Somewhere between the bananas and the potato chips, I stop to reflect on my meander through the supermarket. My path seems to alternate between the purposeful and recreational. Sometimes I intensely pursue items on my grocery list, like Frank Buck, the celebrated hunter, “bringing 'em back alive!' Other times, I leisurely cruise the aisles. Often I dawdle among the imported delicacies, like the $120 bottles of Croatian balsamic vinegar, to see how the other half eats. Why such a dichotomy of behaviors?

An article in the current Knowledge@Wharton summarizes a paper recently published by professors Peter Fader and Eric Breslow, and doctoral student Sam Hui, who set out to answer this question (”The Traveling Salesman Goes Grocery Shopping: The Systematic Inefficiencies of Grocery Paths“). The researchers visited stores and calculated the ”optimal paths“ among products, the most efficient routes necessary to acquire these items and then leave the store. They then studied how 1,000 shoppers adhered to these routes.

Even allowing for customers' lack of knowledge about the exact location of specific products, shoppers tended to spend more time in stores than efficient shopping required. And we're not just talking about small amounts: almost 70 percent of grocery shoppers' time was spent not buying things.

Ultimately, the research exposed shopper inefficiency, but it didn't explain it. Is it for fun? To acquire new knowledge? To sample the supermarket's ambience -- which, in the better stores like Whole Foods, is modeled on the country store? Nor is it not clear, for example, which type of shopper is more ”profitable.“

The Wharton research provides useful empirical descriptions of shoppers' behavior. For example, most shoppers hover on the perimeter of a store, darting into the aisles to make purchases, rather than cruising up and down the aisles, as is commonly the case portrayed in the media and advertisements. (Forget meeting Mr. or Ms. Right in front of the spice rack in back. Try the fried chicken on the hot table up front.) This is prime display space and a good place to sell convenience foods. Common sense, maybe, but now it has scientific validation. John Sherry's ServiceScapes, reviewed on this blog, is another good source of empirical observations, with theory, pertaining to the shopping experience.

The rewards will be high for those who can explain not just how shoppers act as they do, but why, and how they can be directed. Herb Sorensen, whose shopping-research company provides the RFID-based PathTracker technology used in the Wharton research (watch out, Paco Underhill!), observes, ”There will be a huge growth in the use of in-store media to try to influence the way shoppers navigate a store and what they buy: $300 billion of advertising money will move into the retail space in the next five years.“

Path analysis as used by the Wharton researchers is a commercial subset of wayfinding an evolving methodology with roots in sailing, architecture, landscape architecture, and environmental design. Wayfinding is a comprehensive means for understanding and aiding human navigation in complex environments, and not just in the material world. In future entries, I'll get more deeply into the practice of wayfinding with help from experts (like Romedi Passini, co-author with the late Paul Arthur of the classic Wayfinding). Feel free to write with inquiries in the meantime.