Category learning systems

textCategory learning is an essential cognitive function. Empirical evidence and theoretical reasons suggest existence of multiple dissociable category learning systems. Here, a proposal is made that different category learning tasks are dominated by different category learning systems. A dual system theory of category learning COVIS proposes dissociation between an explicit, hypothesis-testing system, and an implicit, procedural learning system. Two studies testing this dissociation are presented, supporting the notion that hypothesis testing, utilizing working memory and explicit reasoning, mediates learning in rule-based tasks, while gradual and automatic S-R learning mediates information-integration tasks. Inconsistent findings in the literature regarding a prototype learning task suggest that two versions of this task, the A/nonA, single prototype task and the A/B, two prototype task, are mediated by distinct category learning mechanisms. A novel methodology for studying the A/nonA task and the A/B task is proposed and utilized in a functional magnetic resonance imaging study. The study reveals that the A/B task is mediated by declarative memory while the A/nonA task is mediated by perceptual learning. We conclude that at least four category learning systems exist, based on four memory systems of the brain: working memory, procedural memory, declarative memory and perceptual memory. The four category learning systems compete or cooperate during learning, each system dominating in a different category learning task. Category learning tasks provide a useful tool to understand learning and memory systems of the brain.Neuroscienc

High coherence among training exemplars promotes broad generalization of face families

How to best tailor learning experiences to promote conceptual knowledge that generalizes to new situations is a fundamental question across many domains. There have been conflicting findings on whether exposing a learner to highly variable exemplars during training improves generalization. In the present study, we used a face family category structure and manipulated the variability within the training set in terms of both the typicality (high vs. low training set coherence) and the number of unique examples (small vs. large training set size). Unlike some of prior work that trained participants to a performance criterion, the length of training was controlled across conditions. We found a clear benefit of high coherence training both in terms of category learning and broad generalization. Further, the category structure was designed such that participants could learn by picking up on shared features across category members and/or by memorizing individual category members and their unique features. The pattern of results from both categorization and an old/new recognition test indicated that high coherence training promoted the abstraction of shared features, whereas low coherence training resulted in difficulty both extracting commonalities among exemplars and memorizing unique exemplars. In contrast to the robust effects of training set coherence, there were minimal effects of training set size on generalization. Taken together, we show that training on typical examples can promote broad category knowledge by helping learners extract the central tendency of the category

Goal-directed dissociation of prototype and exemplar categorization strategies

The goal of this project is to show how distinct task goals can lead to distinct categorization strategies that are traditionally exemplar- or prototype-based. To do so, we will use a between-subjects design. Both conditions will be trained on a subset of exemplar stimuli that come from 2 prototype stimuli and then tested on both old and new exemplars and the prototypes themselves. The between-subjects manipulation will be the task goals, one of which is to categorize the training exemplars during training and the other which is to learn exemplar-scene associations

A Combination of Restudy and Retrieval Practice Maximizes Retention of Briefly Encountered Facts

Contains stimulus bank and spreadsheet with all subject data used for analyses

A Combination of Restudy and Retrieval Practice Maximizes Retention of Briefly Encountered Facts

Is retrieval practice always superior to restudy? In a classic study by Roediger and Karpicke (2006a) long-term retention of information contained in prose passages was found to be best when opportunities to restudy were replaced with opportunities to self-test. We were interested whether this striking benefit for repeated testing at the expense of any restudy replicates when study opportunities are brief, akin to a single mention of a fact in an academic lecture. We were also interested in whether restudying after a test would provide any additional benefits compared to restudying before test. In the current study, participants encountered academically relevant facts a total of three times, each time either studied (S) or self-tested (T). During study, participants predicted the accuracy of their future recall allowing us to track metacognitive awareness of not-yet-mastered material (i.e., metamemory). Final test followed immediately or after a delay (Experiment 1: two days, Experiment 2: seven days). Contrary to prior work, long-term memory was superior for facts the were restudied in addition to self-tested (SST > STT = SSS). We further investigated whether restudy after a test (STS) provides additional benefits compared to restudy before test (SST) but found comparably high delayed recall in both conditions. Finally, exploratory analyses indicated that restudy after test improved metamemory. Together, results show that under some circumstances, balancing repetition and testing can allow for more information to be learned and retained