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BLIND people can pick out the meaning of a spoken sentence more quickly than
sighted folks, researchers in Germany and the US have found. The finding adds
weight to the notion that blind people can hear better than others, their
hearing compensating for the loss of their sight.

“They process language faster than sighted people,” says Brigitte Röder
from the University of Marburg, Germany, who discovered the effect with her
colleagues at the University of Oregon in Eugene. She says it may explain why
some blind people are so fast at “reading” books recorded onto tape. “I have a
blind student who is speeding up all his tapes,” she says. Yet he has no problem
understanding the words.

“This, to me, is a very remarkable finding,” says neuroscientist Steve
Hillyard at the University of California, San Diego. “I would have thought that
language is such a highly over-learned skill in both sighted and blind
individuals that the timing of their language processes would be similar.”

Blind and sighted volunteers listened to sentences with a last word that
either did or didn’t make sense, for example “we sleep in a tent when we go
camping” as opposed to “tomorrow Bobby will be ten years hill”. The brain waves
of both sets of subjects were monitored with an electroencephalograph while they
decided whether or not the sentence made sense.

A brain wave pattern that indicates when semantics are being analysed, known
as the N400 signal, was observed in sighted people about 150 milliseconds after
the sentence ended. In blind volunteers, the pattern was seen in just half that
time.

The researchers also found that in blind subjects, areas at the back of the
brain normally devoted to sight were taken over in part by auditory information
processing. Röder isn’t certain, but she suspects this might be partly
responsible for speeding up blind people’s ability to process language.