japan – reversal of fortune?

a couple of months ago, greg cochran wrote about how a population (any given population) might raise its average iq quickly — like over two or three generations. one possible method, he suggested, was to quit inbreeding. here’s what he said:

“I’ve been thinking, off and on, about sudden changes in the cognitive abilities of populations: groups low suddenly scoring much higher or lower on a time scale too short to be explained by selection: say, three generations or less…. I can think of two perfectly feasible strategies that *would* cause significant one-generation increases in intelligence, in certain populations. Iodine supplementation, in places where it’s short, has a big payoff…. The other practical, low-tech strategy would be stopping cousin marriage. The next generation would be in much better shape, since the children of first cousins take a substantial IQ hit – maybe six points or so.

i think i may have stumbled across an example of a population rapidly dropping cousin marriage and, also very rapidly, gaining iq points.


yesterday, i was working on a completely different post about japan and cousin marriage, when i rediscovered this [pg. 30] (click on chart for LARGER version):

japan consanguinity rates - decline

that’s the decline in the average national consanguinity rates in japan from 1947 to the early-1980s. but the consang rates were even higher in the 1910s-1920s at 22.4% [pg. 29] (and who knows how high the rates might’ve been even further back?), so the chart above should look something more like this (pardon my crayola — and note that i just eyeballed it — click on chart for LARGER version):

japan consanguinity rates - decline - crayola 02

when i rediscovered this yesterday, i remembered what greg had written, and got to wondering if there were any historic data for japanese iqs and if there’d been any changes in those iqs over time. so i googled (as one does) … and found this:

The Rise of National Intelligence: Evidence from Britain, Japan and the U.S.A. [pdf] – lynn and hampson.

from that article [pgs. 27-31]:

“It has been possible to find five studies providing evidence on the secular trend of intelligence in Japan for the post World War II period….

“(1) Ushijima’s study (1961)….

“Here the Ushijima intelligence test was administered to 1365 children in 1953 and to a comparable sample of 1370 children in 1960 with the objective of determining any change in the mean over this relatively short period. The children were aged 9-15 years.

“(i) All age groups show a rise in scores for all abilities. The overall mean increase was 0.66 standard deviations, the equivalent of 9.9 IQ points, and representing an IQ gain of 14.1 IQ points per decade. This is of course a very considerable increase and much greater than anything found in either Britain or the U.S.A.

“(ii) The IQ increases are in general greater among the younger age groups than among the older….”

see my crayola chart above. kids who were fifteen in 1953 would’ve been born way back in 1938 when the consang rates were above 15% — maybe 17 or 18% (remember, i just eyeballed it, so this is a complete guess really) — while kids who were nine in 1953 would’ve been born in 1944 when consang rates were hovering right around 15%, in other words lower. same for the later cohort from 1960: fifteen year olds would’ve been born in 1945, nine years old in 1951. the younger the kids in the cohorts, the less chances their parents were related.

more from the article…

“(2) Kaneko’s study (1970)….

“Kaneko’s invetigation of a possible rise in the scores on this test was carried out in 1963….

“Hence the mean IQ in these schools has risen 10.38 IQ points over the 9-yr period … represents an IQ gain of 11.4 IQ points per decade. This figure is evidently broadly similar to the rise of 14.1 IQ points per decade for 1953-1960 found by Ushijima and confirms a very considerable rate of IQ gain in Japan in these early post World War II years.

“(3) Sano’s study (1974)….

“It will be seen that in all samples there were considerable increases in mean IQ from 1954 to 1972. The increases appear to be a little greater among the city children than among those from the prefrecture. When the results for 10- and 11-yr olds are combined, city children gained 18.04 IQ points and prefrecture children 15.07 IQ points….”

that the city children had greater gains than the rural kids is not surprising if inbreeding is the factor making the difference here. even up to the 1980s, consanguinity rates have been quite a bit lower in urban areas in japan as compared to rural areas (see table in this post for example). (more on this soon in that upcoming post on japan.)

“The average of the two gains is 16.56 IQ points, representing a gain of approx. 9.15 IQ points per decade for the entire sample.

“Sano also considered the question of whether the IQ gains in Japan have been increasing at a constant rate. For this he used Kaneko’s 1964 data which were available for two of the schools. He calculated that the increase in mean IQ was 10.47 points for 1954-1963 and 3.42 for 1963-1972…. ([I]t will also be noted that the gain of 10.47 IQ points for 1954-1963 is closely similar to Kaneko’s figure of 10.38 for the same period.)

“It is apparent therefore that there was a considerable deceleration in the rate of increase in intelligence over the period 1954-1972….”

again, see my crayola chart. the decline in cousin marriage rates is much sharper in the decades preceding 1954 than during those preceding 1963. in other words, there was a deceleration in the reduction of cousin marriages over time, so perhaps we shouldn’t be surprised at a deceleration in the increases in iq over time.

“(4) Wechsler studies….

“Thus after making these adjustments we have Japanese mean IQs of 101.9 for 1951 and 107.4 for 1975. Hence over this 24-yr period (1951-1975) the Japanese mean IQ increased by 5.5 IQ points relative to the American IQ…. This represents a Japanese IQ gain of 5.75 IQ points per decade. This rate of increase for the period of 1951-1975 is somewhat less than Sano’s result of a 9.15 IQ point per decade increase over approximately the same period (1954-1972)….

“A second Japanese study using the WISC and WISC-R is also available (Anon, 1981)…. This gives a rise of 20.03 IQ points over the 24-yr period, making 8.34 IQ points per decade….”

lynn and hampson conclude:

“The conclusion of the Japanese studies is as follows. Two studies of the early post World War II period show substantial IQ gains of 9.9 and 11.4 IQ points per decade. Three studies of a longer period from approx. 1950-1975 show lower IQ gains of 9.1, 8.3 and 5.7 IQ points per decade, giving an average gain of 7.7 IQ points per decade. Since the early part of this period was characterized by a greater rate of gain, it appears that since around 1960 the IQ gains in Japan have decelerated to approx. 5 IQ points per decade….

“It is not particularly surprising that the Japanese gains should have been the greatest of the three countries. Japan was a relatively underdeveloped country in the 1930s with a per capita income about one eighth of that of the U.S.A.”

but the country was probably relatively underdeveloped because the japanese had a lower average iq at the time, and it’s since increased phenomenally … due to the sharp and rapid decline in inbreeding in japan? and so has their economic success obviously.

i’d be curious to know two things:

– why did the japanese quit marrying their cousins? was there some official policy out there discouraging it — as part of their general modernization, “be more like the westerners” move? did the people just naturally adopt it as part of that westernization package? was it connected to christianity in japan? (japanese catholics historically had lower first cousin marriage rates than other religious groups — i’ll get to this in my upcoming post on japanese cousin marriage — the one that i was working on yesterday!). was it related to industrialization and urbanization? all of the above? none of the above?

– has something similar happened in china and/or korea (or elsewhere for that matter — i mean in modern times)? the cousin marriage rates for china are reportedly very low — today — but i’m pretty sure they were much higher in the past — even the recent past (see mating patterns in asia series below ↓ in the left-hand column), but i don’t have as good data for china as what i’ve presented here for japan. but inquiring minds want to know!

see also: Reversal of Fortune

previously: historic mating patterns in japan

(note: comments do not require an email. cool japanese people!)


linkfest – 10/29/12

a day late. sorry! sometimes sh*t just happens. (~_^)

Ethnic disparities in breast cancer survival remain despite socioeconomic similarities“All-cause survival was worse for African-Americans and better for Latinas and Asian-Americans compared with non-Latina whites after adjusting for age, study and tumor characteristics. When the researchers additionally adjusted for treatment and reproductive and lifestyle factors, they found that African-Americans had similar survival rates to non-Latina whites, but the survival rates of Latinas and Asian-Americans remained better.”

Diversity may be fatal, says new government health study“[P]eople suffer less cancer and heart disease when they live among their racial or ethnic peers.” – via mangan’s.

If Smart Is the Norm, Stupidity Gets More Interesting“Human intelligence varies.” – you don’t say?! (it’s in the nyt, believe it or not!)

Do Intelligent People Drink More Alcohol? – yes. yes, we do. (*hic*)

A detour through Europe?“The lithic technology of southwestern France (c. 22,000-17,000 BP) strangely resembles that of the first paleo-Amerindians (c. 12,000). Some people speculate that early Europeans reached North America by crossing the Atlantic. The truth is even more incredible. Early Europeans spread eastward and became the ancestors not only of the Amerindians but also of East Asians.” – from peter frost.

Secular change in the B/W IQ gap (in the US) – from chuck. see also steve sailer.

Penis size and infant mortality – from the autistic nerdling epigone.

Placebo effect may be ‘down to genes’“Those with a particular version of the COMT gene saw an improvement in their health after placebo acupuncture.”

The Evolution of Female Bisexuality – from jayman.

Pitch Perfect: It’s All In The Genes” – maybe/prolly. see also you, too, can have perfect pitch!

Hispanic Bio-Diversity: A Primer – from nelson.

Smoking causes asthma in second generation offspring – epigenetic effects in rats.

Epigenetic inheritance is a wild goose chase“Epigenetics matters, but not between generations.”

Appearance-based politics: Sex-typed facial cues communicate political party affiliation – republican women more feminine looking than democrat women.

Men better multi-taskers than women: study

Who Would Win in a Fight: a Modern Human or a Neanderthal?“We beat them at evolution. But what about fisticuffs?”

The Island Where People Forget to Die“[P]eople on Ikaria were, in fact, reaching the age of 90 at two and a half times the rate Americans do. (Ikarian men in particular are nearly four times as likely as their American counterparts to reach 90, often in better health.) But more than that, they were also living about 8 to 10 years longer before succumbing to cancers and cardiovascular disease, and they suffered less depression and about a quarter the rate of dementia.”

bonus: More Intelligent Birds (Like More Intelligent Humans) Have Evolutionarily Novel Preferences

bonus bonus: Electric Bugs: New Microbe Forms Living, Deep-Sea Power Cables

bonus bonus bonus: New study sheds light on how and when vision evolved“Opsins, the light-sensitive proteins key to vision, may have evolved earlier and undergone fewer genetic changes than previously believed….”

(note: comments do not require an email. intelligent bird.)

linkfest – 04/15/12

Can You Predict a Monkey’s Social Status by Looking at Its Genes?“Does one’s social stature change how one’s genes are expressed. Yes, concludes a new study that used differences in gene expression to identify a monkey’s social status with around 80 percent accuracy.”

Disliking races may be a personality trait“[I]f a person dislikes one group, he tends to have comparatively cool feelings for all groups, even his own.” – from the inductivist.

More thoughts on genetic load – from greg cochran.

Listen up, parents: For toddlers (and chimps), the majority rules“2-year-olds and chimpanzees are more likely to copy actions when they see them repeated by three of their peers than if they see the same action done by one peer three times.”

Dark coloration and male aggressiveness: Is there a link? – from peter frost.

A gaping hole in the Master’s evolutionary theory – chuck @the occidentalist presents evidence that he says suggests that “there are, at most, small genetic differences, with respect to intelligence, between Black and White adults born, respectively, in Africa and in Europe.”

The Downside of Higher IQ – from dennis mangan, esq.

Genetic Variant Influences Brain Size, Intelligence – from parapundit.

What’s in a surname? New study explores what the evolution of names reveals about China“‘When it comes to surnames the Chinese people are unique. 1.28 billion people share 7,327surnames. In fact the 100 most common names account for 85% of the population,’ said Dr Chen. ‘This means Chinese surnames include more cultural and genetic information than in most other countries….’ The team found the highest levels of surname diversity at the Yangtze River basin, particularly around the middle and lower reaches of the river. The team believes this is due to multiple large migrations throughout Chinese history.”

Fire-free land use in pre-1492 Amazonian savannas“Our combined pollen, phytolith, and charcoal analyses reveal unexpectedly low levels of biomass burning associated with pre-A.D. 1492 savanna raised-field agriculture and a sharp increase in fires following the arrival of Europeans.”

More than 20% of Irish children ‘hear voices’“More than one in five Irish children between 11 and 13 have reported hearing voices, a sign some experts believe is a risk factor in mental illness.”

Study Finds Significant Skull Differences Between Closely Linked Groups“The researchers looked at the skulls of 27 women and 28 men who died in Lisbon, Portugal, between 1880 and 1975. They also evaluated the skulls of 40 women and 39 men who died between 1895 and 1903 in the rural area of Coimbra, just over 120 miles north of Lisbon. The researchers found significant variation between female skulls from Lisbon and those from Coimbra.”

bonus: “Race-Baiting” … and Its Discontents – good one from richard spencer.

bonus bonus: On Dinosaur Time“Less time separates us from Tyrannosaurus rex than separated T. rex from Stegosaurus.” – cool!

bonus bonus bonus: Water, water everywhere – but is it essential to life?“New research by scientists at the University of Bristol has challenged one of the key beliefs in chemistry: that proteins are dependent on water to survive and function.”

(note: comments do not require an email. xkcd’s lakes and oceans.)