—“Mean world IQ ≈ 86-87, about one standard deviation lower than in the developed OECD countries and China.”—
First, afaik, the OECD and China cause is (a) climate (b) neoteny, and (c) manorialism.
That also means:
1 – That’s the basal Eurasian IQ. we don’t know why the basal eurasian IQ is higher, and why the basal east asian IQ is higher than that. It appears purely to be the cause of neoteny on one hand an manorialism on the other.
2 – That the basal Eurasian IQ is in the ‘evil 80’s’ where most crime occurs. (Wonder why low trust societies in that range?)
3 – That the basal Eurasian IQ leaves a population HALF of whom can’t serve in a modern military because there is nothing that they can do that isn’t more costly, or dangerous to self others and mission than the value that they can provide.
4 – That the Pareto (power distribution (top 1%) is also shifted one standard deviation lower (from 135 to 120), the top 20% (113 to 98).
IQ AND CAPABILITY
50-69 — Mildly retarded
Educable, can learn to care for oneself, employable in routinized jobs but require supervision. Might live alone but do best in supervised settings. Immature but with adequate social adjustment, usually no obvious physical anomalies.
Moderate and mild retardation, contrary to the more severe forms, are typically not caused by brain damage but part of the normal variance of intelligence, and therefore largely genetic and inherited. This is important with regard to the question whether or not retarded persons should have children; for especially the moderate and mild forms of retardation, with which it is physically possible to have children, are the most likely to be inherited.
70-79 — Borderline retarded
Limited trainability. Have difficulty with everyday demands like using a phone book, reading bus or train schedules, banking, filling out forms, using appliances like a video recorder, microwave oven, or computer, et cetera, and therefore require assistance from relatives or social workers in the management of their affairs. Can be employed in simple tasks but require supervision.
80-89 — Below average
Above the threshold for normal independent functioning. Can perform explicit routinized hands-on tasks without supervision as long as there are no moments of choice and it is always clear what has to be done. Assembler, food service.
This is also the I.Q. range most associated with violence. Most violent crime is committed by males from this range. This does not imply that all males in this range are violent, nor that all violent males are in this range. But when the modal I.Q. of a group is in this range, one may expect trouble with with many male members of that group. When the modal I.Q. of a society or population is raised upward of this range, violence decreases as fewer males fall in this range then, given the shape of an even remotely normal distribution. When the modal I.Q. of a society is below this range to begin with though, raising it may increase violence. The causal mechanism behind the (statistical) relation between crime and below-average I.Q. is likely that lower I.Q. levels inherently tend to go with having less impulse control, being less able to delay gratification, being less able to comprehend moral principles like the Golden Rule, and being overstrained by the cognitive demands of society.
And, this is the range into which men of average or just above average intelligence sink when under the influence of alcohol; alcohol reduces I.Q. by up to about 25 points while drunk (own data), which explains why many drunk men are violent and aggressive (own hypothesis).
90-99 — Average
Able to learn a trade in a hands-on manner and perform tasks involving decisions. Craftsman, sales, police officer, clerk. Studies involving some theory are possible from this range upward.
100-109 — Average
Able to learn from written materials. Employable in senior positions.
110-119 — Above average
Able to learn in “college” format. Bachelor degrees. Manager, teacher, accountant. Just capable of taking high-range I.Q. tests.
120-129 — Above average
Capable of gathering and inferring own information. Master degrees. Attorney, chemist, executive. About 93 % of high-range test candidates score I.Q. 120 or higher.
130-139 — “Gifted”
May just be able to write a legible piece of text like an article or modest novel. Minor literary figures. Ph.D. in the “soft” sciences. In this range lies the mode of scores on high-range tests, and almost 80 % of high-range candidates score I.Q. 130 or higher. Regular psychology’s I.Q. tests should not be trusted beyond this range as their validity breaks down here, if such scores are given at all.
140-149 — Intelligent
Capable of rational communication and scientific work. From this range on, only specific high-range tests should be considered. Important scientific discoveries and advancement are possible from the upper part of this range on.
We do not know if intelligence from about this range on is simply the extreme end of a normal distribution centred at 100 and largely formed by heredity, or if high intelligence in some cases has other causes (non-inherited or non-genetic) which make it deviate from the normal curve centred at 100 and form a “bump” in the far right tail, similar to the bump in the retarded range (which has non-inherited and non-genetic causes). And since we possess no physical, absolute scale of intelligence, these questions are hitherto meaningless altogether.
About one in two high-range test candidates score I.Q. 140 or higher.