November 17, 2010

Your face is a question mark to me


As someone with a terrible memory for faces I was oddly comforted (and slightly disturbed) to read this New Scientist article (via The Rumpus) which suggests that the human ability to read actually cannibalizes parts of the brain used for other visual skills, such as tracking animals… and recognizing faces. Neurologists have long been faced with the “reading paradox” of how our brain contains such a specific area for reading while reading itself has only existed for 5000 years–far too short a time for the reading area of the brain to be an adaptive trait. Experimental Cognitive Scientist Stanislas Dehaene previously proposed a “neuronal recycling hypothesis” in his book Reading in the Brain in which he tried to solve this “reading paradox.” Dehaene suggested that:

Part of our visual system, for instance, is not hard-wired, but remains open to changes in the environment. Within an otherwise well-structured brain, visual plasticity gave the ancient scribes the opportunity to invent reading… The area that reading co-opted originally evolved for the visual acuity needed to track animals.

This visual plasticity may have allowed for humans to “recycle” visual portions of the brain for reading, but not, his new study suggests, without a cost:

Dehaene and colleagues carried out functional MRI brain scans on 10 people who could not read, 22 who learned to read as adults and 31 who did so as children, while they were shown text and images…

But when the researchers showed participants pictures of faces, the visual word form area of those who could read was much less active than that of participants who could not read. So, the researchers speculate, learning to read competes with face recognition ability in this part of the brain at least.

So, no, I don’t know how to track a lemur and I don’t have a clue where I’ve met you before, but I do have a couple of great book recommendations you might be interested in.

And I wouldn’t have it any other way.