Comment »Posted on Wednesday 24 December 2008 at 2:07 pm by Jacob Aron
In Biology, Getting It Right, Health & Medicine

Now call me a cynic if you like, but when I read a story about a blind man navigating a maze that he cannot see my bullshit meter immediatly starts to tingle. As it happens, I’m right – to a certain extent at least.

The news is that man known anonymously as TN has successfully walked along a corridor full of obstacles, despite having been left blind by a series of strokes. This phenomenon is known as “blindsight”, the strange ability of some blind people to perceive objects that they cannot actually see.

Now, as I understand it, there is nothing physically wrong with TN’s eyes. Rather, his brain has been damaged in such a way that he can no longer control vision. He had already been noted to react to people’s facial expressions, so something must be getting through. Clearly, TN experiences a very different form of blindness compared to those who have sustained damage to their eyes.

I’m not suggesting TN is faking his blindness in any way – he really is genuinely blind. I would compare his condition to a digital camera with a broken screen. Such a camera can still take pictures, but with out a screen to view them on the camera is effectively ‘blind’. Contrast this with a camera that has a working screen, but a broken lense, and you can see the distinction I’m making here. What TN’s brain has effectively done is find a USB cable to hook it up to his brain and allow him to view the pictures – even if he doesn’t actively realise.

Why does this distinction matter? It’s all in the way these stories are reported. ‘Blind man can see’ is a very newsworthy story, but it is also cruel to misrepresent the facts to those with a different kind of blindness to TN. With that in mind, let’s see how the mainstream media reported the findings.

For once, they’ve actually all done pretty well. Each story makes it more or less clear that TN’s blindness is due to brain damage, and that his eyes are still fully functional. They all also include a quote from the study leader, Professor Beatrice de Gelder, who makes it pretty clear what’s going on:

“This is absolutely the first study of this ability in humans.

“We see what humans can do, even with no awareness of seeing or any intentional avoidance of obstacles. It shows us the importance of these evolutionarily ancient visual paths. They contribute more than we think they do for us to function in the real world.”

So, Merry Christmas guys; you all receive a Just A Theory “Getting It Right” badge of approval. Try and keep it up in 2009!


Sorry, comments for this entry are closed at this time.