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.     

Children use canonical sentence schemas: A crosslinguistic study of word order and inflections

We propose that children construct a canonical sentence schema as a preliminary organizing structure for language behavior. The canonical sentence embodies the typical features of complete clauses in the input language, and serves as a framework for the application of productive and perceptual strategies. The canonical sentence schema offers a functional explanation of word-order and inflectional strategies based on the child's attempts to quickly master basic communication skills in his or her language. The present research explores sensitivity to the canonical sentence form and to word-order and inflectional perceptual strategies for comprehending simple transitive sentences in monolingual children aged 2;0 to 4;4 in four languages: English (ordered, uninflectional), Italian (weakly ordered, weakly inflectional), Serbo-Croatian (weakly ordered, inflectional), Turkish (minimally ordered, inflectional). The results show that children fail to respond systematically to sequences that violate the canonical sentence form of their particular language. They develop distinct word-order and inflectional strategies appropriate to the regularities of their language. The early behavioral emergence of linguistically appropriate canonical sentences and processing strategies suggests a behavioral foundation for linguistic constraints on the surface form of sentences.     

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.     

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.     

What makes triangles point: Local and global effects in configurations of ambiguous triangles

Perceived pointing of ambiguous triangles was investigated in three experiments. The results show that the probability of seeing an equilateral triangle point in a given direction is strongly influenced by (a) the direction of the ambiguous alternatives, (b) the orientational characteristics of the configuration of elements surrounding the triangle, and (c) the shape of the surrounding elements. These findings are interpreted as supporting the hypothesis that perceived pointing is determined by perceptual reference frames induced at multiple levels of globality: one for the general visual field, one for the entire configuration, and one for the local elements of the configuration.     

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.     

The eyes have it: Exposure times and saccadic movements in visual half-field experiments

Several tachistoscopic visual half-field experiments using exposure times in excess of 150 msec have been reported and arguments have been put forth justifying this procedure. An experiment was done investigating visual field accuracy under conditions where eye movement was allowed, following parafoveal exposure. Two control experiments were done to evaluate the viewing conditions. When eye movement is permitted, accuracy in both visual fields reaches 100%. It is concluded that visual field differences found with exposure times greater than 150 msec are due to the active cooperation of the subjects and not due to the justifications advanced by experimenters using long exposure times.     

Hierarchical structure in perceptual representation

A theoretical framework for perceptual representation is presented which proposes that information is coded in hierarchical networks of nonverbal propositions. The hierarchical structure of the representations implies selective organization: Some subsets of a figure will be encoded as integral, structural units of that figure, while others will not. A context-sensitive metric for the “goodness” of a part within a figure is developed, corresponding to the probability that the subset will be encoded as a structural unit. Converging evidence supporting this position is presented from four different tasks using simple, straight-line figures. The tasks studied are (a) dividing figures into “natural” parts, (b) rating the “goodness” of parts within figures, (c) timed verification of parts within figures, and (d) timed mental synthesis of spatially separated parts into unitary figures. The results are discussed in terms of the proposed theory of representation, the processes that operate on those representations, and the general implications of the data for perceptual theories.     

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.     

The early history of behavior modification of stuttering: A view from the trenches

The attitudes of 644 employers toward stuttering were studied through the use of a questionnaire which required the respondents to indicate their strenght-of- agreement to seven attitudinal statements concerning stuttering. While rejecting the suggestion that stuttering interferes with job performance, the employers agreed that stuttering decreases employability and interferes with promotion possibilities. It was concluded that although stuttering may not typically interfere with job performance, it is a significant vocationally handicapping problem.     

Effects of context-induced processing operations on semantic information acquired from discourse

Effects of context on processes involved in understanding discourse were investigated. An experimental context designed to directly affect discourse processing by inducing subjects to generate inferences involving text content was compared to a context in which subjects simply listened to and recalled the content of a text. The extent of inferential discourse processing was estimated from derived semantic information in subjects' text recalls. The experimental context produced effects on inferred and other derived information in subjects' text recalls which were predicted from a constructive model of discourse processing. Also consistent with this model, the amount of derived information increased with repeated exposures to the text. In a third condition, subjects repeatedly listened to the text in the experimental context, but only recalled it once on the last trial. The context produced very substantial effects on proportions of derived information under this condition. Context effects were still present one week later.     

Representing logical and semantic structure of knowledge acquired from discourse

A network model of logical and semantic structures from which speakers or writers generate linguistic messages at the discourse level is presented. While linguistic structures were considered in developing the model, the semantic and logical networks are defined without reference to linguistic structures and thus may be used to represent knowledge structures acquired from both linguistic and nonlinguistic sources. A second problem addressed is that of determining what logical and semantic information is acquired when a text is understood. To assess acquired knowledge, a procedure is presented for coding a subject's verbal reconstruction of knowledge acquired from a presented text (or other input) against the logical and semantic structure from which the text (or other input) was derived. The procedures are illustrated using data obtained from children who were asked to “retell” simple narrative stories.     

The clinical validity of the process for assessment of effective student functioning

This report presents the results of a study of the clinical validity of A Process for Assessment of Effective Student Functioning. A clinical team composed of social workers, psychologists and psychiatrists saw 300 representative second and fifth grade children, rated them on interview and test protocols, and summarized the evaluation by single and summary qualitative judgments. The clinical validity criteria were established on the basis of independent evaluations of the home environment, the intellectual and emotional status of the child, and the child's ego functioning. Finally, a clinical criterion score was derived from the overall evaluation of the effectiveness of each subject by each member of the team. The multiple correlations of the three screening measures with the clinical criterion score ranged from .49 to .55 for second grade and fifth grade boys and girls. The clinical criterion scores of children who were screened by the recommended multiple cut-off procedure showed that none of the screened group was rated by the clinicians to have better than average adjustment. The multiple correlation and multiple cut-off procedure showed that the Process was valid for predicting independent clinical judgments of the status of these children. Furthermore, the Process was far more efficient in locating potentially handicapped children than either a carefully designed teacher nomination procedure or teacher referral.     

Antecedents of fluent and dysfluent oral reading: A descriptive analysis

Utilizing the method of repeated observations of a single subject, 18 oral reading samples were obtained from a fluent male child. Observations were made when the child was 5.6 to 6.1 yr of age. The reading material contained varying amounts of words neither understood nor produced by the child. Taped samples were analyzed for antecedents and consequences of fluent and dysfluent events, and extraneous verbal and nonverbal stimulus-response sequences. The analysis revealed the presence of five antecedents of dysfluencies: (1) poor lexical control, (2) competing stimulus-response sequences, (3) intraverbal break, (4) poor prosodic control, and (5) unusually strong intraverbal control. The results also suggested that fluency may be a function of appropriate, sequential, discriminative, stimulus control, adequate intraverbal and prosodic control in the absence of overbearing intraverbal control and interfering stimulus-response sequences.     

The development of basic mechanisms of pattern vision: spatial frequency channels

The mature visual system possesses mechanisms that analyze visual inputs into bands of spatial frequency. This analysis appears to be important to several visual capabilities. We have investigated the development of these spatial-frequency channels in young infants. Experiment 1 used a masking paradigm to test 6-week-olds, 12-week-olds, and adults. The detectability of sine wave gratings of different spatial frequencies was measured in the presence and the absence of a narrowband noise masker. The 12-week data showed that at least two spatial-frequency channels with adultlike specificity are present at 12 weeks. The 6-week data did not reveal the presence of narrowband spatial-frequency channels. Experiment 2 used a different paradigm to investigate the same issue. The detectability of gratings composed of two sine wave components was measured in 6-week-olds and adults. The results were entirely consistent with those of experiment 1. The 12-week and adult data indicated the presence of narrowband spatial-frequency channels. The 6-week data did not. The results of these experiments suggest that the manner in which pattern information is processed changes fundamentally between 6 and 12 weeks of age.     

Attention to eye contact opportunity and facial motion by three-month-old infants

Thirty-two 3-month-old infants participated in two experiments showing color videotapes of facial stimuli in a paired comparison format. In Experiment 1, the experimenter, serving as the stimulus, looked either directly at the infant or averted his gaze to the side; the face was presented either still or in motion. Eye contact opportunity had no effect while motion of the head was an effective attractor of visual fixation. In Experiment 2, the amount of available eye contact opportunity was parametrically varied by occluding the eyes with different patterns of blinking, each at the same rate. The no-motion 100% eye contact available condition received less attention than the three blinking stimuli, which were all equally attended to, though they varied with respect to the amount of eye contact opportunity they afforded. The contrast in effect of eye contact availability and rather subtle stimulus motion would imply that 3-month-old infants are comparatively insensitive to being the object of another's visual regard.     

Contextual effects in social judgment

Judges were asked to evaluate the overall performance of hypothetical students, given their scores on two examinations. The distribution of total scores was manipulated in order to investigate the loci of contextual effects. The interaction between the two exams was reversed by manipulation of the distribution. When the distribution of total scores was positively skewed, judgments showed a convergent interaction as a function of the two exams; when the distribution was negatively skewed, the interaction was divergent. The data were consistent with the hypothesis that the distribution of total scores affects only the transformation from integrated impressions to overt responses. This transformation (judgment function) was well-described by an extension of range-frequency theory. The finding that the interaction can be manipulated by changing the stimulus distribution has methodological implications for the popular interpretation of interactions or lack thereof. A good model may be improperly rejected or a bad one improperly retained through lack of attention to contextual effects.     

Misattribution of arousal and attraction: Effects of salience of explanations for arousal

Based on previous research demonstrating that salience of a plausible cause increases the likelihood of causal attribution (S. E. Taylor & S. T. Fiske, in J. Berkowitz (Ed.), Advances in Experimental Social Psychology (Vol. 11), New York: Academic Press, 1978) it was predicted that salience of plausible causes of arousal would affect romantic attraction. Male subjects were differentially aroused by running in place. Aroused subjects were particularly likely to be attracted to an attractive female confederate if they expected to meet her (high salience of confederate) and if cues associated with the running in place were minimized (low salience of exercise). Though results are consistent with a misatribution of arousal hypothesis, it is suggested that emotion schemata are a potentially more useful explanation.     

Attribution bias: On the inconclusiveness of the cognition-motivation debate

Social psychologists have given considerable theoretical and research attention to whether motivational variables bias the attributions people make for behavior. Some theorists maintain that motivational constructs must be invoked to explain certain attributional phenomena; other theorists maintain that information-processing variables can adequately explain these phenomena. The present article critically examines existing cognitive and motivational approaches to attribution and analyzes the assumptions underlying the cognition-motivation debate. We argue that cognitive and motivational theories are currently empirically indistinguishable. In particular, its is possible to construct information-processing explanations for virtually all evidence for motivated bias. We conclude by examining the implications of this indeterminacy of cognitive and motivational explanations. Future research in the area can most profitably be addressed to improving the specificity of cognitive and motivational theories rather than to resolving the between-theory confrontation.