Unidimensional Classification Research Articles

“The ABC of GOLD A-B-C-D”

Chronic obstructive pulmonary disease (COPD) is the cause of considerable morbidity and mortality with the global burden of disease projected to increase even further in forthcoming years [1]. Although significant advances have been made in our understanding, assessment and management of COPD in the past decade, the heterogeneity of clinical features and variability in disease course continue to be only partially explained by currently available metrics. Hence, COPD subtype determination remains challenging. Until the late 1990s, COPD was defined by abnormal expiratory airflow [2, 3]. Although there was no consensus about a universal staging system, forced expiratory volume in 1 s (FEV1) alone was generally used to define disease severity [3]. FEV1 does capture many facets of disease severity and hence algorithms were proposed for the management of COPD, based on the reduction in FEV1 [3]. However, this approach is problematic in that not all aspects of the disease are adequately captured by FEV1. Furthermore, such algorithms were not globally implemented [2] and attention from the healthcare community, scientific societies and government officials for COPD was generally low. In 1997 the Global Initiative for Chronic Obstructive Lung Disease (GOLD) was launched in order to raise worldwide awareness of COPD and improve prevention and treatment of the disease. In the first GOLD workshop summary report [4], COPD was defined as “a disease state characterized by airflow limitation that is not fully reversible and is associated with an abnormal inflammatory response of the lungs to noxious particles or gases”. Furthermore, it stated that “symptoms, functional abnormalities and complications of COPD can all be explained on the basis of this underlying inflammation and the resulting pathology” [4]. A unidimensional classification of disease severity …

Developing Representations of Compound Stimuli

Classification based on multiple dimensions of stimuli is usually associated with similarity-based representations, whereas uni-dimensional classifications are associated with rule-based representations. This paper studies classification of stimuli and category representations in school-aged children and adults when learning to categorize compound, multi-dimensional stimuli. Stimuli were such that both similarity-based and rule-based representations would lead to correct classification. This allows testing whether children have a bias for formation of similarity-based representations. The results are at odds with this expectation. Children use both uni-dimensional and multi-dimensional classification, and the use of both strategies increases with age. Multi-dimensional classification is best characterized as resulting from an analytic strategy rather than from procedural processing of overall-similarity. The conclusion is that children are capable of using complex rule-based categorization strategies that involve the use of multiple features of the stimuli. The main developmental change concerns the efficiency and consistency of the explicit learning system.

One or two dimensions in spontaneous classification: A simplicity approach

When participants are asked to spontaneously categorize a set of items, they typically produce unidimensional classifications, i.e., categorize the items on the basis of only one of their dimensions of variation. We examine whether it is possible to predict unidimensional vs. two-dimensional classification on the basis of the abstract stimulus structure, by employing Pothos and Chater’s simplicity model of spontaneous categorization [Pothos, E. M., & Chater, N. (2002). A simplicity principle in unsupervised human categorization. Cognitive Science, 26, 303–343]. The simplicity model provides a quantitative measure of how intuitive a particular classification is. With objects represented in two dimensions, we propose that a unidimensional classification will be preferred if it is more intuitive than all possible two-dimensional ones, and vice versa. Empirical results supporting this proposal are reported. Implications for Goodman’s paradox are discussed.

Mild Retardation, Academic Achievement, and Piagetian or Psychometric Tests of Reasoning

Unidimensional classification, unidimensional seriation, and number conservation were measured for 80 elementary school children diagnosed as having mild mental retardation. Scores on the Slosson Intelligence Test (SIT), Peabody Picture Vocabulary Test (PPVT-R), and Peabody Individual Intelligence Test (PIAT) were obtained for the same children. Correlations between scores on the Piagetian and Slosson measures of reasoning ability ranged from .56 to .85, and were generally higher for mental age than IQ. Correlations between the Piagetian measures and the vocabulary the children had achieved as measured by the PPVT-R ranged from .61 to .80. Scores on the PLAT achievement measure correlated .57 to .73 with the Piagetian measures. This PIAT achievement measure correlated .72 with SIT MAs. The correlation between the SIT MA and PPVT-R was .88. Raw scores on the PPVT-R and PIAT produced a correlation of .77, an index of convergent validity for these two achievement measures when applied to elementary-school aged children with mild mental handicaps. The SIT had predictive validity for the same population, since both IQ and MA scores correlated with absolute achievement on both standardized measures. The same was true for the Piagetian measures of reasoning ability. The moderate to high correlations between SIT and classification, seriation, and conservation measures indicates that all express important aspects of reasoning for this population. This suggests the possibility of improving some children's reasoning and consequently their academic achievement by helping them to improve their abilities to classify, seriate, and conserve number.

Persistence of Gains From Instruction in Classification, Seriation, and Conservation

Abstract Children who received learning-set instruction on unidimensional classification, unidimensional seriation, and number conservation in the middle of kindergarten were retested at the end of 1st grade. The follow-up tests showed that a 17-percentile-point advantage conveyed by this instruction on the O-LSAT measure of school-related reasoning was essentially intact. It also appeared that a 10-percentile-point gain in mathematics, presumably an indirect effect of the increased competence in reasoning, was also intact. On the other hand, there was no longer any difference between experimental and control children in verbal comprehension. These results are discussed in terms of temporary, permanent, and self-propagating gains.

Differential results of instruction at the preoperational/concrete operational transition

The same cognitive intervention was attempted with children from two schools serving different populations. All children were identified by their teachers as having cognitive difficulties in kindergarten. Within each school, children were randomly assigned to experimental and control groups. Children in the experimental groups received more than 40 short lessons on unidimensional classification (oddity), seriation, and number conservation. These lessons were taught via a learning-set procedure employing 160 kinds of manipulatable objects. Children in the control groups received an equal amount of instruction on verbal and mathematics materials recommended by their teachers. Five months after the instruction was concluded, the experimental group in one school scored significantly better on a psychometric test of reasoning. There was no significant difference in verbal and mathematics achievement. Differences in the significance of outcomes of the intervention at the two schools suggest that children at different stages of cognitive development will benefit differently from cognitive interventions. © 1996 John Wiley & Sons, Inc.

Instruction of young children on number conservation and unidimensional classification

Kindergartners and first graders who were lagging behind their peers in cognitive development were offered either of two forms of special instruction during the fall semester. One group was given learning set training on two forms of simple classification and on number conservation. The other group was given more conventional instruction on letter, word, number, and arithmetic skills. The children who were taught classification and conservation made gains on verbal and arithmetic measures that matched those of the children who were taught verbal and arithmetic skills directly.

Cognitive and Achievement Gains for Kindergartners Instructed in Piagetian Operations

ABSTRACT Unidimensional classification, unidimensional seriation, and number conservation were taught to kindergartners who were lagging in cognitive development. Significant gains on the Otis-Lennon School Ability Test and on Stanford Early School Achievement Test subscales resulted. The gains seemed to be the result of mastery of key cognitive operations at a stage shift in cognitive development by disadvantaged children who were ripe for progress.

Short- and long-term follow-up results for cognitive interventions

Follow-up results for two studies are presented. In both studies, learning-set instruction on early concrete operations—unidimensional classification, unidimensional seriation, and, in the second study, conservation—was offered to children who were not making normal progress. Improvements on psychometric tests of intelligence were associated with gains on the concrete operations. These improvements lasted for at least a year in the first study, and, in a reduced form, for 6 years in the second study.

Acceleration of cognitive development of kindergartners

A curriculum modification was designed to increase the general reasoning ability of kindergarten children who were lagging in cognitive development. The new instructional program was tested with 22 kindergarters who scored in the lowest 9% on the EAS measure of general learning and reasoning ability taken from SRA's Survey of Basic Skills. The experimental children were given “learning set” instruction on unidimensional classification, unidimensional seriation, and number conservation for four months. They received the instruction in groups of six for 15 minutes two or three times per week during the time usually reserved for mathematics. Control children received the normal mathematics instruction, also in groups of six, for matched sessions. The experimental children made twice the gains of the control children on the EAS measure, and matched their gains on reading and mathematics achievement. It appears that integrated “learning set” training on these three Piagetian concepts may be a potent tool for aiding kindergartners who are falling behind their peers in cognitive development.

Evaluation of a new classification system for anemias using consult learning system®

Since the advent of electronic particle counting, anemias have customarily been classified by evaluating cell size (MCV) and hemoglobin content (MCH). Recently a new parameter estimating red cell size heterogeneity (the ‘red cell distribution width’ or ‘RDW’) has been introduced. We have evaluated a proposed classification of anemias based upon this new parameter in a large group of hospitalized patients utilizing an expert system based upon statistical pattern recognition and compared our results to other studies. The potential advantages of using such a system over currently existing uni-dimensional classification systems to evaluate clinical problems are discussed.

Minority Responses to Intergroup Situations

The basic classification of minority responses to intergroup situations was developed by C. S. Johnson and includes three major response alternatives acceptance, aggression and avoidance.' Johnson defines acceptance in terms of acquiescence to the (minority) status defined as appropriate by the institutions and customs of the surrounding culture, while aggression is defined in terms of rejection of this culturally ascribed subordinate status. Aggression is further distinguished from acceptance in that the former is manifested via the actual expression of antagonism toward the institutionalized dominant-minority system. Avoidance simply refers to the attempt to limit the scope and frequency of intergroup contacts insofar as possible in order to minimize exposure to discrimination. Various subtypes of each of these three responses are described by Johnson and, more recently, by Simpson and Yinger.2 Other writers generally have felt that a more extensive set of responses is necessary. Thus Davie analyzes the reactions of Negro Americans into seven classes: acceptance, resentment, avoidance, overcompensation, race pride, hostility and aggression, and protest.3 Unfortunately, this classification blurs the distinction between response to the dominant out-group and identification with the in-group. The failure to distinguish these two aspects of reaction to minority status also characterizes Child's threefold classification of the responses of Italian Americans, namely: the apathetic (withdrawing) response, the in-group response, and rebellion (against Italian ways).4 The crux of the problem is that Johnson, Davie and Child are dealing with purportedly unidimensional classification systems (i.e., in Davie's terms, in a given situation an individual