Spatial field advantages for tactile line bisection as a function of hemispheric specialisation inferred from dichotic listening.

Thirty left-ear advantaged (LEA) and 30 right-ear advantaged (REA) right-handed subjects performed tactile line bisection (TLB) in left and right spatial fields, and at midline. REA subjects were found to perform significantly better in the right spatial field than in the left and LEA subjects significantly better in the left than in the right. Significant directional deviations were found only at midline with the left hand deviating to the right and the right hand to the left. These findings suggest that TLB is primarily a spatial task subserved by feedforward motor processes and that directional deviations are due to the differential scaling of egocentric space.