Small Set Of Items Research Articles

The effect of interstimulus interval on sequential effects in absolute identification

In absolute identification experiments, the participant is asked to identify stimuli drawn from a small set of items which differ on a single physical dimension (e.g., 10 tones which vary in frequency). Responses in these tasks show a striking pattern of sequential dependencies: The current response assimilates towards the immediately preceding stimulus but contrasts with the stimuli further back in the sequence. This pattern has been variously interpreted as resulting from confusion of items in memory, shifts in response criteria, or the action of selective attention, and these interpretations have been incorporated into competing formal models of absolute identification performance. In two experiments, we demonstrate that lengthening the time between trials increases contrast to both the previous stimulus and the stimulus two trials back. This surprising pattern of results is difficult to reconcile with the idea that sequential dependencies result from memory confusion or from criterion shifts, but is consistent with an account that emphasizes selective attention.

Using five questions to screen for five common mental disorders in primary care: diagnostic accuracy of the Anxiety and Depression Detector

Objective Primary care providers are increasingly taking on the role of ad hoc mental health provider. However, before patients in primary care can be treated, they must be identified. This study set out to validate a very brief screening instrument for identifying primary care patients with anxiety and depression. Method Eight hundred one primary care patients completed a questionnaire screening for (1) panic disorder, posttraumatic stress disorder (PTSD) and social phobia, or (2) panic disorder, generalized anxiety disorder (GAD) and major depression. Screening was followed by a diagnostic interview. The properties of the questionnaires were examined to identify a small set of items that effectively and efficiently screened for panic disorder, PTSD, social phobia, GAD and depression. Results Five items were selected across the two versions of the questionnaire, comprising the Anxiety and Depression Detector (the ADD). The sensitivities for the items ranged from 0.62 to 1.00, and the specificity values ranged from 0.56 to 0.83. When a “yes” answer to any of the screening questions was used to predict the presence of any diagnosis, sensitivity values were 0.92 to 0.96 and specificity values were 0.57 to 0.82. Sensitivity and specificity values varied little by gender, age or ethnicity. Conclusions The five items of the ADD appear to comprise a useful screening device for anxiety and depressive disorders in primary care settings.

On a confidence gain measure for association rule discovery and scoring

This article presents a new interestingness measure for association rules called confidence gain (CG). Focus is given to extraction of human associations rather than associations between market products. There are two main differences between the two (human and market associations). The first difference is the strong asymmetry of human associations (e.g., the association “shampoo” → “hair” is much stronger than “hair” → “shampoo”), where in market products asymmetry is less intuitive and less evident. The second is the background knowledge humans employ when presented with a stimulus (input phrase).CG calculates the local confidence of a given term compared to its average confidence throughout a given database. CG is found to outperform several association measures since it captures both the asymmetric notion of an association (as in the confidence measure) while adding the comparison to an expected confidence (as in the lift measure). The use of average confidence introduces the “background knowledge” notion into the CG measure.Various experiments have shown that CG and local confidence gain (a low-complexity version of CG) successfully generate association rules when compared to human free associations. The experiments include a large-scale “free sssociation Turing test” where human free associations were compared to associations generated by the CG and other association measures. Rules discovered by CG were found to be significantly better than those discovered by other measures.CG can be used for many purposes, such as personalization, sense disambiguation, query expansion, and improving classification performance of small item sets within large databases.Although CG was found to be useful for Internet data retrieval, results can be easily used over any type of database.

Right hemisphere superiority for subitising

Lateral differences in the enumeration of small sets of items (i.e., between two and five) were investigated in a normal adult sample. Confounds due to stimulus repetition, which have characterised previous subitising research, were eliminated in a task involving the presentation of purely random item arrays to the left and right visual fields. The results indicated a clear left visual field advantage for the enumeration of arrays containing three to four items. This finding is consistent with the widely held view that the subitising process is used to enumerate arrays of up to four items, and calls into question Butterworth's (1999) recent claim that subitising is a left hemisphere process. The implications for previous pattern recognition and visual process accounts of this ability are considered.

Part-whole number knowledge in preschool children

Ability to reflect on a number as an object of thought, and to isolate its constituent parts, is basic to a deep knowledge of arithmetic, as well as much practical and applied mathematical problem solving. Part-whole reasoning and counting are closely related in children’s numerical development. The mathematical behavior of young children in part-whole problem settings was examined by using a dynamic problem situation, in which a small set of items was partitioned such that one of the subsets remained perceptually inaccessible. Issues addressed include the problem solving strategies successful children used, adaptations children make in response to successive administrations of the task over time, and characterizations of children’s mathematical thinking based on their responses to the task.

A systematic study of visual extinction. Between- and within-field deficits of attention in hemispatial neglect.

Mechanisms of visual extinction were investigated in four patients with right hemisphere damage using a partial report paradigm. Different shapes (star or triangle) were displayed in one, two or four possible locations so that double simultaneous stimuli occurred either across the two hemifields or within the same hemifield. Patients attended either to the location (right, left or both), number (one, two or four) or shape (no, one or two stars among the shapes presented) of stimuli in three separate experiments using the same displays and exposure duration. Reporting the location (Experiment 1) produced marked contralesional extinction, although reaction time was delayed compared with unilateral right trials, indicating unconscious processing. Reaction time was also delayed on correct bilateral and unilateral left trials. In contrast, enumerating stimuli (Experiment 2) caused no significant contralesional extinction on bilateral displays and reaction time was similar on bilateral and unilateral right trials, suggesting that information from both fields was grouped in a single numerable percept in this task. However, patients often detected only one of two stimuli within the left field. Whereas similarity of shapes improved localization and did not affect enumeration, identifying stars among shapes (Experiment 3) revealed a severe inability to detect two similar targets between hemifields as well as within each of the hemifields. Distracting triangles were generally less detrimental to the perception of a concurrent target on either side, but slowed the reaction time regardless of whether they were in the same or the opposite field. Relative difficulty in ignoring distractors correlated with neglect severity on a cancellation task, and was most prominent in one patient with a large amount of frontal damage. These findings suggest that (i) allocation of attention to identical stimuli can be modulated by task demand; (ii) enumerating a small set of items across fields may not require attending to individual stimuli but relies on preattentive subitizing ability, as found in normal subjects; (iii) location information may be critical for attentional mechanisms subserved by the parietal cortex and pathological competition for awareness in extinction; (iv) extinction entails a bilateral deficit in attending to two concurrent similar targets when their features must be identified; and (v) the relevance of the stimuli can modulate the distribution of attention, possibly through frontal top-down control. These findings are consistent with recent neurophysiological evidence of parietal and frontal attentional influences on ventral visual pathways.

The Utility of Item-Level Analyses in Model Evaluation: A Reply to Seidenberg and Plaut

Seidenberg and Plaut (this issue) argue that the implications of our analyses (Spieler & Balota, 1997) for the two extant connectionist models of word naming are limited by two factors. First, variables outside the scope of these models influence naming performance, so it is not surprising that the models do not account for much of the variance at the item level. Second, there is error variance associated with large item-level data sets that obviously should not be captured by these models. We point out that there are a number of variables that have been incorporated within the targeted connectionist models that should provide these models an advantage over the simple predictor variables that we selected as a baseline to evaluate the efficacy of the models (e.g., log frequency, length in letters, and number of orthographic neighbors). We also point out that there is considerable consistency across four large-scale studies of item means. Finally, we provide evidence that even under conditions of a standard word-naming study (with a small set of items), simple word frequency, orthographic neighborhoods, and length accounted for more variance than the extant connectionist models. We conclude that item-level analyses provide an important source of evidence in the evaluation of current models and the development of future models of visual word recognition.

Self-reported somatization symptoms associated with risk for extreme alcohol use.

The high rates of alcohol use in the population, the increased general health care utilization associated with untreated alcohol problems, and the often diffuse nature of somatization symptoms led us to hypothesize that somatization symptoms might be associated with alcohol use. To determine whether a relationship exists between somatization symptoms and alcohol use. Multivariable logistic regression models were used to analyze existing cross-sectional and 1-year longitudinal survey data from the National Institute of Mental Health Epidemiologic Catchment Area Program. Community households. Probability sample. None. Prevalent and incident heavy or binge drinking ("extreme alcohol use"). These measures are part of the National Institute of Mental Health Epidemiologic Catchment Area Program public core data set that was collected without regard for specific hypotheses. After control for sex, age, and education, 13 self-reported somatization symptoms showed independent cross-sectional associations to prevalent extreme alcohol use. The greater the number of somatization symptoms, the greater the risk, up to a maximum increased odds ratio of 138 to 1, of having comorbid extreme alcohol use when reporting all 13 somatization symptoms in the model. A smaller set of items was associated with the risk for subsequent new onset of extreme alcohol use. Self-reported somatization symptoms could add to the detection of extreme alcohol use. In addition, primary care and other physicians should consider somatic complaints as possible indicators of concurrent and future risk for extreme alcohol use. Potential benefits of better detection of extreme alcohol use include supporting primary and secondary prevention efforts and reduced expenditures for the diagnostic workup of somatic complaints.

Numerical Transformations in Five-month-old Human Infants

We explore numerical abilities in five-month-old infants. Wynn (1992) showed that, when an object is added to or removed from a set of one or two hidden objects, fivemonth-old infants can infer the result of this transformation. However, in Wynn’s experiment, the objects were always placed at the same two locations. Hence, it remained an open question whether infants developed numerical or location-based expectations. To address this question, 56 five-month-old infants were tested using a violation of expectation paradigm with possible (1+1=2 or 2‐1=1) and impossible (1+1=1 or 2‐1=2) events. One group was tested in conditions identical to Wynn (1992). The other group saw objects being placed on a rotating tray. Since the locations of objects were not predictable, the development of non-numerical, location-based expectations was prevented. Infants in both groups looked longer at numerically impossible events than at the related possible events. These results suggest that infants use a more abstract representation than object location, the numerical nature of which is discussed. Recent experiments suggest that very young infants, and even newborns, are able to discriminate small sets of items according to their numerosity. Ten- and fourmonth-old infants have been shown to habituate to a set of two or three dots and to dishabituate when the numerosity changes from two to three or vice versa (Starkey & Cooper, 1980; Strauss & Curtis, 1981). Similar results have been obtained with numerosities of three versus four, but not when larger numerosities

Measuring acceptance of computer-mediated communication systems

Three dimensions of acceptance for Computer-Mediated Communication Systems (CMCS) were only moderately interrelated in a longitudinal study of users of four systems: use, subjective satisfaction, and benefits. The methodological objective of this study was to identify generalizable factor structures for acceptance of CMCS, based on a small set of items. Analysis of the items measuring subjective satisfaction identified four factors: satisfaction with the interface, feelings that the system's performance was productive and stimulating, ability of CMCS to support expressive interpersonal communications, and problems with CMCS as a mode of communication and information exchange. Two components of benefits were identified: impacts on productivity and impacts on career advancement. The findings suggest that future studies of CMCS's in particular, and perhaps of computer-based information systems in general, should not assume that usage alone or subjective satisfaction alone are adequate measures of successful implementation. Use, subjective satisfaction and perceived benefits may vary independently. © 1989 John Wiley & Sons, Inc.

Intellectually gifted and nongifted children’s inference from partial knowledge

The present study explored the notion that children of different intellectual abilities vary in their metajudgment when they have partial knowledge. Gifted and average childen rated the likelihood that a protagonist who had knowledge or lack of knowledge about a category of items would remember a particular item of high or low salience. The protagonist was further portrayed as an expert or novice who had previously remembered a large or small set of items. The results show that average children are more likely than gifted children to rate the lack-of-knowledge protagonist as remembering an item. This was especially true when the protagonist was portrayed as an expert who previously had remembered a large number set, and the item to be remembered was highly salient. In contrast, gifted children are less sensitive than average children to the extremity factors of expertise, large set size, and high item salience.

A Significance Test for the Separation of Two Highly Multivariate Small Samples

A statistical technique which has been mathematically discussed in [3] is here given an explanatory derivation with formulas and illustration by application to a particular example whose basic data may be found in [1]. In this example an experiment is performed on 12 human males from 16 to 39 years old showing no alcoholic tendencies. On each individual 62 biochemical items were measured consisting of 8, 30, and 16 items from analyses of blood serum, urine, and saliva respectively, 5 taste thresholds and 3 phagocytic indices. The question is roughly: Is there evidence that the 62 items could be used to distinguish between alcoholic and non-alcoholic? This data has been much analyzed and has motivated a number of new techniques including the present one. For further references to these analyses see Chung and Fraser [2]. These authors present significance tests based on the randomization argument of Pitman [6]; their methods will be compared with the present method at the end of this paper. In general a type of individual or object is contemplated on each example of which a large number k of different characteristics may be measured, and it is supposed that 2 groups of such individuals can be distinguished by means apart from the lk measured items. Suppose a small sample to be available from each group so that the basic data consists of k items measured on each member of 2 samples. Now many questions may be asked about the kind and degree of the relationship between the k measured variables on one hand and on the other hand the two-valued variable which assigns each individual to his proper group. Our concern is with a situation in which the samples do not show a clear and meaningful relation between the group of an individual and his measurements on a single item or small set of items but where