Selection pressures for long hair and beards in humans?

[pood]

Don’t know why that image didn’t just appear in the post — maybe too big? But you can click on the link and then download or view that handsome face!

 

[excreationist]

Don’t know why that image didn’t just appear in the post — maybe too big? But you can click on the link and then download or view that handsome face!

You used WEBP - normally browsers only support JPG, PNG and GIF.
Here it is:

 

[pood]

Ah, that is webp, my bad!

 

[pood]

The key point is that pan-adaptationism (all traits are adaptations) is passe; a lot of evolution is neutral transitions, genetic drift, spandrels, etc. — what Larry Moran calls evolution by accident.

 

[excreationist]

Above, from Smithsonian Magazine, “a facial reconstruction of Homo heidelbergensis, a popular candidate as a common ancestor for modern humans, Neanderthals and Denisovans.”

Look how well-groomed he is! A real lady-killer, I’d wager, unlike some scraggly homeless dude on skid row.

In that photo he isn't very well groomed. Here is a better example with combed hair:

He would also look better if he was clean shaven. I'm saying that if he never cut or combed his hair and beard he would look a lot less attractive.

I ask again: what makes you think our hair, or lack thereof; our beards, or lack thereof; are adaptations? Why can’t they just be accidents?

In this thread I started by asking people about why hair and beards might of evolved - I wasn't happy with the explanations so now I've got the grooming theory. They could be accidents though I'm saying they can also be useful in some ways.

What people find attractive in hair, or hair styling, is subjective; and almost certainly entirely cultural. A young dude with long hair in 1960 in America would have drawn the side eye, and women his age would likely have deemed him a poof and steered clear of him. The same dude with the same hair in 1970 would have drawn armloads of coeds to his side. What happened between 1960 and 1970? It sure wasn’t evolution — it was the Beatles! And the counterculture in general; but that’s the key word, culture, not biology.

I think a man who is well groomed is generally seen as being more attractive than one who has never had their hair or beard ever cut or combed no matter the culture. Same with women especially if she has a bit of facial hair (unless the audience has a fetish) The same goes with a woman who has never cut her leg hair or pubic hair, etc.

 

[bilby]

I wasn't happy with the explanations so now I've got the grooming theory.

That’s not a theory. At best, it’s a highly speculative hypothesis - a guess.

Which goes back to my earlier question; In the unlikely event that one of your guesses were, by chance, correct, how could you ever know?

Having developed an hypothesis, how do you propose to test it?

“I am happy with it” isn’t particularly compelling evidence for the truth of any hypothesis.

 

[excreationist]

I wasn't happy with the explanations so now I've got the grooming theory.

That’s not a theory. At best, it’s a highly speculative hypothesis - a guess.

Yes it's a guess.

Which goes back to my earlier question; In the unlikely event that one of your guesses were, by chance, correct, how could you ever know?

It doesn't really matter.

Having developed an hypothesis, how do you propose to test it?

“I am happy with it” isn’t particularly compelling evidence for the truth of any hypothesis.

Well I think it is the best explanation about the use of hair and beards that I know of. I'm not very concerned about whether it is the actual reason or not.

 

[bilby]

I'm not very concerned about whether it is the actual reason or not.

Then why start the thread?

 

[pood]

Above, from Smithsonian Magazine, “a facial reconstruction of Homo heidelbergensis, a popular candidate as a common ancestor for modern humans, Neanderthals and Denisovans.”

Look how well-groomed he is! A real lady-killer, I’d wager, unlike some scraggly homeless dude on skid row.

In that photo he isn't very well groomed. Here is a better example with combed hair:

He would also look better if he was clean shaved.

You think he would look better clean-shaven. What about all the people who dig great big beards? Beards were all the rage in America in the 1860s -- Lincoln grew his on the advice of a little girl who wrote him a letter saying chicks dug beards and if Abe grew one women would tease their husbands into voting for him (women couldn’t vote back then, of course). So he grew a beard and voila! Back then lots of guys wore long hair, too — Linicoln had hair almost to his shoulders in one photo, though combed back — but by the 20th century long hair and beards had gone out of style and men were expected to be cleanshaven and wear their hair short. This persisted all the way through the fifties. What are we to make of all this? One thing is for certain: It had nothing to do with evolution or adaptation.

 

[excreationist]

I'm not very concerned about whether it is the actual reason or not.

Then why start the thread?

I thought that scientists might have explanations that they think are likely to be true.... then I came up with the grooming explanation.... and at this point I'm not worried if there is in fact some other reason. Though I think my explanation is true to some extent.

 

[Elixir]

Some thoughts - the potential to have long hair and a long beard could exist so it is easy to distinguish between a homeless man and a well groomed man.... the well groomed man would be a better provider.... or something like that....

Sure. Because evolution is really clever, and predicted homelessness as an important survival factor, hundreds of thousands of years before the first artificial shelter was built.

What about something like native Americans who pluck their facial hair and comb their hair vs a man with messy long hair and a long beard? I'm saying the well groomed man is more attractive. I think this theory for hair/beards is better than any other I've come across.

Yeah? Which one above has done the most surviving?

 

[excreationist]

He would also look better if he was clean shaved.

You think he would look better clean-shaven. What about all the people who dig great big beards?

I think it is basically about grooming. Clean-shaven involves grooming. Babylonian/Persian beards involve grooming:

Beards were all the rage in America in the 1860s -- Lincoln grew his on the advice of a little girl who wrote him a letter saying chicks dug beards and if Abe grew one women would tease their husbands into voting for him (women couldn’t vote back then, of course). So he grew a beard and voila! Back then lots of guys wore long hair, too — Lincoln had hair almost to his shoulders in one photo, though combed back — but by the 20th century long hair and beards had gone out of style and men were expected to be clean-shaven and wear their hair short. This persisted all the way through the fifties. What are we to make of all this? One thing is for certain: It had nothing to do with evolution or adaptation.

I think beards and hair can be a sign of whether the person is a good healthy provider. In the Babylonian beard it is very elaborate - and it involves the most powerful person in their society... (as opposed to a homeless person in their society)

 

[pood]

And yet beards were very rare in 1950s America. Meanwhile, 200,000 years ago, no one had combs, razor blades, shaving cream, scissors, and other grooming devices, and women did not shave their legs. And yet everyone kept getting laid. Go figure!

 

[excreationist]

What about something like native Americans who pluck their facial hair and comb their hair vs a man with messy long hair and a long beard? I'm saying the well groomed man is more attractive. I think this theory for hair/beards is better than any other I've come across.

Yeah? Which one above has done the most surviving?

The better athlete and the one with the higher status would have better survival value (though the photos also involve the irrelevant factor of age). Note that if the homeless guy had never cut or combed their hair or beard they'd be even less attractive and accepted in mainstream society (even if we're talking about hunter-gatherers)

 

[Elixir]

The better athlete and the one with the higher status would have better survival value.

Ah but that’s not how it works! (I’m sure you know that)

Evolution doesn’t favor “survival value”, it favors reproductive success. I would bet that the old codger has double digit numbers of great grandchildren, and that the athletic young buck has a riskier lifestyle. Could be totally wrong about that, but it could be so…

 

[excreationist]

And yet beards were very rare in 1950s America.

A lack of beards is still a form of groomed facial hair. Also the photos of the native Americans show no facial hair, same with many other kinds of hunter-gatherers.

Meanwhile, 200,000 years ago, no one had combs, razor blades, shaving cream, scissors, and other grooming devices, and women did not shave their legs. And yet everyone kept getting laid. Go figure!

Fire was apparently invented 300,000 to 400,000 years ago and you're saying they still hadn't discovered combs or sharp instruments for cutting their hair or beards that would usually grow to a foot or a few feet?

 

[pood]

Actually I have no idea what grooming devices, if any, they had 200,000 years ago. I doubt they had any, but I really don’t know or care. My basic point is how we wear our hair, style it, and present it, is cultural. If there were selection pressures among our ancestors it clearly was to lose body hair, perhaps to reduce parasite infestation or to facilitate better evaporative loss of heat in the climate where we orginated. Could be other reasons too, or a complex web of reasons, or part of the explanation is pure happenstance, since natural selection is not the be all and end all of evolution.

 

[excreationist]

Actually I have no idea what grooming devices, if any, they had 200,000 years ago. I doubt they had any, but I really don’t know or care.

If they didn't have any grooming devices their hair and beards would usually be at least a foot or more...

My basic point is how we wear our hair, style it, and present it, is cultural.

In most cultures they'd cut their hair and beards.... that is part of what I mean by grooming. Also hunter-gatherers cut their beards and often are clean shaven. I know the style is cultural but long hair gives them a lot to work with. Hair like apes doesn't allow many possibilities at all.

 

[pood]

Actually I have no idea what grooming devices, if any, they had 200,000 years ago. I doubt they had any, but I really don’t know or care.

If they didn't have any grooming devices their hair and beards would usually be at least a foot or more...

My basic point is how we wear our hair, style it, and present it, is cultural.

In most cultures they'd cut their hair and beards.... that is part of what I mean by grooming. Also hunter-gatherers cut their beards and often are clean shaven.

How do you know this? More important, why is any of this even important? Grooming habits seem astoundingly trivial to me as a subject, and certainly have little value with respect to evolutionary biology. And, of course, as noted, plenty of cultures at different times featured big beards and long hair, while others prized clean shaving and short hair. So what?

 

[bilby]

I'm not very concerned about whether it is the actual reason or not.

Then why start the thread?

I thought that scientists might have explanations that they think are likely to be true.... then I came up with the grooming explanation.... and at this point I'm not worried if there is in fact some other reason. Though I think my explanation is true to some extent.

This is a beautiful encapsulation of exactly why the world is completely fucked.