A house divided? Cognitive functioning with callosal agenesis

An anatomical and behavioral review of 29 reported cases of corpus callosum agenesis is presented. This review addresses itself to two questions: (1) Do acallosals manifest split-brain symptoms? (2) Is the corpus callosum necessary for the establishment of lateralization? Unlike the commissurotomy cases, acallosals show few symptoms of hemispheric disconnection. Behavioral strategies, use of noncallosal commissures, elaboration of ipsilateral pathways, and bilateral representation of function are discussed and evaluated as possible mechanisms of compensation. An impairment in spatiomotor functioning often accompanies callosal agenesis. Results of acallosal lateralization testing are examined and problems in interpretation are discussed. Current evidence does not conclusively establish that the corpus callosum is needed for lateralized development of some functions. However, the corpus callosum may play a role in the satisfactory performance of “lateralized” (i.e., spatial, linguistic) functions.     

Stammering: A stress index in Caribbean classrooms

Speech communities in the British West Indies typically include two major dialect or code distinctions: (1) a standard variety of British West Indian English, and (2) a local variety of English-based dialect. Each dialect or code is intimately linked with political, social, racial, and economic class distinctions. In bicultural settings, characterized by diglossia, there are special situations in which loyalty to one's mother tongue conflicts with social, economic, and political expediency. “No win” speech events or contests, the product of conflicting sociocultural values, become salient features of this particular kind of bicultural setting. A comparatively high incidence of teacher-reported stammering found in two British West Indian speech communities supports this notion and suggests that stress, originating at a sociocultural level, is symbolically expressed through attitudes toward and usages of language. These results further suggest that the classroom, now a “battleground”, will suffer as an effective teaching/learning environment. This paper presents arguments for the teaching of Standard English as a second language with an emphasis on giving regional dialects appropriate and long overdue recognition.     

Response-contingent stimulation as a treatment for developmental failure in infancy

An 8-month-old infant with a developmental quotient of $\text{1}\text{1}\text{2}$ months was given response-contingent stimulation using a pressure-sensitive pillow which turned an overhead mobile. The subject learned to control the mobile by kicking the pillow, and concurrently began smiling at both the mobile and her mother for the first time. After mastering three contingencies on arm, head, and leg movement, she displayed what appeared to be a Piagetian coordinated secondary circular reaction, in which one response provided 4 seconds of access to another contingency. Although the subject remains severely retarded, the results suggest that some forms of developmental delay may be treated at least in part as a failure to develop contingency awareness.     

Discriminative infant smiling to orientations of talking faces of mother and stranger.

Thirty-two infants aged 14 and 20 weeks were presented with a live face in each of eight conditions, which consisted of all combinations of (a) a 0° or 90° orientation; (b) familiar face (the infant's mother) or distinctively unfamiliar face; and (c) talking or silent context. The previous findings that younger infants smile longer at 0° than at 90° faces and that this differential responsiveness to orientation wanes with increasing age were replicated; the hypothesis that older infants would smile longest at their mothers' talking faces in the 0° orientation was confirmed. In addition, infants of both ages smiled more at their mothers than at the stranger, although this effect interacted with orientation and sex of the infant.     

An examination of culture bias in the wonderlic personnel test

Internal evidence of cultural bias, in terms of various types of item analysis, was sought in the Wonderlic Personnel Test results in large, representative samples of Whites and Blacks totaling some 1,500 subjects. Essentially, the lack of any appreciable Race × Items interaction and the high interracial similarity in rank order of item difficulties lead to the conclusion that the Wonderlic shows very little evidence of cultural bias with respect to the present samples which, however, differ appreciably in mean scores. The items which account for the most variance within each racial group are, by and large, the same items that show the largest interracial discrimination.     

Cognitive reference points

Two methods were used to test the hypothesis that natural categories (such as colors, line orientations, and numbers) have reference point stimuli (such as focal colors, vertical and horizontal lines, and numbers that are multiples of 10) in relation to which other stimuli of the category are judged. In Experiment I, subjects placed pairs of stimuli into sentence frames consisting of linguistic “hedges” such as “— is essentially—.” Results were that the supposed reference stimuli were most often placed in the second (reference) slot. In Experiment II, the subject placed a stimulus in physical space to represent his feeling of the psychological distance of that stimulus from another spatially fixed stimulus. Results showed that, when supposed reference stimuli were fixed, other stimuli were placed closer to them than vice versa. The results have substantive implications for the understanding of internal structure of categories and methodological implications for the mapping of reference points, quantification of linguistic intuitions, and the assumption of symmetry in psychological distance judgments.     

Perceptual-cognitive explorations of a toroidal set of free-form stimuli

A polar-coordinate analogue of Fourier synthesis generates organic-appearing “free forms” that can be continuously deformed along any desired number of difficult-to-verbalize dimensions. Since the dimensions are also circular, the forms correspond to points on the surface of a torus which, though conveniently finite, is free of bounding edges. Two experiments explore a particular two-dimensional set of 81 such forms. The first shows that perceived pair-wise similarities among the individual forms are well explained purely in terms of the distances among their corresponding points in the toroidal parameter space. The second, however, establishes that forms that tend to be grouped together as having the same cognitive interpretation define regions in parameter space that are variously shaped or even bimodal and, hence, that cannot be explained solely on the basis of the fixed set of pair-wise similarities. The stimuli appear to offer a novel combination of cognitive richness and low-dimensional parametric control.     

Family resemblances: Studies in the internal structure of categories

Six experiments explored the hypothesis that the members of categories which are considered most prototypical are those with most attributes in common with other members of the category and least attributes in common with other categories. In probabilistic terms, the hypothesis is that prototypicality is a function of the total cue validity of the attributes of items. In Experiments 1 and 3, subjects listed attributes for members of semantic categories which had been previously rated for degree of prototypicality. High positive correlations were obtained between those ratings and the extent of distribution of an item's attributes among the other items of the category. In Experiments 2 and 4, subjects listed superordinates of category members and listed attributes of members of contrasting categories. Negative correlations were obtained between prototypicality and superordinates other than the category in question and between prototypicality and an item's possession of attributes possessed by members of contrasting categories. Experiments 5 and 6 used artificial categories and showed that family resemblance within categories and lack of overlap of elements with contrasting categories were correlated with ease of learning, reaction time in identifying an item after learning, and rating of prototypicality of an item. It is argued that family resemblance offers an alternative to criterial features in defining categories.     

Factors within the 1969 SVIB for women and relationships to Holland's theory

The Basic Interest Scales (BIS) and the Occupational Scales (O-S) of the revised Strong Vocational Interest Blank for Women (TW 398) were assigned Holland codes, and component scores for the BIS and O-S were separately developed, intercorrelated, and evaluated along with standardized composite scores representing each of the 11 O-S Groups on the profile. The dimensionality of the BIS and O-S was similar, and similar in number to Holland's theory, but the components were only partially congruent. Some profile Groups provided relatively good representations of BIS and/or Occupational scale components, and the grouping of the O-S provided important information not otherwise readily available. Holland's dimensions are not uniformly represented in either the BIS or O-S, and despite some similarities, fundamental problems of compatibility appeared to exist in relating the structure of this instrument to Holland's formulations. Women's interests are in need of independent study.     

Basic objects in natural categories

Categorizations which humans make of the concrete world are not arbitrary but highly determined. In taxonomies of concrete objects, there is one level of abstraction at which the most basic category cuts are made. Basic categories are those which carry the most information, possess the highest category cue validity, and are, thus, the most differentiated from one another. The four experiments of Part I define basic objects by demonstrating that in taxonomies of common concrete nouns in English based on class inclusion, basic objects are the most inclusive categories whose members: (a) possess significant numbers of attributes in common, (b) have motor programs which are similar to one another, (c) have similar shapes, and (d) can be identified from averaged shapes of members of the class. The eight experiments of Part II explore implications of the structure of categories. Basic objects are shown to be the most inclusive categories for which a concrete image of the category as a whole can be formed, to be the first categorizations made during perception of the environment, to be the earliest categories sorted and earliest named by children, and to be the categories most codable, most coded, and most necessary in language.