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By
RICK CALLAHAN - Associated Press Writer
01:26
AM ET 04/29/99
The
ability to understand speech is so deeply ingrained that people can
decipher recorded sentences that have been chopped into brief
segments and played backwards, researchers reported today. Digitally
recorded sentences were sliced into very short segments in the
study, then reversed. The distorted speech was played to seven test
subjects. The participants had no problem understanding the
sentences. Their brains were apparently able to perceive the
syllables as sounding nearly the same whether heard backwards or
forwards.
"When
you distort speech, it distorts certain aspects, but other
parameters are still able to convey the message,'' said Kourosh
Saberi, a researcher at the California Institute of Technology's
division of biology.
Saberi and David R. Perrott of California State University in Los
Angeles' department of psychology reported their findings in today's
issue of the journal Nature. Ray Kent, a professor of communicative
disorders at the University of Wisconsin in Madison, said the
research demonstrates that many areas of the brain are used to
handle complicated auditory signals. Not only are both hemispheres
of the brain involved in speech processing, but eyesight plays a
significant role by allowing people to unconsciously lip read to
fill in missing data, Kent said. Anyone who has gone to a party held
in a crowded room filled with music and chattering people has tapped
those skills to understand what others are saying, he said.
"What
this tells us is that speech is quite robust. We can perceive it
even when a number of things have been done to distort or muddy the
signal,'' Kent said. "Somehow the information is preserved or at
least recoverable to us even when it's played backwards.''
Steven Greenberg, a researcher at the International Computer Science
Institute in Berkeley, Calif., said the findings could someday lead
to improved speech-recognition programs that allow computers to
respond to spoken commands. It also adds to a growing body of
evidence disputing the notion that individual vowels and consonants
are crucial to understanding the spoken word, he said.
Also
check out this feature article from Nature Magazine -
Graphic version
or
Acrobat PDF version
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