Effects of subgrouping in stuttering research

The most frequently utilized research design in stuttering research compares stutterers to nonstutterers, with the assumption that stutterers represent a homogeneous group. The present study examines the effects of subgrouping stuttering subjects. Sample populations were randomly selected from a pool of stuttering children, successively increasing the stringency of selection criteria for group membership. The groups were contrasted across five dependent variables. The results indicated that the performance differences between the groups increased as the selection criteria became more stringent. The findings were interpreted as supporting the need to more closely examine the individual differences of stutterers, deviating from the traditional research paradigm.     

Cognitive reference points in judgments of symbolic magnitude

Research on speeded symbolic magnitude comparisons indicates that decisions are made more quickly when the magnitudes of the stimuli being compared are relatively close to an explicit or implicit reference point. Alternative explanations of this phenomenon are tested by seeking similar effects in nonspeeded rating tasks. In accord with the predictions of discriminability models, rated magnitude differences between stimuli in the vicinity of a reference point are expanded relative to differences between stimuli far from it. The inferred locations of cities along a west-east axis varies systematically depending on which coast, Pacific or Atlantic, is specified as the reference point. Scales derived from the rating data are correlated with the pattern of reaction times obtained in a comparable speeded comparison task. In addition, the distance between the cities nearest the locale of our subjects is subjectively stretched. Reference point effects are also observed when the form of the comparative specifies an implicit reference point at either end of a continuum of subjective size; however, these effects are very small and do not clearly support a discriminability interpretation. Stronger evidence for discriminability effects is obtained when an explicit reference point is established at an arbitrary size value. An implicit scaling model, related to range-frequency theory, is proposed to account for the influence of reference points on relative discriminability of stimulus magnitudes. The implicit scaling model is used to develop an account of how symbolic magnitudes may be learned and of how habitual reference points can produce asymmetries in distance judgments.     

Schema induction and analogical transfer

An analysis of the process of analogical thinking predicts that analogies will be noticed on the basis of semantic retrieval cues and that the induction of a general schema from concrete analogs will facilitate analogical transfer. These predictions were tested in experiments in which subjects first read one or more stories illustrating problems and their solutions and then attempted to solve a disparate but analogous transfer problem. The studies in Part I attempted to foster the abstraction of a problem schema from a single story analog by means of summarization instructions, a verbal statement of the underlying principle, or a diagrammatic representation of it. None of these devices achieved a notable degree of sucess. In contrast, the experiments in Part II demonstrated that if two prior analogs were given, subjects often derived a problem schema as an incidental product of describing the similarities of the analogs. The quality of the induced schema was highly predictive of subsequent transfer performance. Furthermore, the verbal statements and diagrams that had failed to facilitate transfer from one analog proved highly beneficial when paired with two. The function of examples in learning was discussed in light of the present study.     

Building theories of reading ability: On the relation between individual differences in cognitive skills and reading comprehension

To date most theories of reading ability have emphasized a single factor as the major source of individual differences in performance. However there has been little agreement on what that factor is. However, candidates have included visual discrimination, phonological and semantic recoding, short-term memory, and utilization of linguistic knowledge and context. The single- factor theories are summarized. Literature is then reviewed to show that no single-factor theory is likely to be right, because a very wide range of component skills and abilities has in fact been shown to correlate with reading success. Among them are discrimination of letter location and letter order during perceptual recognition, use of orthographic regularity as an aid to visual code formation, use of spelling-to-sound regularity in phonological recoding, memory for word order, spontaneous identification of syntactic relations, flexibility in prediction from syntactic and semantic context, and context-specificity in semantic encoding. It is concluded that more complex, multifactor models of reading ability are required, and some recent attempts to collect data conducive to such a model are described. In the process, three different approaches to identifying factors relevant to reading success are delineated. These are general abilities assessment, learning potential assessment, and component skills analysis. Two methods of conducting component skills analysis are presented, and it is recommended that they be used as converging operations. Finally, the results of a component skills analysis are used to construct a tentative example of a class of hierarchical models of reading ability that can be pursued developmentally.     

Auditory processing and perceptual abilities of “organic” and “functional” stutterers

The present investigation was undertaken to determine whether significant differences in auditory processing and perceptual abilities exist between (1) stutterers as a supposedly homogeneous group when compared with controls, (2) two differentiated subgroups of stutterers, and (3) either of the stuttering subgroups when separately compared with controls. Dichotic listening and masking level difference (MLD) tasks were administered to the two groups of school-age stutterers and an age-matched nonstuttering control group. Stuttering subjects were differentiated into “organic” and “functional” subgroups on the basis of neuropsychological test performances. Organic stutterers performed significantly poorer than did controls on one MLD experimental condition. Functional stutterers performed more like control subjects than like organic stutterers.     

Sociodramatic play: Social class effects in integrated preschool classrooms

In previous studies, social class differences in children's sociodramatic play were studied in socially homogeneous, segregated schools. However, social class differences in play behavior were attributed to the abilities or interests of the children rather than to the situation in which they were observed. In the present study, sociodramatic play was observed in middle and lower class children attending the same preschool classrooms. In accord with previous studies, middle class children engaged in a higher level of play than did lower class children. Analyses of individual play components indicated that although middle class children verbalized more frequently, the quality of the language used by the two groups did not differ. Age differences were also significant. With age, play roles became more socially coordinated, the duration of play episodes increased and language became more complex. But social class groups did not differ on these measures. The implications of these results for the developmental lag hypothesis, other explanations of social class differences and classroom strategies are discussed.