ADVERTISEMENT
See Inside June/July 2006

Cracking the Da Vinci Code

What do the Mona Lisa and President Abraham Lincoln have in common?

SPANISH PAINTER EL GRECO often depicted elongated human figures and objects in his work. Some art historians have suggested that he might have been astigmatic—that is, his eyes’ corneas or lenses may have been more curved horizontally than vertically, causing the image on the retina at the back of the eye to be stretched vertically. But surely this idea is absurd. If it were true, then we should all be drawing the world upside down, because the retinal image is upside down! (The lens flips the incoming image, and the brain interprets the image on the retina as being right-side up.) The fallacy arises from the flawed reasoning that we literally “see” a picture on the retina, as if we were scanning it with some inner eye.

No such inner eye exists. We need to think, instead, of innumerable visual mechanisms that extract information from the image in parallel and process it stage by stage, before their activity culminates in perceptual experience. As always, we will use some striking illusions to help illuminate the workings of the brain in this processing.

This is only a preview. Get the rest of this article now!

Select an option below:

Customer Sign In

*You must have purchased this issue or have a qualifying subscription to access this content


It has been identified that the institution you are trying to access this article from has institutional site license access to Scientific American on nature.com.
Click here to access this article in its entirety through site license access.

Rights & Permissions
Share this Article:

Comments

You must sign in or register as a ScientificAmerican.com member to submit a comment.
Scientific American Holiday Sale

Give a Gift &
Get a Gift - Free!

Give a 1 year subscription as low as $9.99

Subscribe Now! >

X

Email this Article

X