[Photo Courtesy Kimberly Vardeman]

By Terry Kosdrosky

Aradhna Krishna


ANN ARBOR, Mich. — Looking at a picture of a hot chocolate chip cookie fresh from the oven, you can almost smell it.

According to new research from U-M Ross Professor Aradhna Krishna, with that picture and some suggestions, it turns out you can — at least in your mind. And that imagined smell can trigger an increased desire for the food. The research has important implications for the multi-billion dollar food advertising industry.

Krishna, the Dwight F. Benton Professor of Marketing, pioneered the field of sensory marketing, which blends the studies of marketing, psychology and neuroscience.

“Scents are used often for personal hygiene products like perfume or deodorant, but we find that food marketers are missing out,” she says. “Even if you can’t embed the smell of a food in the ad, like scent marketers do with a scratch-and-sniff, merely asking consumers to imagine what the food smells like, along with a strong visual, can be very effective.”

Krishna is the lead author on the paper, “Smellizing Cookies and Salivating: A Focus on Olfactory Imagery,” which was co-written with Eda Sayin, a doctoral student at Koc University in Istanbul who spent a year in Krishna’s Sensory Marketing Laboratory, and Maureen Morrin of Temple University. The paper appears in the Journal of Consumer Research.

The authors performed four controlled experiments to see if and how ads could trigger smell memories, a process they call “smellizing.”

Two experiments focused on the interplay between visual and olfactory image processing. They found that test subjects who were prompted to imagine the smell of a cookie while looking at a picture of the treat salivated more heavily than those who were not prompted. The tests also showed that the visual image was necessary to induce the response.

“We decided to measure physiological responses, because self-reporting can be fraught with credibility issues,” Krishna says.

Krishna and her co-authors also measured the effect of these types of ads on consumption. Instead of measuring salivation, test subjects were given cookies after the advertising portion and asked to evaluate them (which provided a cover story for the blind test). They were told to put any unfinished cookies back into the bag provided and were asked questions about their hunger level and mood.
Those prompted to imagine the scent of cookies consumed more only when the ad also had a picture. They also found that actual scents in a food ad enhance responses whether or not they’re accompanied by a picture.

“Smell is a powerful sense that triggers images and memories,” Krishna says. “But it’s not always possible to present your scent to consumers, especially in advertising. We show a way you can get similar benefits with an imagined smell, but you have to accompany that with a strong visual image. So this would be effective in print advertising or television, but not so much in radio or a computer banner ad.”

Overall, Krishna says her research shows that food advertisers can make better use of real and imagined scents.