Fig. 5: Stimulus–stimulus interactions in perceptual suppression without saccades (similar experiment to the retinal paradigm of Fig. 4d).

Subjects fixated and detected brief probe flashes as in the experiments of Figs. 1 and 2; here, the flashes happened around the time of a luminance step (i.e., a sudden change in background luminance) instead of a saccade. The title above each panel indicates the absolute value of the luminance change that took place. a–g Proportion of correct responses as a function of flash time from the time of background luminance step. There was progressively stronger perceptual suppression with increasing contrast of the luminance step, consistent with the retinal results of Fig. 4d. h Summary of panels a–g. Darker colors denote larger absolute values of background luminance changes. Since coarse textures (Figs. 1–4) presumably cause larger contrast variations over retinal receptive fields, this suggests that the image dependence of perceptual saccadic suppression (Figs. 1 and 2) is mediated by stimulus–stimulus interaction effects originating in the retina (Fig. 4d).