Julian De Silva reveals to Insider that a heavily-defined Cupid's bow is the most asked-for feature surrounding the lips. If this is true, then it could be argued that a Cupid's bow's function is to help "shoot an arrow" towards a desired mate.

Why do we have a dip in your upper lip?

The indent, called the philtrum, is just a residual reminder of your time in the womb: in utero, the two sides of your face develop independent of one another, then join at the middle. When the two sides fail to fuse properly, the result is a cleft palate, which occurs in about 1 of every 750 births.

Why do you highlight the cupids bow?

The Cupid's Bow

The 'V' of your Cupid's bow is also a great spot to pop on some highlighter; it creates the appearance of fuller lips. Softly apply it with your finger. When the light catches, your lips will look especially plumped.