Forward and backward blocking in human contingency judgement

Three experiments investigated whether a process akin to Kamin's (1969) blocking effect would occur with human contingency judgements in the context of a video game. Subjects were presented with sets of trials on each of which they could perform a particular action and observe whether the action produced a particular outcome in a situation in which there was an alternative potential cause of the outcome. In Experiment 1 it was found that prior observation of the relationship between the alternative cause and the outcome did indeed block or reduce learning about the subsequent action-outcome relationship. However, exposure to the relationship between the alternative cause and the outcome after observing the association between the action and the outcome also reduced judgements of the action-outcome contingency (backward blocking), a finding at variance with conditioning theory. In Experiment 2 it was found that, just as is the case with forward blocking, the degree of backward blocking depended on how good a predictor of the outcome the alternative cause was. Finally, in Experiment 3 it was shown that the backward blocking effect was not the result of greater forgetting about the action-outcome relationship in the experimental than in the control condition. These results cast doubt upon the applicability of contemporary theories of conditioning to human contingency judgement.     

Aging and implicit learning: explorations in contextual cuing

In contextual cuing, faster responses are made to repeated displays containing context-target associations than to novel displays without such covariances. We report that healthy older adults showed learning impairments in contextual cuing when compared with younger adults. The display properties in the task were altered to artificially increase younger adults' response times to match those of older adults and to produce faster responses in older participants; however, younger participants' learning remained intact, whereas older participants continued to show impairments under these conditions. These results suggest that older adults have intrinsic deficits in contextual cuing that cannot be attributed to their slower overall response speed.     

Out of control: an associative account of congruency effects in sequence learning

The demonstration of a sequential congruency effect in sequence learning has been offered as evidence for control processes that act to inhibit automatic response tendencies (Jiménez, Lupiáñez, &; Vaquero, 2009) via unconscious conflict monitoring. Here we propose an alternative interpretation of this effect based on the associative learning of chains of sequenced contingencies. This account is supported by simulations with a Simple Recurrent Network, an associative (connectionist) model of sequence learning. We argue that the control- and associative-based accounts differ in their predictions concerning the magnitude of the sequential congruency effect across training. These predictions are tested by reanalysing data from a study by Shanks, Wilkinson, and Channon (2003). The results support the associative learning account which explains the sequential congruency effect without appealing to control processes (either conscious or unconscious).     

Are there multiple memory systems? Tests of models of implicit and explicit memory

[Formula: see text] This article reviews recent work aimed at developing a new framework, based on signal detection theory, for understanding the relationship between explicit (e.g., recognition) and implicit (e.g., priming) memory. Within this framework, different assumptions about sources of memorial evidence can be framed. Application to experimental results provides robust evidence for a single-system model in preference to multiple-systems models. This evidence comes from several sources including studies of the effects of amnesia and ageing on explicit and implicit memory. The framework allows a range of concepts in current memory research, such as familiarity, recollection, fluency, and source memory, to be linked to implicit memory. More generally, this work emphasizes the value of modern computational modelling techniques in the study of learning and memory.     

The strong programme for the sociology of science,reflexivity and relativism

David Bloor has advocated a bold hypothesis about the form any sociology of science should take in setting out the four central tenets of his ‘strong programme’ (SP). The first section of this paper discusses how three of these tenets are best formulated and how they relate to one another. The second section discusses how reasons can be causes of belief and how such reasons raise a serious difficulty for SP. The third section discusses how SP is committed to a form of relativism about truth. The fourth section discusses how one might deal with the problem of SP applying both to itself and to other sociological theories. In addition there is, throughout, a discussion of how rules of inference, methodologies, and philosophical doctrines either apply to SP or are exempt from applying. It is argued that SP must be a severely limited doctrine impotent to make evaluative claims about the worth of any theory, including itself.     

The comparator theory fails to account for the selective role of within-compound associations in cue-selection effects

In a human causal learning experiment, we investigated cue selection effects to test the comparator theory (Denniston, Savastano, & Miller, 2001; Miller & Matzel, 1988). The theory predicts that the occurrence of cue selection is independent of whether the relevant learning trials are presented in a standard forward manner or in a backward manner and that within-compound associations are of equal importance in both cases. We found that the strength of the cue-selection effect was positively correlated with knowledge of within-compound associations in the backward condition but not in the forward condition. Furthermore, cue-selection effects were less pronounced in the former than in the latter condition. These results are at variance with the comparator hypothesis but are in agreement with a modified associative theory and with the suggestion that retrospective revaluation might be due to rehearsal processes.     

Conformity to the power PC theory of causal induction depends on the type of probe question

P. W. Cheng's (1997) power PC theory of causal induction proposes that causal estimates are based on the power (P) of a potential cause, where P is the contingency between the cause and effect normalized by the base rate of the effect. Most previous research using a standard causal probe question has failed to support the predictions of the power PC model but recently Buehner, Cheng, and Clifford (2003) found that participants responded in terms of causal power when probed with a counterfactual test question, which they argued prompted participants to consider the base rate of the effect. However, Buehner et al. framed their counterfactual question in terms of frequency, a factor that has been demonstrated to decrease base rate neglect in judgements under uncertainty. In the experiment reported here, we sought to disentangle the influence of counterfactual and frequency framing of the probe question to determine which factor is responsible for encouraging responses in terms of causal power.