Testosterone level varies over the course of the day, being highest in the morning. However, with artificial lighting throwing our circadian clocks off, I wouldn't be so sure that simple statistics can really account for systematic differences in daily routine.
Also, alcohol, cigarette and drug use is probably self reported. At least, I'd be surprised if the testing had been that thorough.
There are a variety of factors which have been alleged to influence testosterone levels. Exposure to sunlight/vitamin D, exercise, winning/losing (even vicariously), fatherhood...
I don't know to what a degree that research is reliable.
Well, anything as long as at the end we can dismiss any sort of differences between groups, because those are forbidden to consider, right?
So we can do an hour of mental gymnastics of the most elaborate sort as long as the end result is that it all comes out exactly even in the wash, somehow... miraculously.
Even though blacks are observed to have all the hallmarks of higher testosterone levels when compared to whites... just as males exhibit as compared to females. Deeper voices, higher aggression, superior athletic performance, higher crime rates, higher sex drive (and the accompanying higher rate of STDs which is inseparable from that) etc.
But I'm sure that's all just cultural and probably artifacts of slavery and such right? though somehow sub-Saharan Africa seems to be largely a permanent basket case of the globe... no connection, I'm sure. The government study on testosterone clearly got it wrong and didn't take enough things into account...
... no possible way that ice age winters might select for greater impulse control, greater ingenuity, greater paternal role in child rearing, fewer sexual partners (because otherwise your offspring might freeze/starve to death if you were off trying to make more instead of sticking around helping) etc. Nah, not possible.
And I'm sure it's a pure coincidence that east Asians, who were subjected to even colder climate at that time, consistently score higher on IQ tests than whites and had advanced civilization, for the most part, a lot earlier than most whites did.
In all seriousness, I really do think it is an unavoidable conclusion that cold weather environments act as a crucible and have a culling effect. Disproportionately trimming off the "grasshoppers" and leaving the "ants" with a larger market share of the gene pools which moved into those environments. In fact, I consider this a genetic inevitability and am aware of no possible mechanism which could prevent it from happening. Other than perhaps what we have now, in the form of coats, and lots of heated indoor environments. Those can certainly fend off natural selection.
To those who steadfastly refuse to consider that there can be differences between what are commonly thought of and referred to as "races" - let me propose two very simple mental exercises which I believe prove that such differences are inevitable:
I'll try to keep these very short because I tend to be wordy.
1.) It's well known and firmly established that incest leads to depressed IQs and a whole host of defects, susceptibilities to disease, etc. This isn't contested. Now, if you have Group A living in one part of the world and Group B living in another, and Group B has had a cultural practice for 2,000 years of marrying first cousins being a common and desirable behavior, how can this possibly not result in Group B's average IQ and gene pool health being lower than Group A's if Group A either didn't have that practice or had it much more sparsely?
I would really like to have someone explain to me how that situation could play out in any way other than Group B having a less healthy gene pool and a lower average intelligence. Is there some magic force which ensures that this doesn't happen so that later down the line, nobody's feelings are hurt?
http://news.bbc.co.uk/2/hi/programmes/newsnight/4442010.stm
"Communities that practice cousin marriage experience higher levels of some very rare but very serious illnesses - illnesses known as recessive genetic disorders."
2.) It's very, very hard (and laughable) to deny at this point that blacks have athletic advantages over whites and other races on average. Note: the first non-white player entered the NBA in 1947, and the NBA was 78% black by 2011. Throughout that entire time, the vast majority of the coaches, team owners, and fans were white. Particularly in the earlier portions of that time. Why would the racist white society we hear so much about, have ever allowed such a shift? I think the answer is obvious. The pressure for teams to win is a good proxy for natural selection, and it tends to be similarly unsympathetic and single-minded. A pronounced genetic advantage outweighed other concerns like racism, etc. Numbers for the NFL aren't far behind.
How about
Olympic running?
"The trends are eye opening: Athletes of African ancestry hold every major male running record, from the 100 meters to the marathon. (Although these same trends hold for female runners, the pattern is more dominant among male runners. This analysis focuses on men because the playing field for them is far more level, as social taboos remain that restrict female access to sports in many parts of the world.) Over the last seven Olympic men’s 100-meter races, all 56 finalists have been of West African descent. Only two non-African runners, France’s Christophe Lemaire, who is white, and Australia’s Irish-aboriginal Patrick Johnson, have cracked the top 500 100-meter times. There are no elite Asian sprinters—or, intriguingly, any from East or North Africa.
Remarkably, the story of East African runners is the mirror image of the West African success story. While terrible at the sprints, runners from Kenya, Ethiopia, Uganda and Somalia, along with a sprinkling of North and Southern Africans, regularly dominate endurance running."
I think it's a safe bet that this dominance in specific sports is tied to the previously mentioned testosterone gap, as well as differences in bone structure and muscle structure (which are established and proven.)
So those who gasp at the idea that there could be differences between racial groups, especially in the area of behavior and intelligence, are really left with only two options on this point:
Either blacks are the Übermensch of humanity who have strong, undeniable physical and athletic advantages over other groups while also having identical cognitive powers, and the story of migration by humanity into Eurasia is basically just all about how humanity got weaker, less manly, and slower...
OR those changes were done in exchange for something else. They purchased something else in Eurasians. Something which explains the civilizational contribution gap... the lack of written language, advanced structures, or the wheel in sub-Saharan Africa prior to outside contact... the status of Africa, Haiti, and Detroit as we speak... and the persistent gaps in IQ scores which have barely budged for decades.
Perhaps our society could come up with better solutions for things like disparities in incarceration, school discipline, and representation within certain walks of life which either require great physical, or great cognitive resources if we permitted ourselves to face unpleasant truths. Perhaps we'd all be happier if we admitted the very obvious, and very logical basis for these observed differences: different evolutionary histories.
For anyone who takes issue with anything I've said here, I would just politely ask you to answer this one question which I eluded to earlier:
What mechanism would prevent a population which moved into an environment where winter had the power to kill from shifting toward being comprised of more "
ants" than "grasshoppers" Or at least more ants than a population which remained in an area that did not have winters?
Unless of course someone wants to claim that human behavioral tendencies aren't subject to biology or evolution somehow... despite them being susceptible to it in every other species.