Spontaneous Recovery From Forward and Backward Blocking.

Abstract

This article demonstrates and analyzes spontaneous recovery of stimulus control following both forward and backward blocking in a conditioned suppression preparation with rats. Experiment 1 found, in first-order conditioning, robust forward blocking and an attenuation of it following a retention interval. Experiment 2 showed, in sensory preconditioning, recovery of responding following both forward and backward blocking. Also, the results of this experiment indicated that response recovery to the blocked stimulus cannot be explained by an impaired status of the blocking stimulus after a retention interval. Experiment 3, also in sensory preconditioning, suggested that spontaneous recovery following both forward and backward blocking in Experiment 2 was due to impaired associative activation of the blocking stimulus' representation during testing with the blocked stimulus. Although no contemporary model of associative learning can explain these results, a modification of R. R. Miller and L. D. Matzel's (1988) comparator hypothesis is proposed to do so.Few findings in the associative learning literature have encouraged as much research as Kamin's (1968) report of the blocking effect. Blocking refers to impaired responding to a conditioned stimulus (CS), X, as a result of its being paired with an unconditioned stimulus (US) in the presence of another CS, A, which receives additional pairings with the US without CS X, relative to a control group that does not receive the additional A-US pairings. Typically, a blocking experiment consists of two different types of training trials (i.e., A-US and AX-US trials) administered in separate phases followed by the presentation of CS X during testing. When the A-US trials precede the AX-US trials, the response impairment to X is called forward blocking, whereas when the A-US trials follow the AX-US trials, it is referred to as backward blocking. The forward blocking effect is quite robust, and explaining it has become a benchmark test of contemporary models of associative learning (e.g., Rescorla & Wagner, 1972). In addition, the study of blocking has strengthened the link between animal conditioning and human learning by providing evidence of this effect in diverse species. Whereas forward blocking was first found in conditioned suppression with nonhuman animals by Kamin and then demonstrated with humans in a causal learning preparation by Dickinson, Shanks, and Evenden (1984), backward blocking was originally demonstrated by Shanks (1985) in a causal learning preparation with humans and then replicated in a classical conditioning preparation with nonhuman animals (Denniston, Miller, & Matute, 1996;R. R. Miller & Matute, 1996b).The first explanation of the forward blocking effect was provided by Kamin (1968), who proposed that it occurred because the US was not surprising during the AX-US trials because of its occurrence being fully predicted by the presence of CS A as a consequence of A's prior training with the US. Therefore, CS X was a redundant CS (i.e., it did not add an...

A response rule for positive and negative stimulus interaction in associative learning and performance

“…The SOCR model (as the extended comparator hypothesis, which serves as its basis) has trouble to explain changes in responding to a CS as function of passage of time. Specifically, the SOCR model fails to explain relevant findings in the stimulus competition literature, such as spontaneous recovery of responding after overshadowing (Kraemer, Lariviere, & Spear, 1988) or blocking (Pineño, Urushihara, & Miller, 2005). The problem of the SOCR model is, not only that there is no mechanism by which passage of time could affect responding to a CS, but also that there is no obvious reason why the mechanisms already existing in the model should be affected by passage of time.…”

Spontaneous recovery from overexpectation

“…Second, there are other instances of recovery from decremental procedures with the passage of time. For instance, Kraemer, Lariviere, and Spear (1988) and Pineño, Urushihara, and Miller (2005) have reported that with the passage of time there is recovery from the adverse effects of overshadowing and blocking, respec- tively. Those results differ from the present ones in that overexpectation involves the depression of a previously well-conditioned stimulus, rather than the attenuation of initial conditioning.…”

Locally Bayesian learning with applications to retrospective revaluation and highlighting.

“…Despite the fact that B is absent in the second phase, it loses strength. Typically, however, the amount of reduction in backward blocking is weaker than the amount of reduction in forward blocking (see e.g., Beckers, De Houwer, Pineño, & Miller, 2005;Kruschke & Blair, 2000;Lovibond, Been, Mitchell, Bouton, & Frohardt, 2003;Pineño, Urushihara, & Miller, 2005;Shanks, 1985). This asymmetry in strengths of forward and backward blocking is a trialorder effect that is challenging for extant time-independent Bayesian approaches.…”