Monday, March 01, 2010

How we learn to see

Pawan Sinha talks about how our brains learn to see, based on his research with blind children and adults in India. Despite what some scientists had extrapolated from animal studies about sight, human brains can learn how to see even after many years of vision deprivation, even into adulthood.

"The one thing that the visual system needs in order to begin parsing the world is dynamic information."

This makes a world of sense when you consider that visual perception is dependent on eye movement. Vision and movement are linked. To quote Wikipedia: "Humans and other animals do not look at a scene in fixed steadiness; instead, the eyes move around, locating interesting parts of the scene and building up a mental 'map' corresponding to the scene. One reason for the saccadic movement of the human eye is that the central part of the retina—known as the fovea—plays a critical role in resolving objects. By moving the eye so that small parts of a scene can be sensed with greater resolution, body resources can be used more efficiently."

Try this. Focus on the red dot in the image below. After a while, the blue circle will start to fade. This illusion is based on how your eyes move.

[If you're like me, you will find it hard to stay focus on the dot once you notice the circle starting to look different. I actually got a headache fighting the impulse to compensate for the lack of microsaccade movement, through the use of gross eye movement.]

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