What are chins all about, anyway?
Sure, they help us to chew things, and if you’re lucky they give you a jawline to make the ladies swoon like Desperate Dan. But why? What’s it all about?
This is actually one of the most puzzling questions scientists have scratched their heads (and chins) over for the last 100 years. It might seem obvious, but our brothers and sisters in the chimp populace don’t have them, and they manage to eat their bananas all the same.
Researchers have come up with several theories about why we’re the only hominid with such a feature.
1. Dietary changes
In the past, when we were gnawing meat from the carcass and cracking nuts with our bare molars (or something), we needed a heavy duty jaw to manage it all. As our dietary habits evolved to the point where a bowl of muesli is more de rigeur, our faces slimmed down accordingly, particularly the top and the middle of the face. So the lower chin became more obvious as the rest of the face stopped overshadowing it.
Another theory goes that having a chin is just, well, sexy. A strong masculine jawline gets people hot under the collar, while for women a narrower face could indicate high levels of oestrogen, Smithsonian reports.
This idea is backed up by the fact men and women have slightly different shaped chins, perhaps to emphasise sexual differences, whereas if chins evolved just because of the food we ate or how we were speaking you would expect their chins to develop in the same way.
3. Learning to talk
Perhaps we have chins because it helps us talk, and form the sounds needed for a sophisticated language. This is one of the most popular theories, and explains why we have chins but chimps don’t.
Researchers from New Zealand published a paper in 2007 saying the chin could have evolved to protecting the jaw from the stress of using certain tongue muscles to speak. Or perhaps the our unique chin shape allows us to create a wider range of sounds?
4. Self domestication
To go back to an earlier point, human beings gradually became more and more boring, to the point where an enjoyable evening now involves watching X Factor, Star Wars or Pointless (whichever is your personal jam) instead of hunting gazelles and headbutting each other out of trees.
As we started to farm the land and live in communities (whereas before we lived mostly in isolation and were hunter-gatherers) we found it helpful to cooperate rather than fight over land. It wasn’t helpful to have so much of the aggression-boosting testosterone, so our hormones changes and as a result we became smaller in general, including our faces, according to anthropologist Robert Franciscus quoted in Mental Floss.