio schedule on which reinforcement was occasionally omitted at the completion of the first component. The duration of the delay occurring in lieu of reinforcement was systematically varied. In Experiment 3, the stimulus that signaled the second component of the schedule was altered to appear either more or less similar to the stimulus that signaled the first component. Two principal results are reported: (1) Response latency decreased and, to a much lesser extent, terminal response rate increased as the delay occurring in lieu of reinforcement decreased; and (2) both latency decrease and response-rate increase were enhanced by a second component stimulus which was similar to the first. The results are evaluated in terms of Amsel’s frustration theory and an analysis by Staddon which suggests that reinforcement inhibits responding. The data appear to support Staddon’s argument that rate increases and latency decreases following reinforcement omission are largely a function of an attenuation of the inhibitory influence of reinforcement, an effect that is enhanced by stimulus generalization. Accordingly, it is proposed that an animal’s response to reinforcement omission is determined by a stimulus complex that minimally includes the omission event and component cues.  相似文献   

9.
The signaling function of the second-order CS (S2) was manipulated in second-order autoshaping by arranging a partial reinforcement schedule. S2 was paired with a well-conditioned first-order CS (SI) on a continuous reinforcement or a 25% reinforcement schedule in different groups. Schedule of reinforcement did not influence the number of S2-S1 pairings required to establish keypecking to S2. However, in the postacquisition sessions, responding to S2 was initially weaker but persisted for many more sessions on the 25% schedule than on the 100% schedule. The data indicate that S2-S1 pairings are responsible both for the acquisition of second-order keypecking to S2 and for the subsequent conversion of S2 into an inhibitory stimulus.  相似文献   

10.
A hurdle-jump escape response was employed to assess the laboratory rat’s aversion or attraction to different types of conspecific odor. Odorant donor subjects received 112 runway acquisition trials on a continuous reward schedule followed by 32 extinction trials, 112 acquisition trials on a 50% schedule of reward and nonreward followed by 32 extinction trials, or 144 “neutral” trials with no reward in the alley. Different groups of test subjects escaped from odor excreted by odorant subjects on (a) nonrewarded acquisition and extinction trials, (b) rewarded trials during continuous reinforcement, (c) rewarded trials during partial reinforcement, or (d) neutral trials; others escaped from a clean box. The principal findings were: (1) significant aversion to “odor of nonreward” appeared after the donor odorants had received 12 exposures to reward; (2) production of odor of nonreward by odorant subjects changed as a function of training experience with reward; (3) after repeated exposure to odor of nonreward, the escape response habituated; (4) greater or different odor excretion in extinction resulted from subjects trained on a continuous reward schedule than on a partial reward schedule. Relationships of the data to frustration theory were discussed, assuming that inferred differences in production of odor reflect differences in frustration reaction.  相似文献   

11.
Rats increased eating that produced access to a running-wheel or increased running that produced access to food, depending on which response was potentially deprived, relative to baseline, by the scheduled ratio of responding. Under both schedules, instrumental responding significantly exceeded appropriate baselines of the noncontingent effects of the schedule. The results contradicted the hypothesis that reinforcement is produced by an overall or momentary probability differential between two responses; instead, they supported the condition of response deprivation as a key determinant of reinforcement. Of several recent quantitative models that predict reversibility of reinforcement by schedule changes, only the predictions of the relative response-deprivation model did not differ significantly from the data of either schedule.  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.
Twenty acquisition curves were obtained from each of 8 pigeons in a free-operant choice procedure. Every condition began with a phase in which two response keys had equal probabilities of reinforcement, and, as a result, subjects’ responses were divided fairly evenly between the two keys. This was followed by a phase in which one key had a higher probability of reinforcement than the other, and the development of preference was observed. In all but a few cases, response proportions increased for the key with the higher probability of reinforcement. In most conditions, the two probabilities differed by .06, but the actual probabilities varied (from .16 and .10 in one condition to .07 and .01 in another). Development of preference for the key with the higher probability of reinforcement was slower when the ratio of the two reinforcement probabilities was small (.16/.10) than when it was large (.07/.01). This finding is inconsistent with the predictions of several different quantitative models of acquisition, including the kinetic model (Myerson & Miezin, 1980) and the ratio-invariance model (Horner & Staddon, 1987). However, the finding is consistent with a hypothesis based on Weber’s law, which states that the two alternatives are more discriminable when the ratio of their reinforcement probabilities is larger, and, as a result, the acquisition of preference is faster.  相似文献   

14.
Blocking was investigated in a free-operant procedure by presenting a response-contingent signal prior to reinforcer delivery. At issue was the way in which blocking effects previously reported with this procedure are related to conditioned reinforcement effects, also previously found with similar procedures. Signal presentation decreased response rate when delay of reinforcement was 0 or .5 sec, but the signal increased response rate when the delay of reinforcement was increased to 3 sec. Thus, which effect (blocking or conditioned reinforcement) occurred depended critically on the response-reinforcer interval.  相似文献   

15.
In the first experiment, a prolonged period of intermittent, unsignaled shocks preceded appetitive runway acquisition, under either continuous (CRF) or partial reinforcement (PRF) and extinction. In the second experiment, the shock treatment came between CRF or PRF acquisition and extinction; and in the third experiment, the shocks intervened between appetitive CRF acquisition and shock-punishment extinction. The main finding was that compared with an unshocked control, shock facilitated acquisition in Experiment 1, and led to increased resistance to extinction and/or punishment in all experiments. In Experiment 1, the shock effect in appetitive extinction was seen mainly in the CRF group; in Experiment 2, the effect was to increase persistence in both the CRF and PRF groups; and in Experiment 3, shock treatment produced stronger resistance to punished extinction. The discussion is in terms of habituation and a general theory of persistence, and the concept of helplessness.  相似文献   

16.
The study reexamines the effect of delayed reinforcement upon contingency behavior in 6- to 8-month-old infants and attempts to account for the temporal discrepancy between span of integration and contingency memory. A modified delayed-reinforcement scheduling procedure enabled a previous methodological criticism to be discounted. The findings confirmed that whereas infants revealed reliable acquisition under immediate reinforcement, a 3-sec delay (whether reset or nonreset) precluded response acquisition, as did 6-sec and 10-sec delay of reinforcement. The findings are interpreted in terms of an informational-load hypothesis which relates short-term memory to the integration and/or segregation of multimodal input.  相似文献   

17.
The effects of different schedule requirements at reinforcement on patterns of responding by pigeons were assessed under conjunctive schedules with comparable response-number requirements, Under one conjunctive schedule (conjunctive fixed-interval fixed-ratio schedule), a response was reinforced after a 6-min interval had elapsedand a specific minimum number of responses had been emitted, Under a second conjunctive schedule, a response was reinforced after the 6-min fixed interval and upon completion of a tandem schedule requirement (conjunctive fixed-interval tandem schedule), This schedule retained the same required minimum number of responses as the first conjunctive schedule, but responses were never reinforced according to a fixed-ratio schedule; the tandem schedule was comprised of a fixed-ratio and a small (.1 to 10.0 sec) fixed-interval schedule, Under the conjunctive fixed-interval fixed-ratio schedule, responding was characterized by an initial pause, an abrupt transition to a high response rate, and a second transition to a lower rate that prevailed or slightly increased up to reinforcement, Under the conjunctive fixed-interval tandem schedule, pauses were extended, response rates were lower, and the initial high rate of responding was generally absent, The above effects depended upon the size of the fixed interval of the tandem schedule, The distinct pattern of responding generated by conjunctive fixed-interval fixed-ratio schedules depends upon occasional reinforcement of fixed-ratio responding and not merely on the addition of a minimum number of required responses.  相似文献   

18.
In these experiments, each rat received two different series of three runs each. The lone group in Experiment 1 received the series 10-0-10 and 10-0-0, where, for example, 10-0-10 means that the rat received three discrete runs (in a runway) that terminated in 10, 0, and 10 pellets, respectively. In Experiment 2, the series were 20-0-0 and 0-0-20 for one group and 20-0-20 and 0-0-0 for another. Of primary concern in both experiments was the rat’s anticipation, as measured by running speed, of 0 pellets on the middle, or second, run of each series. In each experiment, running speed to this 0-pellet event was independent of reinforcement magnitude on the first run of each series and was greater, the greater the reinforcement magnitude on the third run of each series. These results indicate that on the second run of each series the rat was anticipating not merely the 0 pellets associated with that run (intraevent anticipation), but also the reinforcement magnitude associated with the future, third run of each series (interevent anticipation). These results are shown to be consistent with an S-S cognitive view of anticipation and inconsistent with an S-R serial-chaining view of serial learning.  相似文献   

19.
In two experiments, two groups of rats were trained in a navigation task according to either a continuous or a partial schedule of reinforcement. In Experiment 1, animals that were given continuous reinforcement extinguished the spatial response of approaching the goal location more readily than animals given partial reinforcement—a partial reinforcement extinction effect. In Experiment 2, after partially or continuously reinforced training, animals were trained in a new task that made use of the same reinforcer according to a continuous reinforcement schedule. Animals initially given partial reinforcement performed better in the novel task than did rats initially given continuous reinforcement. These results replicate, in the spatial domain, well-known partial reinforcement phenomena typically observed in the context of Pavlovian and instrumental conditioning, suggesting that similar principles govern spatial and associative learning. The results reported support the notion that salience modulation processes play a key role in determining partial reinforcement effects.  相似文献   

20.
The acquisition, maintenance, and extinction of autoshaped responding in pigeons were studied under partial and continuous reinforcement. Five values of probability of reinforcement, ranging from .1 to 1.0, were combined factorially with five values of intertrial interval ranging from 15 to 250 sec for different groups. The number of trials required before autoshaped responding emerged varied inversely with the duration of the intertriai interval and probability of reinforcment, but partial reinforcement did not increase the number of reinforcers before acquisition. During maintained training, partial reinforcement increased the overall rate of responding. A temporal gradient of accelerated responding over the trial duration emerged during maintenance training for partial reinforcement groups, and was evident for all groups in extinction. Partial reinforcement groups responded more than continuous reinforcement groups over an equivalent number of trials in extinction. However, this partial-reinforcment extinction effect disappeared when examined in terms of the omission of “expected” reinforcers.  相似文献   

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