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Abstract

V1SH is the V1 Saliency Hypothesis, and CPD is the Central-Peripheral Dichotomy.
I will explain how they motivate a new framework: Visual attention selects only a tiny fraction of visual input information for further processing. Selection starts in the primary visual cortex (V1), which creates a bottom-up saliency map (V1SH) to guide the fovea to selected visual locations via gaze shifts.
This motivates a new framework that views vision as consisting of encoding, selection, and decoding stages, placing selection on center stage. It suggests a massive loss of non-selected information from V1 downstream along the visual pathway. Hence, feedback from downstream visual cortical areas to V1 for better decoding (recognition), through analysis-by- synthesis, should query for additional information and be mainly directed at the foveal region (CPD). Accordingly, non-foveal vision is not only poorer in spatial resolution, but also more susceptible to many illusions. I will show some illusions arising from V1's feedforward inputs limited by the attentional bottleneck, and use random-dot stereograms to illustrate how top-down feedback constructively utilizes the feedforward inputs in some visual inferences and vetoes feedforward inputs in other cases, depending on the nature of the feedforward inputs.