I mean there were actually two “intelligence” explosions for humans, once as Homo Erectus like 2 million years ago. Then again as Homo Heidelbergensis ~ 700,000 years ago. So way before dogs.
As in we have evidence of H. Erectus with brains as big or even bigger than ours. And by the time of H. Heidelbergensis our brains stabilised around the size they are today.
Willie will forever be my GOAT.