How important is beauty?
...There are some mathematical ideas that really do seem to be linked to beauty... One of the first to be discovered was our preference for an average face shape. Since the 1800s, researchers have known that overlaying images of lots of faces from a particular ethnic group will lead to an average face that is widely considered attractive. Each ethnic group has a different ideal, but essentially, once you've ironed out the oversized chins, lopsided ears and lengthy foreheads, what you're left with is a completely average (if unexciting) hottie.

Pic courtesy/The Mathematics of love, illustration by Christine Rosch

The theory is that when looking for a partner, we tend to dislike unusual face shapes for fear that they mask a weird genetic mutation that we'd like to avoid passing on to our future offspring.