Typoglycemia

I received recently one of those chain e-mails that I found quite intriguing. Here it is (try to read it):

I cdnuolt blveiee taht I cluod aulaclty uesdnatnrd waht I was rdanieg. The phaonmneal pweor of the hmuan mnid, aoccdrnig to a rscheearch taem at Cmabrigde Uinervtisy, is taht it deosn’t mttaer in waht oredr the ltteers in a wrod are, the olny iprmoatnt tihng is taht the frist and lsat ltteer be in the rghit pclae. The rset can be a taotl mses and you can sitll raed it wouthit a porbelm. Tihs is bcuseae the huamn mnid deos not raed ervey lteter by istlef, but the wrod as a wlohe. Such a cdonition is arppoiately cllaed Typoglycemia :)-
Amzanig huh? Yaeh and yuo awlyas thought slpeling was ipmorantt.

First of all, I couldn't find any information about such a study conducted at Cambridge University. It seems like it wasn't published in any academic journal nor could I find any detailed reference to it on the internet. It is however very interesting to see how easy it is to read these sentences, and makes one wonder how our brain is able to accomplish that?

One way to try to understand it is to imagine how a robot would have to be programmed in order to be able to "read" such words. Just like our brain has knowledge of the words that constitute our vocabulary, the robot must have a database of "known" words in its memory. Then, when a word like huamn is presented to it as an input, it would keep the first and last letters where they are and go through all possible combinations of the remaining letters untill it finds a match in its database. But when we read the above sentences we don't feel that we do all this processing but rather read the words spontaneously. I do believe however that our brain does at least to some extent a computation similar to that of the robot. Take the following two sentences for example:

Paesle rlpey to tihs mgssaee itlidaeemmy.

Plesae relpy to tihs mesasge immeidaetly.

It is evident that the second sentence is easier to read than the first one since it is orthographically more similar to the correct spelling of the words, and therefore less computation is required by our brain to recover the perceptual representation of each word.

Elsewhere, I find that such misspelled words must absolutely be placed in a meaningfull sentence in order to decipher them. For example, try reading the following words taken from the above text:

rdanieg, taotl, lteter

It is not nearly as easy to read them as it was initially when they were part of a meaningfull sentence. In this case, our brain must do the described robot-like computation in order to recover the perceptual representation of the words reading, total and letter. Therefore, the reason why we're able to read the misspelled text so easily is, I believe, because the presence of meaningfull sentences adds semantic knowledge about each word in addition to partial orthographic knowledge; whereas each word shown individually gives only orthographic information.

I found one functional neuroimaging study that attempts to recover brain regions involved in some way in retreiving word meaning. It is summarized that visual word processing involves activation of orthographic, but also phonologic and semantic codes in the brain. For example, the brain carries out the mapping between all three following perceptual representations of the word love with it's associated knowledge:

love, luv, I lvoe you

The three representations involve respectivelly orthographic, phonologic and semantic codes.

The reference of the mentioned study:
J. R. Binder, Kristen. A. McKiernan, M. E. Parsons, C. F. Westbury, E. T. Possing, J. N. Kaufman and L. Buchanan. (2003). Neural Correlates of Lexical Access During Visual Word Recognition. Journal of Cognitive Neuroscience, 15, 372-393.
The abstract can be found here.