When I visited Mount Vernon, (where George Washington lived), the beds and doorways were very small. Someone stated that people in general were shorter back in colonial times. Is that true? (I thought evolution would take much longer than that to affect the height of the population.) If we were shorter, what caused us to grow, and are we done growing?
People actually do get taller now (currently increase of the average is as much as 1 centimetre per decade, I read); during the Middle Ages, the average for men was well below 1.60m. There still is a lot of discussion about why; possible reasons are:
- Better and more regular food supply
- Better medical facilities
- The defeat of darkness caused by artificial light; in the old days, the time during which people had light around them was much shorter, and some claim brightness affects the production of growth hormons
One link about this topic:
http://www.tryonpalace.org/pages/classpgs/d11_footpg.html (strangely enough, this site states Washington’s height at 6 feet 2)
Yeah, people are getting taller. Evolution alone wouldn’t produce changes as fast as this - probably the main factors involved are better healthcare and nutrition. Malnourished kids won’t grow as tall as they could because they lack the energy, vitamins and minerals required for healthy growth.
You could also take a look at the following site.
http://www.plimoth.org/Library/l-short.htm
It does seem to me that any of these changes are too small to explain the increasing dimensions of doorways, ceilings, beds etc. The answer to that, I think, has more to do with changing fashions and greater prosperity.
Can’t be. Most of the really huge people out there are professional athletes. 
In all honesty though, better medical care and nutrition have a lot to do with the increased size we enjoy over our predecessors.
It doesn’t take rocket science to work it out.
Just ask any live stock owner/breeder what is needed to produce top quality animals: good nutrition, good hygeine, good health care and good living conditions.
Why shouldn’t the same logic apply in humans? After all, “you and me baby are nothin’ but mammals…” 
Better nutrition and health care are the biggest things responsible for people being taller than those of a couple hundred years ago. I don’t know about this, but would less heavy labor early in life nowadays account for more energy being devoted to growing instead of lifting huge bails of hay around and stunting you a bit? - actually, probably not since not everyone did do such things. I’ve heard that overall (not including nutrition and such) that people are getting slightly taller and thinner, or perhaps about the same height and just thinner. By thinner I mean of course more frail and weak, not weight-wise!. When I was in Europe, we visited a castle and were shown some armor. The chest peice nicely fit a small woman (~5’ tall and <100lbs), but the armored gloves - from the same suit - fit our hefty 6’3 tour guide just right. It’s kind of funny; I’ll bet a fair number of midevil knights and soldiers were built like chimpanzees! (or at least that’s how the conditions at the time allowed them to grow)
People getting taller/more massive genetically? No.
People growing closer to their “programed” potential due to better living conditions (where they exist)? Yeah.
Most of it is due to diet. You can observe the effects of this even in the modern world. People from cultures where the traditional diet is low in fat and protein tend to be much shorter than Americans, who rarely lack for fat and protein. And of course people who were malnourished as children rarely grow to be very large. If you ever happen to meet a family where the parents are, say, Southeast Asian refugees but the children were raised in the US, it will become obvious that childhood diet plays a huge role in determining adult height.
Yeah, I was just thinking of something like that just now. When I was in Thailand (where they tend to eat traditional foods), I was taller than everyone. Out of the thousands of Thais I saw there was exactly one as tall as me (6’), and he was obviously abnormally big for a Thai and working as a security guard. When I walk around here(Canada), I’m looking UP at probly one in five asians who were born and raised here. Better, well, “richer” in a sense food allows people to get closer to their maximum potential size when growing up.
Part of the press materials that came with the “new” S-class Mercedes-Benz land-yachts in the early '90s stated that between the design of their previous model (late '70s, I think) and the new one, the average height of their customers had increased dramatically. Headroom in the new line was increased by 1 1/2 inches.
Yes, they are getting taller. And wider. Or maybe just developing at a faster rate?
Don’t you remember how little the freshmen in high school were? Now they are a good 5’6" or better by the 8th grade.
brag mode on I was 6’ 2" in 7th grade. I also have read that light affects hormones and that our consumption of more fruits and veggies help too.
What about just making smaller doors to allow less heat to escape? Perhaps it’s not that we’re that much taller,overall, but that we find it less acceptable to have to stoop to go through a doorway.
Corr
I always hear that Japanese have the best diet in the world, but they’re shorter, on average, than us. Why’s that the case?
It’s probably mostly due to diet. Earlier posters have mentioned children of immigrants becomming taller than their parents. However, few people realize that Cro-Magnons (living ~35k years ago) had proportions similar to ours. The argument being that the hunter/gatherer diet was healthier than a 1-crop staple diet that was common for hundreds, if not thousands, of years.
Japanese are increasing in height and weight too. I have read somewhere that the average Japanese male from the 1980s wouldn’t be able to fit into the cockpit of a WW2 Zero fighter plane.
In Osaka, I watched gridiron training once, and some of those boys were enormously tall and muscular.
Pointing to the changes in height which most of us have witnessed during our lifetimes doesn’t really address the issue raised by the OP. The standard sizes of doorways, ceilings, beds etc. we now use became common before the spurt in heights witnessed in some developed or developing countries during the late twentieth century. Moreover, the statistics quoted in the two sites posted above by Schnitte and myself actually show that the heights of the inhabitants of late-eighteenth century North America were not that different from their modern counterparts in the mid-twentieth century. Average height has fluctuated over the centuries, no doubt for some of the reasons which have been given above. It remains to be seen whether there is any underlying trend.
It is also far too reductionist to say that the built environment always gets adjusted to accommodate the sizes of those who use it. Even today, when precise statistics are available, manufacturers can be reluctant to make such adjustments. Will future generations look at early-twenty-first century economy class airline seating and say, ‘Of course, they were much smaller then’?
mmmiiikkkeee, much of the armor that survives today was ceremonial and was not made to full size. So yes, it looks pretty small because no adult ever wore it. Armor sized for children was also produced, though seldom worn for anything but show.
Weight gain during pregnancy is also a factor in growth. As recently as 30-40 years ago, women were told by their doctors to gain very little weight (less than 20 lbs), which resulted in lower average birth weights. Now, most doctors allow a mother to gain between 25-35 lbs, which has increased the average birth weight of babies by as much as 2-3 lbs. This is in the US.
When I entered high school (9th Grade), I was 6 feet tall. Most of my friends were between 5’-8" and 6’-1". Even the girls, which were typically (not always, of course) shorter than the guys, were at least 5’-5" tall. By the time I left high school, the freshmen (girls and guys) coming in were between 5’-2" and 5’-7".
Why is that? I noticed that instead of being tall when entering high school (having experienced growth spurts in middle school), as my friends and I had been, the new classes were rather short upon entering high school. They then shot up in height during their four-year stay.
Maybe I should investigate the food at the middle school. I always thought high school cafeteria food was the pits, but perhaps it was leaps and bounds above middle school grub.
Or maybe my sense of superiority in my senior year made me feel taller. 
I think “best” in this case means healthiest, not most conductive to ending up large. The Japanese tend to be shorter than Americans, but they are also far less likely to be overweight.
My Japanese friends tell me that it’s not unheard of for Japanese students who spend a year at school in the US eating an American diet to grow taller – even if they are already in their late teens or early twenties.