[tabi] Fwd: Article: Blind People Create Colorless Maps of the World In Their Heads

  • From: Lighthouse of the Big Bend <lighthousebigbend@xxxxxxxxx>
  • To: tabi <tabi@xxxxxxxxxxxxx>
  • Date: Wed, 10 Oct 2012 15:33:56 -0400

Thought this might be of interest --
---------- Forwarded message ----------
*Blind People Create Colorless Maps of the World In Their Heads*

Natalie Wolchover <http://www.businessinsider.com/author/natalie-wolchover>,
LiveScience <http://www.livescience.com>**|**Oct. 5, 2012, 5:09 PM***


Paul Gabias has never seen a table. He was born prematurely and went blind
shortly thereafter, most likely because of overexposure to oxygen in his

And yet, Gabias, 60, has no trouble perceiving the table next to him. "My
image of the table is exactly the same as a table," he said. "It has
height, depth, width, texture; I can picture the whole thing all at once.
It just has no color."****

If you have trouble constructing a mental picture of a table that has no
not even black or white â that's probably because you're blinded by your
ability to see.****

Sighted people visualize the surrounding world by detecting borders between
areas rich in different wavelengths of light, which we see as different
colors. Gabias, like many blind people, builds pictures using his sense of
touch, and by listening to the echoes of clicks of his tongue and taps of
his cane as these sounds bounce off objects in his surroundings, a
technique called echolocation.****

"There's plenty of imagery that goes on all the time in blind people," he
told Life's Little Mysteries. "It just isn't visual."****

As well as being blind himself, Gabias is an associate professor of
psychology at the ****University** of **British Columbia**** who conducts
research on perceptual and cognitive aspects of blindness. His personal and
professional experience leads him to believe that the brains of blind
around the lack of visual information, and find other ways to
same, vitally important result: a detailed 3D map of space.

The brain region neuroscientists normally think of as the "visual" cortex,
rather than being left to languish, plays a key role in the blind's mental
mapping process. [Do Colorblind People Dream In

In sighted people, visual information first goes to the visual cortex,
which is located in the occipital lobe at the back of the brain. From
there, it goes to the parietal lobe, sometimes referred to as the "where
system" because it generates awareness of a sensed object's location. Next,
the information is routed to the temporal lobe, also known as the "what
system" because it identifies the object.****

Evidence from recent brain-imaging experiments indicates that blind
people's brains harness this same neural circuitry. "When blind people read
Braille using touch, the sensory
being sent to and processed in the visual cortex," said Morton Heller,
psychologist who studies spatial cognition and blindness at ****Eastern** **
Illinois** **University****. "Using touch, they get a sense of space" â and
the relative locations of the raised dots that form Braille letters â
"that's not visual, it's just spatial."****

For blind people who are adept at echolocation, sound information routes
through the visual cortex as well. Their brains use echoes to generate
spatial maps, which are sometimes so detailed that they enable mountain
biking, playing basketball and safely exploring new environments. In fact,
last year, Canadian researchers
even when blind echolocation experts listened to audio recordings of
their tongue clicks echoing off different objects, they could easily
identify the objects that had been present at the time of the recordings.
Scans with functional magnetic resonance imaging (fMRI) showed activity in
areas of their brains associated with visual processing. In other words,
their brain scans resembled those of a sighted person identifying an object
in a photo.****

Clearly, detecting visual contrasts is only one method of many for
perceiving reality. But when trying to imagine a world perceived using
hearing or touch, one tends to automatically picture echoes and textures
generating a visual image built out of contrasts between light and dark.
Gabias cannot conceive of light and dark. So what, exactly, are his mental
images like?****

"I just picture tables. We have no idea what our brain is doing. We just
perceive â that's the wonderful thing about it. This is all
'psychologization' that has made it complicated to explain, but simple to
do. You don't know how you perceive. You just do it," he said.****

"If you know that blind people know where to put their plates on their
table, and you know that blind people deal with tables in the exactly the
same way you do, then you presume that they imagine them in the same way
you do. You have got to presume that what's inside their head is like

*Copyright LiveScience <http://www.livescience.com/>, a TechMediaNetwork
company. All rights reserved. This material may not be published,
broadcast, rewritten or redistributed.*

** **


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