Our Brains Are Shrinking. Are We Getting Dumber?

http://www.npr.org/templates/transcript/transcript.php?storyId=132591244

by srean • 16 years ago

56 52 16 years ago

srean2• 16 years ago

The conversation claims that "humans" have lost an equivalent of a tennis ball volume of the brain. But perhaps a more revealing measure would be weight of brain lost in proportion to the body mass.

Elephants have a much larger brain than us, but smaller when compared to their body mass. (Side note: they are one of the few species that can recognize itself in the mirror)

bluedanieru• 16 years ago

Neanderthals were bigger and stronger than us, but this transcript only references us in comparison with Cro-Magnons. They're still Homo sapiens sapiens so a difference in body mass of 10% seems large (but then so does such a difference in brain mass).

Vivtek2• 16 years ago

Wolves and chihuahuas are the same species, too. Their body mass difference is well over 10%.

stuaxo• 16 years ago

Maybe were just outsourcing the knowledge to the rest of society.

olalonde2• 16 years ago

If cro-magnons really were smarter than us, it just shows how big of a role knowledge and culture play in what we perceive as intelligence.

scotth• 16 years ago

Or the humans who make discoveries are anomalous.

jacquesm• 16 years ago

No, that's just Moores law, with the higher integration levels of the brain we are now seeing more power efficient and smaller brains. It's that new .1 nm process that they're using.

dawgr• 16 years ago

I know it's a joke and you might be right, but I don't think the need to reduce brain size would be such a huge evolutionary pressure to see a decrease of 10% in just 20,000 years, that's relatively little.

Granted that the bigger the brain, the more energy it needs, but if the brain uses 25% of our energy, 0.25*0.1= 2.5%. Even if that's wrong by a few percent, it doesn't sound like such a big advantage to cause that decrease in so little time and as it's been pointed out, it actually started happening when more food/energy was available from agriculture or whatever.

korl4• 16 years ago

Whatever, idiocracy-like event occurred thousands of years ago, I think the one happening now will dwarf it. At least in most western countries and Japan where successful people have less children. It's almost like an anti survival of the fittest, if you are successful, less people in the next generation will carry your genes.

Brain size might or might not be related to intelligence. In any case, this is what Wikipedia has to say "In general, these studies have reported that East Asians have on average a larger brain size than whites who have on average a larger brain size than blacks."[1]

If you ignore who is having children among whites (successful people or not), you still have the white population rapidly declining with a birth rate below replacement levels, I believe that this coupled with mass immigration and the high birth rates of immigrants, specially in Europe, in addition to race mixing in other places like the US, will ensure that brain size in these places decreases at a fast rate. Unless we have mass immigration from East Asian countries, like Vietnam.

In the "racist" comment above, I didn't lie, I didn't insult anybody and I didn't say that one race is more intelligent than the other. I agree that my opinion might not be politically correct.

[1]http://en.wikipedia.org/wiki/Race_and_intelligence#Brain_siz...

olalonde2• 16 years ago

In case you are right, the good news is that this "survival of the dumbest" phenomenon can only be sustained as long as there are enough smart people to take care of the dumb ones. This trend will inevitably be reversed one day.

artmageddon• 16 years ago

Not that I read so from your post, but that's not something to take much comfort in. To be fair, we saw this coming a long time ago... or at least The Onion did:

CHICAGO-In a report with dire implications for the intellectual future of America, a University of Chicago study revealed Monday that the nation's uneducated are breeding twice as fast and twice as often as its educated. "The average member of the American underclass spawns at age 15, compared to age 30 for the average college-educated professional," study leader Kenneth Stalls said. "America's intellectual elite, as a result, are badly losing the genetic marathon, with two generations of dullards born for every one generation of cultured literates." Added Stalls: "At this rate, by the year 2100 there will be five smart people on Earth, swallowed whole by more than 12 billion mouth-breathers incapable of understanding the binary exponentiation that swamped the Earth with their like." High-school dropout Mandi Drucker, 16, said of the findings, "All I know is, we're in love."

May 14, 1997 | ISSUE 31•18

http://www.theonion.com/articles/study-uneducated-outbreedin...

chc• 16 years ago

Isn't that the plot of "Atlas Shrugged"?

Anyway, humans managed to survive back when we lived in caves and got our food by throwing sticks at animals. The threshold of intelligence needed for the race to survive would seem to be far below what we have today.

wladimir• 16 years ago

I hope you are right.

On the other hand, it could be that we have developed advanced, user-friendly, self-maintaining robotics/AI to 'take care of us' by then. The added advantage of human intelligence might be very low in that case and the trend can continue indefinitely.

berntb• 16 years ago

It doesn't matter if stupid people get more children.

In just a few generations, we will certainly get designer kids, where the parents mix and match genes. The world will then get really pretty people which are awesome singers -- and intelligent.

More seriously:

Body sizes were larger during the ice age which tfa talked about (not only for Neanderthals). I'd like to see data for how much that influences brain size?

lkrubner4• 16 years ago

You write:

"At least in most western countries and Japan where successful people have less children. It's almost like an anti survival of the fittest, if you are successful, less people in the next generation will carry your genes."

One interesting scenario you should consider are situations where a researcher comes up with a game theory scenario that they would like to do research with, but the people who play the scenario are smarter than the researcher. The question then arises - can the researcher correctly analyze the strategies pursued by the players? It's an interesting problem for game theorists - the researcher might conclude that the players are making the "wrong" decision, but in fact, since the players are more intelligent than the researcher, they've actually seen nuances in the various options that the researcher did not see when the researcher first designed the scenario.

For a point of comparison, imagine 2 grand masters play a game of chess. One of them wins and one of them loses. Now give a recording of the game to a chess novice. The novice can obviously repeat what moves that happened, but can the novice correctly analyze the game and determine what the losing decision was? Does the novice have the skill to correctly understand whatever gambit the losing master was trying to pursue? Can the novice correctly figure out what the decisive move (or moves) was?

I do not mean to insult your intelligence, but you should consider whether the successful, intelligent couples "in most western countries and Japan" are in fact paying attention to nuances that you have overlooked? Just to throw out some random possibilities (I am not arguing for any of these, only pointing them out):

1.) the path to reproductive success is to make greater investment in less children (more resources per child, given less children)

2.) less children per parent leads to greater health for the child

3.) successful men who marry successful women are secretly (or openly) promiscuous when they are young and have more children than are recognized

Again, I'm not saying any of these 3 options are true, I'm just saying there may be game moves that the very intelligent are considering, which maybe you have overlooked. I'd be cautious about assuming that the most intelligent members of the species are making all of the wrong moves in the game of life.

korl4• 16 years ago

I see what you are trying to say. I'm not saying you are wrong, just what I think.

In my opinion, 1) doesn't make sense in our current society. Nor did it make sense any time before it if having less children but more successful ones didn't translate in those children themselves having more offspring than if they had had brothers. The path to reproductive success is to make sure your children reach adulthood and can have children of their own..., ideally so your descendants grow exponentially. I don't know how making sure my kid has a Playstation 3 and an HD TV guarantees that he will have more reproductive success. College you say? Any lower-middle class person can go to college, you'll just get into debt like everybody else. Besides you don't need a college degree to reproduce, how are immigrants doing it then?

2) I know that you weren't arguing for any of this, but I'd really like to see citation for this one. Maybe during a time of famine it would be true, but how exactly would I be less healthy if I had 10 siblings?

3) I don't know if they are more promiscuous or not, but they are definitely not having more children, that's the whole point of these ideas about idiocracy.

I didn't cover the successful couples that don't have kids at all, which are a lot of them. Please, explain to me how that makes sense, not having children will help your reproductive success because...? How is that not a wrong move?

You might think that it's the right move if having only one well provided child made sure that he went to the top of society, i.e. become a millionaire, which is very unlikely anyway for most people. If your line of descendants has just one child over a few generations, your original DNA that is in that person will be a small part of him. I think the person whose descendants had at least 3 children each generation will have a greater chance of having his genetic legacy survive even if those descendants are a little less well off, which doesn't need to be true.

I would really like to believe that you are right and in fact there is something we are not seeing. But there aren't even any statistics that show that an only child will be richer or healthier in the future.

gjm112• 16 years ago

> I didn't insult anybody and I didn't say that one race is more intelligent than the other.

I suppose you think want us to think you're being honest. It's interesting the way white supremacists treat others with contempt. Perhaps someone less stupid would write more sensible things.

Having read that paragraph, you might want to note that I didn't insult you or call you stupid -- in exactly the same sense as you didn't insult anyone or say that one race is more intelligent than another. In other words, I took care to make sure that the literal sense of my words contains no such claims, so that it's only what you need to add in order to make them make any sense that's insulting and unpleasant.

Just like your own comments which were, yes, racist even though you can chop them into fragments none of which explicitly makes racist statements.

korl4• 16 years ago

By saying "someone less stupid", you are saying that I'm in fact stupid and you are looking for someone less stupid. I didn't disrespect anybody though like you just did.

I don't care though, you are angry because it wasn't politically correct and I know that.

I'm not a white supremacist, I'm not promoting the superiority of the white race, you can actually interpret what I wrote as saying that Asian people are superior to whites. If you don't like what Wikipedia has to say about brain size, you can change it yourself if you have evidence to back it up.

Aside from this ad hominem, do you have anything to say against my points?

ANH• 16 years ago

H.G. Wells predicted this in The Time Machine (okay, I'm being slightly tongue in cheek). He wrote of far future human descendants, the Eloi, who had undergone severe mental and physical degradation due to no longer being required to solve difficult physical and societal problems. http://en.wikipedia.org/wiki/Eloi

chanux• 16 years ago

Explains The Sergey-spot http://popstrip.com/sergey-spot

bhavin• 16 years ago

Got the following from an article:

According to one of the theories on the shrinking of brain, “The big heads were necessary to survive Upper Paleolithic life, which involved cold, outdoor activities.”

Another theory said, “The skulls developed to cope with a chewy diet of rabbits, reindeer, foxes and horses. As our food has become easier to eat, so our heads have stopped growing.”

http://www.themedguru.com/20110102/newsfeature/shrinking-bra...

bennesvig• 16 years ago

Idiocracy wasn't a great movie, but it might be prophetic.

bradleyland• 16 years ago

No mention of surface area or number of folds. It is believed that the vast majority of our intellectual ability resides in our cerebral cortex. I know that anthropologists estimate brain size based on the size of the skull and the brain cavity, but I don't know if they can tell us much about the actual make-up of cro-magnon brains? The question mark is there because I don't know. Can anyone offer any insight there?

It would stand to reason that since the cerebral cortex is the home of our higher-thinking abilities, an overall reduction in brain size might not equate to a reduction in intelligence, were there an increase in the number and depth of the "folds" on the surface of the brain.

joeyo• 16 years ago

  > It would stand to reason that since the cerebral cortex 
  > is the home of our higher-thinking abilities ...

Not only that, but the prefrontal cortex (PFC) is one particular cortical region that has become enlarged in humans with respect to other great apes. PFC is generally implicated in "higher" reasoning, metacognition, and other executive functions. It's possible that cro-magnon brains were larger but that additional volume was allocated to other functions (balance or smell, for example) and that they still had smaller frontal lobes.

jerf• 16 years ago

Also, it is possible that superior cooperation ends up moving non-trivial chunks of intelligence into a group mind, which need only "exist" to the extent that a group of hominids cooperating can outcompete a non-cooperating group (so as to avoid the ultimately-not-even-wrong question of "where it is" or "what it looks like"). See also in AI how frequently and how robustly it turns out that a hordes of less intelligent agents + cooperation can outperform a theoretically smarter single agent on its own.

Symmetry• 16 years ago

The fact that people are getting smarter over time is the firm scientific consensus and I'd think that most science writers should know that: http://en.wikipedia.org/wiki/Flynn_Effect

Brain volume contributes to a lot of things. It might be that we're getting clumsier, or that we're less visually perceptive than our ancestors were. But we can be sure that IQs aren't going down.

dspeyer• 16 years ago

The Flynn effect has been observed over less than a century. Extrapolating it to 20k years is a stretch.

wzdd• 16 years ago

Not at all. This article cites a gain of 0.3 points per year and postulates (admittedly without drawing any conclusions) that the average person in the early part of this century had an IQ of 80:

http://www.americanscientist.org/issues/id.881,y.0,no.,conte...

If we continue to extrapolate, we can conclude that 300 years ago people had an IQ of 10. Not very bright, but a significant improvement over their great-grandparents, who would have had an IQ of -20.

srean2• 16 years ago

Yeah that is a valid point. We have been at the top of the food chain for a long time, no natural predators to avoid. So any mutation that drops some of those self preservatory traits will not get weeded out like it would have been in the prehistoric times. Besides we now can compensate for many of those potentially debilitating mutations with technology.

sin7• 16 years ago

Has anyone actually read the article on the Flynn Effect? Near the bottom it states that studies show that the progression has peaked and in some cases regressed.

lukev4• 16 years ago

In response to all the comments referencing "Idiocracy" - I can't believe so many of you are taking that movie seriously.

1. Even if the effect it claims is true, it wouldn't result in an "everyone's stupid" society, it would result in a split society with an even more distinct intellectual upper and lower class. Not desirable, to be sure, but not necessarily dangerous to the human race as a whole.

2. What we arrogantly see as the "stupidity" of the lower classes is almost entirely caused by social and environmental factors. Genetically, they're not necessarily inferior at all. Even if genetic drift COULD occur within just a few generations, which I doubt, genetic effects would be entirely dominated by environmental factors such as education, nutrition, and socialization.

If you pulled a healthy baby from the worst white trash family at birth, raised it well and gave it an education, there's no reason to think it would be any less intelligent than you.

shin_lao• 16 years ago

I disagree about 2. I really think that there's a genetic factor into how intelligent you can become, and that the part of this genetic factor is everything but minor.

The catch is that you need the proper life experience to unlock your potential.

lukev4• 16 years ago

A genetic factor, sure, but the question is not whether there is a genetic factor, but whether that is what is selected on, given the "stupid/lower class people reproduce faster" assumption.

cullenking• 16 years ago

The problem with babies from the "worst white trash family" are environmental and maybe genetic from past environmental factors. How many white trash parents have you seen driving around smoking with their kids in the car? Fetal alcohol syndrom? etc etc.

lukev4• 16 years ago

And as bad as smoke and fetal alcohol syndrome are, they aren't genetic. A mentally retarded person will have perfectly normal offspring, provided their disability is environmental.

Evolution works by selection. Darwin, not Lamark.

pohl2• 16 years ago

The movie actually did depict a split society. At the top was President Dwayne Elizondo Mountain Dew Herbert Camacho, who operated at a much higher cognitive plane than Frito the lawyer, who operated at a much higher level than the masses - for example the woman operating the Fischer Price diagnostic panel at St. God's Hospital, where Dr. Lexus was clearly high-functioning - presumably well above his undepicted & "tarded" ex-wife, a pilot.

lukev4• 16 years ago

But everyone was still sub-average by "normal" standards.

If this actually happens, you're likely to see an intellectual upper class that is more intelligent than the current average. Selection works both ways, and even if the intelligentsia reproduce more slowly, they still reproduce (mostly) within their own group, leading to ever-smarter offspring.

Assuming genetic factors dominate intelligence anyway.

anamax• 16 years ago

(1) Women's brains are typically smaller by about the difference between Cro-Magnons and Homo Sapiens.

(2) WRT problem-solving ability, bonobo populations are shrinking much faster than chimps (which are increasing in some places). Perhaps that politically correct behavior has consequences....

lkrubner4• 16 years ago

"the actual make-up of cro-magnon brains"

There seems to be no agreement about what the word "cro-magnon" refers to. Possibly the phrase should be disused? I have frequently read that cro-magnon refers to the first homo sapiens who arrived in Europe. With that usage, "cro-magnon" is just a way of referring to us, a synonym for homo sapiens. But the phrase has other uses. Some writers continue to refer to "cro-magnon" as if it refers to some distinct species, different from us. But then, the question arises, which species are we talking about? Who is it related to? Why does it need a unique name?

As far as I know, the most exhaustive coverage of the various human species is in Ian Tattersall's book, Extinct Humans:

http://www.amazon.com/Extinct-Humans-Ian-Tattersall/dp/08133...

Tattersall is among those who refer to cro-magnon as homo sapiens, and therefore makes the phrase "cro-magnon" largely meaningless. One might say, with greater clarity, "Early homo sapiens in Europe."

Having said that, I should add, there is no doubt that Neanderthals (I'm using the spelling suggested by the Google Chrome auto-suggest, which may be out of date) were a distinct species, and that they had larger brain cases that homo sapiens. There is no evidence they were smarter than us. They never showed much advance toward abstract thought, which gives us reason to assume they were dumber than us, at least using traditional (habitual) notions of "smart" and "dumb".

Nick_C• 16 years ago

'cro-magnon' has been out of fashion for quite a while, at least in stuff that I read. I haven't seen the term in any decent book for, I dunno, say, several years.

substack• 16 years ago

I wonder if the decrease in brain size is due in part to infant mortality and trauma in childbirth. Big brains don't exactly... fit as well coming out, although it's also not clear how much early brain size influences brain size later in life.

johngalt• 16 years ago

Then why do IQ test have to be normalized so often? How would you explain the Flynn Effect? http://en.wikipedia.org/wiki/Flynn_effect

ConceptDog• 16 years ago

Much like laundry detergent, they're getting more concentrated.

klbarry• 16 years ago

Keep in mind Einsteins brain was especially small, and nodes were closer together. In addition, women's brains are smaller than mens, but it is fairly well understood that both genders are equally intelligent.

Our Brains Are Shrinking. Are We Getting Dumber?

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