[XorNot]

A hunter gatherer society would be the exact opposite of highly specialised ("doing what you're best at").

It has little margin for loss of function, so a poor performer is better and more likely to survive then losing the performance of the function entirely.

[nullsense]

I'm pretty sure what they meant was "if you need to go and hunt and kill your food, then the physically stronger members of the group have to go and do that, and that means someone has to stay and look after the kids and the members of the group who can produce food for the infants likely fit that bill"