Re: Which mechanism is responsible for our mental pictures as we're reading ?

Bonjour, Marie-Laure, et bienvenue a MadSci!

You are fortunate, because recently, neuroscientists have studied how people 
actually read, by looking at people's brains while they are reading.

In the past, people thought that everyone was reading "visually," because 
people see the alphabet with their eyes.  But this is not the way the brain 
actually works.  People learn to listen to language before they learn to read. 
Languages, like French, English, Spanish, etc. are called "phonetic languages 
because they depend on speech sounds. 

When you learn to read, you are simply looking at visual symbols of the speech 
sounds in your brain. Your eyes "look at" the written alphabet letters, and 
then your brain "hears" the sounds represented by the letters you are reading. 
Fluent readers group the letters together into "syllables" for faster reading. 
A syllable is usually a consonant sound followed by a vowel sound, which is 
called a "C-V pair."  So, when you are reading "so" your brain hears "so" 
not "s" and "o" separately. 

In your brain, your "visual center" (if you are right-handed) is in the RIGHT 
frontal area, and your "auditory center" for language sounds is in your LEFT 
frontal area. So, neuroscience researchers recently looked at people's brains 
while they are reading, to see if reading is really "visual" or "auditory."

One of the most recent studies is: "The role of coherence and cohesion in text 
comprehension: an event-related fMRI study," which was done by researchers at 
the Max-Planck-Institute of Cognitive Neuroscience in Leipzig, Germany. Their 
results were recently published as of 26 December 2000. 

The German researchers noticed that there were two different explanations of 
how people read.  

1.) When neuropsychologists looked at people's behavior while reading, they 
thought that reading is "visual" in the RIGHT frontal area of the brain. 

2.) But, when medical doctors researched people with brain problems, the 
medical doctors noticed that reading problems came from problems in 
the "auditory" LEFT frontal area of the brain.

The German researchers decided to settle this argument, to find out which group 
of people was correct, by looking directly at the normal brains of people while 
they are reading.

The German researchers discovered that the medical doctors are correct.  All 
reading is processed in the LEFT side of the brain, in the areas for "auditory 
processing of language sounds."

So, when you are reading, your eyes "see" the alphabetic letters, but your 
brain is actually "hearing" the sounds that those letters represent. And that 
is how your brain works while you are reading!

[Admin Note:  For additional details, please refer to the following previous 
madsci answers:

* Michael Do's Answer
* Homero Rey's Answer
* Joshua Rodefer's Answer

-- RJS.]