From the reaching behavior at 5 months of age to hand preference at preschool age.

The aim of the study was to examine the reaching behavior at the age of 5 months, and to determine whether and to what extent there is a relationship between hand use at this age and manual laterality at preschool age. 20 participants (13 girls and 7 boys) were investigated on two occasions: At the age of 5 months we assessed the hand use for reaching for four different objects placed at the infant's body midline or in their right or left hemispaces, respectively. At the age of 5 years and 7 months, we assessed the hand use for 22 motor tasks. The handedness status was calculated in order to reflect the sinistrality-dextrality continuum. All but one infant were unimanual reachers at 5 months of age. Preferential reaching was space dependent rather than object dependent at this stage. Children reaching for objects in the right hemispace predominantly with their right hand showed a significantly greater right hand laterality at late preschool age than children who at the age of 5 months had shown inconsistent hand use (p < .05). Children who at the age of 5 months had reached for objects in the left hemispace with their left hand proved to be less lateralized in their right hand use approximately 5 years later (p < .05).