The Peri-Saccadic Perception of Objects and Space
Figure 2
Peri-Saccadic Compression in the Model
(A) Spatial range of compression. The data shows the apparent versus real position of flashed bars in the critical phase from −25 to 0 ms before a 20° saccade for two human subjects (data from Morrone et al. [9]). Estimated stimulus location by the model using L1 and L2 (blue) and only L1 (gray). The area around the saccade target is compressed in L1 whereas stimuli presented at large distances from the saccade target require another layer (L2) with larger receptive field sizes.
(B) The time course of compression. The data shows the apparent position of bars presented at four different locations as a function of time relative to saccade onset of two subjects (data from Morrone et al. [9]). The blue line represents the predicted mislocalization of the model.
(C) The spatial pattern of compression. The data shows the absolute mislocalization with reference to the true position of a flashed dot randomly chosen from an array of 24 dots for four different saccade amplitudes (data replotted from Kaiser and Lappe [11], who plotted the mislocalization relative to a baseline). Vector origins indicate the veridical flash position and vector endpoints indicate the perceived position around saccade onset. The simulation results show the best fits of models with anisotropic or isotropic magnification. In contrast to the isotropic model, the anisotropic model on average does not significantly deviate from the data (section “Computation of mean errors”). Significant deviations (p < 0.05) are indicated by * (two-sided one-sample t-test, α = 0.05, df = 23).