It's quite politically incorrect to discuss, but there is a great book called "IQ and the Wealth of Nations" that was published in about 2006.
The author's thesis was that average IQ of national populations was highly correlated with GDP. Successful countries had smarter people. (Only a few oil-rich countries fell outside the curve).
Congo (Dem. Repub. of.) has an average IQ of 64.
Here is the definition of Mild Retardation from the Medical Dictionary:
Mental retardation occurs in 2.5-3% of the general population. About 6-7.5 million mentally retarded individuals live in the United States alone. Mental retardation begins in childhood or adolescence before the age of 18. In most cases, it persists throughout adulthood. A diagnosis of mental retardation is made if an individual has an intellectual functioning level well below average and significant limitations in two or more adaptive skill areas. Intellectual functioning level is defined by standardized tests that measure the ability to reason in terms of mental age (intelligence quotient or IQ). Mental retardation is defined as IQ score below 70-75. Adaptive skills are the skills needed for daily life. Such skills include the ability to produce and understand language (communication); home-living skills; use of community resources; health, safety, leisure, self-care, and social skills; self-direction; functional academic skills (reading, writing, and arithmetic); and work skills.I will submit that whether the country is nominally capitalist or communist it's probably not going to make that much difference to how things work out there.
The issue is much more about the nature of the people who live their then about the form of government.
This is a problem with "magic dirt" conservatives. They seem to think if you just apply the Bill of Rights to some dramatically different group then the Founders and their progeny that you will get an instant functional "proposition nation". A Somali with a tendency to violence, a culture of tribalism, the traditions of clitorectomy and honor killing, and an IQ of 70 will become a valued member of society once transplanted to Minneapolis.
We actually have the existence proof that this is false at this point.
