Is early manual preference in infants defined by intermanual performance asymmetry in reaching?

[Display omitted] ► Similar numbers of left- and right-handers. ► Lateral toy positions induce predominance of ipsilateral reaching. ► Performance is predominantly symmetric between hands in 5-month-old infants reaching. ► Manual preference is not determined by intermanual performance asymmetry. In the present study we evaluated the relationship between manual preference and intermanual performance asymmetry in reaching of 5-month-old infants. Manual preference was assessed through frequency of reaches toward toys presented at midline, left or right in egocentric coordinates. Intermanual performance asymmetry was evaluated through kinematic analysis. Results showed that performance was predominantly symmetric between hands. Lateral toy positions induced predominance of ipsilateral reaching, while the midline position led to equivalent distribution between right and left handed reaches. No significant correlation between manual preference and intermanual performance asymmetry was observed. These results converge against the notion that manual preference derives from a genetically determined advantage of movement control favoring the right hand.