Letters as spatial-oriented shapes and/or graphemic signs: a developmental study of left- and right-handed girls during the period of learning to read.

This study is concerned with the problem of hemispheric specialization and/or cooperation in relation to development and manual laterality. The processing of alphabetic signs and its relationship to interhemispheric transfer and functional hemispheric asymmetries were studied by comparing left- and right-handed girls during acquisition of reading. The children perform matching tasks with letters having different orientations and with meaningless forms having the same orientations as the letters. Each subject performed the matching under three conditions: right/left intermanual transfer, left/right intermanual transfer, and dichaptic exploration. Results indicate: (1) A differentiated development between the two handednesses. (2) The functional lateralization change was different for left- and right-handed girls, a greater effect of the ability to identify the letter on matching tasks was observed for the right-handed children than for the left-handed children. These last results are discussed with regard to inter-hemispheric transfer and functional hemispheric asymmetry changes. We hypothesized a strategy difference between left- and right-handed girls and a difference in their ability to change their cognitive strategy (left-handers continue to favor a spatial coding with letters).