I hope this need for a citation comes from genuine curiosity and not some misguided ideological want to uphold the notion of equality in intelligence. It just

I hope this need for a citation comes from genuine curiosity and not some misguided ideological want to uphold the notion of equality in intelligence. It just doesn't make sense given a more macroscopic view of things. If inheritance obviously controls the difference in intelligence between the human brain and the dog brain, or the cat brain, or the monkey brain, what black magic makes it so that among humans themselves inheritance controls very little of intelligence? The 70% - 80% statistic seems like a ballpark estimate he pulled out of a anecdotal conclusion based off of a broad spectrum knowledge of the related scientific research. You likely aren't going to find a citation that proves this claim definitively. It does not mean that his point is incredulous nor does it mean that his point isn't part of common sense. His point makes sense. It makes a lot of sense. The same sense as the fact that the covid vaccine protects against the virus even though for the longest time it was NEVER FDA approved (aka no strong citations). The conclusion was obvious despite not meeting the stringent verification of the FDA and many people were able to arrive at this conclusion without the science. Yet many people refused to believe the efficacy of the vaccine due to their political ideology. I believe there's a similar biased attitude coming from the far left side of thinking. The unwillingness to see that the science and common sense points to an inescapable conclusion. There is no unseen magical force that makes all races, all genders and all peoples equal. There are differences, and the differences are biological and obvious. Like literally genes control how ugly and how tall you are but not intelligence at all? By some crazy magic intelligence is the one thing that isn't at all influenced that much by genetics? Seriously, which viewpoint is more realistic here? Seriously the same ultra left people who were calling out the anti-vacc people as stupid and unintelligent for refusing the vaccine are unable to see the exact same kind of ideological stupidity within themselves.