Abstract
Vision includes looking and seeing. Looking, mainly via gaze shifts, selects a tiny fraction of visual input information for passage through the brain’s information bottleneck. The selected input is placed within the attentional spotlight, typically in the central visual field. Seeing decodes, i.e., recognizes and discriminates, the selected inputs. Hence, the main functional role for peripheral vision is looking rather than seeing, in particular, to decide where to shift the gaze. Looking is often guided exogenously by a saliency map created by the primary visual cortex (V1)(Li 2002), where the bottleneck is proposed to start along the visual pathway (Zhaoping 2019). I will show examples of gaze being strongly attracted by peripheral objects indiscriminable to seeing because of visual crowding or loss of discriminative signals (e.g., eye of origin) beyond V1. In peripheral vision, seeing through the bottleneck not only suffers from poor spatial resolution, but is also subject to crowding and is more vulnerable to illusions from misleading, ambiguous, and impoverished visual inputs. I will show how V1 mechanisms for computing saliency intended for looking create side effects in seeing, such as those manifested in crowding. In light of the bottleneck, the Central-peripheral Dichotomy (CPD) theory (Zhaoping 2017, 2019, 2024) proposes that seeing employs top-down feedback to query for extra input information; this happens more in central than peripheral vision. Such queries enable central vision to veto misleading feedforward information that cause the illusions. This predicts illusions which are indeed visible in peripheral but not central vision. Furthermore, the theory predicts that compromising the feedback queries renders central vision vulnerable to the same illusions, as confirmed recently in the reversed-depth illusion. The saccades engendered by peripheral vision allows looking to combine with seeing to give human observers the impression of seeing the whole scene clearly despite inattentional blindness.
