Response selection processes for conjunctive targets.

A model is proposed for identification and response selection of cross-dimensional conjunctive stimuli. The model assumes that the formation of conjunction representations involves processes similar to those used in response selection for single-feature targets. It predicts that discrimination between conjunctive targets leads to separate competitions in each of the relevant component dimensions and that detection of a predefined single conjunctive target is done at the conjunctive map level. Experiments 1 and 2 support these two sets of predictions. Experiment 3 demonstrates that responses to conjunctions of features within the orientation dimension are qualitatively different from those for cross-dimensional conjunctive targets. It is speculated that line-orientation conjunctions are handled by the visual object-recognition system, whereas cross-dimensional conjunctions, as exemplified by the model, may be performed by a different system that is closely associated with response selection processes. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Why are conjunctive categories overextended?

Recent experiments have suggested that subjects tend to overextend conjunctive categories (J. A. Hampton, 1988). We present a series of four experiments that confirm this finding. In Experiment 1, we use Hampton's response scale, on which subjects rate both membership and typicality. In Experiment 2, we find that subjects still overextend their categories when they judge membership alone. In Experiment 3, we introduce more response options and conclude that the tendency to overextend is not an artifact of an insufficient range of possible responses. We propose an explanation of overextension that we term the compensation hypothesis: The more categories that make up a conjunction, the more leniently membership is judged. We argue that this is a result of having to make "best fit" judgments for multiple constraints in real life. We test this hypothesis in Experiment 4, which uses conjuncts of three categories. As predicted, we find that overextensions are greater with triple conjunctions than in appropriate controls in which two categories are combined or categories are judged alone. We consider the theoretical implications of a compensation strategy for categorization. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Exemplar and prototype models revisited: Response strategies, selective attention, and stimulus generalization.

J. D. Smith and colleagues (J. P. Minda & J. D. Smith, 2001; J. D. Smith & J. P. Minda, 1998, 2000; J. D. Smith, M. J. Murray, & J. P. Minda, 1997) presented evidence that they claimed challenged the predictions of exemplar models and that supported prototype models. In the authors' view, this evidence confounded the issue of the nature of the category representation with the type of response rule (probabilistic vs deterministic) that was used. Also, their designs did not test whether the prototype models correctly predicted generalization performance. The present work demonstrates that an exemplar model that includes a response-scaling mechanism provides a natural account of all of Smith et al's experimental results. Furthermore, the exemplar model predicts classification performance better than the prototype models when novel transfer stimuli are included in the experimental designs. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

If it's not there, where is it? Locating illusory conjunctions.

There is evidence that complex objects are decomposed by the visual system into features, such as shape and color. Consistent with this theory is the phenomenon of illusory conjunctions, which occur when features are incorrectly combined to form an illusory object. We analyzed the perceived location of illusory conjunctions to study the roles of color and shape in the location of visual objects. In Experiments 1 and 2, participants located illusory conjunctions about halfway between the veridical locations of the component features. Experiment 3 showed that the distribution of perceived locations was not the mixture of two distributions centered at the 2 feature locations. Experiment 4 replicated these results with an identification task rather than a detection task. We concluded that the locations of illusory conjunctions were not arbitrary but were determined by both constituent shape and color. (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)     

Conjunctive explanations: When two reasons are better than one.

The "knowledge structure" approach in attribution theory suggests that events interpretable as serving an actor's goals may dispose toward conjunctive explanations. In 2 studies, 68 undergraduates were presented vignettes about an individual undertaking goal-related activities and were asked to assign probability ratings to single explanatory reasons and to their conjunctions. Conjunctive explanations were rated more probable than one or more of their components for both mundane and important actions, for triple as well as simple conjunctions, for both goal-based and precondition-based reasons, and for various average probability levels. Conjunction effects were not found, however, for explanations of why an actor failed to take an action. Three theoretical approaches that might account for these results are compared, and it is concluded that a knowledge structure approach is less problematic than either a multiple-necessary and multiple-sufficient schema approach, or one based on H. J. Einhorn and R. M. Hogarth's (1983) model of causal strength. An attempt is made to reconcile conjunction effects with the "discounting principle" of classical attribution theory. (25 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Visual feature integration and focused attention: response competition from multiple distractor features

Predictions from Treisman's feature integration theory of attention were tested in a variant of the response-competition paradigm. Subjects made choice responses to particular color-shape conjunctions (e.g., a purple cross vs. a green circle) while withholding their responses to the opposite conjunctions (i.e., a purple circle vs. a green cross). The results showed that compatibility effects were based on both distractor color and shape. For unattended distractors in preknown irrelevant positions, compatibility effects were equivalent for conjunctive distractors (e.g., a purple cross and a blue triangle) and for disjunctive distractors (e.g., a purple triangle and a blue cross). Manipulation of attention to the distractors positions resulted in larger compatibility effects from conjoined features. These results accord with Treisman's claim that correct conjunction information is unavailable under conditions of inattention, and they provide new information on response-competition effects from multiple features.     

Modeling conceptual structure.

Reviews the book, Categories and Concepts by Edward E. Smith and Douglas L. Medin (1981). This book presents a detailed analysis of three types of models of conceptual structure. The main focus is on object concepts, such as bird, animal, chair, etc., and how these concepts are represented in the human mind. The first model considered is the classical view of concepts that goes back to Aristotle and was presupposed by most researchers in the field of concept attainment from 1920 to 1970. Seven criticisms of the classical view are presented. Although this is an excellent book, certain ways in which it might have been even better did occur to this reviewer, two of which will be mentioned here. First, the authors might have defined explicitly and succinctly what they mean by "concept" and "natural concept." Second, the authors rely primarily on categorization studies to draw inferences about concepts. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The fan effect: New results and new theories.

The fan effect (J. R. Anderson, see record 1975-06644-001) has been attributed to interference among competing associations to a concept. Recently, it has been suggested that such effects might be due to multiple mental models (G. A. Radvansky, D. H. Spieler, & R. T. Zacks, see record 1993-16287-001) or suppression of concepts (M. C. Anderson & B. A. Spellman, see record 1995-16174-001); A. R. A. Conway & R. W. Engle, see record 1994-08314-001). It was found that the Adaptive Control of Thought—Rational (ACT-R) theory, which embodies associative interference, is consistent with the results of G. A. Radvansky et-al. and that there is no evidence for concept suppression in a new fan experiment. The ACT-R model provides good quantitative fits to the results, as shown in a variety of experiments. The 3 key concepts in these fits are (a) the associative strength between 2 concepts reflects the degree to which one concept predicts the other, (b) foils are rejected by retrieving mismatching facts; and (c) participants can adjust the relative weights they give to various cues in retrieval. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Comparison and Contrast in Perceptual Categorization.

People categorized pairs of perceptual stimuli that varied in both category membership and pairwise similarity. Experiments 1 and 2 showed categorization of 1 color of a pair to be reliably contrasted from that of the other. This similarity-based contrast effect occurred only when the context stimulus was relevant for the categorization of the target (Experiment 3). The effect was not simply owing to perceptual color contrast (Experiment 4), and it extended to pictures from common semantic categories (Experiment 5). Results were consistent with a sign-and-magnitude version of N. Stewart and G. D. A. Brown's (2005) similarity-dissimilarity generalized context model, in which categorization is affected by both similarity to and difference from target categories. The data are also modeled with criterion setting theory (M. Treisman & T. C. Williams, 1984), in which the decision criterion is systematically shifted toward the mean of the current stimuli. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Conjunctive and disjunctive conflict: A theory of need conflict.

The ego disjunction theory of conflict for pairs of needs is revised to yield a theory of conjunctive and disjunctive conflict for individual needs: the concept of incompatibility is dimensionalized; the concept of compatibility is introduced; a combined dimension of compatibility-incompatibility is posited for all pairs of needs; however, joint scores of pairs of needs are not independent; the dimension of compatibility-incompatibility is therefore posited for all needs individually. Intensity of conjunctive or disjunctive conflict is specified as a function of the score for the need in relation to the degree of compatibility or incompatibility. Assumptions are made concerning variations of conflict within different populations. The assumptions generate predictions which are generally confirmed. (17 ref.) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Category-specific semantic deficits: The role of familiarity and property type reexamined.

Category-specific deficits for living things have been explained variously as an artifact due to differences in the familiarity of concepts in different categories (E. Funnell & J. Sheridan, 1992) or as the result of an underlying impairment to sensory knowledge (E. K. Warrington & T. Shallice, 1984). Efforts to test these hypotheses empirically have been hindered by the shortcomings of currently available stimulus materials. A new set of stimuli are described that the authors developed to overcome the limitations of existing sets. The set consists of color photographs, matched across categories for familiarity and visual complexity. This set was used to test the semantic knowledge of a classic patient, J.B.R. (E. K. Warrington & T. Shallice, 1984). The results suggest that J.B.R.'s deficit for living things cannot be explained in terms of familiarity effects and that the most severely affected categories are those whose identification is most dependent on sensory information. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Age, plasticity, and equipotentiality: A reply to Smith.

Responds to comments by A. Smith (see record 1984-04428-001) on the present authors' (see record 1982-05864-001) discussion of recovery of function from brain damage. It is argued that current interpretations of the literature on hemispherectomy and childhood aphasia are not consistent with Smith's viewpoints on age, plasticity, and equipotentiality. An evaluation of these concepts and the issues underlying recovery of function must be based on research from normal children and a variety of brain-injured samples. (37 ref) (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)     

Appraisal as a Pervasive Determinant of Anger.

L. Berkowitz and E. Harmon-Jones (see record 2004-15096-001) challenge appraisal theories of emotion by describing 2 sets of conditions (physical discomfort and anger-related muscle actions) in which anger appears to be elicited in the absence of theoretically predicted appraisals. In response, the authors discuss the ability of the specific appraisal model they have developed (e.g., C. A. Smith & L. D. Kirby, 2000, 2001; C. A. Smith & R. S. Lazarus, 1990) to account for such instances of anger. First, a number of issues are clarified relevant to the authors' model, including the nature of both the cognitive operations underlying appraisal and the specific appraisals hypothesized to evoke anger. The authors then describe how their model can account for the instances of anger described by L. Berkowitz and E. Harmon-Jones and how both accounts might be tested. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Culture and context in the evolutionary concept of mental disorder.

The evolutionary theory of the concept of mental disorder as harmful dysfunction that Wakefield (see record 1999-03409-002) proposed (a) does not correspond to how the term disorder is used in psychiatric nosology or in clinicians' everyday practice; (b) does not cover the territory to which the term reasonably could be applied; and (c) is not especially useful for research, clinical, or social purposes. The broad concept of disorder is a polythetic, not a monothetic, concept. As such, there need be no essential characteristic, criterion, or single prototype of disorder. Instead, multiple prototypes with varying features are used to group together a wide range of disparate phenomena by analogy. Useful refinements of our concepts of disorder have come from analyses of the nature of action and intentionality. What are most needed now are careful analyses of the social embedding of our concepts in cultural knowledge and practice. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Fractionating the binding process: Neuropsychological evidence from reversed search efficiencies.

The authors present neuropsychological evidence distinguishing binding between form, color, and size (cross-domain binding) and binding between form elements. They contrasted conjunctive search with difficult feature search using control participants and patients with unilateral parietal or fronto/temporal lesions. To rule out effects of task difficulty or loss of top-down guidance of search, the authors made conjunction search easier than feature search. Despite this, parietal patients were selectively impaired at detecting conjunction targets in their contralateral field. In contrast, the parietal patients performed like the other participants with form conjunctions, with form conjunctions being easier to detect than difficult feature targets. These data indicate a qualitative difference between binding in the form domain and binding across form, color, and size, consistent with theories that propose distinct binding processes in vision. (PsycINFO Database Record (c) 2010 APA, all rights reserved)