Average IQ by Country
These controversial studies argue that the IQ is associated with per capita income and economic indices. Although high income countries are among the top performers, much lower income countries such as China and Mongolia are also among the top performers.
Another factor could be education expenditures. We almost always consider high education expenditures countries have an intelligent population. But we found again countries with medium to low educational expenditures in the top of the ranking.
Some researchers consider that the climate could be an explanation. In general, a hot climate is considered a disadvantage for the development of intelligence because of the high physical energy demand and the resulting stress. We can again argue that it can’t be generalized to the ranking.