Relative judgment and knowledge of the category structure (original) (raw)
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Sequence effects in categorization of simple perceptual stimuli
Journal of Experimental Psychology: Learning, Memory, and Cognition, 2002
Categorization research typically assumes that the cognitive system has access to a (more or less noisy) representation of the absolute magnitudes of the properties of stimuli, and that this information is used in reaching a categorization decision. However, research on identification of simple perceptual stimuli suggests that people have poor representations of absolute magnitude information and that judgments about absolute magnitude are strongly influenced by preceding material. The experiments presented here show strong sequence effects in categorization tasks. Classification of a borderline stimulus was more accurate when preceded by a distant member of the opposite category than by a distant member of the same category. It is argued that this category contrast effect cannot be accounted for by extant exemplar or decisionābound models. The effect suggests the use of relative magnitude information in categorization. A memory and contrast model illustrates how relative magnitude information may be used in categorization.
Psychonomic bulletin & review, 2014
Traditional studies of human categorization often treat the processes of encoding features and cues as peripheral to the question of how stimuli are categorized. However, in domains where the features and cues are less transparent, how information is encoded prior to categorization may constrain our understanding of the architecture of categorization. This is particularly true in speech perception, where acoustic cues to phonological categories are ambiguous and influenced by multiple factors. Here, it is crucial to consider the joint contributions of the information in the input and the categorization architecture. We contrasted accounts that argue for raw acoustic information encoding with accounts that posit that cues are encoded relative to expectations, and investigated how two categorization architectures-exemplar models and back-propagation parallel distributed processing models-deal with each kind of information. Relative encoding, akin to predictive coding, is a form of noi...
Learned Visual Categorical Perception Effects Depend on Method of Assessment and Stimulus Discriminability, 2014
Learned categorical perception (CP) effects were assessed using three different measures and two sets of stimuli differing in discriminability, both of which varied on one category-relevant and one category-irrelevant dimension. Two different kinds of analysis produced patterns of results that depended on both of these variables and show that categorical perception effects are sensitive to variations in assessment task and stimulus discriminability. Only the similarity-rating task produced evidence of between-category expansion effects, suggesting that participants used different strategies for subjective and objective tasks. Generally, there was evidence that category training caused a decrease in the salience of category-irrelevant variation, but when the assessment task cued participants to category-irrelevant differences they were equally apt at identifying category-irrelevant variation as a control group.
The Influence of Stimulus Properties on Category Construction
Journal of Experimental Psychology-learning Memory and Cognition, 2004
It has been demonstrated that when people free classify stimuli presented simultaneously in an array, they have a preference to categorize by a single dimension. However, when people are encouraged to categorize items sequentially, they sort by "family resemblance," grouping by overall similarity. The present studies extended this research, producing 3 main findings. First, the sequential procedure introduced by G. Regehr and L. R. Brooks (1995) does not always produce a preference for family resemblance sorts. Second, sort strategy in a sequential procedure is sensitive to subtle variations in stimulus properties. Third, spatially separable stimuli evoked more family resemblance sorts than stimuli of greater spatial integration. It is suggested that the family resemblance sorting observed is due to an analytic strategy. Monsell for their helpful comments and suggestions on earlier versions of this article. We also thank Lee Brooks and an anonymous reviewer for their invaluable suggestions.
Classification in well-defined and ill-defined categories: evidence for common processing strategies
Journal of experimental psychology. General, 1980
Early work in perceptual and conceptual categorization assumed that categories had criterial features and that category membership could be determined by logical rules for the combination of features. More recent theories have assumed that categories have an ill-defined structure and have prosposed probabilistic or global similarity models for the verification of category membership. In the experiments reported here, several models of categorization were compared, using one set of categories having criterial features and another set having an ill-defined structure. Schematic faces were used as exemplars in both cases. Because many models depend on distance in a multidimensional space for their predictions, in Experiment 1 a multidimensional scaling study was performed using the faces of both sets as stimuli, In Experiment 2, subjects learned the category membership of faces for the categories having criterial features. After learning, reaction times for category verification and typ...
Category variability, exemplar similarity, and perceptual classification
Memory & Cognition, 2001
Experiments were conducted in which observers learned to classify simple perceptual stimuli into low-variability and high-variability categories. Similarities between objects were measured in independent psychological-scalingtasks. The results showed that observers classified transfer stimuli into the high-variability categories with greater probability than was predicted by a baseline version of an exemplar-similarity model. Qualitative evidence for the role of category variability on perceptual classification, which could not be explained in terms of the baseline exemplar-similaritymodel, was obtained as well. Possible accounts of the effects of category variability are considered in the General Discussion section.
Attention and learning processes in the identification and categorization of integral stimuli
The relationship between subjects' identification and categorization learning of integral-dimension stimuli was studied within the framework of an exemplar-based generalization model. The model was used to predict subjects' learning in six different categorization conditions on the basis of data obtained in a single identification learning condition. A crucial assumption in the model is that because of selective attention to component dimensions, similarity relations may change in systematic ways across different experimental contexts. The theoretical analysis provided evidence that, at least under unspeeded conditions, selective attention may play a critical role in determining the identification-categorization relationship for integral stimuli. Evidence was also provided that similarity among exemplars decreased as a function of identification learning. Various alternative classification models, including prototype, multiple-prototype, average distance, and "value-on-dimensions" models, were unable to account for the results.
Stimulus generalization and equivalence classes: a model for natural categories
Journal of the Experimental Analysis of Behavior, 1991
Two three-member classes were formed by training AB and BC using a conditional discrimination procedure. The A and B stimuli were nonsense syllables, and the C stimuli were sets of "short" or "long" lines. To test for equivalence, Cl or C2 was presented as a sample with Al and A2 as comparisons. Once the class-related comparison was chosen consistently, different line lengths were substituted for the training lines in the CA tests. In general, the likelihood of choosing a given comparison was an inverse function of the difference in the length of the test line from the training line. Stimuli in an equivalence class became functionally related not only to each other but also to novel stimuli that rcsembled a member of the equivalence class. The combination of primary generalization and equivalence class formation, then, can serve as a model to account for the development of naturally occurring categories.
Journal of Experimental Psychology: Human Perception and Performance, 2009
The type of visual information needed for categorizing faces and nonface objects was investigated by manipulating spatial frequency scales available in the image during a category verification task addressing basic and subordinate levels. Spatial filtering had opposite effects on faces and airplanes that were modulated by categorization level. The absence of low frequencies impaired the categorization of faces similarly at both levels, whereas the absence of high frequencies was inconsequential throughout. In contrast, basic-level categorization of airplanes was equally impaired by the absence of either low or high frequencies, whereas at the subordinate level, the absence of high frequencies had more deleterious effects. These data suggest that categorization of faces either at the basic level or by race is based primarily on their global shape but also on the configuration of details. By contrast, basic-level categorization of objects is based on their global shape, whereas category-specific diagnostic details determine the information needed for their subordinate categorization. The authors conclude that the entry point in visual recognition is flexible and determined conjointly by the stimulus category and the level of categorization, which reflects the observer's recognition goal.