Diagnosticity and Prototypicality in Category Learning: A Comparison of Inference Learning and Classification Learning.

Category knowledge allows for both the determination of category membership and an understanding of what the members of a category are like. Diagnostic information is used to determine category membership; prototypical information reflects the most likely features given category membership. Two experiments examined 2 means of category learning, classification and inference learning, in terms of sensitivity to diagnostic and prototypical information. Classification learners were highly sensitive to diagnostic features but not sensitive to nondiagnostic, but prototypical, features. Inference learners were less sensitive to the diagnostic features than were classification learners and were also sensitive to the nondiagnostic, prototypical, features. Discussion focuses on aspects of the 2 learning tasks that might lead to this differential sensitivity and the implications for learning real-world categories. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Category Number Impacts Rule-Based but Not Information-Integration Category Learning: Further Evidence for Dissociable Category-Learning Systems.

Category number effects on rule-based and information-integration category learning were investigated. Category number affected accuracy and the distribution of best-fitting models in the rule-based task but had no effect on accuracy and little effect on the distribution of best-fining models in the information-integration task. In the 2 category conditions, rule-based learning was better than information-integration learning, whereas in the 4 category conditions, unidimensional and conjunctive rule-based learning was worse than information-integration learning. Rule-based strategies were used in the 2-category/rule-based condition, but about half of the observers used rule-based strategies in the 4-category unidimensional and conjunctive rule-based conditions. Information-integration strategies were used in the 4-category/ information-integration condition and by the end of training were used in the 2-category/information-integration condition. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Prototype and Exemplar Accounts of Category Learning and Attentional Allocation: A Reassessment.

In a recent article. J. P. Minda and J. D. Smith (2002; see record 2002-00620-002) argued that an exemplar model provided worse quantitative fits than an alternative prototype model to individual subject data from the classic D. L. Medin and M. M. Schaffer (1978) 5/4 categorization paradigm. In addition, they argued that the exemplar model achieved its fits by making untenable assumptions regarding how observers distribute their attention. In this article, we demonstrate that when the models are equated in terms of their response-rule flexibility, the exemplar model provides a substantially better account of the categorization data than does a prototype or mixed model. In addition, we point to shortcomings in the attention-allocation analyses conducted by J. P. Minda and J. D. Smith (2002). When these shortcomings are corrected, we find no evidence that challenges the attention-allocation assumptions of the exemplar model. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

SUSTAIN: A Network Model of Category Learning.

SUSTAIN (Supervised and Unsupervised STratified Adaptive Incremental Network) is a model of how humans learn categories from examples. SUSTAIN initially assumes a simple category structure. If simple solutions prove inadequate and SUSTAIN is confronted with a surprising event (e.g., it is told that a bat is a mammal instead of a bird), SUSTAIN recruits an additional cluster to represent the surprising event. Newly recruited clusters are available to explain future events and can themselves evolve into prototypes-attractors-rules. SUSTAIN's discovery of category substructure is affected not only by the structure of the world but by the nature of the learning task and the learner's goals. SUSTAIN successfully extends category learning models to studies of inference learning, unsupervised learning, category construction, and contexts in which identification learning is faster than classification learning. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Category use and category learning.

Categorization models based on laboratory research focus on a narrower range of explanatory constructs than appears necessary for explaining the structure of natural categories. This mismatch is caused by the reliance on classification as the basis of laboratory studies. Category representations are formed in the process of interacting with category members. Thus, laboratory studies must explore a range of category uses. The authors review the effects of a variety of category uses on category learning. First, there is an extensive discussion contrasting classification with a predictive inference task that is formally equivalent to classification but leads to a very different pattern of learning. Then, research on the effects of problem solving, communication, and combining inference and classification is reviewed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Linguistic and Conceptual Influences on Adjective Acquisition in 24- and 36-Month-Olds.

Two hundred forty English-speaking toddlers (24- and 36-month-olds) heard novel adjectives applied to familiar objects (Experiment 1) and novel objects (Experiment 2). Children were successful in mapping adjectives to target properties only when information provided by the noun, in conjunction with participants' knowledge of the objects, provided coherent category information: when basic-level nouns or superordinate-level nouns were used with familiar objects, when novel basic-level nouns were used with novel objects, and-for 36-month-olds-when the nouns were underspecified with respect to category (thing or one) but participants could nonetheless infer a category from pragmatic and conceptual knowledge. These results provide evidence concerning how nouns influence adjective learning, and they support the notion that toddlers consider pragmatic factors when learning new words. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Memory for Narrative and Expository Text: Independent Influences of Semantic Associations and Text Organization.

The author examined memory for text in terms of the independent influences of semantic knowledge associations and text organization. Semantic associations were operationalized as the semantic relatedness between individual text concepts and the text as a whole and assessed with latent semantic analysis. The author assessed text organization by simulating comprehension with the construction integration model. Text organization consistently accounted for unique variance in recall. Semantic associations strongly predicted expository recall and predicted narrative recall significantly but to a lesser extent, even when the familiarity of the narrative content was manipulated. Results suggest that prior semantic associations and novel associations in the text structure influence memory independently, and that these influences can be affected by text genre. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Role of the Basal Ganglia in Category Learning: How Do Patients With Parkinson's Disease Learn?

The purpose of the present study was to gain a deeper understanding of the role of the basal ganglia in learning and memory by examining learning strategies among patients with basal ganglia dysfunction. Using a probabilistic category learning task (the "weather prediction" task) previously shown to be sensitive to basal ganglia function, the authors examined patterns of performance during learning and used mathematical models to capture different learning strategies. Results showed that patients with Parkinson's disease exhibit different patterns of strategy use. Specifically, most controls initially used a simple, but suboptimal, strategy that focused on single-cue-outcome associations; eventually, however, most controls adopted a more complex, optimal learning strategy, integrating single-cue associations to predict outcomes for multiple-cue stimuli. In contrast, the majority of individuals with Parkinson's disease continued to rely on simple single-cue learning strategies throughout the experiment. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Information-Integration Category Learning in Patients With Striatal Dysfunction.

Information-integration category learning was examined in patients with Parkinson's disease (PD) and in healthy control participants in 2 different conditions. In the linear condition, optimal categorization required a nonverbalizable linear integration of information from the 2 stimulus dimensions, whereas in the nonlinear condition, a nonlinear integration of information was required. Each participant completed 600 trials in each condition and was given corrective feedback following each trial. Results indicated that PD patients were not impaired in the linear condition across all trials, whereas the same patients were impaired in the nonlinear condition, but only later in training. The authors conducted model-based analyses to identify participants who used an information-integration approach, and a comparison of the accuracy rates of those individuals further revealed a specific deficit in information-integration category learning in patients with PD. These findings suggest that the striatum may be particularly involved in information-integration category learning when the rule is highly complex. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Modeling the Effects of Prior Knowledge on Learning Incongruent Features of Category Members.

The authors conducted 3 experiments addressing the issue of how observations and multiple sources of prior knowledge are put together in category learning. In Experiments 1 and 2, learning was faster for critical features, which were predictable on the basis of prior knowledge, than for filler features, and this advantage increased as more observations were made. In addition, learning was fastest for incongruent features that could only be predicted using knowledge from other domains. In Experiment 3, presenting contradictory features that violated prior knowledge led to rote learning rather than use of prior knowledge. The results were simulated with the Baywatch model, which addresses how observations of category members lead to recruitment and selection of sources of prior knowledge. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Item Recognition Memory and the Receiver Operating Characteristic.

Four experiments were conducted to investigate the effects of study time, study repetition, semantic and orthographic similarity, and category length on item recognition memory receiver operating characteristics (ROCs). Analyses of ROC shape rejected A. P. Yonelinas's (1994) dual-process model. The normal unequal variance signal-detection model provided a better account of the data, except for a small but consistent excess of high-confidence errors. It was found that z-transformed ROC slope was increased by similarity, category length, and study item repetition, rejecting R. Ratcliff, G. McKoon, and M. Tindall's (1994) "constancy-of-slopes" generalization for these variables, but slope was relatively unaffected by massed study time. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A Quantitative Model-Based Approach to Examining Aging Effects on Information-Integration Category Learning.

Information-integration category learning was examined in older and younger adults. Accuracy results indicated that older participants learned less well than younger participants in both linear and nonlinear conditions. Model-based analyses indicated that both groups in the linear condition tended to use information integration but that later in training younger participants were more likely to do so. In contrast, the 2 groups in the nonlinear condition were equally likely to use information integration. Further analysis indicated that younger adults were more accurate than older adults when an information-integration approach was adopted, whereas fewer age-related differences were observed when a rule-based approach was used, suggesting that age can have a negative impact on information-integration category learning processes but less impact on rule-based learning. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Memory for Star Trek : The role of prior knowledge in recognition revisited.

Prior studies have found robust knowledge effects on recall of text ideas but have seldom found comparable effects on recognition. This inconsistency was examined in light of recent research on the component processes that underlie recognition memory. Using the remember/know paradigm, the authors found that experts made more remember judgments than novices, but only in response to text ideas relevant to their domain of expertise. Using the process-dissociation procedure, the authors found knowledge effects on recollection estimates, but not on familiarity estimates. The authors contend that knowledge effects have been difficult to detect in recognition because knowledge primarily affects recollection, whereas familiarity gives rise to good performance even among novices. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Category dimensionality and feature knowledge: When more features are learned as easily as fewer.

Three experiments compared the learning of lower-dimensional family resemblance categories (4 dimensions) with the learning of higher-dimensional ones (8 dimensions). Category-learning models incorporating error-driven learning, hypothesis testing, or limited capacity attention predict that additional dimensions should either increase learning difficulty or decrease learning of individual features. Contrary to these predictions, the experiments showed no slower learning of high-dimensional categories; instead, subjects learned more features from high-dimensional categories than from low-dimensional categories. This result obtained both in standard learning with feedback and in noncontingent, observational learning. These results show that rather than interfering with learning, categories with more dimensions cause individuals to learn more. The authors contrast the learning of family resemblance categories with learning in classical conditioning and probability learning paradigms, in which competition among features is well documented. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Category Representation for Classification and Feature Inference.

This research's purpose was to contrast the representations resulting from learning of the same categories by either classifying instances or inferring instance features. Prior inference learning research, particularly T. Yamauchi and A. B. Markman (1998), has suggested that feature inference learning fosters prototype representation, whereas classification learning encourages exemplar representation. Experiment 1 supported this hypothesis. Averaged and individual participant data from transfer after inference training were better fit by a prototype than by an exemplar model. However, Experiment 2, with contrasting inference learning conditions, indicated that the prototype model was mimicking a set of label-based bidirectional rules, as determined by the inference learning task demands in Experiment 1. Only the set of rules model accounted for all the inference learning conditions in these experiments. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Testing Theories of Recognition Memory by Predicting Performance Across Paradigms.

Signal-detection theory (SDT) accounts of recognition judgments depend on the assumption that recognition decisions result from a single familiarity-based process. However, fits of a hybrid SDT model, called dual-process theory (DPT), have provided evidence for the existence of a second, recollection-based process. In 2 experiments, the authors tested predictions of DPT and SDT by comparing the invariance of parameter estimates between yes/no (Y/N) and 2-altemative forced-choice (2AFC) testing paradigms. Both experiments showed DPT recollection estimates in Y/N to be poorly correlated with recollection estimates in 2AFC. In Experiment 2, SDT predictions explained more variance than DPT predictions. The authors evaluate and discuss the extent to which each model possesses theoretical validity versus computational flexibility in curve fitting. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Response Reversals in Recognition Memory.

Using a dynamic sequential sampling model and a recently proposed model for confidence judgments in recognition memory (T. Van Zandt, 2000b), the authors examine the tendency for rememberers to reverse their responses after a primary decision. In 4 experiments, speeded "old"-"new" decisions were made under bias followed by a 2nd response', either a confidence judgment or another simple choice. The data from these experiments showed that participants know when they have made a mistake and that they respond to this knowledge by reversing their responses. Response reversals are thus shown to be important for constructing models of the response-selection process in recognition memory. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Associative Learning Improves Visual Working Memory Performance.

The ability to remember visual stimuli over a short delay period is limited by the small capacity of visual working memory (VWM). Here the authors investigate the role of learning in enhancing VWM. Participants saw 2 spatial arrays separated by a 1-s interval. The 2 arrays were identical except for 1 location. Participants had to detect the difference. Unknown to the participants, some spatial arrays would repeat once every dozen trials or so for up to 32 repetitions. Spatial VWM performance increased significantly when the same location changed across display repetitions, but not at all when different locations changed from one display repetition to another. The authors suggest that a major role of learning in VWM is to mediate which information gets retained, rather than to directly increase VWM capacity. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Developmental Study of the Hippocampal Formation in Rhesus Monkeys (Macaca mulatta): I. Early Ablations Spare Discrimination Learning but Not Recognition Memory.

In clinical cases of amnesia that followed bilateral excisions of medial temporal lobe structures, with some perceptual learning abilities intact, damage to the hippocampus was presumed to be the critical factor. The authors' search for an animal model of amnesia, based on ablations aimed at the hippocampal formation in infant rhesus monkeys, provides support for this view. Ablations of the hippocampal formation in 2-month-old infants tested shortly after recovery from surgery resulted in a deficit on a recognition memory task but left intact the ability to learn the concurrent object discrimination task, even though the latter task was administered with the use of a massed practice procedure. Thus, early damage, unlike that at 2 years of age or later, allowed the authors to dissociate associative learning with repeated trials, independent of hippocampal functions and recognition memory that depends on the integrity of the hippocampus. (PsycINFO Database Record (c) 2010 APA, all rights reserved)