ABSTRACT
Leonardo da Vinci’s portrait of Mona Lisa has puzzled onlookers for nearly 500 years with her on-again, off-again smile-now you see it, now you don’t. Dr. Margaret Livingston, a Harvard neuroscientist, has made a study of this phenomenon. In viewing the painting and staring at it for a time, it seemed to flicker. She noticed the smile would appear and then disappear, depending on where her eyes fixated. When she focused on Mona Lisa’s eyes, as most people do, the smile was apparent but when she focused on her lips, the smile disappeared. Do you find this so when you look at this picture of the Mona Lisa. (The reason for her red eyes, a rhetorical substitution, is explained in Chapter 11, Exercise 2.)
The retina in the eye is made up of two distinct areas for seeing. The small central area called the fovea, which is responsible for color and detail, and the larger surrounding area, which is less responsive to color but is highly responsive to motion and low light levels. Foveal vision is conscious vision while we are normally less aware of the image in the surround area.
