How human brains became so big

May 23, 2018 by Mariëtte Le Roux
Dr Diana Rivas displays a human brain on a working surface at the "Museum of Neuropathology" in Lima, Peru

The human brain is disproportionately large. And while abundant grey matter confers certain intellectual advantages, sustaining a big brain is costly—consuming a fifth of energy in the human body.

It is an oddity that has long flummoxed scientists: while most organisms thrive with small brains, or none at all, the human species opted to sacrifice a degree of body growth for more cerebral capacity.

On Wednesday, researchers said they can finally reveal how and why this happened.

The human brain, they suggested, expanded mainly in response to environmental stresses that forced our species to come up with innovative solutions for food and shelter, and pass the lessons on to our offspring.

The finding challenges a popular theory that the thinking organ grew as social interactions between humans became more and more complex, a research duo wrote in the science journal Nature.

In fact, the inverse may be true.

"The findings are intriguing because they suggest that some aspects of social complexity are more likely to be consequences rather than causes of our large brain size," said paper co-author Mauricio Gonzalez-Forero of the University of St Andrews in Scotland.

"The large human brain is more likely to stem from ecological problem-solving and cumulative culture than it is from social manoeuvering."

From our ape-like Australopithecus ancestors to modern Homo sapiens, the human brain has tripled in size.

But feeding such a big brain has been suggested to come at the cost of slow body growth in childhood—leaving our young dependent and vulnerable for longer than other animals.

Brain over brawn?

Previous research found correlations between large brain size in species and complex social structures, living in challenging environments, and an ability to learn lessons from peers—also described as "culture".

But no studies have been able to conclude whether these factors are the cause of brain expansion, or the result of it.

With colleague Andy Gardner, Gonzalez-Forero developed a mathematical model to measure whether being confronted with ecological and social problems has a measurable impact on brain growth, and if yes, how much.

Model "brains" were presented with ecological challenges—finding prey in bad weather or in tough terrain, for example, preserving food to protect it against mold or heat spoilage, or storing water amid drought.

Social challenges were introduced too, to test the influence on brain growth of cooperation and competition between individuals and groups.

Interestingly, cooperation was associated with a decrease in brain size, the researchers said—probably because it allows individuals to rely on each other's resources and to save energy by growing smaller brains themselves.

"We find that increasingly difficult ecological problems expand brains, but social demands fail to lead to human sized brains," Gonzalez-Forero told AFP.

But why did human brains grow more than those of other animals living in challenging environments?

Probably because of culture—the ability to learn skills from others rather than having to figure everything out for ourselves.

"So, our results suggest that it is the interaction of hard ecology and culture that produced the human ," said Gonzalez-Forero.

Explore further: How big brains evolved could be revealed by new mathematical model

More information: Inference of ecological and social drivers of human brain-size evolution, Nature (2018). 10.1038/s41586-018-0127-x , www.nature.com/articles/s41586-018-0127-x

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rrwillsj
1 / 5 (5) May 23, 2018
Headline conclusions as if they are established facts. Then hastily backtracking with several admissions that the article writer was confusing factual evidence with unproven speculations. Maybe the researchers talked too fast describing their work to the writer/editor?

It is obvious what drove the evolution of big-brains. That there is no obvious answer.

A multituding myriad of events and decisions and accidents and mistakes and sexual impositions produced the mishmash of hominid evolution.

You would have a better chance for a closer to reasonably perhaps accurate answer? If you threw darts at an amphitheater wall covered with small slips of paper. Each describing a different hypothesis.

While blindfolded.

And being spun around your bodily axis.

While stinking drunk.

With people screaming imprecations as they swung at you with whiffle-bats.

Holy shit! Did I just invent a new creation myth?
TheGhostofOtto1923
2.7 / 5 (3) May 23, 2018
"The large human brain is more likely to stem from ecological problem-solving and cumulative culture than it is from social manoeuvering."

'Ecological problem solving' - WTF is that?

Human problems began when they started killing off the predators that were keeping their numbers in check. Their principal problem was competition over resources. Their solution was to band together in TRIBES which aided in securing and protecting these resources.

Larger and more cohesive tribes could defeat others in conflict. Fighters who could conceive and execute more complex tactics and strategies based on knowledge of the enemy, held the advantage.

And the victors in tribal conflict would typically kill all the males and incorporate all the females.

These factors are what forced our brains to grow to such an unwieldy size so quickly.
cont>
TheGhostofOtto1923
2.7 / 5 (3) May 23, 2018
Group selection created modern humans. We stopped evolving by natural selection and began the process of domestication inherent in tribal living.

"In [Darwins] own words, "natural selection, arising from the competition of tribe with tribe,...would, under favourable conditions, have sufficed to raise man to his high position" (Darwin, 1871, i: 97).

"This competition, in his opinion, could be carried out through direct conflict, even in bloody forms. "When of two adjoining tribes one becomes less numerous and less powerful than the other", he maintained, "the contest is settled by war, slaughter, cannibalism, slavery, and absorption". He was quite aware, however, that competition between groups had to be combined with cooperation within them (e.g., Melotti, 1987)"
cont>
TheGhostofOtto1923
2.7 / 5 (3) May 23, 2018
"From the remotest times tribes that were not only robust, but socially cohesive, skilled in organization, technology and weaponry (Darwin called this 'superiority in the arts'), tribes that included "a great number of courageous, sympathetic and faithful members, who were always ready to warn each other of danger, to aid and defend each other", had genetically usurped other tribes (p. 199). As peoples highly endowed with social, but also military discipline, triumphed over others, "the social and moral qualities would tend slowly to advance and be diffused throughout the world"

-The trouble with tribal living is that normal behaviors common to wild animals are antithetical to cohesion and harmony in the tribe. Hence the process of domestication, of systematically selecting individuals who could resist their animal urges in favor of tribal law.

The tribal dynamic - internal amity coupled with external enmity - determined morality. Repro rights became a group thing.
TheGhostofOtto1923
2.7 / 5 (3) May 23, 2018
From the article;

"Model "brains" were presented with ecological challenges—finding prey in bad weather or in tough terrain, for example"

-Liberal academies suffer from some fundamental shortcomings, for instance being constitutionally unable to entertain the fact that hunting and fighting are basically the same thing.

The most successful strategy in either case is often the ambush, which requires careful study of a quarrys activity and movements, of his ability to fight, and of the theater of operations.

It also involves developing strategies beforehand, communicating them to participants effectively, knowing the relative skills of these participants, and so forth.

Hunting animals is easy. Hunting humans who are in turn hunting you is hard. It is the sort of challenge that results in a uniquely human intellect.
rrwillsj
2 / 5 (4) May 23, 2018
otto, I don't think I can agree with your conclusions about competing hunters.

What set Modern Homo Anthropophagus aside from other predators? Was first developing physically into a superb long-ranging endurance runner.

And 2nd, the use of fire as tool and weapon.

It was no accident that when humans burst across the Americas. That they so quickly exterminated the native megafauna. With the same stone and fire weapons used by their ancestors. The native predators were overrun before they could evolve defensive strategies.

While in Africa and parts of Asia and Australia. Leopards and crocodiles continue to this day to prey upon humans. They had hundreds of thousands if years to adapt to human pressure. Before gunpowder changed all the rules.
TheGhostofOtto1923
4 / 5 (2) May 24, 2018
What set Modern Homo Anthropophagus aside from other predators?
So willis what makes you think that dropping esoteric Latin terms is a way to make your arguments more cogent?
Was first developing physically into a superb long-ranging endurance runner
Yes and outflanking your prey is critical in the hunting/fighting ambush.
That they so quickly exterminated the native megafauna. With the same stone and fire weapons used by their ancestors
So what? Fire tech was a big factor in eliminating attritive elements which exacerbated overgrowth and hence competition.

And do take care - these are not my conclusions but those of Darwin, Spencer, malthus, bagehot, and many others.
http://rint.recht...rid2.htm
antialias_physorg
2.5 / 5 (2) May 24, 2018
But why did human brains grow more than those of other animals living in challenging environments?

Well, if you have nothing going for you (no thick hide, no strong legs, no claws, no fangs, no venom, no short gestation time, no short maturation time, no huge amount of progeny, no effective digestive system, ... ) then evolution tends to take the path of least resistance (i.e. most benefit with least amount of change). And that just happened to be 'bigger brains'.
ShotmanMaslo
1 / 5 (1) May 24, 2018
Makes sense, and we can see the effects of this development persist to this day. People whose ancestors lived in harsher environments have on average larger brains and higher intelligence. Careful planning was required for survival in such conditions.

https://upload.wi..._Map.png
rrwillsj
1 / 5 (3) May 24, 2018
otto, the term Homo Anthropophagus is a more accurate description of Modern Human. Than that ridiculous, religious based, racist term Homo Sapiens Sapiens.

Endurance was the key to prehistoric human hunting.
As most prey animals are only able to run short distances before overheating & collapsing.

This is also true among most predators. That use the ambush & sprint method. Exceptions are canines such as the African Red Dog & the Orca.

As for Darwin, Spencer & their colleagues? They represented the education & gentile standards of their society. They did push the science further along. But that was not the end of discovery.

The arts & sciences as complimentary forces, continue to evolve. An honest evaluation of their conclusions must accept that their evidence was seriously circumscribed by the level of technology they had available.

To paraphrase Newton "Each generation stands on the shoulders of giants."

Allowing us a better view of reality.

TheGhostofOtto1923
4 / 5 (2) May 25, 2018
People whose ancestors lived in harsher environments have on average larger brains and higher intelligence. Careful planning was required for survival in such conditions
"Correlational studies have only established a weak to moderate linear relationship between brain size an intelligence... most neuroscientists now believe that the complexity of cellular and molecular organization of neural connections, or synapses, is what truly determines a brain's computational capacity. This view is supported by findings that intelligence is more correlated with frontal lobe volume and volume of gray matter, which is dense in neural cell bodies and synapses, than sheer brain size"

-So what's more harsh than Australia? Brain size might have more to do with trying to keep it cool.
Cont>
TheGhostofOtto1923
4 / 5 (2) May 25, 2018
Competition among tribes is much higher in tropical regions. Reproduction in temperate/subarctic species becomes seasonal which means lower birthrates, which means less competition among equals for resources.

Cave-dwelling neanderthal most likely "lived in nuclear families" instead of tribes. And no, hunting the same animals in the same environmental conditions for millennia does not require innovation and resourcefulness. Only hunting other humans does.

"Excluding a few simple groups such as the Esquimaux, inhabiting places where they are safe from invasion, all societies, simple and compound, are occasionally or habitually in antagonism with other societies... ; and, as we have seen, tend to evolve structures for carrying on offensive and defensive actions..." Spencer

-Tropical cromag invaders had great advantage over euro indigenes; long experience with martial tactics and technology, and higher birthrates.
TheGhostofOtto1923
4 / 5 (2) May 25, 2018
People whose ancestors lived in harsher environments have on average larger brains and higher intelligence. Careful planning was required for survival in such conditions
Shotmans opinions are typical - that euros are smarter and their cultures more advanced because of their environment.

But current euro cultures did not originate in Europe. They're tropical. Euro cultures and religions originated in the tropics where they had developed to survive by outgrowing and overwhelming their adversaries.

For eons, wave after wave of refugees fled north, bringing with them the latest cultural and technological innovations resulting from intertribal competition. They extincted neanderthal and overwhelmed later pagan tribes that had learned to live in harmony with their environment.
Cont>
TheGhostofOtto1923
4 / 5 (2) May 25, 2018
While each innovation has produced advantages against other tribes, they also tended to reduce the need to live sustainably.

Later invaders could ignore the seasons. They could store food and build houses. This accelerated population growth which resulted in aggravated competition which produced more innovation, and so forth.

Agriculture and the fortified cities needed to protect the harvest originated in the tropics, not europe.

What shotman sees is the result of tropical cultures run amok in temperate environments. They innovated because they HAD to, in order to survive competition from other tribes.

European and east Asian history is a record of unending and unremitting intertribal conflict driven by tropical cultural mores and specifically, the judeo/xian religions imported from the tropics.
rrwillsj
1 / 5 (3) May 25, 2018
Coming to the realization that I had let myself be sidetracked from this article.

I opinionate that the size of the human brain is the direct result of ancestral hominids mutating to an upright stance. Long before developing larger brains.

Once upright, developing as a long-range endurance hunter. Adding the resource of learning to utilize fire for processing game and gathered vegetation. Greatly increased the quality of food nutrients consumed.

Becoming upright changed the positioning and spread of the hominid pelvis. Better food means larger fetus, carried longer to birth. Wider pelvis means mothers had a better chance of surviving giving birth to infants with wider shoulders and hips.

Surviving birthing and thru childhood, the adult hominid had better odds at competing. To live long enough to reproduce, passing on physical improvements to future generations.

Then, when the big brain mutations began, the mothers had a better chances at giving live births.
TheGhostofOtto1923
4.5 / 5 (2) May 26, 2018
Willis, your guessing is making me sick to my stomach. Nobody has been more full of shit here at physorg than you.
rrwillsj
1 / 5 (3) May 27, 2018
Oh otto, my dear boy. You are such a sweetheart to continuously acknowledge my modest wisdom and kindly efforts to bring a little bit of humoresque to you bloviates.

I speculate that the greatest difference between you otto, and myself? Is that I am willing to admit that I am speculating and opinionating and provocating. Even admit when I error in fact or presentation.

Pity the rest of you lack the strength of character I aspire to!
TheGhostofOtto1923
4.5 / 5 (2) May 28, 2018
Naw willis you're the one who's full of shit. For instance you think that standing upright caused wider pelvises. Because it just occurred to you so it must be right.

"Humans need narrow hips to walk on two legs, but they also need wide hips to have babies with big brains. This problem is known as the obstetrical dilemma."

-Note how the egomaniac uses the word "I" in most every sentence. A reliable indicator of mental illness. A particularly smelly form of mental illness.
rrwillsj
1 / 5 (3) May 28, 2018
Oh, dear otto. Please stop huffing the fumes from the exhaust ports of your tandy computer. Definitely not helping you control your psychotic episodes. Your friends keep urging you to seek treatment.

Me? "I" find you hilarious and want to thank you. For being such a perfect masochist patsy for me to unleash my sadistic impulses.

Ciao baby.
TheGhostofOtto1923
5 / 5 (1) May 28, 2018
Ah I get it. Another bonafide psychopath has hit physorg. More teaching and learning experiences for everybody.
dear otto... control your psychotic episodes
"the language of the psychopath is two-dimensional. They are, as someone once said, as "deep as a thimble."
Your friends keep urging you to seek treatment
"It is only when a person takes a long and careful look at the full-blown psychopath - a sort of exaggerated Narcissist - that they are able to see the caricature of the traits that then make it easier for them to identify the "garden variety" psychopath - and/or the Narcissist."
Me? "I" find you hilarious ... for me to unleash my sadistic impulses
"we can only say that it seems to be that the psychopath ENJOYS making others suffer. Just as normal humans enjoy seeing other people happy, or doing things that make other people smile, the psychopath enjoys the exact opposite."
https://www.cassi...path.htm

The jig is up willis.
wailuku1943
3 / 5 (1) May 28, 2018
Ah. GhostofOtto again. He's so cute!

I'm reminded of that thing about the fox and the hedgehog.

GhostofOtto is the hedgehog.

No matter the topic: Group selection! Tribes! Group Selection! Tribes!

The man is immune to subtle thought. Or, for that matter, to actual knowledge.

Group selection! Tribes!

TheGhostofOtto1923
4 / 5 (2) May 28, 2018
Wackiloco

How come you guys pick nicks that are so easy to make fun of? You're more than welcome to refute anything I say. Just remember to cite reputable sources when doing so. Like I always do.

And if you're going to side with talentless trolls like willis then you should be prepared to offer evidence that our hips got wider to enable us to run faster, and other such inane bullshit.
rrwillsj
1 / 5 (3) May 29, 2018
Oh deer oddo, since you asked so sweetly. With your usual graceless lack of charm. Put away your comicbooks and try to stay awake long enough to learn and overcome your innate ignorance.

https://en.wikipe...pedalism

Read and weep, baby! That big gourd on top of your neck has to be good for something besides being used as a chekeré.

chicka-boom, chicka-boom, bow wow wow!
TheGhostofOtto1923
5 / 5 (1) May 29, 2018
"The consequences of these two changes in particular resulted in painful and difficult labor due to the increased favor of a narrow pelvis for bipedalism... commonly known as the obstetrical dilemma."

-You really are a psychopath arent you?

and a clown.
rrwillsj
1 / 5 (2) May 30, 2018
I would prefer to think of myself as a burleque comedian.

And the fossils found show that the hominid body evolved long before modern brain size developed.

I mean, do you all expect me to believe that you build your houses from the roof down? Cause that make for a mighty amusing utube feature!
humy
4 / 5 (1) May 30, 2018
the fossils found show that the hominid body evolved long before modern brain size developed.

I mean, do you all expect me to believe that you build your houses from the roof down?

Err, you do know that, unless you are doing handstands, the bulk of the human body is generally positioned BELOW the brain, not above it, right?
rrwillsj
1 / 5 (2) May 31, 2018
flipping out, baby!
torbjorn_b_g_larsson
not rated yet May 31, 2018
The model is the first attempt to quantify this problem, so it pack a lot of punch. It is interesting to see the evolution from a common ancestor where the three factors considered weighted equally, to later species such as ours. Neanderthals were even more susceptible to its harsher environment (with smaller population sizes).

@SM: "People whose ancestors lived in harsher environments have on average larger brains and higher intelligence."

Such racism is not what the map support. Brain size do not correlate to intelligence, nor is the map in any way quantifying intelligence, it is simply brain size without accounting for body size [!]. Female != male, say.

Main hypothesis seems to be cold adaptation:

"Beals et al. (1984) proposed that the primary reason for the variation is climatic adaptation, favoring large round heads in colder climates because they conserve heat and slender heads in warm climates closer to the equator." [ https://en.wikipe...ain_size ]
TheGhostofOtto1923
5 / 5 (1) Jun 01, 2018
And the fossils found show that the hominid body evolved long before modern brain size developed.

I mean, do you all expect me to believe that you build your houses from the roof down? Cause that make for a mighty amusing utube feature!
And willis the clown still insists on making shit up even in the face of expert conclusions.

You need a red nose and a little squeezeball horn to complete the impression.
TheGhostofOtto1923
5 / 5 (1) Jun 01, 2018
"Beals et al. (1984) proposed that the primary reason for the variation is climatic adaptation, favoring large round heads in colder climates because they conserve heat and slender heads in warm climates closer to the equator."

-Well there you go. Thanks tb

Of course then there's this
https://youtu.be/FSuSg6gsnmc

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