"The Mismeasure of Man" is mostly only good for showing how political correctness messes up people's ability to think.
In cases of this type, it's an error akin to relativism. "Suzy is wrong, therefore I should kill her" does a lot of damage, so people start thinking "Nobody is ever wrong". "Members of outgroup X have negative traits, therefore they're subhuman" does a lot of damage, so people start thinking "Members of outgroup X can't have negative traits". It's best to stay on the object level and prove "This group's average brain volume is 95% of that group's" rather than saying "political correctness", for th...
Please remember to have no heroes or villains, but this just looks plain bad to be honest. I'm lowering my estimation of the quality of Stephen J. Gould's work in this area.
USA today:
Haha. Humans.
The paper itself: