Probability of shock in the presence and absence of CS in fear conditioning.
01 Aug 1968-Journal of Comparative and Physiological Psychology (J Comp Physiol Psychol)-Vol. 66, Iss: 1, pp 1-5
TL;DR: 2 experiments indicate that CS-US contingency is an important determinant of fear conditioning and that presentation of US in the absence of CS interferes with fear conditioning.
Abstract: 2 experiments indicate that CS-US contingency is an important determinant of fear conditioning and that presentation of US in the absence of CS interferes with fear conditioning. In Experiment 1, equal probability of a shock US in the presence and absence of a tone CS produced no CER suppression to CS; the same probability of US given only during CS produced substantial conditioning. In Experiment 2, which explored 4 different probabilities of US in the presence and absence of CS, amount of conditioning was higher the greater the probability of US during CS and was lower the greater the probability of US in the absence of CS; when the 2 probabilities were equal, no conditioning resulted. Two conceptions of Pavlovian conditioning have been distinguished by Rescorla (1967). The first, and more traditional, notion emphasizes the role of the number of pairings of CS and US in the formation of a CR. The second notion suggests that it is the contingency between CS and US which is important. The notion of contingency differs from that of pairing in that it includes not only what events are paired but also what events are not paired. As used here, contingency refers to the relative probability of occurrence of US in the presence of CS as contrasted with its probability in the absence of CS. The contingency notion suggests that, in fact, conditioning only occurs when these probabilities differ; when the probability of US is higher during CS than at other times, excitatory conditioning occurs; when the probability is lower, inhibitory conditioning results. Notice that the probability of a US can be the same in the absence and presence of CS and yet there can be a fair number of CS-US pairings. It is this that makes it possible to assess the relative importance of pairing and contingency in the development of a CR. Several experiments have pointed to the usefulness of the contingency notion. Rescorla (1966) reported a Pavlovian 1This research was supported by Grants MH13415-01 from the National Institute of Mental Health and GB-6493 from the National Science Foundation, as well as by funds from Yale University.
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TL;DR: This paper reported the results of two corpus-based studies investigating how various features of the input (frequency distributions, reliabilities of form-function mapping, and prototypicality of lexical aspect) affect the acquisition of tense and aspect morphology.
Abstract: The aspect hypothesis ( Andersen & Shirai, 1994 ) proposes that language learners are initially influenced by the inherent semantic aspect in the acquisition of tense and aspect (TA) morphology Perfective past emerges earlier with accomplishments and achievements and progressive with activities Although this hypothesis has been extensively studied, there have been no analyses of the frequency, form, and function of relevant types and tokens in the input This article reports the results of 2 corpus-based studies investigating how various features of the input—frequency distributions, reliabilities of form–function mapping, and prototypicality of lexical aspect—affect TA morphology Study I determined the relative frequency profiles of exemplars of English TA and employed various statistics to determine the associations between particular verb–aspect combinations Study II expanded the aspect hypothesis, examining whether native speakers judge the most frequent forms in isolation to be more prototypical in lexical aspect Analyses were then matched against acquisition data for different TA patterns by adult learners of English ( Bardovi-Harlig, 2000 ) to determine whether the verbs' acquisition order is determined by their frequency, form, and function in the input Rather than testifying to the effect of 1 factor alone, the results suggest that frequency, distinctiveness, and prototypicality jointly drive acquisition [ABSTRACT FROM AUTHOR]
124 citations
Cites background from "Probability of shock in the presenc..."
...Rescorla (1968) showed that if one removed the contingency between the conditioned stimulus (CS) and the unconditioned stimulus (US), preserving the temporal pairing between the CS and US but adding additional trials when the US appeared on its own, then animals did not develop a conditioned…...
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TL;DR: The evidence suggests that CS-US contingency is neither necessary nor sufficient for conditioning and that the concept has long outlived any usefulness it may once have had in the analysis of conditioning.
Abstract: The assumption that classical conditioning depends on a contingent relation between the conditioned stimulus (CS) and the unconditioned stimulus (US), which was proposed some decades ago as an alternative to the traditional contiguity assumption, still is widely accepted as an empirical generalization, if no longer as a theoretical postulate. The first support for the contingency assumption was provided by experiments in which occasional CS-US pairings produced no response to the CS in random training--i.e., training in which the probability of the US was the same in the presence and absence of the CS. Those early experiments, the results of which too often are taken at face value, are reconsidered along with various later experiments that show conditioning, both of the CS and its context, in random training. The evidence suggests that CS-US contingency is neither necessary nor sufficient for conditioning and that the concept has long outlived any usefulness it may once have had in the analysis of conditioning.
122 citations
TL;DR: One taste-aversion study using male Long-Evans rats and six studies in which lithium chloride was the unconditioned stimulus demonstrate that exposure to the UCS prior to conditioning retards subsequent acquisition of learned taste aversions.
Abstract: One taste-aversion study using male Long-Evans rats in which ethanol was the unconditioned stimulus (UCS) and six studies in which lithium chloride (LiCl) was the UCS demonstrate that (a) exposure to the UCS prior to conditioning retards subsequent acquisition of learned taste aversions; (b) a single preconditioning UCS exposure is sufficient to attenuate conditioning; (c) the preconditioning UCS exposure must occur within a limited period prior to conditioning to attenuate learning; (d) repeated conditioning trials will override the effect of prior exposure to the UCS; (e) tolerance to the UCS is not a necessary condition for the attenuation effect to occur; (f) pairing the preconditioning UCS with a novel flavor other than the CS does not remove the preexposure effect, although it may reduce its magnitude; and (g) the degree of disruption is a positive function of preconditioning UCS dosage and an inverse function of conditioning UCS dosage.
120 citations
TL;DR: In this paper, a real-time neural network model is developed to explain data about the acquisition and extinction of conditioned excitors and inhibitors, which can be used to explain phenomena such as blocking, unblocking, overshadowing, latent inhibition, superconditioning, inverted U in conditioning as a function of interstimulus interval, anticipatory conditioned responses, partial reinforcement acquisition effect, learned helplessness, and vicious-circle behavior.
Abstract: A real-time neural network model is developed to explain data about the acquisition and extinction of conditioned excitors and inhibitors. Systematic computer simulations are described of a READ circuit, which joins together a mechanism of associative learning with an opponent-processing circuit, called a recurrent gated dipole. READ circuit properties clarify how positive and negative reinforcers are learned and extinguished during primary and secondary conditioning. Habituating chemical transmitters within a gated dipole determine an affective adaptation level, or context, against which later events are evaluated. Neutral conditioned stimuli can become reinforcers by being associated either with direct activations or with antagonistic rebounds within a previously habituated dipole. Neural mechanisms are characterized whereby conditioning can be actively extinguished, and associative saturation prevented, by a process called opponent extinction, even if no passive memory decay occurs. Opponent extinction exploits a functional dissociation between read-in and read-out of associative memory, which may be achieved by locating the associative mechanism at dendritic spines. READ circuit mechanisms are joined to cognitive-emotional mechanisms for associative learning of conditioned reinforcers and of incentive motivation, and to cognitive—in particular, adaptive resonance theory—mechanisms for activating and storing internal representations of sensory cues in a limited-capacity short-term memory (STM); for learning, matching, and mismatching sensory expectancies, leading to the enhancement or updating of STM; and for shifting the focus of attention toward sensory representations whose reinforcement history is consistent with momentary appetitive requirements. This total neural architecture is used to explain conditioning and extinction of a conditioned excitor; conditioning and nonextinction of a conditioned inhibitor; and properties of conditioned inhibition as a “slave” process and as a “comparator” process, including effects of pretest deflation or inflation of the conditioning context, of familiar or novel training or test contexts, of weak or strong shocks, and of preconditioning unconditioned-stimulus-alone exposures. The same mechanisms have elsewhere been used to explain phenomena such as blocking, unblocking, overshadowing, latent inhibition, superconditioning, inverted U in conditioning as a function of interstimulus interval, anticipatory conditioned responses, partial reinforcement acquisition effect, learned helplessness, and vicious-circle behavior. The theory clarifies why alternative models have been unable to explain an equally large data base.
118 citations
TL;DR: In this article, the role of a discriminative stimulus (S) in governing the relation between a response (R) and an outcome (O) in an appetitive learning paradigm was examined.
Abstract: In three experiments using rats, we examined the role of a discriminative stimulus (S) in governing the relation between a response (R) and an outcome (O) in an appetitive instrumental learning paradigm. In each experiment, we attempted to distinguish between a simple S-O association and a hierarchical relation in which S is associated with the R-O association. We used three variations on discriminative training procedures and three different assessment techniques-for revealing the hierarchical structure. In Experiment 1, we employed a training procedure in which S signaled a change in the R-O relation but no change in the likelihood of O. Although such an arrangement should not produce an excitatory S-O association, it nevertheless generated an S that controlled responding and transferred that control to other responses. In Experiment 2, we used a discrimination procedure in which two Ss each had the same two Rs and Os occur in their presence but each S signaled that a different R-O combination would be in effect. This design provided the opportunity for equivalent pairwise associations among S, R, and O but unique hierarchical relations. The subjects learned the hierarchical structure, as revealed by the specific depressive effect of a subsequent lithium-chloride-induced devaluation of O on responding only in the presence of the S in which that response had led to that outcome. In Experiment 3, one S signaled two different R-O outcomes. Then, two new stimuli were presented with the original S; the R-O relations were retained in the presence of one of the added stimuli but were rearranged in the presence of the other. The added S came to control less responding when it was redundant with respect to the R-O relations than when it was informative. Although all of the results were of modest size and each has an alternative interpretation, together they provide converging evidence for the hierarchical role of S in controlling an R-O association.
118 citations
References
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TL;DR: This "truly random" control procedure leads to a new conception of Pavlovian conditioning postulating that the contingency between CS and US, rather than the pairing of CS andUS, is the important event in conditioning.
Abstract: The traditional control procedures for Pavlovian conditioning are examined and each is found wanting. Some procedures introduce nonassociative factors not present in the experimental procedure while others transform the excitatory, experimental CS-US contingency into an inhibitory contingency. An alternative control procedure is suggested in which there is no contingency whatsoever between CS and US. This \"truly random\" control procedure leads to a new conception of Pavlovian conditioning postulating that the contingency between CS and US, rather than the pairing of CS and US, is the important event in conditioning. The fruitfulness of this new conception of Pavlovian conditioning is illustrated by 2 experimental results.
1,328 citations
301 citations
TL;DR: In this paper, three groups of dogs were trained with different kinds of Pavlovian fear conditioning for three different types of dogs: randomly and independently; for a second group, CSs predicted the occurrence of USs; and for a third group, S predicted the absence of the USs.
Abstract: Three groups of dogs were Sidman avoidance trained They then received different kinds of Pavlovian fear conditioning For one group CSs and USs occurred randomly and independently; for a second group, CSs predicted the occurrence of USs; for a third group, CSs predicted the absence of the USs The CSs were subsequently presented while S performed the avoidance response CSs which had predicted the occurrence or the absence of USs produced, respectively, increases and decreases in avoidance rate For the group with random CSs and USs in conditioning, the CS had no effect upon avoidance
160 citations
64 citations
TL;DR: Rats in an experimental group were given 30 trials of differential CER and then the CS+ and CS− were combined during CER extinction, resulting in less suppression for the experimental group than shown by a control group, interpreted as a demonstration of the active inhibitory properties of CS−.
Abstract: Rats in an experimental group were given 30 trials of differential CER and then the CS+ and CS− were combined during CER extinction. The combination resulted in less suppression for the experimental group than shown by a control group which had a CS+ and a formerly random stimulus combined during extinction. This was interpreted as a demonstration of the active inhibitory properties of CS−.
44 citations
"Probability of shock in the presenc..." refers background in this paper
...Although such an account is plausible for the present data, it fails to explain the active inhibition of fear found by Rescorla and LoLordo (1965), Rescorla (1966), and Hammond (1967)....
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