I think the darker areas tend to overlap with what some doctors call the kidney stone belt.

"Medicine is a form of politeness we pay to the aristocracy." 
 
- Erasmus 
 
True, ancient doctors could staunch wounds and fix bones, and 17th Century doctors could remove kidney stones, but it took almost a kind of religious faith to tolerate the agony of removing a kidney stone. It was for all the lesser diseases or miseries that a person was better off avoiding a doctor. And only aristocrats really had the option, either way. 
 
What about China? Acupuncture, as far a I can see, was mostly an ineffective but harmless and inexpensive placebo. A lot better than bleeding, and thus a better form of politeness for the aristocracy. Kept those mandarins alive and skeptical of religion.

You might regress the differences (+/- from trend) against population density, or changes in population or rate of economic growth. 
 
Related item: Robert Gordon has a very good paper on increases in income inequality (not nearly as much as thought, when properly calculated) at http://faculty-web.at.northwestern.edu/economics/gordon/SFChallenge_Combined_090307.pdf

New York City is, I think, unique among American cities. Most other major cities have thrown off satellite office parks in their suburbs, in which many of the best-paying jobs are available. This greatly expands the total area in which residences within a reasonable commute of well-paying jobs can be built, 
 
But in New York City, almost all the best-paying jobs, along with culture and city amenities, are still concentrated in a very small area, lower Manhattan. This restricts the area within which people who work at these jobs can live and still have a reasonable commute. 
 
Blame it on the last ice age. When the glaciers came down they cut such deep rivers on either side of Manhattan, the East River and the Hudson, that these streams could not be bridged until the age of steel, the latter 19th Century. By that time, New York City was nearly 300 years old. It had already built up a critical mass of wealth, finance, and other delights that no matter how intolerable the city sometimes became, the really ambitious never wanted to desert its best districts.

Salt Lake City is wedged in between mountains to east and west, and lakes to north and south. 
 
Philadelphia is a famously sprawling city, surrounded by flat country, and its river is narrow and easily bridged for further dispersion

Steves' point: above trend line reflects scarce buildable land, due to geography, land-use restrictions or water availability relative to population growth. Below trend line reflects ample buildable land relative to population growth.

I think a lot of very different people loved this movie simply because it is a high school-early college movie, and we were all a lot more alike in those years than we become later in life. (Okay, banal, but true.)

He got one significant factor obviously wrong. The best economists, like Robert Gordon of Northwestern, agree that the Consumer Price Index overstates inflation, and so understate the increase in real wages and standards of living.

Razib, I think you are what the English used to call a Man of Parts (MoP), rather than an MoC. And Steve Sailer is proof that Saki's summary of Roman law still holds: "the early Christian gets the fattest lion."

"...people who broke small laws tended to be the same people who broke big laws, and putting them away lowered the amount of big crimes..." 
 
That is one reason cops in DC like tough gun laws. They can tail a known perp, dangerous but difficult to convict of his deadly crimes, find a legaly valid excuse to frisk him, get him with a gun, and have him off the streets for a few years in an easy case. 
 
The revolution in the criminal justice system per Warren Court decisions in the mid-1960s undoubtedly had something to do with the post- 1960s rise in crime, but how much is still in question. Basically, it cut the conviction rate per crime dramatically. Then, over the past 30 years, we have steadily raised the sentence-per- conviction rate, increasing the incarceration rate per capita dramatically.  
 
So we have re-established a rough equilibrium, but only by jailing many more people much longer and by being clever about bagging them on relatively small charges.

Just to be orthogonal to the plot-versus-character contest, how do you feel about comedy? 
 
George Meredith thought that civilization could only advance with the help of comedy, which depended on having Society to subject to "thoughtful laughter." And Society, with the capital S, depended on the ability of men and women to meet as social equals.  
 
Meredith was a confirmed Darwinian and believed evolution had produced the individual brawn and brains of his rather advanced Victorian world, but that to get much further, this world would have to take charge of its own development. Ergo, Female Equality -> Society -> Comedy -> Higher Civilization. 
 
Meredith believed that Victorian England had a better chance at keeping this progression going than some other cultures of his time: 
 
"Eastward you have the total silence of comedy among a people intensely susceptible to laughter, as the 'Arabian Nights' will testify. Where the veil is over women's faces, you cannot have society, without which the senses are barbarous and the Comic Spirit is driven to the gutters of grossness to slake its thirst. Arabs in this respect are worse than Italians - much worse than Germans - just in the degree that their system of treating women is worse. 
 
- Meredith, "Comedy and the Comic Spirit"

Check out the latest paper on income inequality, trade, immigration and other factors at the website of Robert Gordon of Northwestern University. Gordon is the best synthesizer of new and traditional economic theories, sifting the wheat from the chaff very cleanly with generally persuasive statistics.

I had thee years of Greek in high school a long time ago and read, with gerat difficulty, the Greek version of The Iliad while my book club was doing the translation. The thing that struck me the most was how onomatopoeiac the Greek often was, compared with the English. That is, the Greek words for, say, crushing someone's bones actually sound like someone is doing some serious bone-crushing. 
 
I assume this is because Greek was closer to the origins of all language than modern English is, or than any language that has developed since writing with the phonetic alphabet became common. When you are inventing a word, I imagine you do try to make it sound like the thing it means.  
 
That would seem to make Greek and other ancient langauges more naturally poetic, since sound tends to match and reinforce sense, an effect that has to be striven for with English, which has so many more words to choose from. And I suppose one reason the Greeks and Latins avoided rhymes was that they would have been so easy and monotonous, given that inflected languages have so many similar endings. A rhymed Greek poem would sound like a very banal sing-song to a Greek.

While we are noticing that the homicidally irrational communism is a kind of religion, we should probably acknowledge that the wonderfully practical free-market model emerged in late 18th Century England, not entirely out of rational motives, but partly out of stubborn religious and political principles about how much power government should have over men, the 'sanctity' of property and mutual promises (contracts) and the state's duty to protect these semi-sacred values. I mean, it's not like the preceding English political philosophers actually expected the steam engine or the railroad.

I think Cervantes was way ahead of us all. Quixote never does get Dulcinea, but his inexplicably loyal disciple, Sancho Panza, does get the island kingdom he has been dreaming of, then finds it is too much trouble to rule the endlessly quarreling natives. And shortly after Quixote was published, the Spanish shrugged and gave up both their dreams and the insane glory of their distant conquests.