Thursday 17 September 2015

North-South divide, Japanese style

Every country seems to have a North-South divide. In Britain the divisions are perceptible and deeply felt. Health and wealth fall off sharply once you cross an oblique line of separation mid country. Italy is another exemplar of North-South divisions. Garibaldi has a lot to answer for. Now Ken, as Kenya Kura modestly and helpfully calls himself when speaking to Western audiences, has had a look at his home country of Japan.

Kenya Kura (2015) Japanese north–south gradient in IQ predicts differences in stature, skin color, income, and homicide rate.  Intelligence Volume 41, Issue 5, September–October 2013, Pages 512–516

doi:10.1016/j.intell.2013.07.001

http://www.sciencedirect.com/science/article/pii/S0160289613000949

Ken begins on a typically bold note: Those who have adapted to the harsh northern climate worldwide are taller, more intelligent, more pro-social, less crime prone, and exhibit less fertility. This is said to be due to the more cognitively demanding long winter season (Lynn, 2006 and Lynn, 2008). In a similar and more speculative vein, the differential r/K theory (Rushton, 1988 and Rushton, 1994) predicts that a more demanding cold climate has induced more intelligent and pro-social personality in general.

Regional differences in IQ are estimated for 47 prefectures of Japan. IQ scores obtained from official achievement tests show a gradient from north to south. Latitudes correlate with height, IQ, and skin color at r = 0.70, 0.44, 0.47, respectively. IQ also correlates with height (0.52), skin color (0.42), income (0.51) after correction, less homicide rate (− 0.60), and less divorce (− 0.69) but not with fertility infant mortali'ty. The lower IQ in southern Japanese islands could be attributable to warmer climates with less cognitive demand for more than fifteen hundred years.

 

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He then tests this out on the prefectures of Japan.The prefectural IQs have been calculated from the national achievement survey uniformly conducted by the government with 11 and 14 year old students. Students at these ages are in their last year of compulsory elementary and junior high school, respectively, in Japan.

The analysis utilized the simplest index of prefectural IQs, the sum of the math subtest scores and verbal subtest scores for those five years (full score = 482, average = 323.5, standard deviation = 102.9). These scores were obtained from more than 4 million students, which account for more than 3% of the whole population.

Latitude is correlated with IQ (r = 0.44) and height (r = 0.70). From many collected IQ measurements, the Japanese average IQ has been estimated to be 104, which is slightly lower than the Chinese and Korean averages (Lynn & Vanhanen, 2006; Lynn, 2008,Lynn and Meisenberg, 2010 and Lynn and Vanhanen, 2012). Assuming that the Japanese population has a standard deviation of 15 as in England, north–south IQ difference is estimated to be 11 points, with the prefecture with the highest IQ prefecture (Akita) having 107 while the one with the lowest (Okinawa) having 96. This is surprising in that it challenges the much-touted homogeneity of Japanese people.

Many people worldwide seem to have an image of Japan as a highly homogeneous nation. However, the Japanese islands were initially populated by the hunter–gatherer Jomon people (Y haplogroup C1, C3 & D1) and experienced a great deal of immigration from the Korean peninsula and mainland China from 2900 to 1500 years ago. These incoming Yayoi people (Y haplogroup O2b from Korea and O3 from China) brought wet-rice agriculture and bronze and iron tools to the islands. Because of these cultural advancements, they had shown much more fecundity and have in number dominated the native Jomon people. There still exists a genetic cline from the Western Yayoi population in the Eastern Jomon population in Japan (Hammer et al., 2006). Haplogroups, C1, C3 and D2 are most common among the Ainu people in the northmost Japan (almost 100%) and in the Okinawans in southmost Japan (about 60%),while the western regions closer to the Korean peninsula are more densely populated by Yayoi descendant haplogroup of O2b and O3 (60–70%).

Since the continental Northeast Asians (Han Chinese and Korean) have a higher intelligence compared to the rest of the Eurasian population, it would be natural to assume that these Yayoi people were more intelligent. This conjecture is based on the facts: 1. The fossil evidence shows that the Yayoi people were 5–8 cm (2–3 in.) taller than the Jomon; 2. Modern-day Koreans are about 3 cm (1.2 in.) taller than the Japanese; 3. The IQs of Chinese and Korean people have continuously outscored that of Japanese people (estimated to be 106 and 105, respectively). Hence, it is reasonable to expect that the prefectures closer to the continent exhibit higher intelligence than those in the Northeast.

However, this tendency was not observed and instead there exists a simple intelligence gradient from south to north. This may be due to an almost perfect admixture within the last 1500 year (about more than 60 generations) as far as genes for taller stature and higher intelligence are concerned, as well as the selective pressures of the last 1500 years of civilization, which have been strong enough to reshape the original east–west IQ gradient into the current north–south cline. This conclusion would be in line with the Hawks, Wang, Cochran, Harpending, and Moyzis (2007)idea of ever-accelerating human evolution. They insist that more and more beneficial mutations swept populations, after the advent of agricultural civilizations with metallurgy, letters and complex hierarchical organizations. The Japanese north–south gradient in height and intelligence can be evidence that modern humans have evolved to higher intelligence within the last two millennia.

In brief, it appears that if humans (or at least the Japanese ones) are cooled down a bit, and the imprudent ones killed off by hard winters, then the survivors are brighter, milder, lighter-skinned and more suicide prone, more socially-conscious and law abiding, divorce less often and have fewer children. Can such Northerners survive the global battle of the cradle, or will they be marginalised and driven further north, to die in the frozen wastes?

21 comments:

  1. Assuming that the Japanese population has a standard deviation of 15 as in England, north–south IQ difference is estimated to be 11 points, with the prefecture with the highest IQ prefecture (Akita) having 107

    Akita prefecture has a reputation for the most beautiful women in Japan. Satoshi Kanazawa has published research on the link between beauty and IQ.

    B.B.

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    1. "Satoshi Kanazawa has published research on the link between beauty and IQ."

      Better study has found no such link.

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    2. But to the extent that IQ is a reflection of lower mutation load, which Charlton and Woodley feel is well established, one would think that there must be some small correlation between IQ and perceived beauty, since more symmetrical people are generally regarded as more handsome.

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    3. There are far many more genes involved in IQ than facial appearance, so it's not too surprising they are uncorrelated.

      And Charlton and Woodley, really?

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    4. Yes, they agree with Cochran, as I recall, and studies show symmetry of face is key...

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    5. Increasing mutation load must disrupt symmetry to some degree.

      Delete
  2. "Every country seems to have a North-South divide. In Britain the divisions are perceptible and deeply felt."

    Yup. Britain, France, Spain, our old pal Italy, and perhaps Korea. (Though in a few countries, like Germany and Ireland, the divide is primarily east-west.)

    "The Japanese north–south gradient in height and intelligence can be evidence that modern humans have evolved to higher intelligence within the last two millennia."

    Yup.

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  3. Based on nothing but casual observation, Japanese women seem prettier and more feminine than Chinese and Korean women. Maybe this is simply a function of observing their representation in their respective pop cultures (we get a lot more of Japanese pop culture).

    I assume the British cline described is more intelligent, taller, etc. in the north not the other way around. Could this be a result of Scandinavian ancestry?

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    Replies
    1. It's higher IQ in the south in Britain.

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    2. Interesting. I wonder if brain drain, people heading south to the more populous areas like London could account for this. It would be interesting if a study could be done testing individuals whose ancestors have lived locally for a long time.

      Also, since Britain has a maritime climate, I wonder if there's a great deal of north-south temperature difference.

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  4. Why then does temperature predict IQ in just the 50 U.S. states, where evolution cannot be the explanation?

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    Replies
    1. Because low temperatures occur near the Canadian border?

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    2. Because people from northern climes in Europe emigrated to colder parts of the US, very noticeably in the upper midwest.

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  5. Hokkaido island have the most smartest of the japaneses??
    Akita province is in the north but not in the extreme north of Japan archipelago.
    Shikoku island seems to be one of the worst regions of Japan.
    Akita have just 1 million of inhabitants. Is expected that ''cognitive elites'' be attracted by greater cities like Tokyo. Shikoku have 4 million people and Okinawa, 1 million people. Is interesting analyse the migrations historical patterns to know if most people of certain area are ancient natives or not.

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  6. ''Like much of the Tōhoku Region, Akita's economy remains dominated by traditional industries, such as agriculture, fishing, and forestry. This has led many young people to migrate to Tokyo and other large cities. Akita Prefecture is where declines in population are most severe in Japan; it is one of four prefectures in Japan registering declines in population since 1945.[citation needed] It also has the lowest number of children as a percentage of the population, at 11.2%.[5] As of 2010, it has a population of just over 1 million people.[6]''

    From wikpaedia

    How many people lived in Akita before 1945??

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  7. The fact that both Akita as Okinawa, presenting small populations, it may be important not we not use their scores in school tests as relevant averages to estimate the average intelligence, from these parameters, in Japan.

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  8. @Kenya,

    Are there any particular regions of Japan notably high in their production of eminent scientists and/or artists?

    Also interesting that Tokyo seems to have a fairly unremarkable IQ. One would think that several centuries of it serving as Japan's economic center of gravity would have created a cognitive clustering effect there but evidently it has not.

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    Replies
    1. Cities tend to be population sinks.

      On the whole, though, I wonder how much this study controlled for the effects of internal migration.

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    2. Shanghai and Beijing are 1/2 S.D. above the Chinese average.

      Moscow is 2/3 S.D. above the Russian average.

      It doesn't seem to be an atypical pattern. I wonder why Japan would be an exception.

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    3. A cognitive clustering effect might be stronger in societies where large population centers are relatively harder to get into, due to a closed off elite culture, geography, high cost, ect. This would be amplified in poorer countries because there is more incentive for smart people to move to cities. This may be the case with China. Countries with highly mobile populations, and where cities are easier to move to (e.g. USA, parts of Europe), would probably have a smaller difference in cognitive ability between rural and urban populations. I would imagine it is the greater incentives and high barriers to traveling that drive cognitive clustering. Japan has had relatively high mobility over the last few hundred years, and the big cities are not as hard to move to.

      The quality of living is probably another factor. The gap in living standards between rural and urban areas is likely smaller in Japan than it is in poorer countries. Thus there is less incentive for smart people to travel to Tokyo. I wonder if we would see a similar situation in Korea and Taiwan.

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  9. The IQs of Chinese and Korean people have continuously outscored that of Japanese people (estimated to be 106 and 105, respectively).

    Has this really been consistent? 1 point is not all that much and the IQs of Chinese in places like Taiwan and Hong Kong could be elevated due to having elites who fled communism.

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