Blocking with serial and simultaneous compounds in a trace conditioning procedure

Abstract

Blocking of conditioned suppression in rats was studied in three experiments using serial and simultaneous compounds in Pavlovian trace conditioning procedures. Experimental groups were first given trace conditioning trials with a 2-sec stimulus (A) presented at least 60 sec before an electric grid shock US. Next, both experimental and control groups received reinforced trials with a compound stimulus (AB). Both A and B were 2 sec in duration and were presented at least 60 sec before the US. For some groups during AB training, the A stimulus preceded the B stimulus; for others, B preceded A; for still others, A and B occurred simultaneously. Conditioning was subsequently assessed separately to both A and B. The results were as follows: First, varying the interval between the onset of A and the US during A training appeared to produce significantly different levels of conditioning to A but did not detectably affect A's ability to block conditioning to B. Second, blocking was observed in both simultaneous and serial procedures. Third, in the serial procedure, A blocked conditioning to B whether it preceded B or followed B in the AB compound. Fourth, in tests given after AB conditioning, the experimental and control groups suppressed similarly to A. The relevance of these results to the conditioning model of Rescorla and Wagner (1972) and to Mackintosh's (l975b) theory of attention are discussed.

Temporal primacy overrides prior training in serial compound conditioning of the rabbit’s nictitating membrane response

“…On the one hand, the weak blocking effect is consistent with previous observations that blocking of eR acquisition to eSA in a serial compound is usually incomplete (e.g., Gibbs, 1979;Kehoe et al, 1981;Kohler & Ayres, 1982). On the other hand, the declines in responding to the pretrained eSB are a novel outcome of a blocking manipulation but do converge with previous observations of the temporal primacy effect.…”

“…Although blocking of CR acquisition to CSA was modest in Experiment 1, there are now enough demonstrations of partial blocking of CSA to indicate that it is a reliable outcome (see Kehoe, 1982, p. 42;Kohler & Ayres, 1982). Contrary to the results, the Sutton-Barto model generally predicts that impair-ments or decreases in responding to CSB should be accompanied by unimpeded CR acquisition to CSA.…”

“…Elsewhere, partial blocking of response acquisition to CSA has been reported in taste aversion learning (Revusky, 1971, pp. 197-203), odor aversion learning (Cheatle & Rudy, 1978), and conditioned suppression (Kohler & Ayres, 1982;Pearce, Nicholas, & Dickinson, 1981), but not in conditioned activity (Holland, 1980). Levels of responding to CSB have been largely unreported.…”

“…Empirically, these experiments were designed to pit the prior training of CSB against the temporal primacy of CSA, both of which can impair conditioned response (CR) acquisition to components of a compound stimulus. That is to say, prior training of CSB can cause blocking of CR acquisition to CSA during subsequent serial compound training (e.g., Gibbs, 1979;Kohler & Ayres, 1982). Converse1y, the temporal primacy of CSA relative to CSB can cause deficits in CR acquisition to CSB (e.g., Egger & Miller, 1962;Kehoe, 1979Kehoe, , 1983Wickens, 1959Wickens, , 1965Wickens, , 1973.…”

A history of morphine-induced taste aversion learning fails to affect morphine-induced place preference conditioning in rats

“…In the design utilized here, the morphine-associated taste was given 20 min prior to the animal's placement in the place preference conditioning apparatus. Although in more traditional blocking designs the two stimuli have been presented concurrently during conditioning, blocking has been reported when the two conditioned stimuli (CSs) are presented in a serial manner (see Kehoe, Schreurs, & Amodei, 1981;Kohler & Ayres, 1982;Solomon, 1977), even in the taste aversion procedure (Revusky, 1971). Third, morphine was given prior to placement of the animals in the place-conditioning apparatus.…”