Since around 1975, average IQ scores have been falling. Some have attributed this to the evolutionary effect of smarter women tending to have fewer children. New evidence suggests this may be because people live longer, and certain types of intelligence falter with advanced age.

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Since around 1975, average IQ scores have been falling. Some have attributed this to the evolutionary effect of smarter women tending to have fewer children. New evidence suggests this may be because people live longer, and certain types of intelligence falter with advanced age.