Our Brains Are Shrinking. Are We Getting Dumber?

www.npr.org...

When it comes to brain size, bigger doesn't always mean better. As humans continue to evolve, scientists say our brains are actually getting smaller.

The downsizing of human brains is an evolutionary fact that took science writer Kathleen McAuliffe by surprise.

"I said, 'What? I thought it was getting bigger!'" she tells NPR's Jacki Lyden. That was the story up to 20,000 years ago, she learned. Then, the brains of our ancestors reversed course and started getting smaller — and they've been shrinking ever since.

Cro-Magnon man, who lived in Europe 20,000 to 30,000 years ago, had the biggest brains of any human species. In comparison, today's human brain is about 10 percent smaller. It's a chunk of brain matter "roughly equivalent to a tennis ball in size," McAuliffe says.

The experts aren't sure about the implications of this evolutionary trend. Some think it might be a dumbing-down process. One cognitive scientist, David Geary, argues that as human society grows increasingly complex, individuals don't need to be as intelligent in order to survive and reproduce.

But not all researchers are so pessimistic. Brian Hare, an anthropologist at the Duke University Institute for Brain Sciences, thinks the decrease in brain size is actually an evolutionary advantage.

Individuals don't need to be as intelligent to survive, I agree, I think

our ancestors were more intelligent,

OH and here is a picture,

Today's human brain is about 10 percent smaller than the Cro-Magnon brain from more than 20,000 years ago.

media.npr.org...

I am not sure who's brain it is.

"A smaller brain is the signature of selection against aggression," Hare tells Lyden. "Another way to say that is an increase in tolerance."

Hare says when a population selects against aggression, they can be considered to be domesticated. And for a variety of domesticated animals like apes, dogs or turkeys, you can see certain physical characteristics emerge. Among these traits are a lighter and more slender skeleton, a flattened forehead — and decreased brain size.

Hare's studies focus on chimpanzees and bonobos. In evolutionary terms, they are much like humans, but are physically quite different from one another. Bonobos have smaller brains than chimpanzees — and are also much less aggressive.

I don't believe it, seems to me man is as aggressive and intolerant as he ever was.

My ipod has gotten smaller over the years and works just as fine as my old ones..although it does do a lot of cool new things =p

Originally posted by Thomas_X
My ipod has gotten smaller over the years and works just as fine as my old ones..although it does do a lot of cool new things =p

you think we can make a comparison there?


I know they say you brain shrinks as you get older but it doesn't effect you intellect,
but I believe drug and alcohol abuse makes the brain shrink yet does affect the intellect,

or I could be wrong about all of it.

shrinkage

I wouldn't be surprised if we are getting dumber. We might even be dumber for thinking we are smarter.

I don't know if this has anything to do with it....like your mentioning alcohol and drugs, but I think we all stay dehydrated all the time. Most all of us. Most all the time. Pretty much.

It can't help. I attended a conference recently, and one of the speakers noted that under times of stress, or any intense emotion, your brain can lose fluids quickly and you should be sipping water most all the time, particularly when you are doing something which requires additional brain work.

A side note: Age causes everything else to shrink, so why not the brain? lol.

reply to post by Stormdancer777


When you say you don't believe it because man is as aggressive as he ever was, make sure you are comparing modern man to those from 20,000+ years ago. I find it much more likely that CroMagnon was in fact more aggressive as the evidence from domestication points towards. You simply see evidence of violence because of the sheer multiplication of enabling that has taken place through technology.

There was also the other comment about the ipod scaling down as well. I think this is a fair analogy to draw as the brain is a computer, increased efficiency with decreased size. Of course this is just speculation.

Here's a good quote from another article talking about genes determining brain size being identified

Walsh points out that bigger brains aren't always smarter brains. In fact, bigger human brains can cause mental retardation. "It's not the size that counts," he says, "it's the organization."

Harvard Gazette: Genes found that regulate brain size

When comparing different species, the ratio of brain weight to body weight does correlate with Intelligence,[citation needed] although the actual brain weight has little or no effect. For example, the ratio of brain weight to body weight for fish is 1:5000; for reptiles it is about 1:1500; for birds, 1:220; for most mammals, 1:180, and for humans, 1:50.[citation needed] Within human population, studies have been conducted to determine whether there is a relationship between brain size and a number of cognitive measures. Studies have reported correlations that range from 0 to 0.6, with most correlations 0.3 or 0.4[2] Some scientists prefer to look at more qualitative variables to relate to the size of measurable regions of known function, for example relating the size of the primary visual cortex to its corresponding functions, that of visual performance.[3][4] The brain is a metabolically expensive organ, and consumes about 25 percent of the body's metabolic energy in some species. Therefore, although larger brains are associated with higher intelligence, smaller brains might be advantageous from an evolutionary point of view if they are equal in intelligence to larger brains. Skull size correlates with brain size, but is not necessarily indicative. Brain size is a rudimentary indicator of the intelligence of a brain, and many other factors affect the intelligence of a brain. Higher ratios of brain-to-body mass may increase the amount of brain mass available for more complex cognitive tasks. Brain size in vertebrates may relate to social rather than mechanical skill. Cortical size relates directly to a pairbonding life style and among primates cerebral cortex size varies directly with the demands of living in a large complex social network.

Brain Size

Pretty sure the bolded part holds the answer. Our brains take up a lot of energy. We became more efficient in our processing, and shed those that consumed the most energy, probably over many harsh periods of time.

i know this thread is far removed from ancient theories and the writings of authors who may not be to everyone's taste but I have been reading Sitchin books about annunaki

seems that even in the times of annunaki people started out with a high level of civilisation and wisdon and then started de-volving - going backwards in matters of high civilisation and brians and wisdom

it seems this is not new - and does not matter if you want to attribute it to annunaki or to another cause

it will be interesting when we do enough research and find out why this is so

Your Ass is expanding... Are you getting fatter? Sorry... Left Yourself open on that one... "Now where did I leave that bag of sweet delicious cotton candy?". Wow... ATS has been oober lame lately. I think people are running out theories on here. No offense of course.

Originally posted by Stormdancer777
Individuals don't need to be as intelligent to survive, I agree, I think

our ancestors were more intelligent,

Don't be so sure, and don't believe everything you read, your source doesn't look so great (mine isn't great either) but you need to do a lot more research than read that one article.

Replica of big skull from 28,000 years ago suggests human brains have started to shrink

Our brains are shrinking, according to scientists who have recreated a 28,000-year-old skull from remains found in France.

The French team, which claims to have produced one of the best replicas yet of an early modern human’s cranium, says it is up to 20 per cent bigger than ours.

No one is suggesting this means our ancestors were more intelligent as studies have found there is only a minor link between brain size and IQ.

Instead, it is believed the skull, called Cro Magnon 1 after the caves in the Dordogne where it found, suggests our brains are becoming more efficient like shrinking computers.

So smaller size might be a result if better efficiency. But I think first we have to assess the statistical validity of this claim. How many cro-magnon skulls have had the brain capacity measured? They only mention one in my source and don't cite a quantity at all in the OP source.

Remember the incorrect conclusions we drew that Neanderthals were misshapen creatures were derived from looking at a malformed specimen and it turns out they weren't all that way. So I don't think we can jump to conclusions.

But if the modern brain really IS smaller (I'm not yet convinced there's statistical proof of this), but at least as intelligent, the greater efficiency may be the result of folding in the cerebral cortex.

Also other claims in the article in the OP sounded laughable to me. The cite bonobo brains are smaller than chimp brains and bonobos are less aggressive, therefore smaller brains are less aggressive....WHAT??? What about the million other reasons bonobos might be less aggressive?

I tried to see who the author was and all it says is "staff". An article written by "staff" isn't a good source my friends.

Anyone else seen idiocracy?


On a more serious note, the decreased brain-size of domestic animals is probably as a result of our selecting against intelligence - a pig, or cow, or horse, or turkey, or dog which has its own mind and cannot be readily bent to our will (stay where you are, have babies, do as I say and become a good meal) is generally not considered one to be bred from widely, and in many cases will be killed before it gets a chance to breed.

In human society, there are relatively few intelligence-based problems which lead to live/die situations (although the Darwin Awards show that the especially stupid are still capable of removing themselves from the gene pool, if given the opportunity) and so, as Idiocracy points out, survival demands are no longer important - now, all that matters, is how much you reproduce.

And, also as Idiocracy points out, people who are just copulating because they want to rather than taking an informed decision and planning for babies, are breeding more.

I'm not going to say which one is more intelligent, but I will say that efficiency of energy consumption is unlikely to be a driving force in making the brain smaller. When did you last hear of someone in the west dying because their brain used up all their energy?

This thread jogged a memory about a girl who had half her brain removed in order to save her life. A few years back she graduated from school with honours, the only symptom seems to be that she is paralysed down one side. The other half of her brain adapted and compensated. abcnews.go.com...

I also remember reading something many years back that said it's the amount of neural connections that count as opposed to brain size, or something along those lines.

It makes perfect sense to me that modern life does not require the same brain capacity as life did before there was as much civilization. You can be pretty stupid in modern society and still get by just fine -- maybe even become president.

I look upon our brain much like our muscles -- use it and it grows, neglect it and it shrinks. Much of the shrinkage of stuff in old age comes from lack of use.

Originally posted by Thomas_X
My ipod has gotten smaller over the years and works just as fine as my old ones..although it does do a lot of cool new things =p

Was just getting ready to point that out. With the advances in our abilities, living longer etc etc, its possible we are being streamlined by evolution.

or....

We have been infected by some alien chemical and they are dumbing us down for an eventual planetary BBQ.

reply to post by ladyinwaiting

A side note: Age causes everything else to shrink, so why not the brain? lol.

exactly,lol

As far as us being less intelligent of course that varies, but I read a lot how ancient books and the way they wrote compared to today's novels , well there is a big difference.

reply to post by Stuffed


When you put it that way , I see your point,

Maybe we aren't as aggressive, but I still think we are capable of it, given the right circumstances, but I hope the aggressive part, when it pertains to war dies out, but aggressiveness isn't always a bad thing either, prolly necessary part of the survival instinct.

Originally posted by wayno
It makes perfect sense to me that modern life does not require the same brain capacity as life did before there was as much civilization. You can be pretty stupid in modern society and still get by just fine -- maybe even become president.

I look upon our brain much like our muscles -- use it and it grows, neglect it and it shrinks. Much of the shrinkage of stuff in old age comes from lack of use.

Yea, I am trying to keep my old brain functioning, not doing to good at times,

reply to post by TheWill

On a more serious note, the decreased brain-size of domestic animals is probably as a result of our selecting against intelligence

OH wow, I didn't know that.

reply to post by Arbitrageur


I found the part about the bonopos interesting there is a example of how being less aggressive can make you extinct,

However I read a article on the subject that disagreed with the bonopos being less aggressive, the experts seldom agree with one-another.

reply to post by Xcathdra

We have been infected by some alien chemical and they are dumbing us down for an eventual planetary BBQ.

I don't have a lot of faith in the school system.

Originally posted by TheWill
I'm not going to say which one is more intelligent, but I will say that efficiency of energy consumption is unlikely to be a driving force in making the brain smaller. When did you last hear of someone in the west dying because their brain used up all their energy?

28,000 years, not the last 200. There have been several famines in the last 28,000 years.