Reflecting upon line bisection: mirror reversal increases the magnitude of pseudoneglect.

In order to investigate the effect of congruent and non-congruent motor actions upon pseudoneglect, 'real' lines and mirror reversed 'virtual' lines were bisected in left and right hemispaces by 50 right handed subjects, 25 males, 25 females, with both left and right hands. Statistical analysis revealed significantly greater pseudoneglect for the non-congruent motor condition (virtual > real), hand (left > right), gender (male > female) and hemispace for virtual lines (left > right). These results are explained in terms of the interaction between three factors whose influence can jointly and severally result in pseudoneglect: right hemisphere specialization for spatial attention, right hemisphere activation resulting from hand use and sensorimotor discrepancies and the allocation of visual attention.