True enough – and yes, I should have said lactase occurs in a large population rather than proportion. I wasn’t arguing that we’ve been changing dramatically, though, but that there has been lots of time for that to happen, which is why I mentioned dogs too.
That suggests to me that we’re not actually tuned up to a Middle Palaeolithic world and failing to move on, but rather to a much more recent one, and if we haven’t changed much it’s more likely because there hasn’t actually been much pressure for adjustment. So saying our brain thinks it’s still 50,000 years ago greatly exaggerates how out-of-date it is.
Maybe that’s me pedantically arguing against a rhetorical fluorish in this case, but I think it’s an idea taken seriously, so I thought I might say something.
