The journal article is here.
There is a significant gap in intelligence in Japan that correlates almost perfectly with latitude and even skin color.
The North-South intelligence gap in Japan is 11 points – 107 IQ in the north and 96 IQ in Okinawa. In addition, Japanese get taller as you go towards the north.
In Japan, lighter skin has a .42 correlation with elevated IQ. In other words, in Japan, the lighter the skin, the higher the IQ.
There is a remarkable correlation between IQ and homicide in Japan that is much greater than the IQ-skin color correlation.
In Japan, the higher the IQ, the lower the homicide rate – the correlation is stunningly high at .079 correlation.
However, there is downside to living in the north of Japan where folks are much more intelligent and vastly less homicidal. Weaker sunlight in the north makes people depressed and increases suicide rates.Apparently rates of depression and suicide rates increase as you go north in Japan.
Higher IQ is probably not more likely to make on depressed or suicidal, though this is an open question. Surely lighter skin is not more likely to make one depressed or suicidal as there is not even a good hypothesis there – why would having lighter skin be more depressing or make you want to kill yourself? It makes no sense.
Instead the correlation is simply due to the obvious – the weather. It is well known that the weaker the sunlight is, the more people get depressed, drink alcohol and commit suicide. Scandinavian countries had high suicide rates under all sorts of economic systems, and Scandinavians do not commit any more suicide than others living in the far north such as Greenlanders, Eskimos and Whites living in the Yukon or Alaska. In addition, Siberians have always had high suicide rates. High rates of alcohol are also found all across the north in these very same areas. When the sun doesn’t come out at all for half the year, that is extremely depressing!
The highest IQ areas in Japan have the lowest homicide rates, and the lowest IQ areas have the highest homicide rates. The relationship between IQ and homicide in Japan is linear and almost perfect. The dumber people are, the more they kill other people. The smarter people are, the less they kill other humans.
In addition, there is an excellent relationship between IQ and income in Japan.
With every 1 IQ point rise, incomes increase by 2.5%. The smarter you are, the more money you make and the dumber you are, the less money you make. In capitalism, many poor or low income people may be poor or low income simply because they are not very intelligent and for no other reason. Societal oppression is not always to blame for poverty and low income in capitalism as capitalism is like a footrace with 1000 sprinters and no matter how hard anyone tries, 300 men will always come in 700th-100th. And that’s if everyone is trying their hardest and running as fast as they can. Poverty is an intrinsic aspect of capitalism. You can’t have capitalism without poverty. It’s baked right into the system.
The Yayoi were the more Neomongoloid types who moved into Japan 2,300 years ago from Korea. They then slowly conquered, killed, enslaved and frankly genocided the Australoid Jomon or Okinawan/Ainu types as they moved north.
The Neomongoloid Yayoi appear to have been were smarter and taller than the Australoid Jomon.
We know this because pure Neomongoloid Chinese Koreans consistently outscore the Neomongoloid/Australoid Japanese on IQ.