Developmental changes in hemispheric specialization for tactual processing in very young children: Evidence from cross-modal transfer.

Examined whether young children show any evidence of right hemispheric specialization for tactual processing. 72 1-, 2-, and 3-yr-old right-handed children were each administered 6 cross-modal tasks in which they palpated a shape with either their left or right hand for 25 sec and then viewed the familiar and a novel shape in a 10-sec test of visual recognition. Although Ss of all 3 ages showed significantly more visual fixation to novel shapes, regardless of which hand had been used for palpation, scores were enhanced among 2- and 3-yr-olds following palpation with the left as compared with the right hand. This left-hand (right hemisphere) superiority was not evident in 1-yr-olds. These results are the first to demonstrate a left-hand superiority for information processing in children as young as 2 yrs and to suggest that this adultlike pattern is developed by at least the 2nd year of life. Left-hand superiority may be due to asymmetries in tactual sensitivity, motor control, and/or information processing. (40 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Models of hemispheric specialization.

Reviews the literature on models of human laterality, including unilateral specialization models (dealing with language, visuospatial functions, motor functions, manipulospatial functions, and focal vs diffuse representation), cooperative interaction models, negative interaction models, parallel models, and allocation models. Although local models designed to deal with smaller, specific topic domains exist, there is currently no general model of hemispheric specialization. It is suggested that the theoretical mechanisms invoked by laterality theorists might serve as the basis for development of a more general theoretical viewpoint. In most current theoretical formulations, the basic unit of analysis is the hemisphere. The author proposes a reformation in terms of smaller neural processing entities, labeled subprocessors. The methodological and theoretical consequences of adopting a subprocessor point of view and the relationships between subprocessors and existing local models are considered. (6 p ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Left hemispheric specialization for learned, skilled, and purposeful action.

Three-dimensional motion analyses were performed on trajectories of repetitive "slicing" gestures by 4 participants with left-hemisphere lesions and limb apraxia, 6 participants with right-hemisphere lesions, and 7 neurologically intact participants. Left hemispheric lesioned participants with apraxia, but not right hemispheric lesioned participants showed impaired coupling of spatial and temporal aspects of wrist trajectories and deficits in interjoint coordination. Both groups of brain-lesioned participants differed from control participants in the 3-D plane of the wrist motion. The deficits of some right hemispheric lesioned participants in controlling the plane of wrist motion may be a consequence of left hemispatial neglect with rightward deviations. In contrast, the deficits of apraxic participants in controlling wrist trajectories and coordinating joint motions seem to reflect a deficit in these participants for the movement plan. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Developmental changes in the effects of landmarks on infant spatial behavior.

The ability of 118 6-, 9-, and 11-mo olds to keep track of positions in space was assessed under 4 conditions varying the presence, salience, and location of landmark information. Each S was trained to expect an event at 1 of 2 windows to either side. Ss were then rotated to the opposite side of the room, and the direction of search was interpreted as an indication of whether the event's location was being coded egocentrically or objectively. Results indicate high proportions of egocentricity at all ages in the absence of landmarks. In contrast, egocentricity decreased at all ages when stripes and lights surrounded the target site. However, whereas the 9- and 11-mo olds switched to consistent objective responding in this condition, the 6-mo olds glanced at both windows, indicating uncertainty as to which reference system should be used. Only the 11-mo-olds showed any evidence of being able to use landmark information presented at the irrelevant window. (8 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Developmental changes in the ability to coordinate perspectives of a large-scale space.

In 2 experiments using a large-scale space and a 3rd using a model of that space, 85 3-, 4-, and 5-yr-olds were trained to find a trinket either to their right or left. The Ss' position in the space was then changed so that their view of the space was reversed. When asked to find the trinket again, Ss' choice of left or right indicated whether they had coordinated the 2 views of the space. While the 5-yr-olds were able to coordinate the views in the large-scale space without landmarks, the 3- and 4-yr-olds did better with landmarks and with the model space. Reminding the 3- and 4-yr-olds that they had changed position enhanced the performance of the 4-yr-olds but not the 3-yr-olds. Data indicate that the ability to coordinate perspectives in large-scale space may be present but not used spontaneously during a transitional stage. Discrepancies between behavior with the 2 types of space are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Processing of tactile spatial information with crossed fingers.

The erroneous perception of 2 objects when 1 object is touched with crossed fingers has been explained as an inability of the brain to correctly perceive the crossed fingers' positions. This account was examined in Exp I, in which the perceived position of stimuli touching the crossed fingers was mapped in 16 adult volunteers. Crossing the 3rd finger over the 4th displaced the perceived stimulus position counterclockwise; crossing the 3rd under the 4th displaced perceptions clockwise. In Exp II, perceived positions among 6 adults were found to fit a model of tactile saturation past the point of the functional range of action of the fingers. It is concluded that tactile stimuli are always perceived as if fingers were uncrossed and that spatial mapping is present only within the functional range of finger excursion. (19 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Integration and interference in the cerebral hemispheres: relations with hemispheric specialization

The two hemispheres of the brain often perform complementary computations and make unique contributions to task performance. This study examines the interaction of linguistic (left hemisphere) and prosodic (right hemisphere) information in speech processing. An individual differences approach is used in which interference between linguistic and prosodic processes in a Stroop-like task is compared between individuals who process the two dimensions in opposite hemispheres (complementary specialization) vs. those who process both dimensions in the same hemisphere (noncomplementary specialization). Complementarity was not related to interference in any way. This finding is consistent with the hypothesis of Chiarello and Maxfield (1996) that interference is equivalent between and within hemispheres when it arises in a response selection stage.     

Influence of hemispheric specialization in sensory processing on reaching in infants: Age and gender related effects.

Music or speech were presented separately to the right or left ears of 48 6- and 8-mo-old infants as they reached for an object. Examination of the latency to contact the object revealed a complex relationship between type of auditory input and locus of presentation as a function of age and gender. In younger males, presentation of speech to the left ear resulted in longer contact latencies than did presentation of music. Younger females showed no asymmetries. Older males took significantly longer to contact when music was presented to their right than to their left ear; older females exhibited a tendency toward the typical adult pattern of specialization in that there was a greater effect of speech at their right than at their left ear, and vice versa for music. Data are discussed in terms of possible sequences in the development of hemispheric specialization. (26 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Structural operational capacities in integrative spatial ability.

Four experiments were conducted to explore a distinction between structural capacity, the maximum number of informational units that can be temporarily stored, and operational capacity, the number of processing operations that can be executed while simultaneously preserving the products of earlier processing. The results, from a synthesis task requiring the integration of successively presented line segments into a composite stimulus, revealed that there were little or no age differences in structural capacity but large age differences favoring young adults in operational capacity. An attempt was also made to determine how much earlier information was available after each additional processing operation, but equivocal results precluded a definitive conclusion about the exact nature of the age differences in operational capacity. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Adult age differences in integrative spatial ability.

Young and older adults were contrasted in three experiments that involved manipulation of the number of required spatial integration operations (Experiments 1 and 2) and manipulation of the amount of information per operation (Experiment 3). Older adults performed at lower levels of accuracy than did young adults in each experiment. However, the magnitude of the age differences tended to increase with each successive integration operation but was constant across different quantities of relevant information. I interpreted these results as suggesting that one factor responsible for age differences in tests of spatial ability is an age-related reduction in the efficiency of executing operations responsible for the accurate and stable representation of spatial information. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Developmental change in children's analysis of spatial patterns.

This study examines the early development of spatial pattern analysis and focuses on changes in the way that preschool children (3–5 yr olds) segment and integrate the parts of simple spatial forms. The results from each of the 3 experiments in this study show that young children analyze spatial patterns in ways that differ systematically from that of older children and adults. Changes with development were observed in the parts children segmented out of the forms and in the relations they used to organize the parts forming the overall pattern. The youngest children segmented out simple, well-formed, spatially independent parts and used simple relational structures to bind these parts together. With development, children constructed forms that included increasingly complex parts and relations. These findings were consistent across several different stimuli using 2 construction mediums. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Developmental differences in implicit learning of spatial context.

The authors examined whether a form of implicit memory that has been unambiguously dissociated from conscious awareness--learning of spatial context on the contextual cuing task introduced by M. M. Chun and Y. Jiang (1998)--is mature in childhood as predicted by an evolutionary view of cognition. School-aged children did not show reliable learning relative to adults who performed the same version of the task or another version that slowed responses to match those of children. Thus, unreliable learning in childhood was mediated by immature implicit representations of spatial context rather than by slower baseline response speed. The present finding is inconsistent with the prediction of the evolutionary view of cognition but consistent with incomplete maturation of medial temporal lobes known to mediate contextual learning. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Developmental change in young children's spatial grouping activity.

The aim of this study was to provide the kinds of detailed data necessary for formulating and eventually testing hypotheses about the conceptual bases of spatial behavior for children 1 to 4 years of age. Forty children between 18 and 42 months of age were tested on four spontaneous block construction tasks. A set of six measures was used to analyze both the products and the process of spatial grouping. The measures included: a categorical analysis of overall configuration of spatial groupings, number of spatial loci or points of origin in a construction, number of directions in which a construction extended in space, types of spatial relations generated, number of different kinds of relations in a construction, and the process of construction. The results confirm and elaborate previously established developmental findings for each measure. Moreover, comparison and integration of data across the set of measures yielded both distinctive profiles of spatial grouping activity at 18 and 42 months and evidence of systematic developmental change between these ages. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Evidence for two types of spatial representations: Hemispheric specialization for categorical and coordinate relations.

Analyses of human object recognition abilities led to the hypothesis that 2 kinds of spatial relation representations are used in human vision. Evidence for the distinction between abstract categorical spatial relation representations and specific coordinate spatial relation representations was provided in 4 experiments. These results indicate that Ss make categorical judgments—on/off, left/right, and above/below—faster when stimuli are initially presented to the left cerebral hemisphere, whereas they make evaluations of distance—in relation to 2 mm, 3 mm, or 1 in. (2.54 cm)—faster when stimuli are initially presented to the right cerebral hemisphere. In addition, there was evidence that categorical representations developed with practice. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Sexual maturation and spatial ability in college students.

194 female and 80 male undergraduates completed mental rotation and card rotation tests of spatial ability and a vocabulary test. Ss were also asked to indicate on a 5-point rating scale when they reached puberty in relation to others of the same sex. Findings provide evidence that the maturation related difference in spatial ability found in adolescents persists into adulthood. Regression analyses demonstrated a significant relation between puberty ratings and performance on the mental rotation test, with later maturers scoring higher than earlier maturers. There were no maturation-related differences on the other tests. Significant sex differences were found on all tests. Consistent with previously reported cognitive differences between males and females, females scored higher on the verbal test, and males scored higher on the 2 spatial tests. (15 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The evolution of sex differences in spatial ability.

It is widely believed that male mammals have better spatial ability than females. A large number of evolutionary hypotheses have been proposed to explain these differences, but few species have been tested. The authors critically review the proposed evolutionary explanations for sex differences in spatial cognition and conclude that most of the hypotheses are either logically flawed or, as yet, have no substantial support. Few of the data exclusively support or exclude any current hypotheses. The hypothesis with the strongest support proposes that range size was the selection pressure that acted to increase spatial ability. The authors suggest ways in which these hypotheses could be tested by presenting explicit predictions and suggesting suitable test species or conditions. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Developmental changes in the attribution of blame.

A story completion test was constructed to measure developmental changes in the methods used by children to assign blame in situations where the cause of unpleasant events was left ambiguous. Ss were 115 elementary school children between the ages of 5 and 12 years. The tendency to blame others decreased with age whereas responses involving sharing of blame or recognition of impersonal and accidental causes increased with age. The story completion method provides a simple way of measuring behavior in this important area of personality development. The findings suggest that a valuable tool for personality assessment of children could be constructed from the stories used in the present study together with story completion items designed to tap mechanisms for coping with other critical stress situations. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Memory and age differences in spatial manipulation ability.

Young and old adults were asked, in 3 experiments, to make decisions about the identity of line segment patterns after either adding or subtracting line segments from the original pattern. On some of the trials, the line segments from the initial display were presented again in the second display to minimize the necessity of remembering early information during the processing of later information. Although this manipulation presumably reduced the importance of memory in the tasks, it had little effect on the magnitude of the age differences in any of the experiments. Because the 2 groups were equivalent in accuracy of simple recognition judgments, but older adults were less accurate when the same types of decisions were required in the context of an ongoing task, the results suggested that older adults may be impaired in the ability to retain information while simultaneously processing the same or other information. (PsycINFO Database Record (c) 2010 APA, all rights reserved)