if he's just speculating with no evidence whatsoever, as he seems to be, then I for one am prepared to fervently disbelieve.

Yeah, and that would be pretty simple to test: find a society where people take on "real life" responsibilities in their teens -- or hell, just round up a bunch of teenage runaways, who've had to deal with life hard and fast, like the "good old days" -- and see what their brains are like. I mean, besides tasty. But all brains are tasty, so that's not really a way to distinguish them.