[ExI] and speaking of qualia...

[Damien Broderick]

<http://www.cosmosmagazine.com/node/4215/full>

Centuries-old debate on perception settled
Monday, 11 April 2011

by Marlowe Hood
Agence France-Presse

'Molyneux's question' asks, "if a man born blind can feel the 
differences between shapes such as spheres and cubes, could he similarly 
distinguish those objects by sight if given the ability to see?"

PARIS: A conundrum about human perception has stumped philosophers and 
scientists alike since it was first articulated by an Irish politician 
in a letter to John Locke 323 years ago. But French scientists now claim 
that they have it solved.

Imagine, William Molyneux wrote to the great British thinker, that a man 
blind from birth who has learned to identify objects - a sphere and a 
cube, for example - only through his sense of touch is suddenly able to 
see. The puzzle, he continued, is "Whether he Could, by his Sight, and 
before he touch them, know which is the Globe and which the Cube?"

For philosophers of the time, answering 'Molyneux's question', as it was 
known ever after, would resolve a fundamental uncertainty about the 
human mind.

‘Nurture vs. nature’

Empiricists believed that we are born blank slates, and become the sum 
total of our accumulated experience. So-called ‘nativists’ countered 
that our minds are, from the outset, pre-stocked with ideas waiting to 
be activated by sight, sound and touch.

If a blind man who miraculously recovered his sight could instantly 
distinguish the cube from the globe it would mean the knowledge was 
somehow innate, they argued.

More recently, this ‘nurture vs. nature’ debate has found its 
counterpart in modern neuroscience. "The beauty of Molyneux's question 
is that it also relates to how representations are formed in the brain," 
said Pawan Sinha, a professor at The Massachusetts Institute of 
Technology (MIT) in Boston and the main architect of the study.

"Do the different modalities, or senses, build up a common 
representation, or are these independent representations that one cannot 
access even though the other modality has built it?" he asked.

Finding the cured blind

Recent studies have suggested that the mental images we accumulate 
through sight and touch do, in fact, form a common pool of impressions 
that can be triggered and retrieved by one sense or the other. But until 
now, no one has been able to design a definitive experiment.

The problem was finding subjects. They would have to have been blind at 
birth and then have had their sight restored, but not until they were 
old enough to reliably participate in tests. Most forms of curable 
congenital blindness, however, are detected and cured in infancy, so 
such individuals are extremely rare.

More precisely, they are rare in rich countries. So in 2003, Sinha set 
up a program in India in cooperation with the Shroff Charity Eye 
Hospital in New Delhi.

Discriminating between similar shapes

Among the many patients he treated, he found five - four boys and one 
girl, aged eight to 17 - who met the criteria for surgery that would 
almost instantly take them from total blindness to fully seeing. Once 
bandages were removed, researchers had to first be sure that the 
volunteers could see well.

Using objects that looked like Lego building blocks, they tested the 
ability to discriminate visually between similar shapes. The subjects 
scored nearly 100%.

They scored nearly as well when it came to telling the difference by 
touch alone, according to the study, published in Nature Neuroscience.

Barely better than a guess

For the critical test, however, in which the children first felt an 
object and then tried to distinguish visually between that same object 
and a similar one, the results were barely better than if they had guessed.

"They couldn't form the connection," said Yuri Ostrovsky, also a 
researcher at MIT and a co-author of the study.

"The conclusion is that there does not seem to be any cross-modal" - 
that is, from one sense to the other - "representation available to 
perform the task," he said.

The answer is 'no'

The answer to Molyneux's question, then, appears to be ‘no’: the data 
blind people gather tactically that allows them to identify a cup and a 
vase, and to tell them apart, is not accessible through vision. At least 
not at first.

"From a neuro-scientific point of view, the most interesting finding is 
the rapidity with which this inability was compensated," said Richard 
Held, an emeritus professor at MIT and lead author of the study. "Within 
about a week, it's done - and that is very fast. We were surprised," he 
said.

The overall results suggest that the human brain is more ‘plastic’, or 
malleable, longer into childhood than previously thought, the 
researchers said.

"This challenges the dogma of 'critical periods,' the idea that if a 
child has been deprived of vision for the first three or four years of 
life, he or she will be unable to acquire any visual proficiency," Sinha 
said.