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We seem to be getting swelled heads. Or at least bigger ones.
A study published in the British Dental Journal ran a comparative study between the skulls of modern day people, and two sets of older skulls. They came to some unexpected results: the shape of the human skull has changed considerably in the six or seven hundred years between the modern and medieval samples.
It would appear that our skulls, and most likely our brains, are getting selectively bigger.
Two sets of older skulls, thirty from London plague victims of the mid-14th century and another fifty-two from the wreck of the Mary Rose in 1545, were measured in several different dimensions, including the height of the cranial vault (the measurement from eye to top of head). The old skulls had an average height for the cranial vault of 80mm. These were compared with a set of modern skulls (measurements taken from dental records). The average cranial vault height for the modern skulls? 90mm 95mm—a more than 18% increase.
What exactly the increase in size means is something else again. The first impulse is to attribute it to an increase in intelligence. Certainly Dr. Peter Rock, who led the study, suggests that the increase in size may reflect an increase in mental capacity, but this seems a little premature. Firstly, it falls to a common misconception that brain size directly relates to mental capacity. This has been proven false a number of times. In general across species, mental capacity relates to the brain size relative to body size, not brain size absolute. Within species the given brain size of an individual seems to have no predictable effect on intelligence, with the exception of specific brain diseases that can lead to abnormally large or small brains. Given that the average human has increased in size and height over the centuries, the measured increase may simply be reflective of this larger change, or it may reflect the very different nutritional status of the modern, first-world human, as compared to most of the rest of humanity throughout history.
Nonetheless, the alteration is something that deserves to be looked at more intensively. The increase in cranial vault height is not the only difference that the researchers found between the modern and medieval skulls, merely the most dramatic. Facial features in the medieval skulls were more prominent, which may be the result of dietary changes to softer more processed foods that require less chewing. In an interesting note, a similar set of changes (increased cranial vault height, decreased prominence in the facial features), was noted when a series of Nubian skulls ranging from 12000 BCE to 1500 CE were measured. The changes in both features were attributed to the Nubians’ change in diet to food which required less mastication, and therefore less development in the muscles and bones used to support jaw activity, rather than to an increase in mental capacity. However, while it is easy to see why less developed jaws and jaw musculature would lead to smaller, less prominent faces, it is less easy to see how it would lead to increased cranial capacity.
Many of the questions raised by studies of this kind are not currently answerable. There is no way we can go back in time to administer a battery of intelligence tests to the owners of the medieval skulls. Nonetheless, the questions themselves are intriguing, and as we gather more data, both ancient and modern, we may find more answers than we think – and of course even more intriguing questions.
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it’s simple: we’re turning into coneheads.
Now I know why Einstein was so bigheaded…
We’re going in circles. Chewing gum will make us look like Neanderthals again.
Maybe it’s just the modern man’s ill conceived importance that is causing his head to swell.
I knew that my hats were beginning to feel tight, but now I can just attribute it to evolution! Thanks, D.I.!
Are we evolving into the stereotypical alien? :]
heh
“The old skulls had an average height for the cranial vault of 80mm. These were compared with a set of modern skulls (measurements taken from dental records). The average cranial vault height for the modern skulls? 90mm—a more than 18% increase.”
a 10 mm increase from 80 to 90 is not an 18% increase – its 12.5%, nearly 30% less….
Whoops – typo! The new measurement average is 95mm, not 90. The original article said 20%, I checked the math and came up with 18.75.
I wonder what it means for people of other races.
I figure it’s primarily related to environmental factors and not evolution, Diet, health care etc. Less than a thousand years it not enough time for random mutation + selection to have an effect. It’s quite possible that in a 1000 years researchers will look back at modern Americans and wonder how they were all so damm skinny. A thought I find curiously amusing.
Two sets of skulls? That leaves considerable room for error, given that maybe these sets were both groups who found small heads attractive.
Has bone shrinkage over time been accounted for? Seems like a logical deduction from the facts. A lot more logical than a major increase in brain size after such little time.
Is an increase in cranial vault height directly related to a larger cranial interior?
gotta think the increase in skull size is the stretching induced while removing our skulls from our anal cavities
I think what could prove more interesting would be the cubic capacity of the brain-cavity itself. The accepted average for humans stands at 1400cc. Is this perhaps an old figure? Could it be closer to 1500cc now? Another interesting factoid is that Neanderthal-man had a LARGER brain cavity than homo-sapiens… They had 1500cc of room for the squishy think-matter, whereas we (assuming modern man doesn’t have some Neanderthal lineage), as was previously hinted at, have only 1400cc (or do we?).
Bigger skulls don’t have bigger brains in them, just some more air. Take George W. Bush as an example.
alipardiwala said: “Bigger skulls don’t have bigger brains in them, just some more air. Take George W. Bush as an example.”
Now that’s funny but true.
Geourge… never ceases to amaze me. I love that guy, or is that hate ?
love and hate, freedom and slavery, where’s the difference these days anyways ?
Interesting article. I remember reading once about an individual with an abnormally large skull. They eventually discovered that while this individual demonstrated excellent intelligence there was only a very small brain, the rest of his skull being filled with fluid. Are you familiar with this case?
Did they do this in porportion to body size. People used to be alot smaller even as recently as 80ish years ago because of crappy nutrition and childhood diseases. …im sorry i can’t spell diseases.
One angle to look at… With the advent of cesarian sections and painkillers, maybe its just easier to give birth to big-headed babies. So more of those survive, and their mothers survive to pop out more of them.
Something to consider at least.
Well, it has never been easy to give birth to big headed babies… even a C-section isn’t much fun… but yes, maybe more big headed babies survive!
It’s like those aliens you see in old science-fiction movies, with the huge heads and tiny bodies. Also, if they say evolution (and I don’t want to start a fight about evolution) happened because of natural selection, i.e. those who survived to reproduce passed on desirable genes, maybe at a certain point mankind will de-evolve. Because life gets so easy that anyone can survive, even those with weak and undesirable traits. Thoughts?
needles said: ” those who survived to reproduce passed on desirable genes, maybe at a certain point mankind will de-evolve. Because life gets so easy that anyone can survive, even those with weak and undesirable traits. Thoughts?”
Seems reasonable enough. I don’t know if we’ll exactly de-evolve, but maybe remain stagnant, or get slightly less advantaged (I mean in general, not over other animals).
I wonder if they have measured precent increase of cranial size in proportion to body size.
Also, have they checked if the plague affects brain size in any way, maybe swelling or shrinking a skull slightly? Doesn’t seem incredibly plausible, but if half the data is from skulls that may possibly have been morphed by disease, it could seriously flaw the data.
Giving hope to large-headed individuals everywhere!
Interesting article.
Does that mean the swelled head of my colleague is indicative of a larger brain ?