An influential theory of visually guided action proposes that (a) conscious
perception of target displacement disrupts on-line action and (b) small ta
rget perturbations are inconsequential, provided the participant is unaware
of them. This study examined these claims in a study of rapid aiming movem
ents to targets. Novel features included on-line verbal reports of target d
isplacement, and the factorial combination of small versus large displaceme
nts occurring near peak saccadic velocity or 100 ms later. Although awarene
ss of target displacement had no effect on movement kinematics. even small
larger displacements near peak saccadic velocity affected kinematic measure
s. These results support both a strong view of visual stream separation in
the on-line control of action and richer spa tial coding by unconscious pro
cesses than has previously been acknowledged.