• Please be advised there is a potential issue with DD collections, which may result in an excessive amount being taken. Please read the stickied thread in Fortean Times Magazine > General Discussion, Subs etc

Human Brain Size (& Evolution; Intelligence; Etc.)

sunsplash1

Gone But Not Forgotten
(ACCOUNT RETIRED)
Joined
Jan 9, 2004
Messages
1,303
Researchers bust head size-intelligence link

The genes that are thought to have helped humans evolve big brains do not appear to play any role in how intelligent we are, according to a DNA study.

This backs separate research that has failed to come up with a link between head size and intelligence, except in extreme congenital abnormalities.

The Queensland Institute of Medical Research (QMIR) study is the first to specifically look at genes, head size and intelligence in a normal population.

The Australian study finds that people who scored highly in intelligence tests did not necessarily possess versions of the genes that are expected to code for big heads and intelligence.

People who did possess the suspected 'smart' versions of the genes were not necessarily the most intelligent or the ones with the biggest brains.

The study will be presented at the 11th International Congress of Human Genetics in Brisbane next week.
Head space

The researchers tested 4,395 teenagers for head size and intelligence.

They also looked at the genes ASPM, MCPH1 and CDK5RAP2, which regulate brain size and activity.

When mutated, these genes result in an abnormally small brain, a condition known as congenital microcephaly.

"Normal variation in these genes has not yet been investigated in relation to head size and intelligence," Dr Michelle Luciano, a research fellow at QMIR, said.

She says the only comparable previous study used MRI imaging to measure brain volume in relation to two microcephaly genes.

"Their findings [about a relation to brain size] were negative and they didn't find a relationship with two of the genes we were looking at," Dr Luciano said.

"We decided to take it a step further and look at intelligence and lo and behold we find a similar negative result."
Ancestral or evolved?

We all carry the three genes the QMIR team investigated but some of us carry 'ancestral', or less evolved, versions and others carry 'derived' or more recently evolved versions.

Some of us carry one of each.

Dr Luciano says researchers had expected that people with evolved versions of the gene would be smarter and have bigger heads, but were surprised to find this was not the case.

"We would predict that if you've got the more recent version you should have a higher IQ," she said.

"We actually found that not to be the case.

"It is unlikely then that selective pressure for these genes is related to the evolution of intelligence in humans."

Rather, she says the genes might be important for a neurological function outside the brain.
Are humans getting smarter?

Professor Colin Groves, an expert in human evolution from the Australian National University, says human brains began getting bigger after our earliest ancestors like Homo habilis appeared.

But our brains have stopped growing and have actually started getting smaller, or at least more 'compact'.

"[Our brains] have got bigger but they're not getting bigger," he said.

"In fact since the late Pleistocene in general they've got smaller."

Professor Groves says while brain size appears to be related to intelligence between species, this does not seem to be the case within a species.

Despite the development of technological advances, he says there is no evidence that Homo sapiens have become more intelligent in the last 50,000 years.

http://www.abc.net.au/news/newsitems/200608/s1704016.htm

So nothing much has changed in the last 50 000 years...
:p
 

rynner2

Gone But Not Forgotten
(ACCOUNT RETIRED)
Joined
Aug 7, 2001
Messages
54,628
Only an hour before stumbling across this thread, I saw a man wearing a t-shirt with the message
"Does my belly look big in this?" !!!

(So is there any correlation between intelligence and belly size?
There's a research project for someone! :D )
 
A

Anonymous

Guest
Love the concept. Bet some council would go for it....ahem, puts on serious and caring face (plus uses PC language). Oh, and regurgitating platitudes. Go on, let me take this one on :lol:

I suspect that we can find an answer. I seem to recall that if I am posh, but have a belly, then I am prosperous. However, if not posh, then I'm a lazy git. I assume a similar finding for belly/brain correlations.
 

EnolaGaia

I knew the job was dangerous when I took it ...
(ACCOUNT RETIRED)
Joined
Jul 19, 2004
Messages
29,623
Location
Out of Bounds
In recent years it's been claimed (and debated) that human brain size has actually been decreasing for the last few thousand years or more - ostensibly as a side-effect of our adoption of technologies, agriculture, etc. A new study calls the hypothesis and the evidence into question ...
The Human Brain May Not Be Shrinking After All

The idea that our brains are shrinking is not one we like to consider. For more than four decades, experts have mostly ignored the hypothesis put forward time and time again by a close-knit group of paleontologists.

Now, the brain shrinkage hypothesis is being put to the test once more, with a team from the University of Nevada, Las Vegas (NLV) saying it doesn't stand up to scrutiny.

The debate really kicked off last year when a paper by paleoanthropologist Jeremy DeSilva and his colleagues, based on a comparison of human fossils to evolutionary patterns in ant colonies, popularized the idea that the human brain had shrunk in volume by about four ping pong balls.

What's more, they claimed this happened just 3,000 years ago.

That's really recent compared to other theories. Some scientists have said human brains started shrinking sometime after the last ice age, which ended about 11,700 years ago.

DeSilva's paper positioned the loss in brain size right around the time that complex human societies arose.

As such, it was suggested a smaller brain developed because information could now be stored in writing or distributed among others in a community.

Our brains, in other words, didn't become dumber; they grew more efficient.

The appealing theory gained worldwide attention, but not everyone was convinced. And the team from UNLV now claims to have uprooted the whole idea. ...
FULL STORY: https://www.sciencealert.com/the-human-brain-may-not-be-shrinking-after-all
 

Cochise

Priest of the cult of the Dog with the Broken Paw
Joined
Jun 17, 2011
Messages
8,034
In recent years it's been claimed (and debated) that human brain size has actually been decreasing for the last few thousand years or more - ostensibly as a side-effect of our adoption of technologies, agriculture, etc. A new study calls the hypothesis and the evidence into question ...

FULL STORY: https://www.sciencealert.com/the-human-brain-may-not-be-shrinking-after-all
Even if it was shrinking why would we worry? Intelligence / ability clearly isn't directly linked to brain size. (Despite all those large brained evil geniuses in fiction). Neanderthals had bigger brains than us and an elephant's brain is roughly 4 times bigger. Elephants are clever, but not 4 times more clever than humans.

And in any case, our brains might be slowly evolving to become more efficient.
 

EnolaGaia

I knew the job was dangerous when I took it ...
(ACCOUNT RETIRED)
Joined
Jul 19, 2004
Messages
29,623
Location
Out of Bounds
It was the supposed decrease in typical brain size that had been cited as the basis for claiming such increased efficiency in earlier studies.

This newly reported UNLV study did not find any evidence for the purported brain size decrease during the most recent past (back to 300,000 years BP). This doesn't necessarily refute the notion of such efficiency gains (whatever one may mean by that ... ). It only means there's no basis for even suspecting such gains based on brain size.
 

JahaRa

Abominable Snowman
Joined
Aug 23, 2021
Messages
506
Location
Albuquerque, NM,U.S.A.
Well, I remember reading somewhere that the Neandethals had bigger heads than the homo sapiens. My family has a lot of Neanderthal DNA and big heads, also very smart children. Not everyone in the family has a big head. My brother had a normal sized head and when he came to visit while he was in the army my 3 year old took his hat and it fit her perfectly (my brother was 6 feet tall). It is a joke in our family that our children have such big heads. My 2 year old grand dauther is also a giant compared to the other kids her age, like her mother was. She is wearing size 4 T and only turned 2 in June. She is the youngest and largest in her nursery school group and she could already wear my brother's hat.
 

Bad Bungle

Tutti but not Frutti.
Joined
Oct 13, 2018
Messages
3,924
Location
The Chilterns
I attended a public lunch-time lecture a few years ago on the evolution of Man in Africa by the UCL Professor of Geography. His opening statement was that everyone in the room (including himself) has tried to kill their mother. He was referring to the disproportionate size of a baby's head to the birth canal and the inherent dangers to both mother and baby in childbirth. There must be an evolutionary advantage in developing a prenatal big head/brain but the risks are relatively enormous. That advantage must also be enormous because as a survival strategy, big heads suck.
 

JahaRa

Abominable Snowman
Joined
Aug 23, 2021
Messages
506
Location
Albuquerque, NM,U.S.A.
I attended a public lunch-time lecture a few years ago on the evolution of Man in Africa by the UCL Professor of Geography. His opening statement was that everyone in the room (including himself) has tried to kill their mother. He was referring to the disproportionate size of a baby's head to the birth canal and the inherent dangers to both mother and baby in childbirth. There must be an evolutionary advantage in developing a prenatal big head/brain but the risks are relatively enormous. That advantage must also be enormous because as a survival strategy, big heads suck.
I am not so sure about that. Maybe it is women with small pelvis that have problems in child birth. No one in my family has suffered in childbirth because their childs head was too big. And I had two children with no drugs and still don't understand what all the fuss is about. Maybe being fit should be a requirement as well, as I used to walk miles 3 to 5 days a week up until my children were born. I don't remember any women my grandmother's or mother's age ever saying childbirth was the most pain they ever went through, but women my age and younger seem to think it is.
 

Bad Bungle

Tutti but not Frutti.
Joined
Oct 13, 2018
Messages
3,924
Location
The Chilterns
I am not so sure about that. Maybe it is women with small pelvis that have problems in child birth. No one in my family has suffered in childbirth because their childs head was too big. And I had two children with no drugs and still don't understand what all the fuss is about. Maybe being fit should be a requirement as well, as I used to walk miles 3 to 5 days a week up until my children were born. I don't remember any women my grandmother's or mother's age ever saying childbirth was the most pain they ever went through, but women my age and younger seem to think it is.
Was some-one in attendance at the births ?
 

JahaRa

Abominable Snowman
Joined
Aug 23, 2021
Messages
506
Location
Albuquerque, NM,U.S.A.
Was some-one in attendance at the births ?
yes, though I don't know about my grandmothers, one lived on a ranch and I think her sister was in attendance. The other had 9 kids and my grandfather moved them around a lot so it is possible that none of them had a doctor in attendance, maybe a midwife.
 

Bad Bungle

Tutti but not Frutti.
Joined
Oct 13, 2018
Messages
3,924
Location
The Chilterns
yes, though I don't know about my grandmothers, one lived on a ranch and I think her sister was in attendance. The other had 9 kids and my grandfather moved them around a lot so it is possible that none of them had a doctor in attendance, maybe a midwife.
That sounds tough. My point was simply that it is risky to evolve a birthing strategy that relies on other people to assist in mid-wifery. I don't think I've explained that well - baby horse, big head, mother can deliver without assistance. Baby human, big (normal) head, mother likely to have trouble if unassisted - every single time.
 

JahaRa

Abominable Snowman
Joined
Aug 23, 2021
Messages
506
Location
Albuquerque, NM,U.S.A.
That sounds tough. My point was simply that it is risky to evolve a birthing strategy that relies on other people to assist in mid-wifery. I don't think I've explained that well - baby horse, big head, mother can deliver without assistance. Baby human, big (normal) head, mother likely to have trouble if unassisted - every single time.
Cattle breeders and dog breeders have changed things so that a lot of types of cattle must have help to deliver their calves, bull dogs can't deliver their puppies because of either big heads or narrow pelvis, not sure what changes were made that caused that. My point was that I don't think it is the big head, I think it is the narrow pelvis. Especially since some people think our heads are getting smaller, which is probably not true, but I think women are less sturdy than they were 80 years ago.
 

ramonmercado

CyberPunk
Joined
Aug 19, 2003
Messages
55,183
Location
Eblana
Smarter than the average neanderthal.

We humans are proud of our big brains, which are responsible for our ability to plan ahead, communicate, and create.

Inside our skulls, we pack, on average, 86 billion neurons—up to three times more than those of our primate cousins. For years, researchers have tried to figure out how we manage to develop so many brain cells. Now, they’ve come a step closer: A new study shows a single amino acid change in a metabolic gene helps our brains develop more neurons than other mammals—and more than our extinct cousins, the Neanderthals.

The finding “is really a breakthrough,” says Brigitte Malgrange, a developmental neurobiologist at the University of Liège who was not involved in the study. “A single amino acid change is really, really important and gives rise to incredible consequences regarding the brain.”

What makes our brain human has been the interest of neurobiologist Wieland Huttner at the Max Planck Institute of Molecular Cell Biology and Genetics for years. In 2016, his team found that a mutation in the ARHGAP11B gene, found in humans, Neanderthals, and Denisovans but not other primates, caused more production of cells that develop into neurons. Although our brains are roughly the same size as those of Neanderthals, our brain shapes differ and we created complex technologies they never developed. So, Huttner and his team set out to find genetic differences between Neanderthals and modern humans, especially in cells that give rise to neurons of the neocortex. This region behind the forehead is the largest and most recently evolved part of our brain, where major cognitive processes happen.

The team focused on TKTL1, a gene that in modern humans has a single amino acid change—from lysine to arginine—from the version in Neanderthals and other mammals. By analyzing previously published data, researchers found that TKTL1 was mainly expressed in progenitor cells called basal radial glia, which give rise to most of the cortical neurons during development.

The researchers introduced both the human and archaic versions of the gene into mice, which typically don’t express either form during development. Mouse brains with the human version produced more basal radial glia, which in turn developed into more cortical neurons, than did mice with the archaic version. ...

https://www.science.org/content/art...ern-humans-grow-more-brain-cells-neanderthals
 

Mythopoeika

I am a meat popsicle
Joined
Sep 18, 2001
Messages
48,896
Location
Inside a starship, watching puny humans from afar
I think human brains might actually be shrinking.
Already, there are signs of obtundation in the general population - an unwillingness or inability to follow reason or logic, an inability to process common sense or stick to facts. Just my personal observation, but I am sure others have noticed the same thing.
Is it caused by the same thing that is reducing sperm levels worldwide? Who knows.
 
Top