Friday, August 24, 2007

Limits of visual awareness

When we briefly examine a scene visually, we can pay attention only to one color at a time. However, we can see it in multiple locations.

New research by Liqiang Huang et al. proves the unexpected fact that our rich visual experience appears to be a substantial overestimation of what we are actually perceiving. We think we are aware of a complex world of varied colors, shapes, and directions of motions, etc. but in fact in any given instant we can see only one color.

What we see is what we can retrieve from visual memory, which does not contain a single image or frame, but what we have perceived in a number of different instants. For example, if we consider a small number of colored monochrome disks on a neutral surface, then if they disks have all the same color, in an instant we can determine that color and the disk's position. If the disks are in more than a single color, then in an instant we can see the disk's locations, but not their colors.

The two experiments required to prove this are not simple and are reported in Science Magazine of 10 August 2007: Vol. 317. no. 5839, pp. 823 - 825. They require to determine what the informational content of any single momentary act of conscious perception is.

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