Shopping Lists as an External Memory Aid for Grocery Shopping: Influences on List Writing and List Fulfillment

We explore the use of shopping lists as an external memory aid to consumers’ grocery shopping by examining the factors that influence the content ofconsumers’ shopping lists and the effectiveness of shopping lists as external memory aids. We analyze the shopping lists and actual purchase behavior of a panel of consumers during multiple grocery shopping trips conducted over a 2-month period. Our results indicate that consumers record on their lists approximately 40% of the items they ultimately purchase. Consistent with the external memory literature, we find that consumers write items on their shopping lists for which there are financial incentives to remember ( e g , manufacturers’ coupons), need-based incentives to remember (e.g., the product is frequently used), and schema-based advantages to remember (e.g,, items purchased on fill-in trips). More than 80% of the items written on the shopping list were actually purchased. Thus, shopping lists appear to be an effective external memory storage device for grocery purchasing. We discuss these and other findings in relation to the literatures on external memory and planned versus unplanned purchasing.