Journey to the center of the category: The dissociation in amnesia between categorization and recognition.

The authors' theoretical analysis of the dissociation in amnesia between categorization and recognition suggests these conclusions: (a) Comparing to-be-categorized items to a category center or prototype produces strong prototype advantages and steep typicality gradients, whereas comparing to-be, categorized items to the training exemplars that surround the prototype produces weak prototype advantages and flat typicality gradients; (b) participants often show the former pattern, suggesting their use of prototypes; (c) exemplar models account poorly for these categorization data, but prototype models account well for them; and (d) the recognition data suggest that controls use a single-comparison exemplar-memorization process more powerfully than amnesics. By pairing categorization based in prototypes with recognition based in exemplar memorization, the authors support and extend other recent accounts of cognitive performance that intermix prototypes and exemplars, and the authors reinforce traditional interpretations of the categorization-recognition dissociation in amnesia. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Alternative strategies of categorization

Psychological studies of categorization often assume that all concepts are of the same general kind, and are operated on by the same kind of categorization process. In this paper, we argue against this unitary view, and for the existence of qualitatively different categorization processes. In particular, we focus on the distinction between categorizing an item by: (a) applying a category-defining rule to the item vs. (b) determining the similarity of that item to remembered exemplars of a category. We begin by characterizing rule application and similarity computations as strategies of categorization. Next, we review experimental studies that have used artificial categories and shown that differences in instructions or time pressure can lead to either rule-based categorization or similarity-based categorization. Then we consider studies that have used natural concepts and again demonstrated that categorization can be done by either rule application or similarity calculations. Lastly, we take up evidence from cognitive neuroscience relevant to the rule vs. similarity issue. There is some indirect evidence from brain-damaged patients for neurological differences between categorization based on rules vs. that based on similarity (with the former involving frontal regions, and the latter relying more on posterior areas). For more direct evidence, we present the results of a recent neuroimaging experiment, which indicates that different neural circuits are involved when people categorize items on the basis of a rule as compared with when they categorize the same items on the basis of similarity.     

Prototype abstraction by monkeys (Macaca mulatta).

The authors analyze the shape categorization of rhesus monkeys (Macaca mulatta) and the role of prototype- and exemplar-based comparison processes in monkeys' category learning. Prototype and exemplar theories make contrasting predictions regarding performance on the Posner-Homa dot-distortion categorization task. Prototype theory--which presumes that participants refer to-be-categorized items to a representation near the category's center (the prototype)--predicts steep typicality gradients and large prototype-enhancement effects. Exemplar theory--which presumes that participants refer to-be-categorized items to memorized training exemplars-predicts flat typicality gradients and small prototype-enhancement effects. Across many categorization tasks that, for the first time, assayed monkeys' dot-distortion categorization, monkeys showed steep typicality gradients and large prototype-enhancement effects. These results suggest that monkeys--like humans--refer to-be-categorized items to a prototype-like representation near the category's center rather than to a set of memorized training exemplars. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Storage and retrieval of associative clusters: A stages-of-learning analysis of associative memory traces.

In this research, the assumptions underlying the unitary trace theory of item representation and acquisition were tested in two cued-recall experiments in which the degree of preexperimental knowledge (typicality) was manipulated. Subjects learned lists of word triads (each of which consisted of a single cue and two targets) to a stringent acquisition criterion. In Experiment 1, typicality was manipulated in the absence of semantic relationships between members of the associative clusters. In Experiment 2, semantic relationships were present among cluster members, and preexperimental knowledge was manipulated by varying the degree of intracluster category membership as measured by whether cue and target items were typical or atypical category exemplars. In both experiments a mathematical model that embodies stages-of-learning distinctions was used to analyze the acquisition data. The results indicated that (1) cues and targets were represented in a single holistic memory trace, and (2) the manipulation of the degree of preexperimental knowledge affected both trace storage and retrieval learning, but had only a minimal impact on retrieval performance between the time a trace was stored and the time retrieval learning was complete. It was argued that these findings are consistent with a single unitary trace interpretation, namely, the modified storage-retrieval model. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Combining graded categories: Membership and typicality.

Forming a conjoint category (square tables) from constituent categories (squares and tables) has traditionally been remodeled by formal set intersection. In this traditional view, in which categories are treated as precisely defined sets, an item is a member of the conjoint category if and only if it is a member of both constituent categories. However, as is now widely believed, many categories should be treated as graded, with members that vary in typicality and boundaries that are inexact. In the present article, it is argued that set intersection is inappropriate for combining graded categories. The authors propose an alternative formal mechanism in which a conjoint category is constructed from constituent categories by forming a joint distribution of values. The proposed model accounts for both membership and typicality of instances in conjoint categories, but only when the constituent categories are independent, or the relation between them is known. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Similarity, frequency, and category representations.

This article studies the joint roles of similarity and frequency in determining graded category structure. Perceptual classification learning experiments were conducted in which presentation frequencies of individual exemplars were manipulated. The exemplars had varying degrees of similarity to members of the target and contrast categories. Classification accuracy and typicality ratings increased for exemplars presented with high frequency and for members of the target category that were similar to the high-frequency exemplars. Typicality decreased for members of the contrast category that were similar to the high-frequency exemplars. A frequency-sensitive similarity-to-exemplars model provided a good quantitative account of the classification learning and typicality data. The interactive relations among similarity, frequency, and categorization are considered in the General Discussion. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Distinguishing prototype-based and exemplar-based processes in dot-pattern category learning.

The authors contrast exemplar-based and prototype-based processes in dot-pattern categorization. In Experiments 1A and 1B, participants provided similarity ratings of dot-distortion pairs that were distortions of the same originating prototype. The results show that comparisons to training exemplars surrounding the prototype create flat typicality gradients within a category and small prototype-enhancement effects, whereas comparisons to a prototype center create steep typicality gradients within a category and large prototype-enhancement effects. Thus, prototype and exemplar theories make different predictions regarding common versions of the dot-distortion task. Experiment 2 tested these different predictions by having participants learn dot-pattern categories. The steep typicality gradients, the large prototype effects, and the superior fit of prototype models suggest that participants refer to-be-categorized items to a representation near the category's center (the prototype), and not to the training exemplars that surround the prototype. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effect of memory decay on predictions from changing categories.

In contrast to the static categories assumed in most categorization experiments, many real-world categories undergo gradual and systematic change in their definitions over time. Four experiments were carried out to study such category change. In these studies, participants successfully adjusted as category change occurred, but also showed a lingering and cumulative effect of past observations. The participants' performance was closely modeled by incorporating memory decay for past observations into J. R. Anderson's (1990, 1991) rational categorization algorithm and into a version of R. M. Nosofsky's (1986) exemplar categorization model. The resulting models suggest that the decay function is closer to a power law than to an exponential and that decay occurs both by item and by time, with the item decay being stronger than the time decay. The finding of power law decay gives additional support to claims that exemplar memories are used in categorization. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Accentuation and sensitization effects in the categorization of multifaceted stimuli.

Categorization affects perceptions in ways that are assumed to underlie social stereotypes. Research on categorization, however, has focused either on very simple stimuli or on judgmental tasks that focus attention only on single dimensions. To more fully understand the role of categorization in social perception, it is important to examine its effects in the case of multifaceted stimuli and holistic judgments. In 3 studies, participants formed an impression of a focal category of multifaceted stimuli either by itself or in the context of another category. They then judged the typicality of exemplars to the focal category. Results showed that categorization in the presence of a context produced both accentuation and sensitization effects: Participants accentuated between-category differences on relevant dimensions, and they were less sensitive to exemplar differences on irrelevant dimensions. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Factoring items and factoring scales are different: Spurious evidence for multidimensionality due to item categorization.

Illustrates how categorization spuriously influences apparent dimensionality inferred from (a) principal components (PC), (b) exploratory maximum likelihood (EML) analysis, and (c) {lisrel}. Simulated continuous, parallel, unifactor "scores," of differing reliability, were categorized in various ways to create "items." All forms of categorization spuriously suggested multidimensionality. PC-based indices were more misleading with less reliable data; the reverse was true with inferential (EML and {lisrel}) indices. Varying item "splits" to create item distribution differences further enhanced these spurious effects. Likewise, multicategory (Likert-type) items were more likely to yield artifacts than dichotomous items using inferential criteria even though the multicategory data were more reliable. Criteria for dimensionality applicable to continuous (scale-level) data are therefore inappropriate for discrete (item-level) data. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Acquiescence and the F Scale: New analysis not supporting Samelson and Yates.

184 undergraduates each responded to the California F Scale, a reversed F Scale, and rated the item pairs on the degree the original item was contradicted by its reversal. Correlations across items indicate a negative relationship between the contradictoriness scale value obtained from the group for each item pair and the number of double agreements given each item pair by the group. Further analysis of data indicates that each S tended to give double agreements when his ratings indicated the reversal basically contradicted the original item. Thus this type of correlation across items can no longer be taken as evidence that Ss give double agreements when the original item is not contradicted by its reversal. (French summary) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Using item response theory to study the convergent and discriminant validity of three questionnaires measuring cigarette dependence.

To determine whether the Cigarette Dependence Scale, the Fagerstr?m Test for Nicotine Dependence, and the Nicotine Dependence Syndrome Scale (NDSS) reliably and correctly assessed both weakly and severely dependent individuals, the authors collected data via Internet from 2,435 current smokers, from 2004 to 2007. They used a 2-parameter item response model to determine the difficulty and discrimination of each question and used correlations between latent scores to assess convergent and discriminant validity. The reliability of all scales was close to or exceeded .70. Both the Cigarette Dependence Scale and the Fagerstr?m Test for Nicotine Dependence had 1 misfitting item. Each NDSS scale had at least 2 misfitting items. The information curve of each of the questionnaires peaked between -2 and 2 and was low at both extremes. All questionnaires had adequate reliability and were more informative for a medium level of the underlying cigarette dependence continuum than for both extremes of this continuum. The correlations between latent scores indicated good convergent validity between questionnaires and low discriminant validity between NDSS subscales, except for Tolerance. This result suggests that nicotine dependence may not be composed of 5 dimensions but may be unidimensional and distinct from reduced sensitivity to the effects of smoking (Tolerance). (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Typicality, familiarity and the recognition of male and female faces.

22 male and 43 female undergraduates provided judgments of typicality, familiarity, and recognition for each of 209 photographs of male and female faces. Results support the notion that the same-sex bias in recognition often found with female Ss is a function of perceived typicality: Female Ss rated female faces to be more typical than male faces, whereas male Ss showed no such bias. The same pattern of results was found for false–positive responses on a test of item recognition. The rated familiarity of the faces was not related to the Ss' recognition judgments, suggesting that the perceived context-free familiarity of faces is not the source of the effects of typicality or sex of face on the recognition of faces. (French abstract) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Reconsidering the unit of analysis: A model of student ratings of instruction.

This paper describes the underlying structure of student ratings of instruction, using three units of analysis. Data were analyzed using individual ratings, class means, and deviations from class means. Course characteristics were then used as independent variables in the prediction of factor scores. Results indicated that the underlying structure of class means is different from the structure yielded by the other units of analysis. Course characteristics described a small percentage of the variance of the factor scores. The usual robust factor structure of ratings, assumed to be due to shared implicit theories about instructor behavior or item similarity, was questioned. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Post-hoc Rasch analysis of optimal categorization of an ordered-response scale

The purpose of this study was to determine the optimal categorization of a self-efficacy ordered-response scale using the Rasch analysis and compare the performance of the Rasch statistics and parameter estimates with conventional statistics. A 50-item scale to measure psychomotor self-efficacy was administered to a total of 2,022 children, including 1,009 boys and 1,013 girls. The data analysis started by collapsing the original five adjacent categories into two, three, and four categories, and a total of 14 data sets were derived. Each of these data sets, including the original one, was analyzed using the Rasch rating scale model, and a set of Rasch model-data fit, category, and separation statistics and parameter estimates, as well as three conventional statistics, were computed and compared. It was found that, instead of the five-category construct designed, the best order of category meanings of the scale in respondents' perceptions was a three-category construct. The Rasch threshold estimates were sensitive indexes in determining the order of the categorization, and that item separation statistics were useful in determining the optimal categorization after its order was confirmed. The commonly used coefficient alpha was found not helpful at all in determining the optimal categorization. The Rasch analysis was demonstrated to be a useful post-hoc analytic approach in determining the optimal categorization of an ordered-response scale.     

Item subtlety and face validity in personality assessment.

Makes a distinction between the concepts of item subtlety and face validity. Face validity is viewed as the contextual relevance of personality test items, whereas item subtlety is conceptualized as the lack of an obvious substantive link between test item content and its underlying construct. An experiment with 193 college students is described; materials included 80 test items, 16 from each of the Abasement, Achievement, Affiliation, Autonomy, and Dominance scales of the Personality Research Form, Form E (D. N. Jackson, 1974). Greater face validity and lower levels of subtlety were associated empirically with higher item validity. Although trait differences in the relationship of item subtlety to criterion validity were found, these were not mediated by desirability. These results are viewed as supporting a rational strategy of test construction emphasizing the use of relevant test item content. (39 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Conjunctions of visually based categories: Overextension and compensation.

The degree to which overextension effects found with conjunctions of semantic categories of visual stimuli was tested in 4 experiments. Overextension occurs when participants categorize a stimulus in the conjunction of 2 categories but fail to categorize the same stimulus as belonging to 1 of the 2 constituent categories considered individually. Stimuli for the present experiments were ambiguous colored letter shapes and cartoon faces that could vary along dimensions of happiness and either apparent intelligence or apparent age. Overextension was found with both stimulus sets, thus showing that the phenomenon is not restricted to categorization in superordinate semantic categories. There was also evidence that typicality in 1 category could compensate for borderline membership of the other. More overextension was found for faces than for letters, and there was evidence for asymmetric compensation between category dimensions. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Phonological typicality influences sentence processing in predictive contexts: Reply to Staub, Grant, Clifton, and Rayner (2009).

In 2 separate self-paced reading experiments, Farmer, Christiansen, and Monaghan (2006) found that the degree to which a word's phonology is typical of other words in its lexical category influences online processing of nouns and verbs in predictive contexts. Staub, Grant, Clifton, and Rayner (2009) failed to find an effect of phonological typicality when they combined stimuli from the separate experiments into a single experiment. We replicated Staub et al.'s experiment and found that the combination of stimulus sets affects the predictiveness of the syntactic context; this reduces the phonological typicality effect as the experiment proceeds, although the phonological typicality effect was still evident early in the experiment. Although an ambiguous context may diminish sensitivity to the probabilistic relationship between the sound of a word and its lexical category, phonological typicality does influence online sentence processing during normal reading when the syntactic context is predictive of the lexical category of upcoming words. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Base-rate effects in multidimensional perceptual categorization

The optimality of human performance when category base rates differ was investigated in 2 multidimensional perceptual categorization tasks. All participants were sensitive to differences in base rate, even during their 1st experimental session. Nearly half of the participants learned the optimal decision bound by their final experimental session. Little evidence for conservative cutoff placement was found (i.e., an underestimation of category base-rate differences). In fact, participants who did not learn the optimal decision bound tended to use a decision bound that overestimated the base-rate difference. Across all conditions participants showed a clear shift toward the optimal decision bound with experience. These data suggest that experienced participants are highly sensitive to differences in category base rate. The model-based analyses suggest that the decision-bound model of categorization (Ashby, 1992a; Ashby & Maddox, 1993; Maddox & Ashby, 1993) provides a powerful tool for investigating the limits of human categorization performance.     

"Social categorization and the truly false consensus effect": Correction to Krueger and Zeiger.

Reports an error in "Social categorization and the truly false consensus effect" by Joachim Krueger and Joanna S. Zeiger (Journal of Personality and Social Psychology, 1993[Oct], Vol 65[4], 670-680). In this article, the second and third column headings of Table 2 were inadvertently transposed. The corrected table is provided in the erratum. (The following abstract of the original article appeared in record 1994-33435-001.) The false consensus effect involves adequate inductive reasoning and egocentric biases. To detect truly false consensus effects (TFCEs), item endorsements were correlated with the differences between estimated and actual consensus within Ss. In Exp 1, Ss overgeneralized from themselves to gender in-groups and to the overall population, but not to gender out-groups. Exps 2 and 3 demonstrated intuitive understanding of consensus bias. Another person's choices were inferred from that person's population estimates or estimates about the gender in-group. In Exp 4, Ss inferred that consensus estimates for a behavior were higher among people who were willing to engage in that behavior than among those who were not. Implications of these findings for general induction, social categorization, and the psychological processes underlying TFCEs are discussed. [A correction concerning this article appears in Journal of Personality and Social Psychology, 1993, Vol 65(6), 1090. The second and third column headings of Table 2 were inadvertently transposed and the corrected table is included.] (PsycINFO Database Record (c) 2010 APA, all rights reserved)