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1.
Two groups of dogs were compared on the ability of an aversive Pavlovian CS to evoke a negatively reinforced instrumental response. For one group, the instrumental training was avoidance; for the other, escape. When presented alone, the CS evoked the instrumental response only from the avoidance group. Failure of the CS to evoke the response from the escape group poses difficulties for theories which characterize the initiation of avoidance responses as “escapes” from CS. 相似文献
2.
Information was sought on how the strength of fear, acquired and extinguished in a classical conditioning paradigm, might be affected by certain of the circumstances that normally are associated with the course of avoidance learning. Following preconditioning exposures to the conditioned stimulus, one group of rats (Group PRF) was given continuous conditioned stimulus-unconditioned stimulus (CS-US) acquisition trials followed by stepwise reductions in US probability (given the CS) over three phases to about 11% for the final phase. Another group, Group US(lo), was given continuous CS-US pairings throughout, but, following acquisition, received stepwise reductions in US intensity (to permit evaluation of a progressively changing feature of the US over a wide range without having to employ excessive shock) over the same phases. A third group, Group US(hi), received unchanging (from acquisition) CS-US pairings over these phases, and an explicitly unpaired control group (Group RU) was included. Although outcomes differed somewhat depending upon whether suppression ratios or absolute measures of responding were considered, the major findings were that suppression to the CS was complete by the end of acquisition and persisted thereafter throughout the three phases for all but control subjects. In contrast to Group US(lo), which showed relatively little resistance to extinction of suppression to subsequent CS-only exposures, Groups US(hi) and PRF displayed marked resistance over two separate, extended sets of extinction sessions. Suppression to context cues was pronounced only for Groups US(hi) and RU, and varied as a function of US parameters and not whether the shocks were or were not signaled. Theoretical reconciliation of these findings was most difficult for Groun PRF. 相似文献
3.
Resistance to extinction of discriminated barpress avoidance in rats was assessed through the use of three procedures, each of which served to break the response-reinforcement contingency, classical extinction (CE), operant extinction (OE), and a variable-ratio shock schedule (VR). Greatest resistance to extinction was found for the VR group, followed by OE and then by CE Ss. thus supporting a discriminative rather than a motivational analysis. Reacquisition rates following extinction suggested evidence of “learned helplessness” in some Ss exposed to noncontingent CS-US presentations. 相似文献
4.
A recent study found that avoidance extinction is equally facilitated by response prevention (blocking) whether the latter involves CS-alone or CS-shock presentations. An experiment was performed to determine whether this result was due to the use of a lengthy shock (5 sec) during response prevention. Five groups of rats were extinguished: (1) without prior blocking, (2) after blocking with CS only, (3) after blocking with a lengthy (5 sec) CS-contingent shock, (4) after blocking with a brief (.5 sec) CS-contingent shock, or (5) after blocking with a brief (.5 sec) shock only. The group blocked with the brief CS-contingent shock was substantially more resistant to extinction than the other four groups. The unblocked group and the group blocked with brief shock only required more trials to extinguish than the groups blocked with CS only or with lengthy CS-contingent shock, but did not differ from each other. The groups blocked with CS only or with lengthy CS-contingent shock also failed to differ from one another. The data support a significant role for Pavlovian conditioning processes in the effect of response prevention upon avoidance extinction. 相似文献
5.
Nigel W. Bond 《Learning & behavior》1984,12(3):323-331
Rats of the Australian High Avoider (AHA) and Australian Low Avoider (ALA) strains and their reciprocal crosses were exposed to 50 trials of one of three shuttlebox procedures. The avoidance group received pairings of a tone and shock. If the animals shuttled during the tone, they avoided the shock. If they waited until the shock came on, they could then escape it. The classical group received pairings of the tone and a brief inescapable shock. If they shuttled during the tone, the tone ceased and they immediately received the shock. If they did not shuttle, they received the brief shock at the termination of the tone. The pseudoconditioning group received the tone and the shock explicitly unpaired. If they shuttled during either the tone or the shock, the stimulus was terminated. There was no acquisition of anticipatory responding under the pseudoconditioning procedure. All groups evidenced an increase in anticipatory responding over trials under the classical procedure. The AHAs acquired the response faster and reached a higher asymptote than did the ALAs. Performance of the two reciprocal crosses fell in between. A similar pattern was observed under the avoidance procedure, albeit at slightly higher response levels. Subsequent studies established that the AHAs acquired a one-way avoidance response quickly, but were impaired on a passive avoidance task, whereas the reverse was the case for the ALAs. The reciprocal crosses were proficient at both tasks. These results suggest that shuttlebox avoidance is largely accounted for by classical conditioning of the predominant defensive response. When that response is compatible with performance on the task, acquisition is rapid (AHAs), and when it is not, acquisition is slow (ALAs). 相似文献
6.
Dale Swartzentruber 《Learning & behavior》1995,23(2):123-143
Pavlovian conditioning has traditionally been thought to involve the acquisition of excitatory and inhibitory associations between a conditioned stimulus (CS) and an unconditioned stimulus (US). Recent research, however, has encouraged the view that Pavlovian learning may also encompass a higher order modulatory mechanism, in which animals use information about another stimulus to control responding to the CS. Positive modulators signal a positive relationship between the CS and the US, whereas negative modulators signal that the CS-US relationship is not in force. In both cases, the modulatory control appears to be orthogonal to the modulator’s direct associations with the US. This article reviews and evaluates the literature on this Pavlovian modulatory mechanism. 相似文献
7.
Peter C. Holland 《Learning & behavior》1979,7(4):424-432
The form of rats’ Pavlovian conditioned responses to visual and auditory conditioned stimuli (CSs) paired with a variety of unconditioned stimuli (USs) was examined in three experiments using direct behavioral observation techniques. In Experiment 1, the form of conditioned behavior occurring most frequently during later portions of the CS-US interval depended only on which of several appetitive USs was used, but the form of behavior occurring most frequently during early portions of the CS-US interval depended only on the nature of the CS. US-dependent behaviors resembled the response to the US, and CS-dependent behaviors resembled the original orienting response (OR) to the CS. In Experiment 2, the use of larger magnitude appetitive USs resulted in higher frequencies of US-dependent behaviors, but lower frequencies of CS-dependent behaviors in the presence of auditory and visual CSs. In Experiment 3, US-dependent conditioned behavior to auditory and visual CSs paired with shock was more frequent when high-intensity shocks were used, but CS-dependent behavior was more frequent when low-intensity shocks were used. These results suggested that Pavlovian conditioned responding may involve two independent types of behavior—one appropriate to the US and another based on the original OR to the CS. 相似文献
8.
Prior research has demonstrated renewal, which is the ability of contextual cues to modulate excitatory responding to a Pavlovian conditioned stimulus (CS). In the present research, conditioned lick suppression in rats was used to examine similar contextual modulation of Pavlovian conditioned inhibition. After Pavlovian conditioned inhibition training with a CS in one context, subjects were exposed to pairings of the CS with an unconditioned stimulus (US) either in the same or in a second context. Results indicated that, when the CS was paired with the US in the second context, the CS retained its inhibitory control over behavior, provided that testing occurred in the context used for inhibition training. However, when the CS-US pairings occurred in the inhibition training context, the CS subsequently proved to be excitatory regardless of where testing occurred. These observations indicate that conditioned inhibition is subject to renewal. 相似文献
9.
In Experiment 1, two groups of pigeons were autoshaped to a green keylight CS and then administered either CS only or truly random control (TRC) response-elimination procedures with the green keylight CS. The groups ceased responding at comparable rates. In a subsequent reacquisition test with a vertical-line key stimulus, the group administered CS only during response elimination reacquired the keypecking CR more rapidly. The two groups were then administered the alternative response-elimination treatment with the vertical-line CS. Again, the groups ceased responding at comparable rates. In a subsequent reacquisition test with a red keylight CS, the group administered CS only during the immediately preceding response-elimination phase reacquired the keypecking CR more rapidly. In Experiment 2, following initial acquisition, the CS-only and TRC response-elimination treatments were administered under the context-change and no-context change conditions. The TRC/context-change and CS-only/context-change groups ceased responding more rapidly than either the TRC/ no-context-change or CS-only/no-context-change groups. In subsequent reacquisition to a novel CS, the CS-only/no-context-change group reacquired the fastest, the TRC/no-context-change group reacquired the slowest, and the CS-only/context-change and TRC/context-change groups reacquired at similar intermediate rates. Implications of these results for the context-blocking hypothesis are discussed. 相似文献
10.
Four experiments test the hypothesis that escape learning in response to shock will transfer to a similar food-reinforced response and affect resistance to appetitive extinction. In the first two experiments, subjects were given escape training in a straight alley followed by continuous food reinforcement and then extinction. Prior escape training resulted in greater resistance to extinction of the food-reinforced response as compared to several control procedures. In the third experiment, the escape response was manipulated to be compatible or incompatible with the subsequent food-reinforced response. Greater resistance to extinction was shown when the two responses were compatible. The fourth experiment confirmed and extended this finding. The relationship of the present results to Amsel’s theory of persistence was discussed. 相似文献
11.
Animals given electroconvulsive shock (ECS) following active avoidance training were found to exhibit poor retention of the active avoidance response. However, this deficit was alleviated if the animals received an extinction trial for active avoidance prior to retention testing. That the trial was an extinction trial was demonstrated by the fact that exposure to the trial decremented the performance of animals not given ECS after learning. The implications of these findings for explanations of retrograde amnesia are discussed. 相似文献
12.
Random presentations of keylights and food retarded acquisition and suppressed asymptotic rates of keypecking in autoshaping. Sequences of 10 sessions of random training alternated with 10 sessions of autoshaping resulted in poor performance (in terms of both the acquisition and asymptotic indices) relative to a group that received sequences of CS-only (rather than random) training alternating with autoshaping. When the birds that previously were trained with the random sequence were exposed to CS-alone extinction, retardation of acquisition was alleviated but the asymptotic suppression was not (Experiment 1). Pigeons with a history of autoshaping without prior random training showed no asymptotic suppression when exposed to the random procedure. These birds, when switched between two-session sequences of random training alternating with two-session sequences of autoshaping, were able to (1) surpass pigeons that received CS-only rather than random treatment in terms of asymptotic levels of responding in autoshaping, and (2) showed improvement in extinction performance with repeated random/autoshaping sequences (Experiment 2). Detailed observations of pigeons in random training showed that stereotypic activity behaviors were acquired, and these generally persisted in autoshaping; the degree of change in these behaviors was related to asymptotic rates of keypecking in autoshaping (Experiment 3). The same kinds of behaviors were observed when pigeons initially were autoshaped, and these persisted in subsequent random and fixed-interval 10-sec training. We suggest that the suppression effect is reflected in activity, conditioned in random training, which persists in autoshaping (especially if the activity is compatible with the kinds of behaviors elicited by the autoshaping contingency itself), and that the effect may be a deficit due to performance factors rather than to associative learning. 相似文献
13.
Following barpress training with different terminal fixed ratios (FR), rats were given the interpolated experiences of runway acquisition and extinction (as part of another experiment) followed by 2 months of vacation. Then they were tested in FR 10 barpress reacquisition, FR 10 barpress extinction, consistently reinforced runway reacquisition, and a second runway extinction. In a start (response initiation) measure, resistance to extinction during the FR 10 extinction and in the second runway extinction was positively related to the terminal FR values of the initial barpress training, an indication of highly durable differential persistence effects attributable to the initial training to different terminal fixed ratios of barpress responding. 相似文献
14.
“Comparator” accounts of associative conditioning (e.g., Gibbon & Balsam, 1981; Miller & Matzel, 1988) suggest that performance to a Pavlovian CS is determined, by a comparison of the US expectancy of the CS with the US expectancy of general background cues. Recent research indicates that variation in the excitatory value of cues in the local temporal context of a CS may have a profound impact on conditioned responding to the CS (e.g., Kaplan & Hearst, 1982), implicating US expectancy based on local, rather than overall, background cues as the critical comparator term for a CS. In two experiments, an excitatory training context attenuated responding to a target CS. In Experiment 1, the context was made excitatory by interspersing unsignaled USs with target CS-US trials. In this case, posttraining extinction of the conditioning context restored responding to the target CS. In Experiment 2, the target CS’s local context was made excitatory by the placement of excitatory “cover” stimuli in the immediate temporal proximity of each target CS-US trial. In this experiment, posttraining extinction of the proximal cover stimuli, not extinction of the conditioning context alone, restored responding to the target CS. An observation from both experiments was that signaling the otherwise unsignaled USs did not appear to influence the associative value of the conditioning context. The results are discussed in relation to a local context version of the comparator hypothesis and serve to emphasize the importance of local context cues in the modulation of acquired behavior. Taken together with other recent reports (e.g., Cooper, Aronson, Balsam, & Gibbon, 1990; Schachtman & Reilly, 1987), the present observations encourage contemporary comparator theories to reevaluate which aspects of the conditioning situation comprise the CS’s comparator term. 相似文献
15.
Dennis J. Delprato 《Learning & behavior》1974,2(1):59-62
Delayed termination of the warning signal following extinction responses has been shown to facilitate extinction of discriminative avoidance. In order to determine the relative roles in extinction of delayed termination per se and postresponse exposure to the warning signal, which is necessarily confounded with delayed termination treatment, seven groups of rats were first trained on a one-way avoidance task in which a buzzer served as part of the warning-signal complex. Then, on nonshock extinction trials, the buzzer (a) terminated immediately with a response and was not reinstated in the postresponse interval, (b) terminated immediately with a response and was reinstated for a 5- or 10-sec period 5 or 15 sec following the response, or (c) terminated 5 or 10 sec following a response (delayed termination). Results indicated that exposure to the buzzer at postresponse intervals greater than 5 sec following responses was critically involved in reducing resistance to extinction. This finding supports a conditioned relief interpretation of the delayed warning signal termination effect and is consistent with the effect of response prevention techniques on extinction. 相似文献
16.
The present experiment used a transfer-of-training procedure in rabbit nictitating membrane response (NMR) conditioning to determine whether a retention interval and/or extinction could reduce associative strength. The experimental design required that groups receive 0, 3, 15, 45, 150, or 240 CS-US pairings in Stage 1. Next, the groups were given, in succession, a 10-day retention interval and 480 CS-alone trials. In Stage 2, all groups obtained 240 CS-US pairings for NMR conditioning. Another group was also employed and received only the 240 CS-US pairings in Stage 2. The results indicated that 15 to 240 CS-US pairings in Stage 1 substantially enhanced NM CR performance in Stage 2 despite the interpolation of the retention interval and CS-alone trials. When 3 CS-US pairings had been given in Stage 1, no augmentation in the NM CR performance rate occurred in Stage 2. However, the 3 CS-US pairings were effective in prohibiting the 480 CS-alone trials from retarding subsequent NM CR performance. Without any pairings in Stage 1, the 480 CS-alone trials produced strong latent inhibition of NMR conditioning in Stage 2. The data were used to support the theoretical view that associative strength resulting from CS-US pairings is relatively permanent. Moreover, the findings were relevant for an evaluation of Pearce and Hall’s (1980) recent statements concerning CS associability and the relationship between excitatory and inhibitory processes. 相似文献
17.
James F. Brennan 《Learning & behavior》1975,3(4):277-281
Following 300 training trials in two-way shuttle avoidance signaled by a tone (CS+), two groups each of weanling and adult rats were given Pavlovian discrimination training in which the CS+ was followed by inescapable shock, and a more intense tone (CS—) signaled no shock. An additional group at each age level received both tones paired randomly with shock or no shock. Subsequent generalization tests along the frequency dimension indicated that both pups and adults tested at the CS+ intensity showed similar gradients of frequency control. Gradients for the adults tested at the CS — intensity tended to be inverted, with least responding at CS—, a result not found in the young subjects. The results were considered in light of Pavlovian extradimensional influences on the control of avoidance behavior. 相似文献
18.
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
19.
Gerbils and rats learned equally well to discriminate the lighted, safe arm from the unsafe arm during Y-maze avoidance trials. Gerbils, however, were inferior to rats in initiating this response in time to avoid shock. Two subsequent experiments on passive avoidance did not support the interpretation of these data based on a greater incidence of shock-induced activity suppression in gerbils. In both experiments, gerbils required more shocks than rats to learn a staying response, indicating a pronounced locomotor response bias in gerbils that is not compatible with the required passive avoidance response. A fourth experiment, using a shuttlebox, found that the relative active avoidance performance by these species depends upon whether intertriai responses are permitted and punished. When they are, gerbils are inferior to rats, since their high level of locomotor responding is not compatible with the behavior required, i.e., staying during the intertrial interval and running during the CS-US interval. On the other hand, gerbils are not inferior when intertrial responses are prohibited, since their locomotor bias is not punished and is compatible with the required avoidance response. 相似文献
20.
Three experiments examine transfer from appetitive Pavlovian conditioning to appetitive instrumental responding by varying the similarity between conditions of Pavlovian reinforcement and instrumental reward. After conditioning with rats confined in a restraining device, a CS for electrical stimulation of the brain (ESB) produced substantial facilitation of operant responding for ESB, while a CS for food facilitated operant responding for food. However, no effects on rate of responding for food were seen during a CS for ESB. In a fourth experiment, four groups of rats were trained to barpress for rewarding electrical stimulation of the brain (ESB) and then given discriminative Pavlovian conditioning with ESB. The groups differed in the degree of similarity between the stimulus-response sequences present during Pavlovian conditioning and those occurring in instrumental responding. As similarity increased, so did the degree of conditioned facilitation in subsequent transfer tests. These results indicate that conditioned incentive responses or reinforcer-derived expectancies are specific to the conditions under which they develop, rather than generalized emotional or motivational responses. 相似文献