The following folktale from the Hausa of present-day Nigeria explains how old customs can be abandoned once they are called into question.

A certain woman had two daughters. One was married to a man who lived in a town where no one was allowed to go to sleep, the other to one in a town where no one might spit.

One day the woman cooked a dish of sweetmeats to take to the daughter who lived in the town where no one was allowed to go to sleep. As soon as the dish was ready she started off and, when she arrived, all the household said to her, "Welcome, welcome!" Food was prepared for her, for the son-in-law said, "See, my mother-in-law has come."

But the daughter said, "O parent, no one may sleep here. Do not eat too much lest...