8 ms·

Our Brains Are Shrinking. Are We Getting Dumber?

56 points by srean 16y ago

srean 16y 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 16y 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).
  - Vivtek 16y ago
    Wolves and chihuahuas are the same species, too. Their body mass difference is well over 10%.
    - lkrubner 16y ago
      Not the same species, only the same genus: http://en.wikipedia.org/wiki/Canis http://en.wikipedia.org/wiki/Canis They are related. That does not mean they are the same species.
      - Vivtek 16y ago
        Second paragraph of this link: "Wolves, dogs and dingos are subspecies of Canis lupus." Did you think I just made it up?
stuaxo 16y ago
Maybe were just outsourcing the knowledge to the rest of society.
olalonde 16y 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 16y ago
  Or the humans who make discoveries are anomalous.
jacquesm 16y 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 16y 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.
korl 16y 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_size http://en.wikipedia.org/wiki/Race_and_intelligence#Brain_siz...
- olalonde 16y 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 16y 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-outbreeding-intelligentsia-2to1,4282/ http://www.theonion.com/articles/study-uneducated-outbreedin...
ANH 16y 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 http://en.wikipedia.org/wiki/Eloi
chanux 16y ago
Explains The Sergey-spot http://popstrip.com/sergey-spot http://popstrip.com/sergey-spot
bhavin 16y 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-brains-leading-unintelligent-humans-study-86143216.html http://www.themedguru.com/20110102/newsfeature/shrinking-bra...
bennesvig 16y ago
Idiocracy wasn't a great movie, but it might be prophetic.
bradleyland 16y 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 16y 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 16y 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 16y 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 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 16y ago
  The Flynn effect has been observed over less than a century. Extrapolating it to 20k years is a stretch.
  - wzdd 16y 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.,content.true,page.1,css.print/issue.aspx 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.
- srean 16y 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 16y 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.
lukev 16y 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 16y 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.
  - lukev 16y 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 16y 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.
  - lukev 16y 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.
deleted 16y ago
[deleted]
cschneid 16y ago
Random theory that is in no way provable. It used to be (in caveman days) that merely getting to adulthood indicated some level of competence, either intelligence or physical. Organized society made it so that moderatly, or less competent people got to adulthood. But the sexual characteristics we enjoy didn't change. "Ugg like big boob". So the relatively dumber (not necessarily dumb, just not as quick as it used to be) "bimbo" (or "hunk") got to reproduce, where in the past they would have died a beautiful death. And that's the end of cschneid's wild speculation that is in no way provable.
anamax 16y 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....
lkrubner 16y 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/0813339189/ref=sr_1_1?ie=UTF8&qid=1294160996&sr=8-1 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 16y 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 16y 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 16y 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 http://en.wikipedia.org/wiki/Flynn_effect
ConceptDog 16y ago
Much like laundry detergent, they're getting more concentrated.
klbarry 16y 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.

56 points by srean 16y ago

srean 16y 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 16y 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).
- Vivtek 16y ago
  Wolves and chihuahuas are the same species, too. Their body mass difference is well over 10%.
  - lkrubner 16y ago
    Not the same species, only the same genus: http://en.wikipedia.org/wiki/Canis http://en.wikipedia.org/wiki/Canis They are related. That does not mean they are the same species.
    - Vivtek 16y ago
      Second paragraph of this link: "Wolves, dogs and dingos are subspecies of Canis lupus." Did you think I just made it up?

stuaxo 16y ago

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

olalonde 16y 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 16y ago
Or the humans who make discoveries are anomalous.

jacquesm 16y 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 16y 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.

korl 16y 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_size http://en.wikipedia.org/wiki/Race_and_intelligence#Brain_siz...

olalonde 16y 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 16y 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-outbreeding-intelligentsia-2to1,4282/ http://www.theonion.com/articles/study-uneducated-outbreedin...

ANH 16y 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 http://en.wikipedia.org/wiki/Eloi

chanux 16y ago

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

bhavin 16y 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-brains-leading-unintelligent-humans-study-86143216.html http://www.themedguru.com/20110102/newsfeature/shrinking-bra...

bennesvig 16y ago

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

bradleyland 16y 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 16y 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 16y 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 16y 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 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 16y ago
The Flynn effect has been observed over less than a century. Extrapolating it to 20k years is a stretch.
- wzdd 16y 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.,content.true,page.1,css.print/issue.aspx 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.
srean 16y 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 16y 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.

lukev 16y 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 16y 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.
- lukev 16y 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 16y 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.
- lukev 16y 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.

deleted 16y ago

[deleted]

cschneid 16y ago

Random theory that is in no way provable. It used to be (in caveman days) that merely getting to adulthood indicated some level of competence, either intelligence or physical. Organized society made it so that moderatly, or less competent people got to adulthood. But the sexual characteristics we enjoy didn't change. "Ugg like big boob". So the relatively dumber (not necessarily dumb, just not as quick as it used to be) "bimbo" (or "hunk") got to reproduce, where in the past they would have died a beautiful death. And that's the end of cschneid's wild speculation that is in no way provable.

anamax 16y 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....

lkrubner 16y 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/0813339189/ref=sr_1_1?ie=UTF8&qid=1294160996&sr=8-1 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 16y 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 16y 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 16y 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 http://en.wikipedia.org/wiki/Flynn_effect

ConceptDog 16y ago

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

klbarry 16y 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.