That pre-colonial farming in Africa required relatively few hours of labor is well-known. I don't have a great link but "female farming system" is a term to sta

That pre-colonial farming in Africa required relatively few hours of labor is well-known. I don't have a great link but "female farming system" is a term to start from (seriously, I didn't make it up). The reason, if I understand right, was that the limit on human population was set by disease not labor. In northern climates (where fewer of the diseases we evolved with thrive) instead the marginal farmer was on some stony hillside from which maximum effort could only just produce enough calories for winter. I'm less sure whether such societies were involved in more warfare, it's possible (the men had time on their hands & soccer hadn't been invented...) but I don't know the data. I also don't know how to extrapolate this to the future of our society.