A Mind Forever Visualizing

I find reading Oliver Sacks to be, well, unnerving.  His detailed accounts of the fragility of the human brain upset my latent Cartesianism; the reduction of all that I hold dear about consciousness to electro-chemical reactions invites harrowing comparison with my own high school laboratory experiences.  In his recent article for The New Yorker, Sacks discusses the capacity of the brain devoted to visual processing to adapt to blindness, whether in children or adults, suddenly or gradually.
It seems that the brain can, in some cases, retain a visual faculty for processing images without visual input, drawing instead from other senses as well as the imagination.  This, of course, provoked my epistemological paranoia; how would I know if (any of) my senses were subtly but significantly impaired, particularly if they had been so since childhood or earlier?  (For more in this vein, see Sacks’s forthcoming study of this writer, The Man Who Mistook His Life For A Novel.)

The plasticity of the brain to adapt to new mental activities to which Sacks attributes the visual processing of blind people seems to jibe with (my understanding of) what we know about the development of the brain (as the father of a toddler, I am anxiously aware of Conventional Wisdom regarding how best to stimulate and mold children’s brains).  Though trained as a scientist, Sacks inevitably turns to questions of philosophy when the limits of neurology have been reached.  The result here is a guarded claim for self-actualization: the blind may retain their sight, if they truly want to.

More immediately provocative to me were the implications of one of the examples Sacks gives of varying capacities for visual processing:

I first became conscious that there could be huge variations in visual imagery and visual memory when I was fourteen or so.  My mother was a surgeon and comparative anatomist, and I had brought her a lizard’s skeleton from school.  She gazed at this intently for a minute, turning it around in her hands, then put it down and without looking at it again did a number of drawings of it, rotating it mentally by thirty degrees each time, so that she produced a series, the last drawing exactly the same as the first.  I could not imagine how she had done this, and when she said that she could "see" the skeleton in her mind just as clearly and vividly as if she were looking at it, and that she simply rotated the image through a twelfth of a circle each time, I felt bewildered, and very stupid. I could hardly see anything with my mind’s eye—at most, faint, evanescent images over which I had no control.

Proponents of the infamous female inferiority in spatial relations may dismiss Sacks’s mother as a statistical outlier and may cling to evidence of the effects of early hormone exposure upon fetal brain development, but I can’t help wondering if the plasticity demonstrated by blind people who "practice" visualization might not also avail people with predetermined (chromosomally or otherwise) deficiencies in certain mental faculties.  As I consider how best to expose my child to a hyperstimulating world, these questions lose their ponderousness.