By Janet Fang
Posting in Technology
At first sight: the 'newly sighted' can't immediately recognize an object visually if they've only ever known it by touch.
Would a blind person, on regaining the ability to see, be able to immediately recognize an object by sight something previously known only by touch?
This question, posed by philosopher William Molyneux in 1688, may finally have been answered this week.
When (re)gaining their sight for the first time, congenitally blind children aren’t able to recognize something by sight if they've only ever touched it, a new study shows.
So in a sense (so to speak), we must learn to see. The ability is not innate: we have to learn that how objects look reflect how they feel.
Richard Held of MIT and colleagues studied a group of 5 children who are treated by Project Prakash, which treats curable blindness in parts of India where medical services are often inadequate. Study coauthor Pawan Sinha founded an organization in 2003.
The patients were ages 8 through 17, and they have all been blind from birth because of congenital cataracts or an opaque cornea (which should normally be transparent).
- First, they each had a cataract removal or received a corneal transplant.
- Within 48 hours of gaining sight, the patients were asked to feel a Lego-like brick.
- They were shown 2 different looking bricks, and then asked to match the brick they felt with one of them.
These patients were unable to correctly match the blocks they felt to what they only saw. Their average success rate was 58%. "They couldn't form the connection," says study coauthor Yuri Ostrovsky of MIT.
However, after they were retested 5 days later with no further training, some of these children showed a substantial improvement. Their accuracy was above 80%.
"Experience with the natural world was most likely responsible for the improvement," says Held.
So to answer the centuries old question: "initially no," Sinha says, “but subsequently yes.”
The study was published in Nature Neuroscience this week.
Image by benfuji via Flickr
Apr 13, 2011
"Would a blind person, on regaining the ability to see, be able to immediately recognize an object by sight something previously known only by touch?" Du-uh. If you've never seen something, you're not going to know what it looks like. However, if you've felt it, you may have some idea of what it might look like.
This was clearly demonstrated in the Discovery Channel four part mini series "Human Body Pushing the Limits" (DVD available, I highly recommend) in the segment on sight where they showed a 40 something year old male regaining the ability to optically see again after losing his sight at age three due to a freak chemical accident. With the removal of the bandages the first sight they put before him was his wife's smiling face. He didn't know what he was looking at and had to cognitively analyze, deconstruct, and think about the optical information and come to the conclusion that this was a face. Clearly sight is an action of multiple senses working together (think taste as requiring AT LEAST the tongue AND nose to function.) As this article points out there is a whole visual memory, learning about the meanings of objects, colors, shadings, size, distance, movements, etc. that we are unconsciously constantly bringing into play in order to see. But why limit the notion of learning and each sense actually being multiple senses working in coordination? Why wouldn't all our senses work this way? This points out a huge potential pitfall of specialization/narrow thinking (not to diminish the benefits of specialization, why be half assed in this thread?) That is that our experiences of our senses actually depends on a holistic functioning of our bodies. As the section heading (Rethinking Healthcare) of this piece possibly suggests, I think we must rethink/re-image our understanding of the body and how it works to come up with care and treatment programs that are effective both in the outcome of treatment and the cost of producing that outcome. Much is happen these days (like articles such as this one) that is beginning to create the needed dialogs for these much needed changes to occur. Hopeful indeed!
Read An Anthropologist On Mars by Oliver Sachs. Seeing is a lot more than fixing an eyeball. For doctors to ignore these issues makes the outcome of these procedures pointless.