【英语时差8,16】蒙娜丽莎的微笑-下（在线收听）

The area around the fovea is better at detecting motion, shadows, and stark, black and white contrasts. When we look at a person’s face, according to Livingstone, we usually focus centrally on the eyes. Gazing at Mona Lisa’s eyes, our less accurate peripheral vision notices the mouth, picking up shadows from the cheekbones. The shadows play visual tricks, hinting at the curve of a smile. But when we look directly at the mouth, our central vision doesn’t see the shadows, and so the smile suddenly disappears. As our eyes scan different parts of the portrait, Mona’s smile seems to fade in and out. Did da Vinci intend to create this flickering smile effect? Perhaps. In any case, he was genius enough to paint shadows subtle enough to astound viewers for half a millennium. Meanwhile, Mona Lisa will keep smiling. And not.