Associative learning theories assume that cue interaction and, specifically, retrospective revaluation occur only when the target cue is previously trained in compound with the to-be-revalued cue. However, there are recent demonstrations of retrospective revaluation in the absence of compound training (e.g., Matute & Pineño, 1998a, 1998b). Nevertheless, it seems reasonable to assume that cue interaction should be stronger when the cues are trained together than when they are trained apart. In two experiments with humans, we directly compared compound and elemental training of cues. The results showed that retrospective revaluation in the elemental condition can be as strong as and, sometimes, stronger than that in the compound condition. This suggests that within-compound associations are not necessary for retrospective revaluation to occur and that these effects can possibly be best understood in the framework of general interference theory. In the literature of animal conditioning and human associative learning, it is well known that if a cue, X, is consistently followed by an outcome, O (i.e., X–O), X is generally learned as a predictor of the occurrence of the outcome. It is also well known that responding to X in a subsequent test phase becomes altered if another cue, A, is trained in compound with X as a predictor of the same outcome. Some classic instances of these cue interaction effects in the animal learning literature are overshadowing (Pavlov, 1927), blocking (Kamin, 1968), conditioned inhibition (Pavlov, 1927), and the relative stimulus validity

Most theoretical accounts of backward blocking place heavy stress on the necessity of the target cue having been trained in compound with the competing cue to produce a decrement in responding. Yet, other evidence suggests that a similar reduction in responding to the target cue can be observed when the outcome is later paired with a novel cue never trained in compound with the target cue (interference between cues trained apart). The present experiment shows that pairing another nonassociated cue with the same outcome may be sufficient to produce a decremental effect on the target cue, but the presence of a within-compound association between the target and the competing cue adds to this effect. Thus, both interference between cues trained apart and within-compound associations independently contribute to backward blocking.

In this study, we describe the influences of qualitative changes to the reasoning problem on the reasoning process. The first manipulation is the quality of the test context: A rule is learned in a certain context and contradicted in another. The belief in the rule is then measured in the learning context, the contradictory context, and a new context. The second manipulation is the quality of contradiction: The contradictory rule can neutralize or inverse the learned rule. Both qualitative changes influence the belief revision process.

The impairment in responding to a secondly trained association because of the prior training of another (i.e., proactive interference) is a well-established effect in human and animal research, and it has been demonstrated in many paradigms. However, learning theories have been concerned with proactive interference only when the competing stimuli have been presented in compound at some moment of the training phase. In this experiment we investigated the possibility of proactive interference between elementally-trained stimuli at the acquisition and at the retrieval stages in a behavioral task with humans. After training a cue-outcome association we observed retardation in the acquisition of an association between another cue and the same outcome. Moreover, after asymptotic acquisition of the secondly trained association, impairment of retrieval of this secondly trained association was also observed. This finding of proactive interference between elementally-trained cues suggests that interference in predictive learning and other traditional interference effects could be integrated into a common framework. Interference among cues is a central topic in associative learning research. Cue interference is well represented by Kamin’s early studies (e.g., 1968) with rats, where he found that the training of two cues in compound after the isolated

Backward blocking (BB) and interference between cues (IbC) are cue competition effects produced by very similar manipulations. In a standard BB design both effects might occur simultaneously, which implies a potential problem to study BB. In the present study with humans, the magnitude of both effects was compared using a non causal scenario and a within subjects design. Previous studies have made this comparison using learning tasks framed within causal scenarios. This posits a limit to generalizing their findings to non-causal learning situations because there is ample evidence showing that participants engage in causal reasoning when tasks are causally framed. The results obtained showed BB and IbC effects of the same magnitude in a non causal framed task. This highlights the methodological need for an IbC control in BB experiments. Backward Blocking 3

Retroactive interference between cues trained apart has been regarded as an effect that occurs because the target and interfering associations share a common outcome. Although this view is consistent with evidence in the verbal learning tradition (Underwood, 1966) and, more recently, in predictive learning with humans (Pineño & Matute, 2000), little research has been conducted to ascertain whether the occurrence of this effect critically depends on the target and interfering associations sharing an identical outcome. The present experiment examined, in predictive learning with humans, retroactive interference between cues trained apart as a function of the similarity of the outcome paired with the cues. Interference was found to be stronger when the cues were paired with the same outcome than when they were paired with either similar or different outcomes.

Backward blocking (BB) and interference between cues (IbC) are cue competition effects produced by very similar manipulations. In a standard BB design, both effects might occur simultaneously, which implies a potential problem for studying BB. In the present study with humans, the magnitude of both effects was compared using a non-causal scenario and a within-subjects design. Previous studies have made this comparison using learning tasks framed within causal scenarios. This posits a limit to generalizing their findings to non-causal learning situations because there is ample evidence showing that participants engage in causal reasoning when tasks are causally framed. The results obtained showed BB and IbC effects of the same magnitude in a non– causally-framed task. This highlights the methodological need for an IbC control in BB experiments.