This is partly because vision is expensive—psychophysiologically expensive; neurologically expensive. Very little of your retina is high-resolution fovea—the very central, high-resolution part of the eye, used to do such things as identify faces. Each of the scarce foveal cells needs 10,000 cells in the visual cortex merely to manage the first part of the multi-stage processing of seeing.74 Then each of those 10,000 requires 10,000 more just to get to stage two. If all your retina was fovea you would require the skull of a B-movie alien to house your brain. In consequence, we triage, when
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