Shelving cheese near wine can nudge shoppers into impulsively buying a bottle of Bordeaux. And posting an attractive salesperson with a small selection of samples--five is often more effective than 50--seems to boost buying.
Some products have a lucrative rub-off effect. A supermarket-strategy firm found that shoppers who buy silver polish tend to spend more than $200 a trip. So even though it's a low-turnover product, shelving experts keep it around.
To capitalize on customers loyal to certain brands, supermarkets make sure that popular labels, such as Heinz ketchup and Cheerios, are easy to spot and positioned...