Need for social skills helped shape modern human face

Need for social skills helped shape modern human face
Skulls of hominins over the last 4.4 million years. Credit: Rodrigo Lacruz

The modern human face is distinctively different to that of our near relatives and now researchers believe its evolution may have been partly driven by our need for good social skills.

As large-brained, short-faced hominins, our are different from other, now extinct hominins (such as the Neanderthals) and our closest living relatives (bonobos and chimpanzees), but how and why did the modern evolve this way?

A new review published in Nature Ecology and Evolution and authored by a team of international experts, including researchers from the University of York, traces changes in the of the face from the early African hominins to the appearance of modern human anatomy.

They conclude that social communication has been somewhat overlooked as a factor underlying the modern human facial form. Our faces should be seen as the result of a combination of biomechanical, physiological and social influences, the authors of the study say.

The researchers suggest that our faces evolved not only due to factors such as diet and climate, but possibly also to provide more opportunities for gesture and nonverbal communication—vital skills for establishing the large social networks which are believed to have helped Homo sapiens to survive.

"We can now use our faces to signal more than 20 different categories of emotion via the contraction or relaxation of muscles", says Paul O'Higgins, Professor of Anatomy at the Hull York Medical School and the Department of Archaeology at the University of York. "It's unlikely that our early human ancestors had the same facial dexterity as the overall shape of the face and the positions of the muscles were different."

Instead of the pronounced brow ridge of other hominins, humans developed a smooth forehead with more visible, hairy eyebrows capable of a greater range of movement. This, alongside our faces becoming more slender, allows us to express a wide range of subtle emotions—including recognition and sympathy.

"We know that other factors such as diet, respiratory physiology and climate have contributed to the shape of the modern human face, but to interpret its evolution solely in terms of these factors would be an oversimplification," Professor O'Higgins adds.

The human face has been partly shaped by the mechanical demands of feeding and over the past 100,000 years our faces have been getting smaller as our developing ability to cook and process food led to a reduced need for chewing.

This facial shrinking process has become particularly marked since the , as we switched from being to agriculturalists and then to living in cities—lifestyles that led to increasingly pre-processed foods and less physical effort.

"Softer modern diets and industrialised societies may mean that the human face continues to decrease in size", says Professor O'Higgins. "There are limits on how much the human face can change however, for example breathing requires a sufficiently large nasal cavity."

"However, within these limits, the evolution of the human face is likely to continue as long as our species survives, migrates and encounters new environmental, social and cultural conditions."


Explore further

Research to raise a few eyebrows: Why expressive brows might have mattered in human evolution

More information: The evolutionary history of the human face, Nature Ecology and Evolution (2019). DOI: 10.1038/s41559-019-0865-7 , https://www.nature.com/articles/s41559-019-0865-7
Journal information: Nature Ecology & Evolution

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Apr 15, 2019
Not evolution. Domestication. Our domestication is written all over our faces. Humans systematically eliminated the attritive elements active in natural selection, condemning us to perpetual overpopulation. We congealed into tribes to secure and protect resources.

Tribes with greater internal cohesion coupled with external animosity and aggression consistently prevailed in competition. Group selection replaced natural selection.

The wholly artificial demands of tribal living in the context of technology required us to deny our animal urges in favor of those which benefitted the tribe.

"The killing-off of relatively feeble tribes, or tribes relatively wanting in endurance, or courage, or sagacity, or power of co-operation, must have tended ever to maintain, and occasionally to increase, the amounts of life-preserving powers possessed by men... A no less important benefit bequeathed by war, has been the formation of large societies." spencer 1873

Apr 15, 2019
"Rude tribes and... civilized societies... have had continually to carry on an external self-defence and internal co-operation - external antagonism and internal friendship. Hence their members have acquired two different sets of sentiments and ideas, adjusted to these two kinds of activity... A life of constant external enmity generates a code in which aggression, conquest and revenge, are inculcated, while peaceful occupations are reprobated. Conversely a life of settled internal amity generates a code inculcating the virtues conducing to a harmonious co- operation" (Spencer, 1892)

-As cited in the excellent essay
'Human Evolution and the Origin of War: a Darwinian Heritage
by J.M.G. van der Dennen; Center for Peace and Conflict Studies, University of Groningen, the Netherlands'
http://rint.recht...rid2.htm

-The author doesnt distinguish between evolution and domestication. But the artificial environment wich created todays human is undeniable.

Apr 15, 2019
I doubt that anyone could get any "ruder" then our modern American society's fixation with ignoring the genetic mashup of our beloved "Peculiar Institution"?

Changes in jaw & bone structure are much more influenced by nutrition & caloric intake than anything else. Especially during pregnancy.

Dental care & fluoride in public water & immunizations & birth control.

I mention skull shapes separately except for deliberate skill deformation practices.
Usually the causes were unskilled birthing practices, damaging the newborn.

But overall, this is a complex subject. With addituibal contributions from diseases &
defective XY chromosomes,
Violence against pregnant women as well as accidents.

With plenty of opportunities for accumulative causes.

Wearing shoes cut down to getting hookworm.
While increasing the chances for stumbling & falling down.

Apr 15, 2019

I think I am a good example of the physiological effects combing genes & diet.

I bear a strong family resemblance to my Father & paternal Grandfather.
& from old photos, similar to their progenitors.

Except for three items. My size & weight is above normal for my Father's side of my genes including modern cousins.
At my advanced age, I still have a full, lush head of hair. & if I had any less melanin. I'd be am Albino!

The first was a better than average diet the last couple of generations. Than normal for an old-line impoverished Hillbilly family.
On a controlled diet, I still probably consume twice the calories of my great-grandfathers.

I acquired my height & head of hair from my Mother's Father. Who was a big Dutch Seaman.

My constant sunburn is courtesy of my Mother's Mother.
A Karelian-Finn peasant, sold into America.

Apr 15, 2019
They didn't mention the whites of our eyes, also different from other primates, and, useful for communication (think of hunters, giving direction silently to each other, simply by looking at something, the whites tell us where they are looking...).

Apr 15, 2019
What?
No mention of the latest evolution; plastic surgery, and that hideous expression of perpetual surprise.
Then again, this study is about the human face and most of those end up looking like completely different species.

Apr 16, 2019
Even plastic surgery won't make your baboonish expressions nor comments look like human comments, but keep trying the comedy is hilarious ;)

Apr 16, 2019
Not evolution. Domestication. ... Group selection replaced natural selection.


Of course it is evolution. The paper title says so, and if they have looked 4+ million years into the past (or even 2 generations genetically, in the latest observations of evolution in modern populations) they have looked at trait evolution.

Domestication is evolution, already Darwin knew that. And *we* know, after decades of observation, that "group selection" is neither expected - since gene selection is selfish - nor observed.

I note that you have peddled this - in all honesty - crap before, still without even trying to support your claims with valid references. You even try to wave away the reference that tests your ideas as erroneous!

Apr 16, 2019
They didn't mention the whites of our eyes, also different from other primates, and, useful for communication (think of hunters, giving direction silently to each other, simply by looking at something, the whites tell us where they are looking...).


Do you mean the article, or the paper? Since they - presumably - looked at fossilized traits, maybe they could not tell anything on that.

Apr 16, 2019
Group selection:

"Criticism

The use of the Price equation to support group selection was challenged by van Veelen in 2012, arguing that it is based on invalid mathematical assumptions.[52]

Richard Dawkins and other advocates of the gene-centered view of evolution remain unconvinced about group selection.[53][54][55] In particular, Dawkins suggests that group selection fails to make an appropriate distinction between replicators and vehicles.[56]

The psychologist Steven Pinker concluded that "group selection has no useful role to play in psychology or social science", since it "is not a precise implementation of the theory of natural selection, as it is, say, in genetic algorithms or artificial life simulations. Instead it is a loose metaphor, more like the struggle among kinds of tires or telephones."[57]

- tbctd -

Apr 16, 2019
The evolutionary biologist Jerry Coyne summarized the arguments in The New York Times in non-technical terms as follows:[58]

"Group selection isn't widely accepted by evolutionists for several reasons. First, it's not an efficient way to select for traits, like altruistic behavior, that are supposed to be detrimental to the individual but good for the group. Groups divide to form other groups much less often than organisms reproduce to form other organisms, so group selection for altruism would be unlikely to override the tendency of each group to quickly lose its altruists through natural selection favoring cheaters. Further, little evidence exists that selection on groups has promoted the evolution of any trait. Finally, other, more plausible evolutionary forces, like direct selection on individuals for reciprocal support, could have made humans prosocial. ...

- tbctd -

Apr 16, 2019
... These reasons explain why only a few biologists, like [David Sloan] Wilson and E. O. Wilson (no relation), advocate group selection as the evolutionary source of cooperation.[58]""

https://whyevolut...lection/

"The idea that adaptations in organisms result from "group selection" (selection among groups that differentially bud off subgroups, with those having good "group traits" becoming more numerous), rather than from selection among genes themselves, usually within individuals, has undergone a bit of resurgence in popular culture. This is in stark contrast to the views of most evolutionary biologists, who see group selection as a logical possibility, but one that doesn't easily work in theoretical models and, more important, has explained almost nothing about nature. ...

- tbctd -

Apr 16, 2019
In contrast, the gene-centered view of evolution worked out by biologists like W. D. Hamilton, Robert Trivers, and John Maynard Smith, and popularized by Richard Dawkins, has been immensely fruitful.

I've posted a lot on the intellectual vacuity of group selection, particularly its failure to explain the evolution of traits like human altruism and cooperation (see, for example, here, here, and here). If you want an elegant and easily digestible explanation of the weaknesses of group selection, Steve Pinker has just published a nice essay on John Brockman's Edge website, "The false allure of group selection." If you're interested in seeing three smart biologists take group selection apart, there's an excellent paper by West, Griffin, and Gardner (reference below), ...

- tbctd -

Apr 16, 2019
So if group selection is so intellectually and scientifically unproductive, why do we hear so much about it? I think there are two reasons.

First, its few proponents make a lot of noise. ...

Second, people *want* to believe in group selection. ...

With all that money and all those megaphones behind it, the idea of group selection persists in the public mind while slowly dying in the scientific community. Yes, it's dying, but it refuses to lie down."

[TL: At a minimum, I want advocates for "group selection" to think carefully why and what they are - so far uselessly - peddling. And please provide useful science, in articles or as a basis for somewhat interesting discussions! Because this is not such a subject: it is - based on easily accessible evidence - a zombie.]

Apr 16, 2019
I note that you have peddled this - in all honesty - crap before, still without even trying to support your claims with valid references. You even try to wave away the reference that tests your ideas as erroneous!
But I've always provided valid refs. You dont return to the threads where I present them in response to your criticism.

And like I say I dont think you appreciate the uniqueness of the human species. Group selection among tribes is entirely different from whatever it might be in nature. So your refs from evolutionary academies do not apply. Academies CANNOT and will not entertain theories that threaten the existence of their institutions.

But it is undeniable, when for instance celtic tribes were annihilated and extincted by Germanic tribes in central europe, that this is in fact group selection at work. And that this sort of group selection has been at work since protohumans began using weapons against their enemies of other species as well as their own.

Apr 16, 2019
And please provide useful science
Like I say, there is abundant evidence. The article above offers valid evidence of very unnatural domestication, the result of group selection among weapon-wielding tribes, and it needs to be interpreted as such. The rapidity for instance at which our adaptions progressed can only be explained by group selection - tribes with unique physiological, cultural, or technological advantages attacking and obliterating tribes without them.

Tribalism has no time for natural evolution. Islam spread so rapidly across northern africa not because believers had sharper claws. They had a superior social system which enabled them to replace more primitive ones. And they acted as a group - a TRIBE - not as individuals, emulating the 12 tribes of Israel in their quest to rid the holy land of unworthy tribes. An allegory of ALL of human history.

And again, this process has been with us throughout our existence. It has made us human. See the above article.

Apr 16, 2019
Tribalism in contemporary politics

"We live in a time of tribes. Not of ideologies, parties, groups, or beliefs—these don't convey the same impregnability of political fortifications, or the yawning chasms between them. American politics today requires a word as primal as "tribe" to get at the blind allegiances and huge passions of partisan affiliation. Tribes demand loyalty, and in return they confer the security of belonging. They're badges of identity, not of thought. In a way, they make thinking unnecessary, because they do it for you, and may punish you if you try to do it for yourself. To get along without a tribe makes you a fool. To give an inch to the other tribe makes you a sucker."

"More in Common found that "tribal membership predicts differences in Americans' views on various political issues better than demographic, ideological, and partisan groupings.""
https://www.newyo...of-trump

Apr 16, 2019
Interesting is the distinctly tribal message of the article itself...

"Everything in American politics today entrenches tribalism: our winner-take-all elections, the dehumanizing commentary on cable news and social media, the people we choose to talk to and live among."

-Ok, that sounds like a reasonable and objective start. But in the next sentence:

"The trends are not new, but they've dramatically accelerated and intensified under a President who rules by humiliation because he lives in fear of being humiliated."

-the author presents an extremely tribal message. It either demonstrates just how blind our tribal tendencies can make us, or it reveals how calculating and deceptive the progressive media has become in presenting its own tribal message as fact. Or more likely, this is a tribalist who willingly accepts the mandate from his leaders to attack at all costs.

Tribalism is a universal biological phenomenon in humans. Blaming it on the opposition is an expected tactic.

Apr 16, 2019
Domestication is evolution, already Darwin knew that
Darwin was unwilling to equate us with domesticated animals, even though he described the process. Heres evidence Ive previously posted.

"To identify signs of a self-domestication process in humans, researchers made a list of genes associated with domestication features in humans, out of the comparison with the genome in Neanderthals and Denisovans, extinct human species. Then, they compared this list to the genome from some domesticated animals and their wild relatives, for instance, dogs compared to wolves, and cattle compared to wisents.

"Results showed that this overlap was only relevant between domesticated species and humans. "Those modern humans' selected genes under selection may prove central to a relevant process of domestication, given that these interactions may provide significant data on relevant phenotypic traits," said Boeckx."

Apr 16, 2019
"group selection" is a euphemism for racial bigotry & misogyny.
Masked within the
pseudo-science of eugenics.

The best example of that is the horrors inflicted on racehorses by the abusive usage of the Official Stud Book.

Another means of determining the fallacious belief in group selection? Name me a descendant , to the last couple of generations.
Of a famous historical person.
Who has achieved anywhere near the fame & influence of their progenitor.

A Washington or Lee?
Edison or Tesla?
Churchill or Maxwell?
Vanderbilt or Dupont?
Roosevelt or Rockefeller?
W Buckley or WJ Bryan?
A Rand or HL Menecken?

When we speak of racists, bigots & misogynists?
A pragmatic observation of their base inferiority & lack of moral character?
Brings to my mind,
to paraphrase Clemens:
"They are lizards.
Boasting of being descended from dinosaurs."

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