The theory is that a white sclera surrounding a darker iris and pupil helps people work out where everyone else is looking.
The theory is that a white sclera surrounding a darker iris and pupil helps people work out where everyone else is looking.
这个理论表示，围绕在瞳孔和一圈深色虹膜之外的白色巩膜帮助人类看出其他人视线的方向。