Bigger heads....
... and not getting taller ..... but getting wider...
Sounds more like Jabba the Hutt than the Mekon if you ask me
Certain Americans' heads are getting larger at a "dramatic" rate, say researchers at the Forensic Anthropology Center at the University of Tennesse, citing a 6.8 per cent increase in skull length in the past 100 years across their sample. At this rate, the heads of this group of Americans will have doubled in length sometime …
While in Las Vegas, was had a family competition, a little like pub cricket, the game you can play while driving in the car.
We called it, SPOT THE SALAD DODGER...
In the space of 30 minutes walking between the New York and the Venitian we scored 368 runs between us.
Single fat person- one run
Two fat people together- a four
Four fat people together- six
Two thin people together- out.
And multiples there of...
I scored my first century in a matter of minutes
>Americans are known for their superior intellect.
Brought to by Carl Jr's Big Ass Fries tm. Idiocracy makes a lot more sense than this garbage. Still thank goodness for IQ being one of those traits that push towards the mean regardless of parents genetics (ie two stupid people or two smart people children tend to move towards the average) or else we would be putting Brawdo on our crops.
Very true, but perhaps unnecessary.
A height increase of 5.6% is mentioned over the same period. (The article says this has stopped in recent years, but there's no evidence that the head increases haven't stopped, too.) That's a volumetric increase of 17%, which on an average modern brain size of 1260 cm3 (wikipedia) would be an increase of 190cm3 from an inferred 19th century value of 1070cm3.
Isn't this more likely to be due to improved diet than evolution?
Up until the last century, greater intelligence would have given an evolutionary advantage; and this may still be the case in undeveloped countries. But I would argue that in the developed West, including America, intelligence is no longer a trait that leads to successful breeding.
Isn't this more likely to be due to improved diet than evolution?
That depends on whether you think a diet full of growth hormones is an improvement.
It might even be why there's a difference between American and European rates of change
https://en.wikipedia.org/wiki/Beef_hormone_controversy
"intelligence is no longer a trait that leads to successful breeding"
Actually lack of intellience is a trait for successful breeding. To bring children up properly is expensive and time consuming so smart people usually plan for it and thus have one or two children.
Morons just get drunk or stoned and shag anything with a pulse. The government then supports their children instead of letting them starve to death from neglect.
Religious nutters believe that God wants them to keep breeding more and more 'Sheep' so end up with eight to ten god fearing children (pick any religion as they're all the same)
I think the growing American head is due to the growing ego, not the growing IQ
The evolutionary advantage of higher intellect seems to be very flimsy, and 100 years is just 5 generations or so. There's no way evolution has any measurable effect on something so poorly correlated to reproduction in just 5 generations. It's probably due to diet or medicines or something like that.
Not in 5 generations, and not for something this subtle. Evolution can be fast, but only when there's spectacular selective pressure (like, a deadly virus or a genocide).
That said, I like the infant mortality explanation. Big-headed babies are less likely to die at birth today. I just think that the observed increase is almost entirely explainable as a statistical effect, not an evolutionary one. I.e. the same number of big-headed babies are conceived as a century ago, but more of them survive birth today. This can cause an evolutionary effect so that more big-headed babies are actually conceived, but it would take hundreds of generations.
Something has affected head size the same way diet affected height. Humans haven't evolved to be any taller since we were cavemen. In fact palaeolithic humans on a largely fatty, meat based diet were quite tall, with heights comparable to today. It was during the switch to a neolithic diet largely composed of grains and vegetables with sparing amounts of meat and dairy that caused height to take a nosedive until the 20th century. Since we now can all afford to eat whatever we want, with ample amounts of marconutrients even in the worst junk food diet, that height has probably stopped increasing generation by generation. The same will no doubt happen for head size.
"They found that in that time skull capacity had increased by 200 cubic centimetres for men in the sample, equivalent "to the size of a tennis ball". The researchers found that the average height from the base to the top of the skull in men had increased by 8mm. In the women in the sample, the corresponding increases were 7mm and 180 cubic centimetres."
If I read this correctly, in women the skull capacity increased by 7mm while the body has increased by 180 cubic centimetres. That accounts for all the fat American ladies.
Well, if the human brain were getting larger, that would be very good news.
It doesn't even have to complicate childbirth. If our brains just kept on growing at the same rate, rather than slowing down their rate of growth when we are two years old, we could have our heads stay the same size at birth, and yet have much larger brains as adults.
My first born had to be delivered via C-section. After ~30 hours in labor, they realized he was stuck and his cranium was too large for the opening in the pelvic bone. He was around 33k USD.
My second born was recommended C-section because of the cutting damage after the first. Of course, that one was also ~50k USD, so you might be correct.