Selective visual attention modulates the direct tilt aftereffect

One's being able to allocate attention to particular regions or properties of the visual field is fundamental to visual information processing. Visual attention determines what input is carefully analyzed and what input is mo re or less ignored. But at what stage of the visual system is this process evident? We describe three experiments that demonstrate an effect of volunt ary spatial attention and voluntary object-based attention on an orientatio n illusion (the tilt aftereffect) that is believed to take place in primary visual cortex. This finding, in which selective visual attention influence s adaptation to visual orientation information, contributes to mounting evi dence for a view of visual perception in which mutual interaction takes pla ce between high-level and low-level subsystems.