Comparing left and right hand in line bisection at different ages

Sixty preschool children (31 boys, 29 girls, 5-6 years old), 60 young adult s (30 men, 30 women, 20-45 years old), and 66 older adults (23 men, 43 wome n, 60-94 years old), bisected 11 lines of different lengths, 1 time with ea ch hand. All participants were French and right-handed. In all age and sex groups the mean transection was at the left of the true center regardless o f the hand used. Accuracy of the left hand was better than accuracy of the right hand in children, but the opposite pattern was observed in older part icipants (better right hand), and there were no between-hands differences i n accuracy among young adults. The observed patterns of correlation between the left and the right hand, which were age and sex dependent, are present ed. These results are discussed in relation to age-related changes in hemis pheric interaction and to the need for additional research on the reliabili ty,and extent of the "neglect" in normal individuals.