With my own offspring I got a useful insight into history and archaeology: never underestimate what very small children can accomplish. At about 3 my younger daughter only had to be shown when a given vegetable or fruit was ready to be picked and she could do it accurately, if slowly, at a Pick Your Own farm; even maize, which I find difficult to judge. In a hunter-gatherer society she would already have been a productive member of the group. Very small children will pick stones from a field for much longer periods of time than older children have the patience to do, and the same for a lot of tedious jobs. The insight was, very small children were productive workers; the slightly cynical thought derived was, to keep three and four years out of mischief, put them to work in the household. She was very good indeed at things like podding peas and polishing.