[bksvol-discuss] Fw: Weird links with words and colours in the mind

  • From: "Shelley L. Rhodes" <juddysbuddy@xxxxxxxxxxxx>
  • To: <bksvol-discuss@xxxxxxxxxxxxx>, <bookshare-discuss@xxxxxxxxxxxxx>
  • Date: Mon, 23 Aug 2004 22:44:16 -0400

On one of these lists we were talking about Synasthesia and I guess we have
a book on the topic in the collect on it.  this is an interesting news item.



Weird links with words and colours in the mind

10:00 23 August 04
New Scientist Print Edition

Synaesthesia, a condition in which people make weird sensory associations,
may rely more on the plasticity of the brain than
on any genetic predisposition. This might mean that all of us are capable of
having a synaesthetic experience.

People with synaesthesia often say that letters, words and numbers have
innate colours. Even when tested years later, their
associations remain consistent. But no one really knows why or how these odd
associations form.

In 1996, Simon Baron-Cohen and his team at the University of Cambridge, UK,
estimated that about one in every 2000 people had
the condition and that it was likely to be a genetic trait encoded on the X
chromosome (Perception, vol 25, p 1073).

But now a study of blind and blindfolded people by Megan Steven and
colleagues at the University of Oxford suggests that
while genes almost certainly play a role, it may be a minor one.

Musical notes

Steven and her team recruited six "late-blind" subjects, all of whom were
synaesthetes before losing their sight. For three
of them, their synaesthesia changed after they became blind.

One man, JF, for instance, had always thought of days and months as having
colours. Instruments in an orchestra and even his
pay scale at work were also colour-coded in his mind. After learning
Braille, he began experiencing colours when he touched
the raised Braille characters denoting letters, numbers or musical notes -
or even when he simply thought about touching
them.

Knowledge of Braille, instruments and remuneration are all learned, Steven
points out, so people such as JF must be adapting
their pre-existing synaesthesia to incorporate them. But that still leaves a
big question: can all brains adapt to make these
unusual associations, with the ability only being unmasked in a select few
people? Or are the associations themselves rare?

Evidence from a blindfolding experiment hints that the associations might be
universal. For instance, DB, who was not known
to be synaesthetic, was blindfolded for five consecutive days, and saw very
vividly a frightening face whenever he listened
to a specific passage of Mozart's Requiem. It only happened while he was
deprived of vision.


Auditory inputs

Though this mental association was not genuine synaesthesia, it did have
many of the hallmarks of the condition, the
researchers claim. It could be reproduced, was consistent and was triggered
by something specific.

Perception

This suggests that even non-synaesthetes may have the neural machinery for
generating a synaesthetic experience and that
changes to the brain might expose them, they say in a forthcoming issue of
Perception.

"It can't be entirely genetic," Steven says. She speculates that in
non-synaesthetes, the input of visual signals may be
inhibiting tactile and auditory inputs to the "visual" areas. "When there's
no more visual stimulation, maybe other
connections become more important," she says.

Baron-Cohen agrees that genes and environments are likely to interact in
shaping synaesthesia. But he questions whether
atypical cases like these can teach us much about more common varieties. His
main work is in autism and he points out that up
to 40 per cent of congenitally blind children show autistic behaviours in
early childhood, such as persistent rocking. But
blind kids tend to grow out of such rocking behaviour, while those with true
autism do not.

"We should be wary of assuming phenomena that resemble synaesthesia - such
as coloured hallucinations in a subject
blindfolded for five days - involve the same brain mechanisms that give rise
to 'naturally occurring' synaesthesia."

Alison Motluk

© Copyright Reed Business Information Ltd.

http://www.newscientist.com/news/news.jsp?id=ns99996294






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