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1.
A series of experiments was performed to determine whether sign-tracking would occur in rats with intravenous (i.v.) cocaine
as the unconditioned stimulus. In Experiment 1, a retractable lever paired with food produced strong sign-tracking, but a
lever paired with one of three doses of i.v. cocaine did not elicit any approach or contact behavior. Experiment 2 demonstrated
that doses of cocaine that did not elicit sign-tracking would function as a positive reinforcer for a lever contact operant.
In Experiment 3, an artificialconsummatory response was added to make the cocaine reinforcement episode more behaviorally comparable to that occasioned by food. Although the
rats readily performed this response when it was required to receive cocaine infusions, they still did not contact a lever
that signaled the availability of these infusions. It appears that cocaine is different from other positive reinforcers (e.g.,
food, water, warmth, or intracranial stimulation) in that it will not produce sign-tracking in rats. 相似文献
2.
Two experiments were conducted to investigate functional similarities between “hunger CRs” of Konorski’s (1967) model of appetitive classical conditioning and sign-tracking behavior in rats. Konorski’s model predicts that hunger CRs will be facilitated (1) when a nonrein-forced stimulus similar to the reinforced CS is introduced, and (2) when some CS presentations are unexpectedly nonreinforced. In Experiment 1, hungry rats acquired a leverpress response to a retractable lever that was paired with response-independent food. Following this training, a second lever was introduced whose presentation was not followed by food. The effect of the presence of this second lever was to facilitate responding to the original lever. In Experiment 2, single-lever autoshaping training was followed by a shift from 100% pairing of the lever with food to only 50% of the lever presentations being followed by food. The introduction of partial reinforcement produced an immediate and durable increase in leverpressing. The findings of both experiments are consistent with predictions from Konorski’s model of classical conditioning if sign-tracking is considered as a “hunger CR.” 相似文献
3.
In four experiments, we examined how the spatiotemporal proximity to food of the two elements of a serial conditioned stimulus (CS) influenced the pattern of CS-directed versus food-site-directed behavior in rats. Experiment 1 showed that only temporal proximity affected responding when the serial CS consisted of two successive 4-sec presentations of either a spatially near or a spatially far lever (NN or FF). However, Experiment 2 showed that behavior depended markedly on whether rats received a near followed by a far lever (NF) or a far followed by a near lever (FN). Experiment 3 showed that the effects of Experiment 2 could be changed by increasing the duration of the second CS element, and Experiment 4 showed that these changes were not related to previous training. We concluded that behavior produced by the spatiotemporal qualities of the lever elements can be attributed to a mapping between the temporal qualities of the CS elements and an underlying sequence of search modes related to finding food. 相似文献
4.
SingleParamecium caudatum were conditioned by pairing ac-generated electric shock (US) with a vibratory stimulus (CS) produced by an auditory speaker. Naive paramecia subjected to shock reliably exhibited a backwards jerk and axial spinning similar to the avoiding reaction described by Jennings in 1904. Such responses did not occur initially to CS alone, but increasingly appeared during the CS period preceding shock pairing (delayed conditioning paradigm). Control subjects given the CS and UCS at the same intervals, but explicitly unpaired, did not show a sustained increase of responses to the CS alone. Short-term memory was demonstrated by subjects first conditioned and then presented CS alone during extinction. These subjects were readily reconditioned. Paramecia trained and stored for 24 h showed reliable memory savings as compared to stored control subjects. Other paramecia were differentially conditioned by training with two CSs. Following the recommendations of Rescorla (1967), a procedure was designed for truly random presentation of the CS and UCS as an additional control for pseudoconditioning. Single paramecia were conditioned with intervals between CSs randomly ranging from 8 to 32 sec. Control subjects received the same number of CSs and UCSs, which were administered independently and randomly during the same total session duration. Thus, CS and UCS were occasionally paired for control subjects. The responses to CS in the conditioned group were anticipatory conditional responses due to the pairing contingency and not wholly due to pseudoconditioning. 相似文献
5.
Second-order conditioning of social approach to a female conspecific in male Japanese quail was investigated in four experiments. Subjects that received paired first- and second-order trials acquired second-order conditioning in both Experiments 1 and 2. In contrast, subjects that received paired first-order but unpaired second-order trials, and subjects that received unpaired first-order but paired second-order trials, did not acquire second-order conditioning. In Experiment 3, subjects for whom the first-order conditioned stimulus was presented in extinction showed second-order conditioning comparable to that shown by subjects in a control group that did not receive the extinction procedure. In Experiment 4, subjects approached a second-order stimulus less when sexually satiated than when sexually deprived. These findings suggest that second-order sexual conditioning in quail is mediated by an association of the second-order stimulus with a representation of the unconditioned stimulus. 相似文献
6.
Anthony Dickinson 《Learning & behavior》1976,4(4):416-420
In Experiment 1, four groups of rats received conditioned suppression training in which a tone was reinforced with shock. If the tone had been previously paired with response-independent food, aversive conditioning was slightly facilitated by comparison to control groups preexposed either to the tone randomly associated with food or to the tone and food unpaired. However, by comparison to a control which was not preexposed to the tone, animals receiving prior pairings of the tone and food showed retarded aversive conditioning. Experiment 2 replicated the facilitation in aversive conditioning after the tone had been paired with food relative to the random control condition and demonstrated that this difference occurred even if the tone and background stimuli continued to be associated with response-independent food during aversive conditioning. This result suggests that pairing a stimulus with an appetitive reinforcer reduces the retardation of aversive conditioning produced by stimulus preexposure. 相似文献
7.
Suppression of operant responding during a conditioned stimulus (CS) was studied in two procedures. In both procedures, operant leverpressing was maintained by a variable-interval 1-min food-delivery schedule, and insertion of a second lever served as the CS. In the first procedure, autoshaping, food followed each CS presentation irrespective of a subject’s behavior during the CS. In the second procedure, omission training, contact with the CS canceled the delivery of food scheduled for the end of that CS. In the first experiment, subjects were exposed to omission training followed by autoshaping; these procedures were reversed in the second experiment. In each experiment, the omission contingency resulted in fewer CS contacts and less suppression of operant responding during the CS than did autoshaping. These differences were more notable in subjects receiving the sequence autoshaping→omission training (Experiment 2). Direct observations in Experiment 2 revealed that, for subjects that were contacting the CS frequently when the omission contingency was introduced, reductions in signal contacts were accompanied by redistributions of behavior. The form of these redistributions depended upon behavior allocation at the time the omission contingency was imposed. 相似文献
8.
The present research examined the temporal distribution of responding in a lick suppression paradigm. In Experiment 1, rats were trained with either a 30- or a 120-s conditioned stimulus (CS), which was followed either by a footshock (unconditioned
stimulus [US]) or nothing. Licking during the CS was suppressed only in the former condition. Suppression was more pronounced
early in the CS. In Experiment 2, rats were exposed to two 30-s or two 120-s CSs, with delivery of the shock being contingent on CS1 for half of the animals
and on CS2 for the other half. For both the paired and the unpaired conditions, suppression at the beginning of CS1 was observed
for all the groups. By discounting the possibility of generalization between CS1 and CS2, it appears that this initial suppression
was not a conditioned response to the CS, but an unconditioned one due to mere exposure to the shock US. 相似文献
9.
Three experiments demonstrated Pavlovian appetitive discrimination learning in the marine mollusc,Aplysia californica. In each experiment, subjects were exposed to two conditioned stimuli; one stimulus (CS+) was paired with food presentations and the other stimulus (CS?) was never followed by food. In Experiments 1 and 3 different chemosensory stimuli were used, and in Experiment 2 different tactile stimuli were used. For both types of conditioned stimuli, bite responses occurred significantly more often to the CS+ than to the CS?. Experiment 2 also showed thatAplysia could learn a reversal of this discrimination. Experiment 3 showed that nonreinforced presentations of CS+ resulted in a decline in the frequency of conditioned biting. The implications of these results for neurobiological analyses of learning are discussed. 相似文献
10.
John Karpicke 《Learning & behavior》1978,6(2):216-224
Three experiments evaluated an alternative to accounts of positive conditioned suppression that stress central (i.e., motivational or emotional) states. This “competing-response” interpretation was tested by analyzing directed movements that develop in rats during a visual or an auditory stimulus (CS) that signals an appetitive reinforcer (US) in a situation where the subject is also emitting an instrumental response for food. In each experiment, positive conditioned suppression (i.e., a reduction in the rate of such instrumental responding during CS presentations) was accompanied by responses directed toward the CS source and/or the US-delivery site. In Experiment 1, a diffuse (auditory) CS signaled a US delivered at some specific place in the chamber and rats approached the US-delivery site during CS. In Experiments 2 and 3, the spatial proximity of a localized visual CS and US-delivery site determined whether CS-directed or US-directed behavior predominated during the CS. The results suggest that the topographies of conditioned responses on any positive conditioned suppression procedure depend upon the spatial arrangements of features that elicit and support these behaviors. They further suggest that the identification of these features and their spatial arrangements is necessary for the analysis of appetitive classical-instrumental interactions. 相似文献
11.
Water-deprived adult rats were used in a conditioned-suppression-of-licking procedure to determine the effect of inhibitory training with a novel stimulus trained in simultaneous compound with a previously established conditioned inhibitor. This procedure constitutes an inhibitory analogue to the excitatory blocking procedure in classical conditioning. The conditioned-inhibition training consisted of either explicitly unpaired CS and US presentations or negative contingency training, in which the likelihood of the US was greater in the absence than in the presence of the CS, but the CS and the US were occasionally paired. To assess conditioned inhibition, a retardation test was used, and comparable retardation was obtained for subjects that were administered the blocking treatment and control subjects given similar conditioned-inhibition training with a compound stimulus in which the nontarget element was not previously established as a conditioned inhibitor. 相似文献
12.
In two experiments, the influence of exposure to a CS? on the acquisition and retention of a conditioned odor aversion was examined. Preweanling rats were given exposure to the CS? either prior to (CS?/CS+) or following (CS + /CS?) the pairing of a second odor (the CS+) with footshock. The results of Experiment 1 indicated that subjects in both of the treatment conditions acquired aversions of comparable strength to the odor paired with footshock and that retention of the odor aversion was not affected by order of stimulus presentation during conditioning. Experiment 2 indicated, however, that the effectiveness of pretest exposure to various elements of the conditioning episode in reactivation of the memory for conditioningwas dependent on the order of stimulus presentation during conditioning. This differential effectiveness of the various reactivation treatments is discussed in terms of their relationship to the associative “status” of the stimuli present during conditioning and in terms of the information provided to the animal by the reactivation treatment. 相似文献
13.
These studies demonstrated the acquisition and extinction of conditioned tolerance to the analgesic effect of nicotine in
rats. In Experiment 1, distinctive environmental cues were either paired or unpaired with nicotine. Following acquisition,
the paired group was more tolerant to nicotine than the unpaired and saline groups. Conditioned tolerance was extinguished
in the paired group after placebo sessions in the distinctive environment. Experiment 2 examined whether the distinctive environment
functioned as a CS or as an occasion setter for injection cues. After acquisition, exposure to the distinctive environment,
with or without placebo injections, resulted in extinction. This demonstrates that the distinctive environment served as a
CS, not as an occasion setter for injection cues. 相似文献
14.
Twenty-eight male albino rats were given a single 4-sec 1-mA electric-grid-shock unconditioned stimulus (US). In the same session they received two 12-sec conditioned stimuli (CSs). One CS (explicitly unpaired) terminated 180 sec before the US began; the other (backward paired) began immediately after the US terminated. The CSs used were a 1000-Hz 85-dB tone and an 84-dB click; their roles were counterbalanced. Over the next 2 days, each CS was presented for 2 min while the rats drank from a water bottle. The backward-paired CS was found to suppress licking more than the explicitly unpaired CS. This suppression was accompanied by an increase in defensive behavior (freezing and freeze/nod) and by a decrease in other activity. The suppression did not seem to be due to a maintained or enhanced CS-orienting response reflex, nor could it be attributed to an adventitiously reinforced interfering operant. The results support the presumption made in previous reports that the lick suppression evoked by a backward CS reflected one-trial backward excitatory fear conditioning. 相似文献
15.
Learning & Behavior - Four experiments with rat subjects assessed conditioned analgesia evoked by a discrete visual CS repeatedly paired with a shock US. In Experiment 1, rats that received... 相似文献
16.
Peter C. Holland 《Learning & behavior》2014,42(4):365-382
Initially neutral conditioned stimuli paired with food often acquire motivating properties, including serving as secondary reinforcers, enhancing instrumental responding in Pavlovian-instrumental transfer procedures, and potentiating food consumption under conditions of food satiation. Interestingly, cues associated with the cancellation of food and food cues may also potentiate food consumption (e.g., Galarce and Holland, 2009), despite their apparent negative correlations with food delivery. In three experiments with rats, we investigated conditions under which potentiation of feeding by such “interruption stimuIi” (ISs) develops, and some aspects of the content of that learning. Although in all three experiments ISs enhanced food consumption beyond control levels, they were found to act as conditioned inhibitors for anticipatory food cup entry (Experiment 1), to serve as conditioned punishers of instrumental responding (Experiment 2), and to suppress instrumental lever press responding in a Pavlovian instrumental transfer procedure (Experiment 3). Furthermore, when given concurrent choice between different foods, an IS enhanced consumption of the food whose interruption it had previously signaled, but when given a choice between performing two instrumental responses, the IS shifted rats’ choice away from the response that had previously yielded the food whose interruption had been signaled by IS (Experiment 3). Thus, the effects of an IS on appetitive responses were opposite to its effects on consummatory responding. Implications for our understanding of learned incentive motivation and the control of overeating are discussed. 相似文献
17.
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
18.
Two experiments attempted to establish vicious-circle behavior through fear motivation combined with secondary punishment. In Experiment 1, rats were trained with two CSs, a tone and a buzzer, paired with shock in different contexts. Secondary punishment based on delay and trace conditioning procedures facilitated running in fear-motivated rats, relative to four control groups. In Experiment 2, rats were given pairings of a tone CS with shock, and a buzzer CS with a drop into a water tank. Fear-motivated rats which received secondary punishment during either 33% or 100% of test trials exhibited self-punitive running relative to a nonpunished (0%) group and a backward-conditioning control group. Results indicate that “all secondary” vicious-circle behavior can be established through Pavlovian conditioning, thus supporting a conditioned fear interpretation. 相似文献
19.
The ability of visual CSs previously paired with flavored substances to substitute for those substances as conditional discriminative cues was examined in two Pavlovian appetitive conditioning experiments using rat subjects. In Experiment 1, a visual stimulus was first paired with the delivery of a sucrose solution. Then the rats were trained in conditional discrimination tasks in which sucrose delivery alone served as a conditional cue signaling whether or not a subsequent tone would be reinforced with food pellets. Subjects rapidly acquired discriminative performance to the tones, especially in a feature-negative condition in which sucrose delivery signaled when the tone would not be reinforced. In a subsequent test in which neither food nor sucrose was delivered, presentation of the visual CS also controlled discriminative performance to subsequently presented tones. Experiment 2 showed the ability of a visual CS to substitute for a flavored substance as a conditional cue to be highly stimulus specific. Experiment 2 also showed that a flavored substance was less effective as a conditional cue when it was made to be expected by preceding it with a previously associated visual signal than when it was made to be surprising by preceding it with a visual stimulus signaling another flavored liquid. These results indicate that CS-evoked representations of events can substitute for those events themselves in the control of previously established conditional discrimination performance. 相似文献
20.
Little responding develops to a conditioned stimulus (CS) that is placed in a random relation to an unconditioned stimulus (US). However, if the USs not preceded by that CS are themselves signaled by another stimulus, then the CS does come to elicit responding. This result has been attributed (e.g., by Durlach, 1983) to the signal’s blocking of conditioning to background cues that otherwise would prevent conditioning of the CS. However, Goddard and Jenkins (1987) have suggested the alternative that signaling the USs promotes responding due to the adventitious creation of periods of signaled nonreinforcement. Two experiments were conducted to assess this alternative, involving an autoshaping preparation in pigeons. In Experiment 1, little responding to a keylight CS presented in a random relation to a food US occurred, despite the explicit presentation of a discrete noise signaling periods of no food in the intertrial interval (ITI). Experiment 2 was designed to replicate the procedure of Goddard and Jenkins, in which an auditory stimulus extended throughout the ITI of a random schedule, terminating only prior to extra USs and during the CS. Contrary to their findings, little responding developed to the target CS. However, responding did develop when the sound-free period occurred only prior to the extra USs. These results offer little support for the hypothesis that signaled periods of nonreinforcement promote responding on random schedules. However, they are consistent with the view that signaling of ITI USs acts by preventing conditioning of potentially competitive background cues. 相似文献