Another function of fixating a target prior to contacting it with the hand, is to provide information about where the contact location is in space to the arm's motor system (Land & Hayhoe,
2001; Soechting et al.,
2001). This function becomes apparent by ‘look ahead fixations’ to future targets and obstacles (Hayhoe, Shrivastava, Mruczek, & Pelz,
2003; Johansson et al.,
2001; Land et al.,
1999; Pelz, Hayhoe, & Loeber,
2001). Extra-retinal information such as efference copies and proprioception of the eyes is proposed to play an important role in localizing a target in space so that an appropriate hand movement to the contact location can be made (Abrams, Meyer, & Kornblum,
1990; Helsen et al.,
1998; Pélisson, Prablanc, Goodale, & Jeannerod,
1986). Several experimental findings stress that fixations provide the hand with information about the contact location, rather than stressing the function of providing visual feedback of the approaching hand. For example, the locking of gaze on the target until the pointing movement as found by Neggers and Bekkering (
2001) was independent of vision of the hand. Pélisson et al. (
1986) showed that despite the absence of visual information about the effector, online corrections to reach a displaced target can be made. In the study by Abrams et al. (
1990), wrist movements to a target suffered if participants were not allowed to look at the target, even when the effector was not visible. If the main function of fixations during grasping is to determine the contact location in space, we expect an attraction by the contact location of the thumb, as this is the guiding digit. Consistent with this, Schiegg, Deubel, and Schneider (
2003) found that in a grasping task without vision of the hand, attention was drawn to the to be grasped branches of an x-shaped object, and especially to the contact location of the thumb.