盲人的触觉更加灵敏

On October 9th, we reported that cats born deaf develop enhanced vision. Now researchers find that blind people perceive touch faster than do those with sight. The work is in the Journal of Neuroscience. [Daniel Goldreich et al., citation to come.]

Volunteers who were sighted or who had varying levels of vision loss were asked to sense the movements of a small probe tapped against the tips of their index fingers. Everyone did well distinguishing light taps from stronger taps.

But when a light tap was followed almost instantly by a big, long-lasting vibration, those who had been blind since birth perceived each touch much better than did the sighted volunteers or those with only partial vision loss.

The researchers also varied the period between the tap and the vibration, and then measured the minimum separation time needed for participants to perceive the two separately. And congenitally blind people needed less time than anyone else. They were also the fastest Braille readers in the group.

The study suggests that the brain adapts to early blindness with a faster perception of touch. But the researchers admit that a lifetime of practicing Braille could also get the credit.

—Steve Mirsky