Once, twice, six times a grocery shopper. In the first test of detailed consumer-buying habits by categories at more than one chain store selling groceries, a team of business school researchers found that shoppers weren’t monogamist or bigamist but rather polygamist in their choice of outlets. In fact, it turns out that grocery categories such as dessert toppings, motor oil, candles and refrigerated ethnic foods were some of the leading products that lure customers to separate stores. Source 4e.