As Mr. Giffen suggested more than 100 years ago, goods whose price and demand move in the same direction are most likely to be essential products such as food on which households spend a large part of their incomes. Wheat flour and rice fit the bill in central China. When the price of the good falls, the household in effect has become richer, with more income to spend. But rather than buy more rice at the cheaper price, the household might instead choose to spend its extra income on more expensive and previously unattainable items like meat.