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Society Japanese north–south gradient in IQ predicts differences in stature, skin color, income, and homicide rate

Maciamo

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17 Jul 2002
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I found this 11-year-old Japanese study on the correlation between IQ, body height and lower homicide rate within Japan.

Japanese north–south gradient in IQ predicts differences in stature, skin color, income, and homicide rate

Highlights
  • In Japan, there is IQ gradient from north to south.
  • Stature and average income cline is also from north to south.
  • Homicide rates increase from north to south.
  • Fertility rates and suicide rates decrease from north to south.
  • Infant mortality is not correlated with latitude.
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The study found that the prefectures with the highest average IQ (Toyama, Fukui, Ishikawa Yamagata and Akita) generally also had some of the highest body heights and the lowest homicide rates. Conversely those with the lowest IQ (Okinawa and Kochi, as well as Osaka for IQ and homicide rate but not for height) had the shortest stature and the highest murder rate.

There have been many other studies in other countries correlating IQ and body height. This is usually explained by the fact that people from higher socio-economic background tend to grow up with a better diet, which promotes a healthy development of both the body and the brain.

It may be a coincidence but the prefectures of Toyama Ishikawa and Akita also ranked first in Japan for the average size of homes. On the other hand, Toyama has long been one of the richest region of Japan. The Maeda clan based in Kanazawa reputedly had the highest income of any daimyo clan.

They have also been many studies showing that more intelligent people are less likely to commit murder. This seems to hold true even in a very homogeneous society like Japan.
 
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Interesting. Are there any comparative studies in other countries?
 
Slightly related, although not based on IQ but on education:

According to the first nationwide study of its kind in Japan, individuals with a low educational background face a higher risk of early death compared to those who attained a university-level education. The study revealed that premature death rates were 40% higher among individuals who had no education beyond junior high school and approximately 20% higher among senior high school graduates. Previous research in Japan has also indicated that people with fewer formal education opportunities tend to smoke more and undergo cancer tests less frequently. These health-related behaviours are believed to contribute to the observed differences in mortality rates.


Researchers analyzed statistics on about 8 million people between the ages of 30 and 79 by linking the national population census and death records from the government's vital statistics. They estimated age-adjusted death rates, which are corrected for population distribution bias, for three categories: graduates of university or higher education, high school graduates and junior high school graduates. By cause-specific death rates, differences between graduates of university or higher education and those with less education were particularly large for cerebral vascular diseases, lung cancer, ischemic heart diseases and gastric cancer, according to the study. The research team said educational inequalities in mortality tend to be smaller than in the United States and Europe. In the United States, for example, male death rates from cancer among high school graduates are about 2.3 times of those among graduates of university and higher education, compared with about 1.1 times in Japan.


 
I notice that I forgot to reply to this thread. The correlation between IQ/intelligence and body height has been well established by numerous independent studies in many countries. That's nothing new. There is even a whole article about it on Wikipedia with all the sources.

research on the subject has shown that there is a small but statistically significant positive correlation between height and intelligence after controlling for socioeconomic class and parental education.

An individual's taller stature has been attributed to higher economic status, which often translates to a higher quality of nutrition. This correlation, however, can be inverted to characterize one's socioeconomic status as a consequence of stature, where shorter stature can attract discrimination that affects many factors, among them employment, and treatment by educators.[2] One such theory argues that since height strongly correlates with white and gray matter volume, it may act as a biomarker for cerebral development which itself mediates intelligence.[3] Competing explanations include that certain genetic factors may influence both height and intelligence,[4][5] or that both height and intelligence may be affected in similar ways by adverse environmental exposures during development. Measurements of the total surface area and mean thickness of the cortical grey matter using a magnetic resonance imaging (MRI) revealed that the height of individuals had a positive correlation with the total cortical surface area. This supports the idea that genes that influence height also influence total surface area of the brain, which in turn influences intelligence, resulting in the correlation.[6]

Likewise there has also been plenty of studies confirming that a correlation between lower intelligence and a higher propensity to commit violent crimes. Hence lower IQ correlates with higher homicide rates. Here are a few examples.

Cambridge University Press: Association between intelligence quotient and violence perpetration in the English general population

Results
There were 6872 participants aged ⩾16 years included in this study. The prevalence of violence perpetration decreased linearly with increasing IQ [16.3% (IQ 70–79) v. 2.9% (IQ 120–129)]. After adjusting for demographic and behavioral factors, childhood adversity, and psychiatric morbidity, compared with those with IQ 120–129, IQ scores of 110–119, 100–109, 90–99, 80–89, and 70–79 were associated with 1.07 [95% confidence interval (CI) 0.63–1.84], 1.90 (95% CI 1.12–3.22), 1.80 (95% CI 1.05–3.13), 2.36 (95% CI 1.32–4.22), and 2.25 (95% CI 1.26–4.01) times higher odds for violence perpetration, respectively.
Conclusions
Lower IQ was associated with violence perpetration in the UK general population.

Intelligence and criminal behavior in a total birth cohort: An examination of functional form, dimensions of intelligence, and the nature of offending

Highlights
  • Examined a total birth cohort of Finnish males born in 1987
  • Lower levels of intelligence are associated with greater levels of offending.
  • The IQ-offending association is mostly linear.
  • Pattern is consistent across multiple measures of intelligence and offending.

The relationship between lower intelligence, crime and custodial outcomes: a brief literary review of a vulnerable group

there is a wider consensus that individuals with below average functioning (in particular cognitive impairments) are disproportionately represented within the prison population.

there is evidence that lower IQ is associated with delinquency which can naturally set younger individuals on a different life course (Lynam, Moffitt, & Stouthamer-Loeber, Citation1993). At the very least, it is noteworthy that a significant amount of literature has found delinquent boys have lower levels of functioning intelligence (Culberton, Ferel, & Gabby, Citation1989; Moffitt, Gabrielli, & Mednick, Citation1981).

A body of research has also demonstrated that individuals with lower IQ levels are more likely to commit more severe (and violent) offences (Crocker & Hodgins, Citation1997; Hayes & McIIwain, Citation1988; Martell, Citation1991). Additionally, evidence exists which demonstrates that criminal offenders have lower IQ's than non-offenders (Feldman, Citation1993; Herrnstein & Murray, Citation1994; Wilson & Herrnstein, Citation1985). In fact, a large body of early research found clear links between lower intelligence and criminal behaviour (Hischi & Hindelang, Citation1977; McGarvey, Gabrielli, Bentler, & Mednick, Citation1981; Culberton et al., Citation1989). This may be because of deficits in the "executive functions" of the brain, which are thought to be associated with abstract reasoning and concept formation, as well as sustaining attention and concentration (Moffitt, Citation1990). Alternatively, it may be expected that individuals with lower intelligence are more vulnerable to engage in reactive-based offences, as they have a reduced capacity to comprehend as well as communicate effectively, particularly to possible interpersonal threats (Welte & Wieczorek, Citation1999).

So there is nothing revolutionary or controversial in the study by Kenya Kura that I posted in the OP. That's just an application of correlations that were already well known and studied to Japanese society.
 
I apologize if I'm misrepresenting your words, but before you get "angry" at me, please revisit this thread:


(I used to go by the username "jt_", but I asked thomas to change it for me a while back as it overlapped with a user who I felt was an incredibly abusive and toxic presence here.)

In that thread I was comparing head sizes (from an anthropological point of view).

I never said that the Japanese were mentally and emotionally inferior to Westerners. I even explained (here and here) in that thread that intelligence was not necessarily related to brain size as we had to take into account neuron density. I did study neurology as part of my biomedical education, so I think I know a thing or two about the subject.

I also clearly stated that intelligence depended on education, "quality of pregnancy" (nutrition and health of the mother), quality of the environment during childhood, etc.

So all I see is that you are twisting my words and my intentions and trying to make me look bad.
 
@thomas -- Could I ask you to delete all my above comments?

As you know, I was in a bad place last night and nothing I wrote above reflects my actual feelings toward Maciamo.

@Maciamo -- I fully understand if you do not accept this apology, but I sincerely regret the gratuitous and hurtful words I directed at you yesterday.

I've been suffering from serious mental health issues lately and am often incapable of doing much but spouting vitriol -- alternately at others and at myself. I have been trying to stay off the internet for my own sake and for others, but sometimes I give in and the results are ugly.

I sincerely apologize and will do my best to ensure that it does not happen again.
 
@thomas -- Could I ask you to delete all my above comments?

As you know, I was in a bad place last night and nothing I wrote above reflects my actual feelings toward Maciamo.

@Maciamo -- I fully understand if you do not accept this apology, but I sincerely regret the gratuitous and hurtful words I directed at you yesterday.

I've been suffering from serious mental health issues lately and am often incapable of doing much but spouting vitriol -- alternately at others and at myself. I have been trying to stay off the internet for my own sake and for others, but sometimes I give in and the results are ugly.

I sincerely apologize and will do my best to ensure that it does not happen again.
I am sorry to hear about your mental health issues. I accept your apology.
 
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