When the Blind Can Suddenly See, Do They Know What They’re Looking At?

By Valerie Ross | April 11, 2011 5:07 pm

What’s the News: Neuroscientists have found a preliminary answer to a question that has puzzled philosophers for centuries: If someone who has always been blind is one day able to see, can they recognize by sight objects they already know by touch? In a new study published online by Nature Neuroscience, patients who had been blind since birth underwent sight-restoring surgeries as children or adolescent. In the day or two following surgery, patients seemed unable to match what they felt with their hands with what they saw, the researchers found, but a week later, they could.

This results suggests that the brain doesn’t have the innate ability (or maybe has limited innate ability) to tie input from different senses to the same concept—but that it can learn, and pretty fast. Just how fast, the researchers wrote, suggests that the neuronal machinery needed to bring together visual and tactile information may already be there; it just has to be started up.

How the Heck:

  • The researchers worked with five patients, aged 8 to 17, who had recently had surgeries to remove congenital cataracts or correct a cloudy cornea. The patients were all part of Project Prakash, a program one of the researchers began that works to restore sight to blind children in India.
  • Within 48 hours of the surgery, the researchers presented each child with a distinctively shaped object made of Lego-like blocks to feel without looking at. Afterwards, they gave the child two objects—one the same shape as the first and one a new shape–and had them say, again by feel and not sight, which was the object they’d just held.
  • Then, using a new set of objects, the researchers did the same thing—only this time the child could see the two objects but not touch them and asked which was the one they’d previously felt. (The scientists also tested whether the kids could see well enough to distinguish between the objects—which they could—to rule out the possibility that their vision wasn’t yet up to the task.)
  • The children were great at identifying the objects by feel, but when they identifying objects by sight, they were right just 58% of the time: not much better than chance.
  • Five days to a week later, the researchers had the children do the same tests, with new sets of objects. Now, they found, the children could visually recognize the object they’d touched about 80% of the time.

What’s the Context:

  • The history of this scenario goes back to 1688, when Irish natural philosopher William Molyneux first posed the question of whether people blind from birth could visually recognize familiar objects—now called Molyneux’s Problem—in a letter to John Locke.
  • Harvard neuroscientist Alvaro Pascual-Leone agrees that the change happens too quickly for the brain to undergo significant rewiring. When the children switch from recognizing objects by feel to recognizing them by sight, he told ScienceNOW, “they’re not starting from zero.”

Reference: Richard Held, Yuri Ostrovsky, Beatrice deGelder, Tapan Gandhi, Suma Ganesh, Umang Mathur & Pawan Sinha. “The newly sighted fail to match seen with felt.” Nature Neuroscience online, April 10, 2011. DOI:10.1038/nn.2795

Image: Flickr / GaelG

CATEGORIZED UNDER: Health & Medicine, Mind & Brain
  • http://tispaquin.blogspot.com Douglas Watts

    This is unbelievably not surprising and not even worthy of a story. But if you have to do anything to sell a story, go for it. Pollute the atmosphere.

  • brian

    Yeah, I wish I could get paid to research the obvious in this economy. This would even beat being a weatherman, because the outcome would be correct more often.

  • Tracy Lucas

    I found this interesting. Worth the read to me.

  • dg

    “Unbelievably not surprising” and “obvious”? Sounds like the attitude of 19th century luminiferous aether supporters.

    You can’t be sure of something until you actually look. That’s the core of science.

  • PB

    I, too, found this really interesting. We didn’t know if the brain “just knew” what shapes “look” like. And if not, how long does it take to connect the visual with the tactile? If a long time, relatively speaking, that says the connections need to be built from the beginning. If quickly, as it appears is the case, then that seems to indicate that the connections are there, but had never been primed. It’s all good stuff in our quest to understand how our amazing brains put information together.

  • Robert E

    Obviously not “unbelievably not surprising” and “obvious” or people wouldn’t have been asking the question for the last 300+ years.

  • Pat A

    I don’t know why that should surprise them, The blind cannot see top, bottom etc nor depth or width so would have a hard time until they had seen and under stood these concepts then their brain would use them in a feel – see connection. The same is true for Corner or round, bumpy or smooth, these concepts first need to be learned before they can relate feeling them to seeing them.

  • Jon

    I propose we stop doing science and instead publish Douglas and Brian’s intuitions.

    I think this is a very interesting insight into how the brain might work.

  • Tim

    The researchers are also working to restore eyesight to blind children in India. So learning something while helping is pretty damn great IMHO.
    The research is great as it helps build a better picture of how the brain works.

  • me

    I thought this was pretty interesting. Also, makes me wonder if the blue I see is the same blue you see.

  • Vex

    Quite interesting! The more we learn about our brain and how it works, the better! The quick turnaround time for the patients to be able to recognize images based on sight is pretty neat and I’d like to see more studies done to expand on these findings.

  • Vincent

    Not surprising? This study takes the scientific method to an epistemological question in a way that is not often possible. In this case, looks like there’s a score for the empiricists.

  • Craig

    I would be interested in studies similar to this involving color blind people. If you go from not having the ability to having the ability how your brain would respond to these new stimuli. I assume it would be similar to this but any thoughts?

  • Beta

    I’d love to know which common aspects of vision Douglas Watts and brian think the “newly sighted” cannot learn, even after a year or so of sight. If they can accurately guess, then they have astounding insight into neurology; if they don’t have a clue, then their remarkable powers of intuition apply only in hindsight, in something akin to Anton-Babinski syndrome (or what’s commonly known as “hot air”).

  • Jason Hancock

    This may or may not be interesting. I would like to see how sighted people would do on such test. I think it is entirely possibly that if you blindfold sighted people and give them a complex lego-shape object to feel, then unblinfold them and ask them which of two objects they felt, that many people would not get it right. It really depends on how complex and similar the objects are.

    I also think anyone who takes a test initially may improve their score on a second try because they have had “practice”.

    This may be interesting but it may also not tell us anything at all about newly sighted people.

  • Yuri Ostrovsky

    @ comment #15 (Jason Hancock)
    It’s a good question, but the object matching task is not very difficult for the normally sighted, and in fact is not even particularly difficult for this newly sighted population after just 1-4 weeks of experience, as evidenced by their very good performance in the follow-up phase.

    Also, although in the follow-up phase they did have some practice from part 1, the objects were entirely novel, so they did not have _any_ practice with these particular objects. Moreover, the study only observed improvements in that particular condition (touch-to-vision), and not in any of the other conditions (vision-to-vision or touch-to-touch), so the practice effect cannot explain the overall finding. Remember, the vision-to-vision condition is also a completely new task for these children, yet they perform it remarkably well right from the beginning. If all conditions had shown improvement, it would indeed be difficult to tell this apart from simple practice on the task itself, but that is not what was observed.

    (It should be noted, however, that this does not show that _vision_ is completely normal after sight onset. In fact, it is not, as shown in other studies by some of the same authors. Nor does it show that the touch-to-vision mapping is _completely_ learned after this short period of time, only that there is rapid progress. The stimuli for this experiment were carefully chosen to be simple enough so as to make sure that vision would not be the relevant limiting factor — a nuance that was missing from most prior attempts to answer this question. All these details are extremely interesting but will take long efforts to pin down.)

    @ comment #7 (Pat A)
    Your intuition touches the core of the question. Does the brain have these concepts due to innate mechanisms stemming from evolution, or does it acquire them from experience? I have observed a roughly 50-50 split in a room-full of neuroscientists when asked about their intuitions to the Molyneux question, and almost no one would have predicted that acquisition would happen so rapidly. Regarding some of the concepts you mention, there is actually some evidence in the infant literature that there may be innate mappings for this small subset of features. But it is difficult to interpret these findings sometimes, because even a few days of experience by the infant can lead to learning. One of the ironic things about neuroscience is that the mind’s intuitions about itself (even when properly reasoned out) are often wrong, hence, as many of the commenters have pointed out, this is why we do such “obvious” studies.

  • Smritimala

    Really interesting…..

  • James Lee

    Learning a skill (playing a guitar,piano,or any other musical instrument) while blind would seem to me a much harder task to re-aquaint. Yet many have in a short period of time. Could this be due to the early learning as a (by ear) factor.Conversly there are those that learned prior to loosing sight and have a diffucult time re-establishing the quality of play after the loss. Yet they usually do given time. peace jla

  • http://WWW.kingofmount21.net Claudie Barnhurst

    Youcompletedsome valid

  • sean

    Was wondering whether a connection that needs priming by experience is common among all senses. ie when the deaf hear (cochlea implants in congenitally deaf people) do they know what they are listening to?


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