Selective attention and the formation of linear decision boundaries: Reply to Maddox and Ashby (1998).

In this reply to W. T. Maddox and F. G. Ashby's (see record 1997-38560-018) commentary, the author argues that (a) Maddox and Ashby's current stance represents a marked departure from their previously published claims about the unimportance of selective attention in categorization, (b) they are inconsistent with their own work when they criticize S. C. McKinley and R. M. Nosofsky's (see record 83-21759) tests of the linear-boundary models, (c) their arguments about modeling averaged data have no bearing on the central conclusions reached by McKinley and Nosofsky, and (d) they make incorrect assertions regarding the application and predictions of the exemplar model. Finally, the author defends the theoretical progress that has been made in recent years with the exemplar model and argues instead that it is the decision-bound theory of Ashby and Maddox that is in need of greater constraints. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

On the relationship among identification, similarity, and categorization: Reply to Nosofsky and Smith (1992).

R. M. Nosofsky and J. K. Smith (See PA, Vol 79:33888) challenged the theoretical, methodological, and empirical results of F. G. Ashby and W. W. Lee (1991). This reply (1) shows that models derived from general recognition theory (GRT) can predict categorization from identification without incorporating selective attention, at least in the data sets suggested by Nosofsky and Smith; (2) argues that the categorization processes postulated by GRT are extremely dissimilar to the exemplar-based similarity model proposed by Nosofsky (1986); (3) criticizes Nosofsky and Smith's post hoc analysis of Ashby and Lee's identification-confusion data; (4) answers questions raised by Nosofsky and Smith about the identification and similarity models tested by Ashby and Lee; and (5) argues that with the excellent fits reported by Ashby and Lee (i.e., 99.7% of variance accounted for), least squares and maximum likelihood model fitting procedures lead to similar conditions. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

"Selective attention and the formation of linear decision boundaries": Erratum.

Reports an error in the original article by S. C. McKinley and R. M. Nosofsky (Journal of Experimental Psychology: Human Perception & Performance, 1996[Apr], Vol 22[2], 294–317). In each row of Table 2, the Akaike's information criterion (AIC) fits for the models are in error by a roughly constant amount. (When calculating the fits, the constant portion of the log-likelihood function that enters into the AIC computation was inadvertently deleted.) The relative AIC fits of the models, the proportion of variance accounted for, as well as all conclusions based on these fits, remains the same. The corrected table appears here. (The following abstract of this article originally appeared in record 1996-03036-003.) Classification experiments were designed to compare the predictions of a linear decision bound model with those of an exemplar-similarity model incorporating an explicit selective attention mechanism. Linear boundaries could account for the data only in tasks involving separable dimension stimuli and where the boundary separating the categories was orthogonal to the psychological dimensions. Linear boundaries provided poor fits to the classification data in situations involving integral dimensions or when the boundary needed to be oriented in oblique directions in the space. The results were consistent with the selection-attention assumptions embodied in the exemplar model. It was argued that similar assumptions about selective attention need to be incorporated within decision bound models. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Confusable and discriminable stimuli: Comment on Nosofsky (1986) and Shepard (1986).

R. M. Nosofsky (see record 1986-16297-001) modeled identification and categorization performance with highly similar stimuli by using a model involving a "Gaussian" relationship between similarity and Euclidean distance. Nosofsky found that this model fitted his data better than a model involving similarity as an exponential decay function of city-block distance. Nosofsky's stimuli evoked independent perceptual dimensions. By using a multivariate model of similarity, in which perceptual variation is included, this article provides a possible reconciliation of the kind of result found by Nosofsky (1986) and Shepard's (1986) theory concerning the relationship between similarity and perceptual distance. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Categorization of sounds.

The authors conducted 4 experiments to test the decision-bound, prototype, and distribution theories for the categorization of sounds. They used as stimuli sounds varying in either resonance frequency or duration. They created different experimental conditions by varying the variance and overlap of 2 stimulus distributions used in a training phase and varying the size of the stimulus continuum used in the subsequent test phase. When resonance frequency was the stimulus dimension, the pattern of categorization-function slopes was in accordance with the decision-bound theory. When duration was the stimulus dimension, however, the slope pattern gave partial support for the decision-bound and distribution theories. The authors introduce a new categorization model combining aspects of decision-bound and distribution theories that gives a superior account of the slope patterns across the 2 stimulus dimensions. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Thirty-Something Categorization Results Explained: Selective Attention, Eyetracking, and Models of Category Learning.

An eyetracking study testing D. L. Medin and M. M. Schaffer's (1978) 5-4 category structure was conducted. Over 30 studies have shown that the exemplar-based generalized context model (GCM) usually provides a better quantitative account of 5-4 learning data as compared with the prototype model. However, J. D. Smith and J. P. Minda (2000) argued that the GCM is a psychologically implausible account of 5-4 learning because it implies suboptimal attention weights. To test this claim, the authors recorded undergraduates' eye movements while the students learned the 5-4 category structure. Eye fixations matched the attention weights estimated by the GCM but not those of the prototype model. This result confirms that the GCM is a realistic model of the processes involved in learning the 5-4 structure and that learners do not always optimize attention, as commonly supposed. The conditions under which learners are likely to optimize attention during category learning are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

What is coded into memory in the absence of outcome feedback?

Although people often have to learn from environments with scarce and highly selective outcome feedback, the question of how nonfeedback trials are represented in memory and affect later performance has received little attention in models of learning and decision making. In this article, the authors use the generalized context model (Nosofsky, 1986) as a vehicle to test contrasting hypotheses about the coding of nonfeedback trials. Data across 3 experiments with selective decision-contingent and selective outcome-contingent feedback provide support for the hypothesis of constructivist coding (Elwin, Juslin, Olsson, & Enkvist, 2007), according to which the outcomes on nonfeedback trials are coded with the most likely outcome, as inferred by the individual. The relation to sampling-based approaches to judgment, and the adaptive significance of constructivist coding, are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Executive control of visual attention in dual-task situations.

A theory of executive control is presented that proposes that executive processes control subordinate processes by manipulating their parameters, reconfiguring them to respond in accord with the current task set. It adopts C. Bundesen's (1990) theory of visual attention (TVA) and R. M. Nosofsky and T. J. Palmeri's (1997) exemplar-based random walk (EBRW) as the theory of subordinate processes. It assumes that a task set is a set of TVA and EBRW parameters sufficient to perform a task and that set switching involves changing those parameters. The theory solves 2 computational problems that emerge in dual-task situations. the binding problem and the serial order problem. It can perform dual tasks in series or in parallel but prefers the serial strategy because it is faster and it solves the binding problem naturally. The theory accounts for concurrence cost, set-switching cost, crosstalk between tasks, and the modulation of crosstalk by task set. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

ALCOVE: An exemplar-based connectionist model of category learning.

ALCOVE (attention learning covering map) is a connectionist model of category learning that incorporates an exemplar-based representation (D. L. Medin and M. M. Schaffer, 1978; R. M. Nosofsky, 1986) with error-driven learning (M. A. Gluck and G. H. Bower, 1988; D. E. Rumelhart et al, 1986). ALCOVE selectively attends to relevant stimulus dimensions, is sensitive to correlated dimensions, can account for a form of base-rate neglect, does not suffer catastrophic forgetting, and can exhibit 3-stage (U-shaped) learning of high-frequency exceptions to rules, whereas such effects are not easily accounted for by models using other combinations of representation and learning method. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Selective attention to threatening stimuli and field independence as factors in the etiology of paranoid behavior.

Tested a theory that selective attention to threatening stimuli induces paranoia. An attempt was made to manipulate attention to threatening and nonthreatening statements among 60 college students and examine the effects on 3 indices of paranoia. Although manipulation checks indicated that attention was varied in the desired manner, hypothesized results in which selective attention to threatening statements would lead to greater scores on the paranoia measures were not found. However, a measure of field independence showed a predicted positive correlation with the indices of paranoia for Ss who were manipulated to attend selectively to threatening statements. These same correlations tended to be negative or zero among Ss manipulated to attend to nonthreat and among unbiased attenders. These data suggest that susceptibility to development of paranoid behavior through selective attention to threat cues may increase as a function of field independence. (17 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Theories of automaticity and the power law of practice.

In a recent reanalysis of numerosity judgment data from T. J. Palmeri (see record 1997-03378-004), T. C. Rickard (see record 1999-00904-017) found that mean response times did not decrease as a pure power law of practice and standard deviations systematically increased and then decreased with practice in some conditions. Rickard argued that these results were consistent with the component power laws (CMPL) theory of strategy shifting (Rickard, 1997), but were inconsistent with instance theory (G. D. Logan, 1988) and the exemplar-based random walk (EBRW) model (R. M. Nosofsky & Palmeri, 1997). In this article, the author demonstrates how a slightly more complex power function fitted the numerosity data nearly as well as the CMPL function, and how race models, such as instance theory and the EBRW, can predict deviations from a pure power law of practice and can predict nonmonotonic changes in standard deviations with practice. Potential limitations of CMPL are also discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Predicting category intuitiveness with the rational model, the simplicity model, and the generalized context model.

Na?ve observers typically perceive some groupings for a set of stimuli as more intuitive than others. The problem of predicting category intuitiveness has been historically considered the remit of models of unsupervised categorization. In contrast, this article develops a measure of category intuitiveness from one of the most widely supported models of supervised categorization, the generalized context model (GCM). Considering different category assignments for a set of instances, the authors asked how well the GCM can predict the classification of each instance on the basis of all the other instances. The category assignment that results in the smallest prediction error is interpreted as the most intuitive for the GCM—the authors refer to this way of applying the GCM as “unsupervised GCM.” The authors systematically compared predictions of category intuitiveness from the unsupervised GCM and two models of unsupervised categorization: the simplicity model and the rational model. The unsupervised GCM compared favorably with the simplicity model and the rational model. This success of the unsupervised GCM illustrates that the distinction between supervised and unsupervised categorization may need to be reconsidered. However, no model emerged as clearly superior, indicating that there is more work to be done in understanding and modeling category intuitiveness. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Multidimensional psychophysics and selective attention in animals.

Notes that the hypothesis that animals selectively attend developed mainly in explanations of certain conditioning and discrimination learning phenomena. This hypothesis of selective attention is evaluated against a continuity (nonattentional) theory, and most, if not all, facts of simple learning can be accounted for by a nonattentional analysis. Thus, the usefulness of selective attention as an explanatory notion remains in doubt, and few phenomena can be regarded as exemplars of selective attention. In contrast, many examples of selective attention phenomena have been discovered in human information processing experiments. Emphasis in these experiments is on instructional and stimulus variables as they affect steady-state performance rather than response learning. Recent research with animals, modeled on human steady-state tasks, promises to provide similar instances of selective attention effects in performance. (2 p ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Selective attention and the formation of linear decision boundaries.

Classification experiments were designed to compare the predictions of a linear decision bound model with those of an exemplar-similarity model incorporating an explicit selective attention mechanism. Linear boundaries could account for the data only in tasks involving separable dimension stimuli and where the boundary separating the categories was orthogonal to the psychological dimensions. Linear boundaries provided poor fits to the classification data in situations involving integral dimensions or when the boundary needed to be oriented in oblique directions in the space. The results were consistent with the selection-attention assumptions embodied in the exemplar model. It was argued that similar assumptions about selective attention need to be incorporated within decision bound models. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Sequence Effects in the Categorization of Tones Varying in Frequency.

In contrast to exemplar and decision-bound categorization models, the memory and contrast models described here do not assume that long-term representations of stimulus magnitudes are available. Instead, stimuli are assumed to be categorized using only their differences from a few recent stimuli. To test this alternative, the authors examined sequential effects in a binary categorization of 10 tones varying in frequency. Stimuli up to 2 trials back in the sequence had a significant effect on the response to the current stimulus. The effects of previous stimuli interacted with one another. A memory and contrast model, according to which only ordinal information about the differences between the current stimulus and recent preceding stimuli is used, best accounted for these data (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Theory of attentional operations in shape identification.

This article presents a theory of selective attention that is intended to account for the identification of a visual shape in a cluttered display. The selected area of attention is assumed to be controlled by a filter that operates on the location information in a display. The location information selected by the filter in turn determines the feature information that is to be identified. Changes in location of the selected area are assumed to be governed by a gradient of processing resources. Data from three new experiments are fit more parsimoniously by a gradient model than by a moving-spotlight model. The theory is applied to experiments in the recent literature concerned with precuing locations in the visual field, and to the issue of attentional and automatic processing in the identification of words. Finally, data from neuroanatomical experiments are reviewed to suggest ways that the theory might be realized in the primate brain. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Exemplars, Prototypes, and the Flexibility of Classification Models.

J. P. Minda and J. D. Smith (2001) showed that a prototype model outperforms an exemplar model, especially in larger categories or categories that contained more complex stimuli. R. M. Nosofsky and S. R. Zaki (2002) showed that an exemplar model with a response-scaling mechanism outperforms a prototype model. The authors of the current study investigated whether excessive model flexibility could explain these results. Using cross-validation, the authors demonstrated that both the prototype model and the exemplar model with a response-scaling mechanism suffered from overfilling in the linearly separable category structure. The results illustrate the need to make sure that the best-fitting model is not chasing error variance instead of variance attributed to the cognitive process it is supposed to model. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Vigilance performance in a bimodal task.

Evaluated the need for an arousal construct in a theory of vigilance, as opposed to a theory based on a selective attention construct. Performance over time was examined in a situation involving 2 detection tasks, 1 in each of 2 modalities. 34 undergraduates were instructed to direct their attention to 1 of the 2 tasks, the primary task; the other task was of secondary importance. The main concern was in discovering whether the vigilance decrement would be specific to the primary task, as would be suggested by the selective attention theory, or whether it would be seen in both tasks, as suggested by the arousal construct. Data show that the decrement is task specific. However, it is not always the primary task which shows the decrement. It is argued that neither the construct of arousal nor that of selective attention is adequate, alone, to deal with the vigilance decrement. Results are discussed in terms of these 2 concepts and in terms of some practical implications for the design of real-life displays. (15 ref.) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

When selective adaptation and contrast effects are distinct: A reply to Diehl, Kluender, and Parker.

Two alternative conceptualizations of selective adaptation with speech have recently received attention: the adaptation level theory (AL) outlined by R. L. Diehl (see record 1981-05067-001) and a 2-stage model outlined by the 1st author and P. Jusczyk (see record 1982-00351-001). Diehl et al (see record 1986-05428-001) reported evidence of streaming in selective adaptation and claimed that their results provide a counterdemonstration to recent studies that have argued against the AL approach. It is shown how the Diehl et al results can be accounted for by both the 2-stage model and AL theory. Results are presented from a study with 74 undergraduates that compared adaptation and paired-comparison procedures. These results are precisely as predicted by the 2-stage model, but they cannot be accounted for by AL theory. (26 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Separating perceptual and decisional attention processes in the identification and categorization of integral-dimension stimuli.

Four observers performed matching, identification, and categorization with stimuli that varied along the integral dimensions: brightness and saturation. General recognition theory (F. G. Ashby & J. T. Townsend, 1986) was applied to quantify the separate influences of perceptual and decisional processes within and across tasks, with a focus on separating perceptual from decisional attention processes. Good accounts of the identification data were obtained from perceptual matching representation. This perceptual representation provided a good account of the categorization data, except when decisional selective attention to 1 stimulus dimension was required. Decisional selective attention reduced the attended-dimension perceptual variance relative to the unattended-dimension perceptual variance, with a larger reduction resulting when brightness, as opposed to saturation was attended. Implications for color vision research are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)