A rose isn't just a rose — when its aim is to push product. According to a study by the Smell & Taste Treatment and Research Foundation in Chicago, scent can mean the difference between a browser and a buyer. When asked to rate two identical pairs of Nike sneakers--one showcased in an unscented room and one in a room that had been sprayed with floral scent — 84 percent of study participants rated the sneakers in the scented room more highly. They even indicated that they would be willing to pay $10 more for the fragrantly presented treads.

Odors alter brain wave activity and produce emotional responses that can be persuasive marketing tools. Peppermint is known to stimulate, lavender to relax, and citrus to uplift, for instance. Sarah Harrop, director of The Aroma Company in the U.K., says scents can do more than put shoppers in the mood to buy; they can increase brand value by creating a more pleasant environment. Her company, for instance, injects the subtle scent of new-mown grass into passenger lounges at British Airways terminals so as to "bring the outside inside to jaded passengers who move from office to plane to office."

Color also influences consumer behavior. Many fast-food restaurants use bright colors such as orange, red, and pink because they are known to cause excitement. As a result, consumers eat and vacate tables more quickly. Other retailers use softer tones such as blue in order to relax shoppers and influence them to browse and shop a little longer.