Belgian researchers report the enticing aroma of chocolate inspired bookstore shoppers to stick around longer, and boosted sales of certain genres.

Great news for independent booksellers striving to keep their shops profitable in an Amazon-dominated marketplace. Researchers in Belgium have discovered a simple, inexpensive way to keep customers in the store longer and, quite possibly, boost sales.

They report shoppers are more likely to engage in leisurely browsing—and ultimately purchase books in certain popular genres, including romance novels—if the store is infused with the scent of chocolate.

Writing in the Journal of Environmental Psychology, a research team led by Lieve Doucé of Hasselt University describes a 10-day experiment conducted in a general-interest bookstore in Belgium.

“Retailers can make use of pleasant ambient scents to improve the store environment, leading consumers to explore the store.”

For approximately half of its open-for-business hours (either morning or afternoon, depending upon the specific day), the scent of chocolate was dispersed into the store from two locations. The smell was subtle enough that it wasn’t immediately noticeable, but strong enough so that it could be instantly identified once it was pointed out.

Researchers tracked the actions of every fifth customer to enter the store—a total of 201 people. They report that when the scent was activated, shoppers showed a greater tendency to take their time, check out a variety of titles, and/or chat with an employee.

Specifically, “customers were 2.22 times more likely to closely examine multiple books when the chocolate scent was present in the store, compared with the control condition,” they write.

In addition, when the aroma was present, shoppers were less likely to search out one specific book and take it directly to the cash register. Something about the store’s environment made them want to hang out a bit longer than they perhaps had planned.

The researchers tracked sales of books in four popular genres. A panel of students had previously ranked two of them (food and drink and romance novels) as congruent with the smell of chocolate, and another two (history books and mysteries/crime thrillers) as particularly incongruent with that aroma. Altogether, 119 of the 201 tracked shoppers bought at least one book in one of those categories.

They report sales for books in the first category increased by an impressive 40 percent when the chocolate smell was in the air. Perhaps even more encouragingly, those in the second category also rose, by a more modest but still substantial 22 percent, over the hours when the store was scentless.

Interestingly, the customers were more likely to check out the crime thrillers and history volumes when the aroma was absent. The scent of chocolate apparently steered people away from those genres.

But after controlling for the gender of the observed shoppers, sales of those books increased anyway during the chocolate-scented hours, apparently because those who did peruse the mystery or history aisles were more likely to buy multiple volumes.

These results lead the authors to offer some practical advice: “Retailers can make use of pleasant ambient scents to improve the store environment, leading consumers to explore the store.” Ideally, they add, the scents should be congruent with the merchandise on sale—say, the salty smell of the sea for a surf shop.

It’s certainly worth a try for hard-pressed independent bookstores—or even for a certain struggling chain. Indeed, the customer-pleasing power of chocolate might even inspire thoughts of a merger. Who wouldn’t want to shop at Barnes and Nestlés?