If that were so then why have stupid people survived all these millenia? According to your method of "natural selection" the stupids should have been weeded out thousands of years ago.
I wish that were true. At one time it was ‘in check’. Humans are hardy species, even fool-hardy. Say, for example, that 15% of the 1939 US population fell into that category (a reasonable number).
With decades of social liberal policies, based on lower-tier population propagation rates (US Nat’l rate is .9...we’ll use 2x that for this example, equivalent to the Phillipines), that 19 million would become +112 Million unto itself in 2014, ironically supporting the Bama ratio of voters.
And GROWING...