高考英语《流行话题 语境识词4500》Unit 73　You Make Mona Lisa Smile素材.docVIP

高考英语《流行话题 语境识词4500》Unit 73　You Make Mona Lisa Smile素材 Unit 73　　You Make Mona Lisa Smile　　For nearly 500 years, people have been gazing at Leonardo da Vincis portrait of the Mona Lisa with puzzle. First she is smiling. Then the smile fades. A moment later the smile returns only to disappear again. What is it with this ladys face? How did the great painter capture such a mysterious expression and havent other artists copied it? The Italians have a word to explain Mona Lisas smile: sfumato. It means blurry, ambiguous and up to imagination.　　 But now according to Dr. Livingstone, a Harvard neuroscientist, there is another, more concrete explanation. Mona Lisas smile comes and goes, because of how the human visual system is designed, not because the expression is ambiguous. Dr. Livingstone is an authority on visual processing, with a special interest in how the eye and brain deal with different levels of contrast and illumination.　　In staring at the picture, Dr. Livingstone noticed a kind of flickering quality. The smile comes and goes as a function of where the viewers eyes are. The human eye has two distinct regions for seeing the world. A central area, called the fovea, is where people see colors, read fine print, pick out details. The peripheral area, surrounding the fovea, is where people see black and white, motion and shadows.　　 When people look at a face, their eyes spend most of the time focusing on the other persons eyes, thus when a persons center of gaze is on Mona Lisas eyes, his less accurate peripheral vision is on her mouth. And because peripheral vision is not interested in detail, it readily picks up shadows from Mona Lisas cheekbones. These shadows suggest and enhance the curvature of a smile. But when the viewers eyes go directly to Mona Lisas mouth, his central vision doesnt see the shadows, youll never be able to catch her smile by looking at her mouth. The flickering quality -- with smile present and smile gone -- occurs as people move their e