In the ANOVA of the accuracy data, all three of the factors were significant: saccade (none vs. pre-saccade, [
F(1, 3) = 11.28,
p < 0.05]), target location (up or down, [
F(1, 3) = 21.06,
p < 0.05]), and mask (up, down, or none, [
F(2, 6) = 74.81,
p < 0.001]). There were significant interactions of saccade and target location [
F(1, 3) = 13.13,
p < 0.05] and of target location and mask [
F(2, 6) = 48.17,
p < 0.001] and a three-way interaction [
F(2, 6) = 20.64,
p < 0.01]. To understand the source of the three-way interaction, we did separate two-way ANOVAs on the target-up and target-down conditions. These revealed significant interactions of mask and saccade effects for both target positions [target up
F(2, 6) = 15.12,
p < 0.01; target down
F(2, 6) = 11.40,
p < 0.01], although the nature of these two interactions was quite different. When the target was in the upper location, there are significant (Tukey's
p < 0.05) differences in accuracy in both the no-saccade [
F(2, 6) = 168.40,
p < 0.001] and pre-saccade [
F(2, 6) = 20.94,
p < 0.01] conditions, even though the effect of the mask is much larger in the no-saccade condition, which is the source of this interaction. This result demonstrates that the typical retinotopic masking effect is reduced in the pre-saccade condition, and this is highlighted on the left side of
Figure 3. When the target is in the lower location, in contrast, the interaction of masking with the saccade occurs because of a qualitatively different pattern of masking in two saccade conditions. With no saccade, there are significant (Tukey's
p < 0.05) differences between mask down and no mask, and no difference between mask up and no mask, demonstrating that the mask is only effective when it overlaps with the target. When a saccade is about to be executed, there is now a significant difference between mask down and no mask and between mask up and no mask (Tukey's
p < 0.05), but no difference between mask up and mask down. This is highlighted on the right side of
Figure 3 by an arrow pointing out the drop in accuracy in the target-down mask-up condition when a saccade is about to be executed.