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Americans' heads have been growing, scientists say
June 5th, 2012
02:43 PM ET

Americans' heads have been growing, scientists say

If you're American with an average-sized head, your noggin is likely bigger than your ancestor's was seven generations ago.

That's the implication of research by Richard Jantz and colleagues at the Forensic Anthropology Center at the University of Tennessee.

The scientists analyzed about 1,500 skulls, dated from various years in the 1800s and 1900s. The researchers focused on Caucasian individuals because there weren't as many skulls from blacks and Hispanics. Although their conclusions are about white Americans, there is no reason to believe these patterns don't pertain to other races, Jantz said. More research just needs to be done.

Over the last 150 years or so, it appears that skulls got narrower from side to side by about 5 to 7 millimeters, and higher from top to bottom by an average of nearly 10 millimeters, Jantz said. And the overall size of the head has, on average, increased by an amount equivalent to the size of a tennis ball, he said.

Jantz speculates that there are several factors in the American environment that help contribute to this trend:

For one, there is far more nutrition than ever before in the United States. The problem of obesity - of over-nutrition - is more of a concern than undernourishment. People's work has become less physically-intensive, and even manual labor is often assisted by machines in some way.

Because of cars, people walk less. Because of vaccines, epidemic diseases that once killed many children no longer do.

Mothers who might not have survived childbirth two centuries ago are now living, thanks to medicines and procedures such as Caesarean sections - their children are surviving, too. And people don't often choose mates with the very same ethnicity – particularly not from the same part of Europe as their own ancestors – as they would have before.

"That has resulted in opening up the gene pool," Jantz said.

Brain size is probably correlated with skull size, so this means Americans' brains may also be getting bigger, but this has yet to be proven. The next step for researchers would be to see if certain parts of the brain have expanded, which might give an indication of whether there are particular abilities that have been enhanced as a result of this change over time.

The researchers did not directly measure the circumference of the head, so it's hard to say whether this trend has had any effect on hat size.

Is the increase in skull size part of a larger pattern of the human body growing in general? It's true that people are on average taller today than in the 1800s, but height has plateaued. What about our heads?

"I think the skulls will continue to change, and I think the direction depends on the direction the environment goes," Jantz said. "Obviously there have to be limits on how narrow or on how tall it could get, so I don't know if I want to predict how much longer this trend will continue."

The researchers hope to get this research published. They presented their findings at the American Association of Physical Anthropologists meeting in April.


soundoff (232 Responses)
  1. bob

    science supports that americans have big heads. in the old days, people's heads were measured and those with bigger heads were considered smarter. then real scientists showed up and debunked that. now it's happening again. must be the same group that convinced people global warming is non-science. remember, at one time people who drilled holes in people's heads to let out evil spirits were called doctors.

    June 5, 2012 at 23:29 | Report abuse | Reply
    • escher7

      Now people who drill those holes are the CIA.

      June 6, 2012 at 01:08 | Report abuse |
    • Alyssa

      They're not claiming that bigger heads lead to smarter people. They only posit that bigger head may mean bigger brains. But bigger brains don't mean smarter people either. Men have bigger brains than women, on average, but but have more tightly packed neurons than men, meaning that men aren't smarter than women. Elephants have very large brains compared to humans and also aren't smarter. "Smartness" appear to be tied to neuronal capacity, and not just mere size.

      June 6, 2012 at 07:34 | Report abuse |
    • HMMM.

      Skull size is correlated to brain size and brain size is correlated to IQ. google it. The skull size to IQ is correlation is a modest .19. Significant nonetheless and there may be some positive selection for larger heads as it is a visual way to judge IQ potential and there may therefore be some sexual preference of larger head individuals.

      June 6, 2012 at 07:43 | Report abuse |
    • Doozer

      Republican brains are getting smaller.

      June 6, 2012 at 08:01 | Report abuse |
    • Richard

      Paranoid leftist alert!

      June 6, 2012 at 08:14 | Report abuse |
    • Chris B.

      But global warming is non-science.

      June 6, 2012 at 08:29 | Report abuse |
    • Will S

      A correlation of .19 is actually quite low by scientific standards. Low enough to dismiss out of hand, actually. A scientist would call that "weak" at best.

      June 6, 2012 at 09:01 | Report abuse |
  2. paganguy

    Larger heads may mean a thicker skull or just more water inside that skull.

    June 5, 2012 at 23:38 | Report abuse | Reply
    • Amy

      ....says the guy with the tiny little head.

      June 6, 2012 at 05:32 | Report abuse |
    • Common Sense

      Jealous much?

      June 6, 2012 at 18:51 | Report abuse |
  3. ChazH

    They had me until...
    "...there is far more nutrition than ever before in the United States. The problem of obesity – of over-nutrition – is more of a concern than undernourishment."
    That statement shows the researchers' total disconnect from the nutrition research of the United States. Americans are obese because the "food" they gorge themselves with has virtually zero nutritional value which leaves them undernourished, hence unsatisfied, hence, always craving.
    I think the evolution angle is more to the mark.

    June 5, 2012 at 23:44 | Report abuse | Reply
    • Reason & Logic

      It's not the amount of food we intake, it's our decreased level of activity. Our ancestors took in more calories but also burned more. Today, on the average people take in less calories than their ancestors but burn much, much less calories due to the automobile, lack of physical labor, and sitting on our behinds (like I'm doing) at the computer or in front of the TV. Spend 90 minutes every day at the gym and weight loss will occur in spite of the same intake of calories. It's basic math.

      June 6, 2012 at 01:33 | Report abuse |
    • nepawoods

      Yes, we have junk food that wasn't around long ago, but we also have an abundance, and we didn't evolve (no species did) to cope with excess food, as, historically, there never was an excess. We store fat so we can survive through times without food, but such times no longer happen.

      Evolution? There's no selective pressure any more. If anything, natural selection (if we can call it natural any more) will now be favoring genes that contribute to indiscriminate reproduction – people having more children than they can care for. In "the wild", that wouldn't work, but in our welfare society, it leads to having far more grandchildren.

      June 6, 2012 at 04:10 | Report abuse |
    • Mike

      Wrong Chaz. If anything, human evolution will lead to small heads and dumber people. It's not survival of the fittest anymore. It's survival of those who have the most children. It is stupid people that have the most children, while smart people tend to wait and then only have a few.

      The reason is nutrition. We have an overabundance of food. The average person is taller, bigger, in every aspect, including head, than our ancestors.

      June 6, 2012 at 07:51 | Report abuse |
  4. the captain

    probz bogus science

    June 5, 2012 at 23:45 | Report abuse | Reply
    • escher7

      If God can give you a small brain he can give the rest of us larger ones.

      June 6, 2012 at 00:55 | Report abuse |
  5. Frogz

    We American's made the world what it is today. We pioneered, industry, science and modern technology in every way. Its natural we would be becoming smarter than the rest of the world.

    June 5, 2012 at 23:57 | Report abuse | Reply
    • Arkwright

      Actually science was pioneered in Europe and China, industry was pioneered in Europe. You might have a reasonable case about modern technology.

      June 6, 2012 at 00:45 | Report abuse |
    • escher7

      America did not even exist as a country when most of the great minds were changing the world. And most scientific achievements came from stolen German technology and brain power after the war or other non-Americans. The space race and yes even relativity came from the Germans. And then of course Isaac Newton and his predecessors from Italy, France, etc etc brought us out of the flat earth society. Most of the great nuclear scientists (M Planck, M Curie, H. A Lorentz, A Einstein, P Langevin, Ch. E Guye, C. T. R Wilson, O. W Richardson to name a few), were either not American or were immigrants. Don't get me started on Asian electronic advances. Yes, America is the great brain trust of the world. That is why education here is among the worst of the developed countries.

      June 6, 2012 at 01:06 | Report abuse |
    • Reason & Logic

      Arkwright: science and technology weren't pioneered in America, Europe, or China. They were pioneered in Egypt by the Egyptians and in Central America by the Mayans.

      June 6, 2012 at 01:38 | Report abuse |
    • Delmar Knudson

      If this comment is not meant to be sarcastic, then it seems irrelevant, or even a bit silly. People from every nation have contributed to modern society and our industrial and technological age. We stand on the shoulders of those who came before. There have been some concentrations of bright people or those who have contributed much from a number of countries. Americans have come from every corner of the world. If we are reasonably bright, then we won't be smug. ... An American with ancestors from four different countries.

      June 6, 2012 at 01:40 | Report abuse |
    • SSimpson

      And that is why internationally our student test scores are so low – hmmm

      I am a proud American too – but perhaps we shouldn't take credit for everything – many of the tools we use today (such as mathematics) were around LONG before this country was –

      We are a cog in the wheel of time – nothing more – I don't know if you've looked out the window lately, but our star is dimming – that kind of arrogance will ensure its demise...

      June 6, 2012 at 02:15 | Report abuse |
    • Howard

      There's no denying the deficiencies of American education, or that much of the modern world originated elsewhere, but curiously Americans win more Nobels in science and medicine and economics than most of the rest of the world combined.

      June 6, 2012 at 02:46 | Report abuse |
    • Guest1351235

      Hem, Howard, USA is only 15th in number of nobel prizes per capita...

      15th is not bad by itself, but we are speaking about USA which enjoy a very high synergiscic effect on having such a large first world population AND being the center of almost every kind of sciences. In science (I speak by experience) this means a lot... this means that you will easily find someone in your country with whom you could collaborate for example...

      More about the subject, people who lived a century ago were MUCH smaller than us, and an imcrease in the size of the brain could be simply due to the fact that we are taller... women have a brain 10% lighter than men, but it as been shown that men have a brain 10% more fat than women ....

      To conclude, this discovery is for the moment a non-event for people who are not working in the field

      June 6, 2012 at 03:49 | Report abuse |
    • WaitWhat?

      Typical American ego talking with incorrect statements to boot. That's why so many countries hate us. USA ranks somewhere around 12-17 worldwide on education quality. Not too impressive and its declining. We are getting fatter and dummer.

      June 6, 2012 at 04:37 | Report abuse |
    • World Traveler

      Really? That's funny.
      I know your head is getting bigger.... Although a bigger head and an assumed bigger brain should reflect greater intelligence, that is a dumb statement.

      June 6, 2012 at 06:11 | Report abuse |
  6. cosmo

    my skull is 8 3/8 inches making base ball hats hard to find..........to fit my gi normus brain

    June 6, 2012 at 00:11 | Report abuse | Reply
    • mmi16

      So why are you trying to play baseball...for the beanings?

      June 6, 2012 at 02:22 | Report abuse |
  7. escher7

    Republican effect. Things will be back to normal after the election.

    June 6, 2012 at 00:53 | Report abuse | Reply
  8. ewpriogperghklk

    ..as the balls are withering away.

    June 6, 2012 at 01:05 | Report abuse | Reply
  9. moonster

    I have a 'big' head even doctors have commented on it. Its hard to find a good hat or eyeglasses that fit. I am just average intelligence. Maybe also it is a mixture of ethnic groups which is more prominent in American society too.

    June 6, 2012 at 01:15 | Report abuse | Reply
  10. Delmar Knudson

    It doesn't seem that the researchers are necessarily equating "bigger head equals bigger brain equals smarter"; nor should they conclude that. There may be no relationship between these bigger heads and a smarter person; on the other hand there could be. It would be very difficult, if not impossible to set up such an experiment on thousands of people from the past and present. I'm sure that Donald Trump, Rush Limbaugh, Bill Maher, and others consider themselves smarter than their ancestors, or their contemporaries; though I would submit that Ben Franklin and Sir Isaac Newton were a bit smarter than these. It may not be much of a stretch to make the assumption that a tiny monkey is less intelligent than a modern human; but this small change in the human skull is only proof that our skulls are getting very slightly bigger; if it even proves that.

    June 6, 2012 at 01:31 | Report abuse | Reply
    • mmi16

      The current political climate would indicate that while skulls are getting somewhat larger in the external dimension, they must be getting thicker internally as no additional intellegence is being indicated from any additional productive gray matter – in fact among politicians it would appear the brain cavity and resulting brain matter is shrinking right before our eyes.

      June 6, 2012 at 02:34 | Report abuse |
  11. bernie

    I think Peyton Manning has already proven this

    June 6, 2012 at 01:32 | Report abuse | Reply
    • Mohan

      I find myself conmig back to your web-site only because you have lots of awesome insights and also you happen to be at this a while, which is very impressive and tells me you know your stuff.

      September 14, 2012 at 01:43 | Report abuse |
  12. Reason & Logic

    Women, we know where you think us men's brains are, right? And they ain't getting any bigger.

    June 6, 2012 at 01:35 | Report abuse | Reply
  13. highprolawyer

    This Site had a story on how some scientists believe that to be linked with Sumerians and thus proof that we have been merged with an alien race

    June 6, 2012 at 01:52 | Report abuse | Reply
  14. highprolawyer

    Sorry The site was http://www.LowPage.com

    June 6, 2012 at 01:53 | Report abuse | Reply
  15. Steve

    The fact that head size and shape is changing means some selection pressure must be driving the change. One obvious one is mate choice. Are taller narrower larger heads more attractive than round small ones? I am sure some enterprising sociologist or anthropologist could check this. Even so seven generations is a rather short time to see a change.

    June 6, 2012 at 01:56 | Report abuse | Reply
    • Carolina

      Tom:I direct a cirminal justice reform organization called Friends of Justice. I am currently researching the Curtis Flowers case in Winona and was shocked to learn about Lydia Chassaniol's address to the CCC. Any idea why the Clarion-Ledger hasn't picked up on that story? Also, can you give me the name of the best person at the Ledger to complain to about it?Alan Bean817-688-6765

      September 12, 2012 at 03:36 | Report abuse |
  16. beavis

    So our brains are larger than Isaac Newton's? And how do we utilize that increased brain power? We watch "KEEPING UP WITH THE KARDASHIANS!" YESSS!

    June 6, 2012 at 02:09 | Report abuse | Reply
  17. Chris

    The changes to head structure are not without detriment. The study should further describe neck structure and upper airway – respiratory obstruction. The correlated obesity diabetes begs more inquiry.

    June 6, 2012 at 02:12 | Report abuse | Reply
    • Tanu

      Good blog. I got a lot of good information. I92ve been wanitchg this technology for awhile. It92s intriguing how it keeps shifting, yet some of the core components remain the same. Have you seen much change since Google made their latest acquisition in the area?

      September 14, 2012 at 00:11 | Report abuse |
  18. Manu

    And the interesting part is all the aliens are show with a BIG ffing head all the time, I wonder if those stories are true.

    June 6, 2012 at 02:17 | Report abuse | Reply
  19. roxann

    this comment is for Richard Jantz and his colleagues at the Univ. of Tennessee, in ur article u talk about skull sizes and then u say researchers conclude that caucasian skulls were the basis for the study, because there weren't enough black r hispanics skulls to study. Do u Mr. Jantz and ur colleagues realize that there r only three races on this planet and that they are the Caucasian, black and oriental r asian race, and then it is broken down into ethnic groups. I am of hispanic-native american origin and with only a business college degree, even l know that there r only three races. U need to go take a class on races and ethnic backgrounds at u. of tenn. and then do a real study on something u can research on. Oh, roxann is the name l use to post comments.

    June 6, 2012 at 02:22 | Report abuse | Reply
    • Kam

      Can't tell if you're serious or trolling but, the idea that there are only three races is incredibly outdated. That is definitely not the model science using today.

      June 6, 2012 at 09:09 | Report abuse |
  20. eric

    How is it that our skulls are supposedly getting larger, yet studies show our brains are becoming smaller?
    http://www.npr.org/2011/01/02/132591244/our-brains-are-shrinking-are-we-getting-dumber

    June 6, 2012 at 03:09 | Report abuse | Reply
  21. CW

    So...why then is the average American intelligence dropping? Doh.

    June 6, 2012 at 03:18 | Report abuse | Reply
  22. AtheistHuman

    Too bad our penises are not getting any bigger eh?

    June 6, 2012 at 03:57 | Report abuse | Reply
    • J-Boogie

      Speak for yourself 🙂

      June 6, 2012 at 09:02 | Report abuse |
  23. Zap

    So they tested skulls from about 150 years ago. Its known that bones typically get smaller as we age correct? What if the skulls they are measuring from the past were once a bit larger when the person was alive and when they were younger?

    June 6, 2012 at 04:06 | Report abuse | Reply
  24. DDNB

    TL; DR :
    We are still evolving.
    Oh yeah.

    June 6, 2012 at 05:00 | Report abuse | Reply
  25. Bob B

    Our heads might be getting bigger, but our brains are getting smaller. Just turn on the news and you'll see this to be quite true.

    June 6, 2012 at 05:09 | Report abuse | Reply
    • Chedar

      I think that will be those wisconsenites you just describe who voted for Scott Walker.

      June 6, 2012 at 05:26 | Report abuse |
  26. Chedar

    This reminds of ET. Our next generation will evolve to look more like ET with big head and small body. But it kind of contradict rot what this article mention. Let see, take my word back. The next generation I can envision to look like an Octopus head.

    June 6, 2012 at 05:23 | Report abuse | Reply
  27. unowhoitsme

    Bigger brain and smaller IQ.

    June 6, 2012 at 05:38 | Report abuse | Reply
  28. Hammy McHammerson

    You know what they say, guys with a big head have a big *********

    June 6, 2012 at 06:23 | Report abuse | Reply
    • Bob B

      Let me guess, is it a mouth.

      June 6, 2012 at 08:26 | Report abuse |
  29. brainz

    the brains aint.

    June 6, 2012 at 06:25 | Report abuse | Reply
  30. mike

    I personally know quite a few people with big,fat, heads . I don't think they are any smarter than the rest of us.

    June 6, 2012 at 06:26 | Report abuse | Reply
  31. Franny

    After the fiasco in Wisconsin? I'd say maybe the head's bigger, but it's apparent the brain has shrunk in the voters!

    June 6, 2012 at 06:58 | Report abuse | Reply
  32. angryersmell

    People are also driving bigger SUVs, but are putting less in them. Use it or lose it, fellow rocket scientists.

    June 6, 2012 at 07:00 | Report abuse | Reply
  33. Hot Carl

    Although the same size, blacks' skulls are much thicker, leaving less room for brain, making them stoopider.

    June 6, 2012 at 07:01 | Report abuse | Reply
  34. larry5

    This is what someone got when they paid for this study? My advice. Get your money back.

    June 6, 2012 at 07:06 | Report abuse | Reply
  35. Jorge

    And just now some boondocks college professor from Tennessee has come to realize that? Well duh, no sh.., Sherlock. Everyone else in the world knows Americans have the fattest heads among the human species, too bad with them it's not a vital organ.

    June 6, 2012 at 07:36 | Report abuse | Reply
  36. whatthe

    this is exactly what America needs, more head.

    June 6, 2012 at 07:38 | Report abuse | Reply
  37. Zoglet

    Is this about Sheryl Crow?

    June 6, 2012 at 07:51 | Report abuse | Reply
  38. DRX

    One day people will learn that, as was the case with our primitive ancestors, extraterrestrial beings have been slowly changing humans by combining their DNA with ours, in effect making us more improved hybrids. Think about it. Had the evolotionary calendar continued un-interrupted by this, "modern man" would have taken several million more years to develop to the point we are at now. It is the only logical explanation because we should not have evolved as rapidly as we did, and apparently continue to do so. Read Genesis 6 again – the clues have been in front of us always.

    June 6, 2012 at 08:07 | Report abuse | Reply
  39. Brooks

    If this comment is not meant to be sarcastic, then it seems irrelevant, or even a bit silly. People from every nation have contributed to modern society and our industrial and technological age. We stand on the shoulders of those who came before. There have been some concentrations of bright people or those who have contributed much from a number of countries. Americans have come from every corner of the world. If we are reasonably bright, then we won't be smug. ... An American with ancestors from four different countries

    on the Technology topic......Steve Jobs...American...nuff said

    June 6, 2012 at 08:13 | Report abuse | Reply
  40. Jokesterer

    It's called the Barry Bonds effect.

    June 6, 2012 at 08:22 | Report abuse | Reply
  41. ricardo1968

    I would say that you probably can't accurately measure a skull that is a hundred years old. It probably isn't the same size as it was after death. Warping happens in anything that was once living, like wood. An individual skull will probably change shape over time depending on the conditions with which it is stored. For the same reason, they say that a Stradivarius violin doesn't sound like it did 400 years ago when it was made.

    June 6, 2012 at 08:22 | Report abuse | Reply
  42. James PDX

    Oh, great, we're turning into a race of Peyton Mannings. Ick.

    June 6, 2012 at 08:24 | Report abuse | Reply
  43. tesla1908

    I've got a big head right here. (grabs crotch).

    June 6, 2012 at 08:32 | Report abuse | Reply
  44. Maverick2591b

    Of course heads are getting bigger...look at the Kardashians, Rush Limbaugh, and any of the shows on Lifetime. Unfortunately larger heads do no equal higher intelligence (I refer back to the three examples).

    June 6, 2012 at 08:33 | Report abuse | Reply
  45. Jacknyd

    Heads may be getting bigger??? hmmm Just look at Obama, how big his head is now .lol

    June 6, 2012 at 08:41 | Report abuse | Reply
  46. Josh

    200+ years ago, babies with larger heads killed their mothers during childbirth. Today, that doesn't happen. So, babies with larger heads live, grow up, and produce new generations of larger head babies.

    June 6, 2012 at 08:44 | Report abuse | Reply
  47. hecep

    "And the overall size of the head has, on average, increased by an amount equivalent to the size of a tennis ball" said Jantz. This increase is huge, say people with heads the size of tennis balls.

    June 6, 2012 at 08:47 | Report abuse | Reply
  48. Swearengen

    Heads are getting bigger, brains seem to be getting smaller.

    June 6, 2012 at 08:51 | Report abuse | Reply
    • SokrMom

      So true. It's unbelievable what's going on in politics, with bone-headed voters and politicians making comments about what is good for the American economy that leave economists in disbelief.

      June 6, 2012 at 09:04 | Report abuse |
  49. SokrMom

    Maybe our heads are just trying to catch up with our waistlines...

    June 6, 2012 at 09:01 | Report abuse | Reply
  50. Largekettle

    The explanation of why Republicans have big heads is simple: lots of hot air

    June 6, 2012 at 09:03 | Report abuse | Reply
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