The role of target information on manual-aiming bias

Three experiments were conducted to examine the role of target information in manual aiming. The key manipulations in this experiment were the use of two target contexts (the two forms of the Müller-Lyer illusion) and the visual conditions under which subjects moved. In Experiment 1, we demonstrated that the inward- and outward-pointing arrows biased manual-aiming movements in a manner consistent with their well-known influence on perceptual judgements. The elimination of visual feedback during the aiming movement (Experiment 2), and visual information about the target-aiming layout prior to the movement (Experiment 3) increased the magnitude of the bias. Together, these results demonstrate the strong effect of target information on manual aiming, and specifically, on the movement-planning processes that precede movement.