The location of objects


ScienceDaily has an item (here) about the work of M. McCloskey on a subject called AH reported in the book, Visual Reflections: A Perceptual Deficit and Its Implications. She had an unusual visual perception deficit that caused her to see objects in the wrong locations.

“When AH looks at an object, she sees it clearly and knows what it is, but she’s often dramatically wrong about where it is. For example, she may reach out to grasp a coffee cup that she sees on her left, but miss it completely because it is actually on her right. And when she sees an icon at the top of her computer screen, it may really be at the bottom of the screen….Studying AH has taught us about how the brain codes where things are — some parts of the visual brain use codes very much like the x and y coordinates we learned about in algebra class… They discovered that when an object was stationary and remained in view for a least a second or two, AH often would see it in the wrong place. However, if an object was shown to her very briefly, or if the object was put in motion, she was able to see its location accurately…. These results tell us that the visual system has separate pathways, one for perceiving stable, non-moving objects, and the other for objects that are moving or otherwise changing. AH’s pathway for stable objects is abnormal, but her pathway for moving or otherwise changing objects is normal…”

As well as saying something about how the brain handles location, it seems to say something about how the brain creates objects. There is an implication that objects are made up of a lot of separate aspects. It is not so much that there is binding of various properties like colour to an object but perhaps the object perception itself is nothing but its various bindings. A number of qualia bound together = object. Worth thinking about…

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