Hernán I Savastano

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Twenty-four college students participated in an experiment with stimulus compounds. Subjects learned to discriminate color stimuli that correlated with varying probabilities of reinforcement. Reinforcement consisted of points. For all subjects, two colors signaled a .80 reinforcement probability, and two others signaled a .20 probability. For(More)
The effectiveness of a stimulus as a conditioned reinforcer depends on the temporal context of reinforcement, that is, the overall rate of reinforcement in the situation. The dominant view has been that context determines the learned value of a stimulus directly, according to delay-reduction theory. By contrast, the contextual choice model (CCM) maintains(More)
Time has played only a limited role within the traditional theories of Pavlovian conditioning. Although temporal factors certainly contribute to whether conditioning occurs, the traditional assumption in the associative framework has been that associations lack temporal information. Recently, the temporal coding hypothesis has challenged that view, arguing(More)
Seven undergraduates participated in a concurrent-choice experiment with monetary reinforcers. Response-independent analogues of variable-interval and variable-ratio schedules were used to assess whether subjects would maximize reinforcement rate. The optimal pattern of behavior, in terms of maximizing reinforcement rate, involved a large bias toward the(More)
The Hall-Pearce (1979) negative transfer effect in rats was used to examine whether temporal relationships are coded as part of the informational content of associations that results from CS-US pairings. The transfer effect consists of a deficit in conditioned responding following CS-USstrong pairings in Phase 2 that results from prior CS-USweak pairings in(More)
Three experiments with rats used conditioned suppression of barpress to test predictions of the extended comparator hypothesis, which assumes that the effectiveness of (first-order) comparator stimuli in modulating responding to a target conditioned stimulus (CS) is itself modulated by other (second-order) comparator stimuli. Experiment 1 demonstrated that(More)
In 3 Pavlovian conditioned lick-suppression experiments, rats received overshadowing treatment with a footshock unconditioned stimulus such that Conditioned Stimulus (CS) A overshadowed CS X. Subjects that subsequently received CS X paired with an established signal for saccharin (CS B) exhibited less overshadowing of the X-footshock association than(More)
In the study of Pavlovian conditioning, preexposure to a conditioned stimulus (CS) and overshadowing are two treatments that are known to attenuate excitatory conditioned responding. However, Blaisdell, Bristol, Gunther, and Miller (1998) recently showed that the compound effect of these treatments is not to summate their deleterious effects on conditioned(More)
E. Fantino (2000) argued that R. C. Grace and H. I. Savastano's (2000) experiments fail to elucidate the relationship between stimulus value and temporal context. His reasoning is that predictions for R. C. Grace and H. I. Savastano's probe tests based on delay-reduction theory (DRT) and the contextual choice model (CCM) are indistinguishable. However, his(More)
I was glad to read the abstract of Harrison et al. (1) on the Web; this paper supports our work currently being done. I just returned from a cooperative program in Australia with Forestry and Forest Products-CSIRO, where methods were being developed to replace asbestos in fiber-cement products. In the study in Australia, a new approach is being taken by(More)
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