A memory-based account of retrospective revaluation

Computational and empirical simulations of selective memory impairments: Converging evidence for a single-system account of memory dissociations

Current theory has divided memory into multiple systems, resulting in a fractionated account of human behaviour. By an alternative perspective, memory is a single system. However, debate over the details of different single-system theories has overshadowed the converging agreement among them, slowing the reunification of memory. Evidence in favour of dividing memory often takes the form of dissociations observed in amnesia, where amnesic patients are impaired on some memory tasks but not others. The dissociations are taken as evidence for separate explicit and implicit memory systems. We argue against this perspective. We simulate two key dissociations between classification and recognition in a computational model of memory, A Theory of Nonanalytic Association. We assume that amnesia reflects a quantitative difference in the quality of encoding. We also present empirical evidence that replicates the dissociations in healthy participants, simulating amnesic behaviour by reducing study time. In both analyses, we successfully reproduce the dissociations. We integrate our computational and empirical successes with the success of alternative models and manipulations and argue that our demonstrations, taken in concert with similar demonstrations with similar models, provide converging evidence for a more general set of single-system analyses that support the conclusion that a wide variety of memory phenomena can be explained by a unified and coherent set of principles.

Cultural Differences in Revaluative Attributions

Culture can impact cognitive processes, including effects on causal attributions. This study examined cultural differences in revaluative attributions when two potential causes of an outcome are initially present, but new relevant causal information is later available, suggesting potential adjustments could be made with respect to the original judgment. Study 1 ( N = 206) found that both Chinese and American participants showed revaluative attributions regarding the target cause when a nontarget cause was decreased in its validity during a subsequent phase. That is, the target cause was later judged as more valid when a nontarget cause was decreased in validity (the deflation effect). However, only American participants exhibited a significant decrease in the perceived validity of a target cause when the nontarget cause was increased in its validity (the inflation effect). Study 2 ( N = 189) replicated these findings and also showed that dialectical thinking was a mediator of this cultural difference in revaluative attributions. The present study shows that culturally shaped cognitive processing can influence multicausal inferences.

An instance theory of associative learning

We present and test an instance model of associative learning. The model, Minerva-AL, treats associative learning as cued recall. Memory preserves the events of individual trials in separate traces. A probe presented to memory contacts all traces in parallel and retrieves a weighted sum of the traces, a structure called the echo. Learning of a cue-outcome relationship is measured by the cue's ability to retrieve a target outcome. The theory predicts a number of associative learning phenomena, including acquisition, extinction, reacquisition, conditioned inhibition, external inhibition, latent inhibition, discrimination, generalization, blocking, overshadowing, overexpectation, superconditioning, recovery from blocking, recovery from overshadowing, recovery from overexpectation, backward blocking, backward conditioned inhibition, and second-order retrospective revaluation. We argue that associative learning is consistent with an instance-based approach to learning and memory.