Smells can evoke memories. The scent of a certain perfume can prompt visions of a first love, perhaps. Smells can provide comfort, as any practitioner of aromatherapy will tell you. And smells can encourage you to buy something – which is why clever realtors often bake cookies in homes they're trying to sell.

Marketing experts at Washington State University (WSU) and Switzerland's University of St. Gallen wanted to find out which scents are most effective at getting consumers into a “shopping state of mind.” In the Journal of Retailing, they report that simple scents are better.

They exposed hundreds of Swiss shoppers to a simple orange scent and to the more complex aroma of orange-basil and green tea. A look at the cash register receipts revealed a bump in sales when it was just the scent of orange in the air.

An uncomplicated scent is also a benefit for doing cognitive tasks. WSU researchers exposed students to different scent conditions as they worked on word problems. The students solved more problems in less time when the simple scent was in the air, than they did when there was just the complex scent or none at all.

Eric Spangenberg, dean of WSU's College of Business, says a simple scent is easier for the brain to process, so the mind can better focus on thinking, working…or shopping.