Experimental challenges to theories of classical conditioning: Application of an attentional model of storage and retrieval.

Abstract

Several studies have recently challenged the accuracy of traditional models of classical conditioning that account for some experimental data in terms of a storage deficit. Among other results, it has been reported that extinction of the blocking or overshadowing stimulus results in the recovery of the response to the blocked or overshadowed stimulus, backward blocking shows spontaneous recovery, extinction of the training context results in the recovery from latent inhibition, interposing a delay between conditioning and testing in latent inhibition increases latent inhibition, and latent inhibition antagonizes overshadowing. An existing neural network model of classical conditioning (N. A. Schmajuk, Y. Lam, & J. A. Gray, 1996), which includes an attentional mechanism controlling both storage and retrieval of associations, is able to quantitatively describe these results.

Connectionism and Classical Conditioning

“…Of course, much of the success of the Rescorla-Wagner model rests with its ability to explain experimental results (Miller et al, 1995;Walkenbach & Haddad, 1980). Furthermore, to the extent that the model is challenged, the challenges begin by citing experimental results that the Rescorla-Wagner model does not fit well (Schmajuk & Larrauri, 2006).…”

Reinstatement of conditioned fear and the hippocampus: An attentional-associative model

“…Parameter values used in our simulations were identical to those used by Schmajuk and Larrauri (2006) and Larrauri and Schmajuk (submitted). These values are similar to those used in Schmajuk et al (1998), Schmajuk et al (1996), Buhusi et al (1998), andSchmajuk et al (2001), with exception of the parameter that controls an inhibitory effect of the OR on the CR, which was set to zero in order to avoid incorrect results when suppression ratios are used (see Schmajuk and Larrauri, 2006, for a complete discussion).…”

“…The Schmajuk, Lam and Gray (1996) model of storage and retrieval Schmajuk, Lam, and Gray (SLG, 1996;Schmajuk and Larrauri, 2006) proposed a model of classical conditioning that incorporates and extends the properties of several previous models. The SLG model includes (1) a recurrent system that stores between-CS and CS-US associations and permits the generation of inferences, (2) a real-time attentional variable regulated by the novelty of the US, the CSs, and the CX, and (3) a competitive rule that describes CS-US and between-CS (i.e., CS-Other CS, CX-CS and CS-CX) associations.…”

“…A formal description of the model as a set of differential equations is presented in Schmajuk et al (1996). The model can describe numerous classical conditioning paradigms (Schmajuk et al, 1996;Schmajuk, 1997;Schmajuk and Larrauri, 2006).…”

“…The goal of the present study was to provide a mechanistic account of fear reinstatement through application of the neural network model of classical conditioning introduced by Schmajuk, Lam, and Gray (SLG, 1996), which also describes challenging experimental results that alternative models fail to explain (Schmajuk and Larrauri, 2006), as well as the results of behavioral manipulations following extinction (Larrauri and Schmajuk, submitted). Furthermore, by introducing changes in the computation of some of its variables, showed that the SLG model can describe many of the effects of hippocampal dysfunction on classical conditioning.…”