[gui-talk] Fwd: Article: Blind perceive touch faster than sighted

[Steve Pattison]

 From:    Karim Lakhani karim.lakhani at shaw.ca
 To:      Access L access-l at access-l.com

Blind perceive touch faster than sighted

CBC news, Tuesday, October 26, 2010 

Among the blind people tested in the study, those who perceived
most quickly were the swiftest braille readers. (David
Mdzinarishvili/Reuters) 

People who are blind from birth are able to perceive information
relayed by their sense of touch faster than people who are
sighted, a new study finds.

People blind at birth typically are better at reading braille -
which represents the alphabet through arrangements of raised dots
- than those who go blind in adulthood.

Scientists knew that the brains of people who are blind since
birth show changes, such as how the vision part of the brain
tends to be taken over by touch and hearing.

Daniel Goldreich, an associate professor of psychology,
neuroscience and behaviour at McMaster University in Hamilton,
was interested in if those changes have perceptual consequences,
such as faster processing of the sense of touch.

To find out, the neuroscientists designed an experiment involving
precise microscopic vibrations to time how long the brain takes
to detect tactile information. The findings were published in
Wednesday's issue of The Journal of Neuroscience.

"We discovered that congenitally blind people are indeed faster
to perceive a tap on the fingertip than are sighted people," said
Goldreich, who came to McMaster from Pittsburgh in 2005. 

"What's more, among the blind people we tested, we discovered
that those who perceived most quickly were the swiftest braille
readers."

The experiment focused on 89 sighted and 57 people with various
levels of vision loss from the Greater Toronto Area. Their
ability to perceive the movement of a small probe against the tip
of their index finger was assessed in the lab.

In the experiment, participants felt a small tap followed a very
short time later by a longer vibration that cuts off the brain's
ability to process the tap.

Accelerated processing
On simple tasks like distinguishing small taps versus stronger
taps, the two groups performed equally. But for complex tasks
that required the brain to quickly the tap before the
interference, the 22 congenitally blind participants outperformed
the sighted participants.

The researchers think that the longer the time between the tap
and the vibration, the better formed the perception of the tap
will be, and the less interference the vibration will cause.

The researchers don't know why touch perception is faster in
people who are blind.

In Wednesday's issue of The Journal of Neuroscience, the
researchers concluded that "perceptual processing is accelerated
in congenitally blind braille readers."

It is not known whether the advantage is due to the brain
adapting to the absence of vision - a change called plasticity -
or to a lifetime of practicing braille.

"The heightened skill of tactile integration seems to account for
the remarkable speed of braille-reading demonstrated by some
congenitally blind individuals," Richard Held, an expert in the
brain and visual development at the Massachusetts Institute of
Technology, who was not part of the research, said in a release.

Next, Goldreich's team is creating computer programs to mimic the
sense of touch, and they hope to track blind people as they learn
braille to track their perceptual ability.

The research was funded by the U.S. National Eye Institute and
the Natural Sciences and Engineering Research Council in Canada.

from:
www.cbc.ca/technology/story/2010/10/26/blind-touch-percept
ion.html#ixzz13Vo8gQPC

Regards Steve
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