One assumption is that infant and child mortality was so prevalent, that parents must have steeled themselves against the loss, by not caring so much. Then you factor in the fostering system, plus many incidents where infants were babysat by toddlers, or where children were left alone so the parents could work. What this doesn't take into account is that both parents *had* to work, and hanging a swaddled baby in the tree or on the wall was actually much safer than leaving and infant in a cradle on the floor to be mauled by a pig (which happened).