"For example, at the level of a nation it's worth measuring mean IQ and being concerned about any persistant annual declines in IQ" Then the nation should filt

"For example, at the level of a nation it's worth measuring mean IQ and being concerned about any persistant annual declines in IQ" Then the nation should filter its immigrants by IQ and promote natality for the most smart stratum of its own people. As research using twins followed by 30 years in adoptive family claims majority of IQ is genetic.[1] [1] - https://www.sciencedirect.com/science/article/pii/S0160289621000635 https://www.sciencedirect.com/science/article/pii/S016028962...