@NeurotrashWarrior
IQ tests have been shown to only test a narrow field of intelligence. And as a standardised test, likely to include more aspects of problem solving that, due to gendered nature of educational toys, peer pressure interests etc, more men may have had experience with, purely as a result of how stereotypes play out in education.
Boys play tends to fine-tune the abilities of three-dimensional mental rotation, to give one example. Traditional boys' games do that, computer games do that. So there's quite a bit of practice which was invisible until people thought about it.
One study had girls play a computer game aimed at improving those scores and just a week playing that game raised the girls' scores on the three-dimensional mental rotation.
And yes, IQ tests are narrow. They were created to find out which children can manage normal schooling, initially (by Binet), and later they have been used for various purposes, many focusing on those who score in the lower tail.
One problem with crude comparisons of the test results across countries is that they are used for different reasons in different places, and the people selecting themselves for the test (when they do select) are not necessarily similar groups in all countries.
IQ tests do not measure creativity or memory or some other similar aspects of intelligence.
On the greater male variance in test-taking: This, too, seems not to necessarily stay constant. Some US tests show the results of aptitude tests become more similar in the distributions by male and female test-takers over time.
I am also interested in how guessing affects the final distributions in various test, because men and boys are more likely to guess than girls and women who are more likely to leave the answer blank. Depending on how the tests are marked different risk-taking could explain some aspect of greater male variability..