Engines of Our Ingenuity

No. 1833:
LEARNING TO SEE

by John H. Lienhard

Today, we learn to see. The University of Houston's College of Engineering presents this series about the machines that make our civilization run, and the people whose ingenuity created them.

Michael May is news at summer's end, in 2003. May is the president of his own company, and he's an excellent skier as well. The surprising thing about May is that he'd forgotten what it was to see, for a chemical explosion blinded him when he was only three.

In 2000, a doctor did a radical operation that restored sight in one of May's eyes. May is not the first lifelong-blind person to have sight restored, but such cases are very rare. Now May, articulate and analytical, is helping us to understand how vision works.

And so I turn to an old essay by neurophysiologist Richard Gregory. Gregory tells how seventeenth century philosophers asked what a person's reaction to the sudden acquisition of sight might be. They got their answer after Isaac Newton died. Newton's physician, William Cheselden, went on to restore sight to a boy born blind. He did so by operating on congenital cataracts.

It turns out that the philosophers had predicted the boy's response quite accurately. At first, vision made no sense. Then the boy expected to be able to touch everything his eyes showed him. He was amazed by portraits. They had the same general content as real faces; but, when he touched them, they were flat and formless.

Being suddenly able to see for the first time is the stuff of movie plots; but those plots are not based on experience. The learning curve is long and slow. Like that eighteenth-century boy, Michael May still struggles with nearness and distance. How to sort out a landscape — why can't one touch trees in the distance? May also echoes old cases histories with his dislike of sights that're not smooth, clean, and hard edged. Others have expressed repugnance at any imperfection. And, at the heart of all cases, is a need to use one's fingers to make sense of visual images.

May also reports being stunned by what he called the faucet of color that'd been turned on. He'd heard that his wife was blonde. But, when he finally saw her hair, he was bewildered by the array of colors it presented. He couldn't separate the hues in her hair from the shadows that hair cast upon her face.

After three years, May still struggles with that mountain cliff of a learning curve. He can catch a ball, but he can't recognize faces. To identify his own wife, he needs to add sound, touch, and context to the sight of her. When he skis, he has to close his eyes, now and then, to keep his bearings.

May is providing physiologists with the chance to learn all kinds of things about how the mind learns to see. They now have a much clearer idea how the mind loses the ability to accommodate certain new sense data, after a certain age.

Still, this all leaves one key question hanging: What would it be like for you or me to gain another sense? I try to conceive a sixth sense, and I cannot. Try as I may I find myself couching any new sense in terms that I already know — reading minds or seeing the future, feeling a presence, smelling fear — or tasting joy.

I'm John Lienhard, at the University of Houston, where we're interested in the way inventive minds work.

(Theme music)


R. L. Gregory, At First Sight. Even Odder Perceptions, New York: Routledge, 1994, Chapter 8.

For material on Michael May, see:
http://www.sciencedaily.com/releases/2003/08/030826065256.htm
http://ucsdnews.ucsd.edu/newsrel/soc/sightregained.htm
http://www.guardian.co.uk/science/2003/aug/26/genetics.g2

sixth sense


The Engines of Our Ingenuity is Copyright © 1988-2003 by John H. Lienhard.