A wrinkled nose, raised eyebrows, a frowning mouth--all can say a lot without uttering a single word. Facial expressions are the closest thing humans have to a universal language, and it could change our relationship with androids and other human-like robots. There are a lot of us. But no matter where we come from or the languages we speak, by using these we can still connect with other humans. There are so many purposes of facial expressions.

Why did our ancestors develop a prominent protruding nose when most primates have flat nasal openings? A new study suggests that our unusual nose may have gained its shape simply as a by-product of other, more important changes in the structure of our face – although other researchers insist that some human noses have been directly shaped by natural selection. One of the many functions of the nose and nasal cavity is to act as an "air conditioner". Together, they make sure that the air an animal breathes in is made warm and humid enough to avoid damaging the delicate lining of the lungs. But Takeshi Nishimura at Kyoto University, Japan, and his colleagues argue that the human nose performs this job poorly.