Touch and Sight Linked

Can a blind person after regaining sight recognize an object known only through touch is a question posed in 1688 by Irish philosopher William Molyneux, and answered centuries later.

Within 48 hours of their surgery, five children between the ages of 8 and 17 who had been previously blind from birth were used in a study by Richard Held and his colleagues at the Massachusetts Institute of Technology. They gave a toy block to the children who had to feel without looking at it. Then, they were shown two blocks, one of which they had touched, and by just looking were asked to identify the one they had touched.

The results proved that the right responses happened by chance and that mapping touch to sight is learned behavior. Nevertheless, in a matter of a few days, even without training, the children learnt to recognize the objects they touched and saw.

Loes van Dam at the Max Planck Institute for Biological Cybernetics in T�bingen, Germany, states, "The fact that this learning needs so little time suggests that the necessary hardware and wiring was already in place in these children before the operation" despite never having been used.

Alvaro Pascual-Leone, a neurologist and neuroscientist at Harvard Medical School in Boston says," The change in the children's ability to integrate touch and vision happens too fast to be explained by major rewiring in the brain." They needed a little bit of visual experience to learn to translate between the two senses.

So, although Molyneux's question is answered negatively in the beginning, it becomes a �yes' very soon.



Source: Medindia