There's plenty of evidence for those who want to learn instead of split hairs.
I'd start with a search on "general intelligence factor".
Is this the 'g' factor? What studies do you find compelling? Any done after the early 1900s or on adults?
So you've got nothing to offer?
Are you really lmgtfy-ing on Hacker News?
Is this the 'g' factor? What studies do you find compelling? Any done after the early 1900s or on adults?