Testing the top-down feedback in the central visual field using the reversed depth illusion

In a new framework to understand vision, an information bottleneck impoverishes visual input information downstream of the primary visual cortex along the visual pathway; to aid ongoing visual recognition given the bottleneck, feedback from downstream to upstream visual stages queries for additional information. According to the central-peripheral dichotomy theory, this feedback is primarily directed to the central, rather than the peripheral, visual field. Counterintuitively, this theory predicts illusions visible only in the peripheral visual field, which lacks the feedback query to veto the illusions arising from misleading and impoverished feedforward signals. A paradigmatic example is the predicted and confirmed reversed depth illusion in random-dot stereograms. This theory further predicts that disrupting the feedback renders this illusion visible in the central visual field. We test and confirm this prediction using visual backward masking to disrupt the feedback. This feedback privilege for the central visual field underpins visual understanding through analysis-by-synthesis.