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

Abstract

This experiment was conducted to determine whether young children show any evidence of right hemispheric specialization for tactual processing. Seventy-two 1-, 2-, and 3-year-old right-handed children were each administered six cross-modal tasks in which they palpated a shape with either their left or right hand for 25 s and then viewed the familiar and a novel shape in a 10-s test of visual recognition. Although children of all three 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-year-olds following palpation with the left as compared with the right hand. This left-hand (right hemisphere) superiority was not evident in 1-year-olds. These results are the first to demonstrate a left-hand superiority for information processing in children as young as 2 years and to suggest that this adult-like pattern is developed by at least the second year of life.There is now ample evidence that the right and left hemispheres of the human brain differ anatomically and functionally in adults, with language and analytical sequential processing lateralized in the left hemisphere and visuospatial and nonsequential processes lateralized in the right hemisphere (e.g., Gazzaniga, 1970;Sperry, 1982). Fundamental questions remain, however, as to how and when these basic differences between the left and right brain emerge. Lennenberg's (1967) review of the literature available in the 1960s led him to conclude that lateralization of function develops over time and is not complete until puberty. However, recent evidence suggests that certain anatomical, electrophysiological, and motor

The contributions of vision and haptics to reaching and grasping

“…In fact, infants as young as 2 months of age show the ability to retain haptic information better when that information is exposed to the left hand than when exposed to the right hand ( Lhote and Streri, 1998 ). This result in infants aligns with other studies in early childhood that reported that 2-year-olds display an advantage for visually recognizing novel geometrical shapes that were previously haptically manipulated with the left (but not the right) hand ( Rose, 1984 ). This left-hand advantage for novel object recognition has also been reported in older children (6–12 year olds; Witelson, 1974 , 1976 ).…”

Handedness hangups and species snobbery

“…For example, the dichotomy of visually guided reaching versus manipulative behavior for the left and right hands, respectively, would be difficult to maintain had the authors incorporated the findings of Ettlinger and colleagues in which a left hand preference was observed in monkeys for haptic perception involving manipulative behavior (see target article, Footnote #1). This left-hand haptic preference is not dissimilar to that observed for right-handed children as young as 2-years-old, who showed more accurate perception of objects palpated with the left hand, than with the right, which is considered to be a manifestation of right-hemisphere specialization for form perception (Rose 1984). The findings of Ettlinger and colleagues, and the results of the other studies of hand preferences in nonhuman primates, are all consistent with right-hemisphere specialization in monkeys for aspects of form and space perception, with the left-hand preference for the activities that draw on these processes being a result, or a reflection, of the contralateral hemisphere's functional specialization.…”

Relation of stable hand‐use preferences to the development of skill for managing multiple objects from 7 to 13 months of age

“…An infant's handedness status, by ensuring differences in haptic experience between the two hands, can contribute to the establishment of differences in the processes of sensorimotor control and patterns of perceptual-motor organization between the two hemispheres (Michel, 1988). These asymmetrical differences between the hemispheres may account for the differences between the hands both in patterns of tactual exploration of objects and in sensitivity to differences in tactile stimuli among children as young as 2 years (Rose, 1984). Thus, it is conceivable that a hand-use preference will have a significant impact on how infants manage the possession and exploration of multiple objects.…”