The case of Michael May, the blind man who can now "see" gives us a fascinating instance of the mind-brain conundrum and how habits shape perception.
May was blinded in both eyes at the age of three by an explosion of calcium carbide. The jar of powder he had placed in water produced a gas which was accidentally ignited by a spark from a nearby incinerator. He narrowly escaped death. After six months in hospital, he emerged with only light and bright colour perception and then lost total sight in his left eye as a teenager. A series of early cornea transplants failed.
Then in 1999, May underwent a pioneering epithelial stem-cell transplant of new tissue to replace damaged scar tissue. This was followed some four months later by the transplant of a donated cornea. The next day, when bandages were removed, May could see colours and objects hundreds of feet away.
The problem for him was and remains interpreting what is seen, making sense of shapes and colours, let alone shapes and colours in motion. After two years of sight, May, once a fine blind skier, still can't ski easily with his eyes open. Nor can he recognise his wife until she speaks. Although he has very good "optical acuity", he can't process what he sees or, as he says, "catalogue" it. His visual language is growing slowly, but it is still a foreign language.
May's case disproves the notion that we can see independently of conceptual frameworks. Seeing things over and over - that is learning - somehow gives us frameworks through which to interpret sensation from then on.
The way May experiences "sight" also throws light on our models of the brain. One of the standard models, borrowed from the computer world, would be that we're born hard-wired (brain) with the ability or not to run certain programmes (mind). Michael May was born with the hard-wiring for seeing, but somewhere along the way that hard-wiring was altered by the altered workings of his mind.
The day-to-day running of life, we could say, reshaped his hardwiring. Seeing was no longer there, and the new programme put in place by years of blindness reprogrammed the hard-disk.
One of the many things I learned in shadowing neuroscientists for a year is that the older notions that discrete parts of the brain engage in narrowly discrete functions - sight, speech and so on - are moving quickly past their sell-by date. At its simplest level, seeing may be merely the registering of light and reacting to it. When we move into the complexities of perception and recognition, which also involve memory and a lifetime of habit, much more than the visual cortex comes into play.
At its most plastic in early childhood, the brain none the less carries on shifting and changing throughout life. Perceptual abilities may deteriorate through disuse. Other forms of ability can step in to fill the lack or to reshape our ways of thinking and being.
Michael May was a very successful blind man. Among his many achievements, skiing apart, is the development of various kinds of hi-tech navigational and computer systems. Now, he's reinventing himself as a person with sight, which means reinventing a great deal of himself. In a radio interview, he said he wasn't sure how much visual language he could actually (re)-learn. After all, it's more difficult to learn languages with age.
His case, and the brain complexities it pinpoints, could alert us to the impact of other kinds of perceptual and behavioural habits - and how difficult they may be to shed in order to learn new ones. For instance, what neural differences are there between a generation of (mostly) boys shaped by zapping away at computer games, and their parents? What bits of the neural anatomy cease to fire or misfire when they stop zapping and how does it affect how they "see" the rest of the world?
We could pose the same question of alcoholics or smokers: some of the best fiction has purportedly been written in inebriated states and certainly on a nicotine high. What happens to our hard-wiring after years of "seeing" in the ways such chemicals induce. Is relearning earlier ways possible?
Conversely, is it wise to offer drugs too easily for a variety of psychic and life ills, particularly to the very young, since returning to prior perceptual habits once these are taken away, may prove horribly difficult?
Finally, in this neuro-scientific age, when brain scanning has become obligatory for any number of ills and laboratory pursuits, I wonder whether it would make sense to try to measure the impact of living for some 30-odd years under a tyranny and what that does to one's perceptual habits. Would one then recognise faces in different ways? I imagine the habit of fear can have an effect on hard-wiring almost as significant as the habit of listening or seeing.Would we be more patient with impairments visible on a brain scan than with those we can't thus far measure?
Michael May says that after two years of sight, he still has to close his eyes when he sees a beggar, so overwhelmingly vivid is the impression of a person lying on the pavement. It's too bad that our politics haven't caught up to the possibilities of stem cell surgery.
The writer spent last year as writer in residence at the Open University's Brain and Behaviour LaboratoryReuse content