Visual slippage

The visual slippage induced by our own motion is just one of many cues that our brain edits out of our conscious belief. Many other features set our conscious world apart from the blurry signals that reach our senses. When we watch TV, for instance, the image flickers 50 to 60 times per second, and recordings show that this hidden rhythm enters our primary visual cortex, where neurons flicker at the same frequency. Fortunately we do not perceive those rhythmic flashes; the fine-grained temporal information that is present in our visual areas is filtered out before it reaches our awareness. Likewise, a very fine mesh of lines is encoded by our primary visual cortex, even though it cannot be seen.

But our consciousness is not just nearly blind: it is an active observer that dramatically enhances and transforms the incoming image. On the retina and at the earliest stages of cortical processing, the center of our vision is massively expanded relative to the periphery: many more neurons care about the center of our gaze than about the surroundings. Yet we do not perceive the world as though giant magnifying lens; nor do we experience a sudden expansion of whichever face or word we decide to look at. Consciousness ceaselessly stabilizes our perception. ~ Page 144