Chins

Post by **mistermack** » Sun Mar 15, 2015 6:55 pm

Why do we humans have pronounced chins? Other apes don't have one. The jaw recedes.
Even the Neanderthals never had a chin, like ours. What is it for?
Speculation invited.

My own suggestion is that we have thinner necks than any ape, or any of our ancestors.
I think maybe the chin protects the throat, in an attack. Children instinctively pull their chin down, in front of the throat, if you tickle their neck. And also when they are upset or scared.
Adults often also tuck their chin onto their chest, if they are adopting a purely defensive position.

Post by **cronus** » Sun Mar 15, 2015 7:11 pm

mistermack wrote:Why do we humans have pronounced chins? Other apes don't have one. The jaw recedes.
Even the Neanderthals never had a chin, like ours. What is it for?
Speculation invited.

My own suggestion is that we have thinner necks than any ape, or any of our ancestors.
I think maybe the chin protects the throat, in an attack. Children instinctively pull their chin down, in front of the throat, if you tickle their neck. And also when they are upset or scared.
Adults often also tuck their chin onto their chest, if they are adopting a purely defensive position.

Aquatic ape. We lived near the sea more than other apes. Chin is to swim. The ability to gulp a lot of air whilst swimming under water chasing fish.

Post by **JimC** » Sun Mar 15, 2015 8:20 pm

It exists in normal people to act as a visual contrast to chinless aristocrats.

Post by **mistermack** » Sun Mar 15, 2015 8:27 pm

JimC wrote:It exists in normal people to act as a visual contrast to chinless aristocrats.

It's funny how we assign personality characteristics to a chin. A lot of bad actors had a good career just because they had an ''impressive'' jawline.
And there are few politicians who make it big, without a pronounced chin.

Alec Douglas-Hume is the only one I can remember, and that was long long ago. And he got the piss taken out of his looks.

Post by **Rum** » Sun Mar 15, 2015 8:32 pm

Our esteemed..ahem..ex minister for education. Need I say more?

: gove.jpg (6.13 KiB) Viewed 1886 times

Post by **mistermack** » Sun Mar 15, 2015 8:57 pm

Rum wrote:Our esteemed..ahem..ex minister for education. Need I say more?

gove.jpg

Could they be related ?

Post by **Hermit** » Mon Mar 16, 2015 2:09 am

Prominent chins are evolution at work in modern times. It gives formula one race drivers an aerodynamic advantage. Two examples among many:

Mark Webber

David Coulthard

Post by **mistermack** » Mon Mar 16, 2015 3:41 am

And of course, , ,

Post by **Hermit** » Mon Mar 16, 2015 3:48 am

Of course! Seven times formula one world champion. Evolution works right through to this day! What more can you say?

Post by **JimC** » Mon Mar 16, 2015 4:18 am

Did he breed before his accident?

Post by **Hermit** » Mon Mar 16, 2015 6:27 am

Yes. Meet Mick Schumacher, age 15.

He's been racing go karts until this year, when he started racing formula 4 cars. A couple of days ago he crashed his car at about 160km/h and got out of it unhurt. Crashes too are a Schumacher trait.

Post by **PsychoSerenity** » Mon Mar 16, 2015 10:55 am

Could just be a spandrel. As a result of our relatively flat faces.

In evolutionary biology, a spandrel is a phenotypic characteristic that is a byproduct of the evolution of some other characteristic, rather than a direct product of adaptive selection.

Post by **mistermack** » Mon Mar 16, 2015 12:42 pm

PsychoSerenity wrote:Could just be a spandrel. As a result of our relatively flat faces.
In evolutionary biology, a spandrel is a phenotypic characteristic that is a byproduct of the evolution of some other characteristic, rather than a direct product of adaptive selection.

Very possibly. Although there are some fossils of some extinct very flat-faced apes, and they don't have the pronounced chin.
That doesn't rule it out though. It just seems to indicate that it's not inevitable that the chin gets more pronounced with flattening of the face. But it could still happen.
Hard to confirm it or rule it out.

The other thing we evolved is a descended larynx, which is pretty vital for our enhanced speech capabilities. Maybe the chin protects the larynx, as well as the other vital bits in the neck.
With the descended larynx, humans are much more prone to choking than any other ape.
A chimpanzee can't choke on it's own vomit, and you don't need to clear the airway, if you are giving one resuscitation. Handy to know.

Post by **hackenslash** » Mon Mar 16, 2015 3:37 pm

Without chins, the Hong Kong phone book would be much smaller.

Post by **Rum** » Mon Mar 16, 2015 5:07 pm

With too many though there's an increased chance of winging the wong number...

rationalia.com

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