Hello ! I'm only 39 minutes in, but I wanted to say that, regarding the g-factor being largely genetic, it would be important to consider to which extent gene expression due to lifestyle or traumas or whatever life circumstance would affect or not the g-factor. I'm not drawing any sorts of conclusions, just raising a point I deem worth investigating.,(reply>), Hello again, I just reached the 50 minute mark and Richard Haier addresses my very point 👍