When the economy hit the skids a few years ago, we responded with tactics that have gotten us through previous recessions: We stopped eating out and traveling as much, curbed our discretionary spending and chose generic items for basics like groceries. But then something strange happened: We began to prefer many of those store brands. Increasingly, we’re willing to pay even more for them. What’s going on here? According to the Wall Street Journal, stores have raised the prices of private-label nonperishable food by 5.3%, compared to a 1.9% increase for goods made by national brands. Store-brand versions of perishable...