Colour binding

Science Daily (here) reports on a paper by S. Shevell, Color-Binding Errors during Rivalrous Suppression of Form. The work shows how the brain integrates the multiple features of an object, such as shape, color, location and velocity, into a unified whole.

“The brain’s neural mechanisms keep straight which color belongs to what object, so one doesn’t mistakenly see a blue flamingo in a pink lake. But what happens when a color loses the object to which it is linked? Research at the University of Chicago has demonstrated, for the first time, that instead of disappearing along with the lost object, the color latches onto a region of some other object in view – a finding that reveals a new basic property of sight.

The research shows that the brain processes the shape of an object and its color in two separate pathways and, though the object’s shape and color normally are linked, the neural representation of the color can survive alone. When that happens, the brain establishes a new link that binds the color to another visible shape.”

It is as if entities are stored in working memory with ‘tags’ to their attributes and these ‘tags’ can sometimes be lost, misplaced or (in synesthesia) be applied to inappropriate entities. However, there must be two sorts of ‘tag’: the vivid attributes of conscious sensory experience which presumably still have access to the primary sensory areas of the cortex, and the much less vivid attributes of memory and imagination where the primary sensory input is long gone or never was.

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