[ScubaDiver]

That’s one of the several hypothesis. Some think that as our faces shrank (other primates have much bigger faces relative to head size than humans do), perhaps the chin became a kind of plumage like birds will sometimes use to attract mates.

For the longest time, the prevailing opinion was that the chin developed to better help leverage chewing forces. But, a few years ago, that was largely debunked by researchers. Somehow, the were able to demonstrate the size of the chin had no bearing on bite force.

So, it’s either sexual selection, speech related or perhaps just an meaningless artifact of evolution.

[blam]

It is said that our jaws/faces shrank because we began to cook our food and didn't need massive jaws to eat, the food was softer, etc.
Many people today have dental problems (to many teeth for a smaller mouth) because of smaller jaws/faces.

I've read about studies that show people find smaller faces more attractive. Also, that women from NW Europe are considered the most attractive in the world.