Effects of background knowledge on object categorization and part detection.

Abstract

Previous research has shown that background knowledge affects the ease of concept learning, but little research has examined its effects on speeded categorization of instances after the category is well learned. Subjects in 4 experiments first learned novel categories. At test, they categorized a new set of novel stimuli that were either consistent or inconsistent with background knowledge given about the categories. Background knowledge affected categorization responses in an untimed task, with usual reaction time instructions, with a response deadline, or when the stimuli were presented for 50 ms followed by a mask. Three other experiments using a part-detection task showed that subjects were more likely to notice missing parts that were critical than noncritical according to background knowledge. The mechanisms by which background knowledge affects categorization and part detection are discussed.Human categorization is a cognitive proceSs in which people decide whether an instance is a member of a category by comparing the instance with their conceptual representations. Categorization research in the 1970s and early 1980s primarily focused on certain issues of representation, such as whether concepts are represented by prototypes (summary representations of an entire category) or by exemplars (individual instances of the categories). Despite the differences between these models of conceptual representation, they share some common assumptions. One assumption is that concepts are collections of features; another is that categorization involves feature matching and computation of feature similarity between the instance to be categorized and the concept with which the instance is compared (see Smith & Medin, 1981, for a review).More recently, however, a growing number of researchers have argued that similarity computation by feature matching is insufficient to explain conceptual coherence and the nature of conceptual representation. One type of argument is that the similarity relation between an instance and a concept can vary widely across contexts, but the featurematching process used by most models cannot capture this flexibility (Murphy, 1993). Another type of argument points to the evidence that perceptual similarity is not the sole factor that contributes to conceptual coherence; underlying beliefs about the nature of the category greatly influence coherence and category decisions (Keil, 1989;Medin & Ortony, 1989;Murphy & Medin, 1985;Rips, 1989;Rips & Collins, 1993). For example, people expect members of a biological kind to have an underlying genetic relation and artifacts of the same type to have a similar function. Thus, Emilie L. Lin and Gregory L. Murphy, Beckman Institute, University of Illinois.Correspondence concerning this article should be addressed to Gregory L. Murphy, Beckman Institute, University of Illinois, 405 North Mathews Avenue, Urbana, Illinois 61801. Electronic mail may be sent to gmurphy@s.psych.uiuc.edu.researchers have begun to propose that an account of concepts and categorization ...

Role of prior knowledge in implicit and explicit learning of artificial grammars

“…Similarity and distance knowledge could develop within about a second per string (as the above chance similarity and distance knowledge in the time pressure inconsistent condition suggests). This finding is broadly consistent with categorization research showing that general knowledge can be applied early on during categorization (e.g., Lin & Murphy, 1997;Luhmann et al, 2006;Palmeri & Blalock, 2000).…”

“…This condition allows us to distinguish between performance factors that require time to develop and ones that do not. For example, perceptual categorization research has shown that the application of background knowledge can be fast (Lin & Murphy, 1997;Luhmann, Ahn, & Palmeri, 2006;Palmeri & Blalock, 2000). Other researchers (Sloman, 1996;Smith & Sloman, 1994) equate knowledge-based categorization with rule-based processing, which they consider as time and effort demanding and contrast it with similarity-based categorization, which they consider automatic.…”

La Edad Se Correlaciona Directamente con la Fuerza de los Estereotipos de Género: Evidencia Obtenida en una Tarea de Memoria de Reconocimiento

“…Una vez que se posee el concepto, este afecta el procesamiento cognitivo (Bower, Clark, Lesgold & Winzenz, 1969;Lin & Murphy, 1997). En algunos casos el concepto puede hacer el procesamiento más eficiente.…”

Altering object representations through category learning

“…Theorists have also explored the possibility that the descriptions given to concept members do not only in¯uence, but are also in¯uenced by, the learned concepts. Several empirical results and theoretical treatments lead to the suggestion that the relation between perceptual descriptions and concept representations is not unidirectional, but rather is bi-directional and mutually supporting Goldstone, Steyvers, Spencer-Smith, & Kersten, 2000;Lin & Murphy, 1997;Schyns, Goldstone, & Thibaut, 1998;Schyns & Murphy, 1994;Schyns & Rodet, 1997;Wisniewski & Medin, 1994).…”