Contrast dependence of saccadic blanking and landmark effects

Two phenomena have been reported to affect the perceived displacement of a visual target during saccadic eye movements: the blanking effect and landmark effect. In the blanking effect, temporarily blanking the target after a saccade improves displacement judgments. In the landmark effect, illusory target displacement occurs when a continuously presented landmark is displaced during a saccade, and the target is temporarily blanked after the saccade without displacement. We show that the strengths of the blanking and landmark effects vary with stimulus contrast. In the blanking effect, target displacement detection rate increased with luminance contrast of the target. In the landmark effect, illusory target displacement decreased with luminance contrast of the target. Moreover, the landmark effect was found even for stimuli without luminance contrast (equiluminant color stimuli), while the blanking effect disappeared. These results can be attributed to a reduction in sensitivity of target displacement by a reduction of luminance contrast, which suggests that changes in luminance, or transient signals, play a critical role in visual stability across saccades.