4 ms·

>In 2003, Pawan Sinha, a professor at MIT in Boston, set up a program in India as a part of which he treated 5 patients that almost instantly took them from tot

by jere 14y ago

>In 2003, Pawan Sinha, a professor at MIT in Boston, set up a program in India as a part of which he treated 5 patients that almost instantly took them from total congenital blindness to fully seeing.[8][9] This provided a unique opportunity or answer the Molyneux's problem experimentally. Based on this study, on April 10, 2011, he concluded that the answer, in short, to Molyneux's problem was "no". Although after restoration of sight, the subjects could distinguish between objects visually as effectively as they would do by touch alone, they were unable to form the connection between object perceived using the two different senses. That is a really counterintuitive result for me. I always assumed that one could construct a spatial model of something by touching it, without that directly being related to vision.

Shinkei 14y ago
I think that's why the problem is so interesting and the answer so telling about the human brain. The way I picture it is that if you closed your eyes and held a ball, you would picture a sphere... but it is because you have in internalized image of a sphere. If you had never seen a sphere, you probably wouldn't be able to imagine one... even if you could feel all it's dimensions. Your mental 'canvas' is not only lacking paints... you don't even have a brush.
andrewflnr 14y ago
You'd think, because it all boils down to coordinates, right? Or at least relative coordinates. Apparently not. It's more like pattern matching, where the patterns are much more abstract than a coordinate system, where the connection between felt and seen patterns has to be learned, and the translation of either into "coordinates" has to be consciously worked at. I don't really know, not being anything like a neuroscientist. I'm also reminded of the way babies are born seeing upside down, and learn naturally to invert their vision. Apparently if one wears glasses that invert their vision, it eventually flips back. Is that a built-in transformation, or is it deduced from first principles, just to make a simpler mapping between seen data and other data, e.g., to more simply reconcile feeling your hand move one direction and watching it move in another? If from first principles, what else is it doing? And we know the brain adds stuff to the picture before it's presented to the conscious mind, too.
- raldi 14y ago
  > I'm also reminded of the way babies are born seeing upside down Do you have a source for that?
  - Houshalter 14y ago
    I believe he means that the light receptors on your eye are inverted like this: http://www.northlight-images.co.uk/content_images_2/digital_pinhole/pinhole_geometry_2.gif http://www.northlight-images.co.uk/content_images_2/digital_... But the idea that people "see upside-down" is a common misconception. How the inputs map onto your brain spatially don't really matter. Well they do, but it doesn't matter if it's inverted or not because your brain learns (or likely is hardwired biologically) to map signals that come from the bottom to being located at "top" and signals that come from the top as "bottom".
    - andrewflnr 14y ago
      Right, it's precisely that learning I'm interested in. I could well be wrong in that specific example. IIRC, I first got that from one of those "science" books for kids.
    - deleted 14y ago
      [deleted]
  - jleader 14y ago
    I suspect the GP is thinking of this or similar studies: http://en.wikipedia.org/wiki/Perceptual_adaptation#Experimental_support http://en.wikipedia.org/wiki/Perceptual_adaptation#Experimen...
StavrosK 14y ago
You probably can. You can't construct a spatial model of something by seeing it unless you've already gotten used to the various effects (perspective, parallax, etc) and how they represent space, though. Or, at least, that's my totally untrained opinion.
shmageggy 14y ago
You absolutely can, and there's even been recent research into the computational mechanisms that are behind this kind of inference [1]. They build a computational model that learns spatial/visual representation from (simulated) haptic stimuli with performance similar to human subjects. I think the reason Sinha's experiment had a negative result was, as other commenters have mentioned, that this ability is a learned behavior. Those who are blind from birth simply never developed the ability to form abstract representations from visual stimuli, therefore haptic information cannot be translated into these visual representations. The other commenters who are saying there is no pathway between the two modalities are wrong, and it's easy to set up an experiment to show it. Just blindfold someone and hand them an unfamiliar object, then, without showing it to them, have them draw it. It's clear that we can do this to some extent. [1] http://www.bcs.rochester.edu/people/robbie/jacobslab/abstracts.html#Yildirim13 http://www.bcs.rochester.edu/people/robbie/jacobslab/abstrac...
- w1ntermute 14y ago
  Right, there is a physical difference between the brain of a person who has been blind from birth and someone who has not. This also means that if you restore sight to someone who once had it and then lost it, they should have no trouble picking out an object they hadn't seen (only felt), even if it was an object they had neither seen nor felt prior to losing their vision.
hcarvalhoalves 14y ago
> I always assumed that one could construct a spatial model of something by touching it, without that directly being related to vision. You can do that if you are able to see, close your eyes and touch it. What you'll be doing is seeing "in the mind's eye". Someone might have researched that, but you'll probably be exercising some cortex area related to vision. Apparently, for people born blind, they can't make that connection since they don't have the experience to draw from. I would think it's like singing two songs one octave apart and asking someone who was deaf which had a higher pitch. Even though he can hear, he wouldn't have this intuition developed yet.

by jere 14y ago

Shinkei 14y ago

I think that's why the problem is so interesting and the answer so telling about the human brain. The way I picture it is that if you closed your eyes and held a ball, you would picture a sphere... but it is because you have in internalized image of a sphere. If you had never seen a sphere, you probably wouldn't be able to imagine one... even if you could feel all it's dimensions. Your mental 'canvas' is not only lacking paints... you don't even have a brush.

andrewflnr 14y ago

You'd think, because it all boils down to coordinates, right? Or at least relative coordinates. Apparently not. It's more like pattern matching, where the patterns are much more abstract than a coordinate system, where the connection between felt and seen patterns has to be learned, and the translation of either into "coordinates" has to be consciously worked at. I don't really know, not being anything like a neuroscientist. I'm also reminded of the way babies are born seeing upside down, and learn naturally to invert their vision. Apparently if one wears glasses that invert their vision, it eventually flips back. Is that a built-in transformation, or is it deduced from first principles, just to make a simpler mapping between seen data and other data, e.g., to more simply reconcile feeling your hand move one direction and watching it move in another? If from first principles, what else is it doing? And we know the brain adds stuff to the picture before it's presented to the conscious mind, too.

raldi 14y ago
> I'm also reminded of the way babies are born seeing upside down Do you have a source for that?
- Houshalter 14y ago
  I believe he means that the light receptors on your eye are inverted like this: http://www.northlight-images.co.uk/content_images_2/digital_pinhole/pinhole_geometry_2.gif http://www.northlight-images.co.uk/content_images_2/digital_... But the idea that people "see upside-down" is a common misconception. How the inputs map onto your brain spatially don't really matter. Well they do, but it doesn't matter if it's inverted or not because your brain learns (or likely is hardwired biologically) to map signals that come from the bottom to being located at "top" and signals that come from the top as "bottom".
  - andrewflnr 14y ago
    Right, it's precisely that learning I'm interested in. I could well be wrong in that specific example. IIRC, I first got that from one of those "science" books for kids.
  - deleted 14y ago
    [deleted]
- jleader 14y ago
  I suspect the GP is thinking of this or similar studies: http://en.wikipedia.org/wiki/Perceptual_adaptation#Experimental_support http://en.wikipedia.org/wiki/Perceptual_adaptation#Experimen...

StavrosK 14y ago

You probably can. You can't construct a spatial model of something by seeing it unless you've already gotten used to the various effects (perspective, parallax, etc) and how they represent space, though. Or, at least, that's my totally untrained opinion.

shmageggy 14y ago

You absolutely can, and there's even been recent research into the computational mechanisms that are behind this kind of inference [1]. They build a computational model that learns spatial/visual representation from (simulated) haptic stimuli with performance similar to human subjects. I think the reason Sinha's experiment had a negative result was, as other commenters have mentioned, that this ability is a learned behavior. Those who are blind from birth simply never developed the ability to form abstract representations from visual stimuli, therefore haptic information cannot be translated into these visual representations. The other commenters who are saying there is no pathway between the two modalities are wrong, and it's easy to set up an experiment to show it. Just blindfold someone and hand them an unfamiliar object, then, without showing it to them, have them draw it. It's clear that we can do this to some extent. [1] http://www.bcs.rochester.edu/people/robbie/jacobslab/abstracts.html#Yildirim13 http://www.bcs.rochester.edu/people/robbie/jacobslab/abstrac...

w1ntermute 14y ago
Right, there is a physical difference between the brain of a person who has been blind from birth and someone who has not. This also means that if you restore sight to someone who once had it and then lost it, they should have no trouble picking out an object they hadn't seen (only felt), even if it was an object they had neither seen nor felt prior to losing their vision.

hcarvalhoalves 14y ago

> I always assumed that one could construct a spatial model of something by touching it, without that directly being related to vision. You can do that if you are able to see, close your eyes and touch it. What you'll be doing is seeing "in the mind's eye". Someone might have researched that, but you'll probably be exercising some cortex area related to vision. Apparently, for people born blind, they can't make that connection since they don't have the experience to draw from. I would think it's like singing two songs one octave apart and asking someone who was deaf which had a higher pitch. Even though he can hear, he wouldn't have this intuition developed yet.