This thesis examined how task demands shape the category representations formed through classification, inference and incidental learning. Experiments 1 to 3 examined the claim that the representations formed through inference learning are based only on the encoding of prototypical features (e.g., Yamauchi & Markman, 1998, 2000). Adults learned artificial categories through exemplar classification or feature inference. Inference learning either did or did not require attention to prototypical features. At test, all participants classified exemplars and inferred the values of missing features. Classification learning resulted in the encoding of both prototypical and atypical features. Inference learning also led to the representation of both prototypical and atypical features when attention to both was required during learning. Experiment 4 extended these results to inferences about novel items varying in similarity to training items. Inference learners required to attend to prototypical and atypical features during training were more sensitive to exemplar similarity when making novel inferences than those who attended only to prototypical features. Experiment 5 examined developmental change in the impact of noun and feature labels on feature inferences. Adults, 7-year-olds, and 5-yearolds were shown pairs of base and target exemplars. The base was given a noun or feature label. Participants were asked to predict the value of a missing feature of the target, when it was given the same or a different label as the base. Both adults and children were more likely to make inferences based on noun than feature labels. Hence, by five years of age, children grasp the inductive potential of noun labels. Experiments 6 to 9 compared incidental category learning with intentional classification. Adults classified categories of geometric shapes or learned the categories through an incidental task. Incidental recognition learning resulted in a broader allocation of attention than classification learning. Performing recognition before classification resulted in a broader attentional allocation than performing recognition after classification. Together with the results from mathematical modelling, these findings support a view of category learning in which the specific attentional demands of different learning tasks determine the nature of the category representations that are acquired.

Thesis (Ph. D.)--University of California, Santa Cruz, 1993. / Typescript. Includes bibliographical references (leaves 34-35).

Thesis (B.Sc)--University of Hong Kong, 1994. / "A dissertation submitted in partial fulfilment of the requirements for the Bachelor of Science (Speech and Hearing Sciences), The University of Hong Kong, April 29, 1994." Also available in print.

Thesis (M.S.)--Villanova University, 2006. / Psychology Dept. Includes bibliographical references.

We present a framework for learning abstract relational knowledge with the aimof explaining how people acquire intuitive theories of physical, biological, orsocial systems. Our approach is based on a generative relational model withlatent classes, and simultaneously determines the kinds of entities that existin a domain, the number of these latent classes, and the relations betweenclasses that are possible or likely. This model goes beyond previouspsychological models of category learning, which consider attributesassociated with individual categories but not relationships between categories.We apply this domain-general framework to two specific problems: learning thestructure of kinship systems and learning causal theories.

abstract: Learning and transfer were investigated for a categorical structure in which relevant stimulus information could be mapped without loss from one modality to another. The category space was composed of three non-overlapping, linearly-separable categories. Each stimulus was composed of a sequence of on-off events that varied in duration and number of sub-events (complexity). Categories were learned visually, haptically, or auditorily, and transferred to the same or an alternate modality. The transfer set contained old, new, and prototype stimuli, and subjects made both classification and recognition judgments. The results showed an early learning advantage in the visual modality, with transfer performance varying among the conditions in both classification and recognition. In general, classification accuracy was highest for the category prototype, with false recognition of the category prototype higher in the cross-modality conditions. The results are discussed in terms of current theories in modality transfer, and shed preliminary light on categorical transfer of temporal stimuli. / Dissertation/Thesis / M.S. Psychology 2011

This study examines the relationship between language and cognition with a focus on Chinese numeral classifiers (CNCs). NCs are ideally suited to exploring the link between language and semantic categorization, as classifier selection depends on the physical attributes of the associated noun (e.g., Mandarin zhi is used for long and rigid objects and tiao for long and flexible objects). Previous studies on numeral classifiers have addressed the language-cognition link by comparing the cognitive performance of monolingual as well as bilingual speakers of different languages (Lucy, 1992; Saalbach & Imai, 2005; Gao & Malt, 2009). In contrast, the present study sought to address the cognitive effects of numeral classifiers via a training study that investigated whether exposure to CNCs influenced Native-English speakers’ object categorization preferences, inhibitory control and memory retrieval. The participants of this study were 99 Native-English speaking College students. They were randomly assigned to an experimental group, which received training on four commonly used CNCs during the initial phase of the experiment, or a control group, which did not receive similar treatment during the initial phase. After the initial phase, the experimental group and the control group were assessed on a Forced Choice Task, a Go/No-Go Task and a Memory Task. A Mixed-design ANOVA indicated that the experimental group displayed a preference for objects sharing the same classifier in the Forced Choice Task and the Go/ No-Go Task (i.e. Go trials) when compared to the controls. The effect of exposure to numeral classifiers on inhibitory control was supported with a significantly lower false alarm rate (in the No-Go trials) for the experimental group. However, no group differences were observed in the results of the analysis of the participants’ median reaction times in the Go/No-Go tasks. Similarly, the differences between the two groups’ scores on the Memory Task was not found to be significant. The results of the study indicated that exposure to CNCs influenced Native-English speakers’ categorization. The results also revealed partial support for the influence of exposure to CNCs on inhibitory processing, but not in the case of object clustering.

abstract: Most people are experts in some area of information; however, they may not be knowledgeable about other closely related areas. How knowledge is generalized to hierarchically related categories was explored. Past work has found little to no generalization to categories closely related to learned categories. These results do not fit well with other work focusing on attention during and after category learning. The current work attempted to merge these two areas of by creating a category structure with the best chance to detect generalization. Participants learned order level bird categories and family level wading bird categories. Then participants completed multiple measures to test generalization to old wading bird categories, new wading bird categories, owl and raptor categories, and lizard categories. As expected, the generalization measures converged on a single overall pattern of generalization. No generalization was found, except for already learned categories. This pattern fits well with past work on generalization within a hierarchy, but do not fit well with theories of dimensional attention. Reasons why these findings do not match are discussed, as well as directions for future research. / Dissertation/Thesis / Ph.D. Psychology 2013

This present study investigated whether face-type (stereotypical or nonstereotypical) facilitates stereotype-consistent categorization and decision-making. Previous literature regarding adults has suggested an associative link between stereotypically Black facial features and assumed criminality. This study seeks to extend these findings by investigating whether the same heuristic processes that underpin biased decisions regarding adult phenotypic racially stereotypical features (e.g., broad nose, full lips) extend to children’s faces. That is, do the negative stereotypes (i.e., criminal Black male) that influence face-type judgments in adults extend to child face-type judgements as well. In two studies testing face-type categorization and disciplinary judgments, people were more likely to miscategorize children with stereotypical faces into negative roles more than positive roles. People were also more likely to increase their disciplinary judgments from one infraction to another for children with stererotypical faces compared to atypical faces. Results suggest that face-type cues do extend to children and also engender negative associations.

In bioinformatics there exist research topics that cannot be uniquely characterized by a set of key words because relevant key words are (i) also heavily used in other contexts and (ii) often omitted in relevant documents because the context is clear to the target audience. Information retrieval interfaces such as entrez/Pubmed produce either low precision or low recall in this case. To yield a high recall at a reasonable precision, the results of a broad information retrieval search have to be filtered to remove irrelevant documents. We use automated text categorization for this purpose. In this study we use the topic of conserved secondary RNA structures in viral genomes as running example. Pubmed result sets for two virus groups, Picornaviridae and Flaviviridae, have been manually labeled by human experts. We evaluated various classifiers from the Weka toolkit together with different feature selection methods to assess whether classifiers trained on documents dedicated to one virus group can be successfully applied to filter literature on other virus groups. Our results indicate that in this domain a bibliographic search tool trained on a reference corpus may significantly reduce the amount of time needed for extensive literature recherches.