ONSET OF BIMANUAL HANDEDNESS IN INFANTS

The results of the present research suggest that infants have begun to demonstrate handedness in bimanual tasks by or shortly after the end of the first year of life. In a longitudinal study, 23 of 24 infants (18 right-handed, 5 left-handed) gave evidence for the onset of bimanual handedness between 10 and 18 months of age. Considerable stability in this preference was maintained during the subsequent 5-month interval. In a cross-sectional study, 85 of 100 14- to 16-month-olds (71 right-handed, 14 left-handed) were credited with bimanual handedness. Fourteen of the remaining 15 infants were retested between 18 and 21 months of age. Taking into account the retest data, 94 infants (77 right-handed, 17 left-handed) were credited with bimanual handedness. © 1979 Ablex Publishing Corporation.