It's a question of how the eye and the brain work.
这个问题有关眼睛和大脑的工作原理。
Different areas of the eye are responsible for picking up different information about light and dark, colors, background and foreground.
眼睛的不同区域负责获取关于明暗、颜色、背景和前景的不同信息。
The information takes different channels through the brain.
信息通过大脑的不同渠道传递。
Luiz Martinez Otero, a Spanish scientist, said in an interview,
西班牙科学家路易斯马丁内斯奥特罗在接受采访时表示,
“Sometimes one channel wins over the other, and you see the smile.
“有时这个渠道胜过了其他,你就看到是笑的。
Sometimes others take over, and you don't see the smile.”
有时其他渠道占了上风,你就看不到笑容。”