What's fascinating is that, after the commuters were subjected to the olfactory factor, they were much more likely to frequent, Dunkin' Donuts says, a Dunkin' Donuts store. Over the course of the campaign, more than 350,000 people "experienced" the ad, Cheil estimates -- and sales at Dunkin' establishments located near bus stops increased 29 percent. The sound-scent combination -- the synaesthetic approach to advertising -- seemed to be, in this case, effective.
So the use of scents makes ... well, you know. The power of smell when it comes to human cognitive connection is well documented; it's fitting and unsurprising that marketers would want to capitalize on that power when it comes to brand associations. The Dunkin' advertisers orchestrated their experiment to optimize immediacy; the point was to create a scenario in which commuters would hear Dunkin' Donuts, then smell Dunkin' Donuts, then see Dunkin' Donuts ... and then, you know, taste Dunkin' Donuts. After buying Dunkin' Donuts.
What's innovative in the Dunkin' approach is the precise orchestration of odors. Because smell-o-vision-style advertising, of course, is nothing new. Recall North Carolina's steak-smelling billboard, or the UK's scent-releasing bus stops, or the many odors of the Magic Kingdom, or city streets' infamous Subway Smell, or magazines' scented papers, which are themselves the olfactory offspring of the perfume-strip ads that have been around since the 80s. Traditionally, however -- to the extent that scent-based advertising is traditional -- smells have been used bluntly. Scent is notoriously indiscriminate: It reaches all those in its proximity, promiscuously.
Which means that, as an ad tactic, scent is particularly aggressive. It's the physicality of the thing, sure -- the fact that scent makes literal consumers of us -- but it's also the invasiveness. We advertisees have developed fairly sophisticated methods of avoiding ads as sensory intakes: we tune out unpleasant sounds with headphones, we avert our eyes from unpleasant images. Scent, however, is harder to ignore. And -- Proustian memory! -- it's also harder to forget. Dunkin' Donuts wasn't just advertising to people on those buses in Seoul; it was also imprinting itself into their lungs and onto their memories.
It was also, however, targeting its particular strain of ad aggression toward people who might actually appreciate it -- and at a time when those people might actually be primed to do the appreciating. Probably half the bus -- a conservative estimate, if my own caffeine cravings are any indication -- was already wanting coffee when the Dunkin' spot was presented. The radio ad and the olfactory ad simply worked in tandem to capitalize on those cravings. This was ad targeting as applied to the realm of human senses: relatively strategic, relatively useful. A giant billboard emanating the smell of steak, after all, is ineffective as well as disgusting. It's John Wanamaker's old adage -- "I know half of my advertising is wasted; I just don't know which half" -- writ enormous and meaty. Similar inefficiences exist in the Dunkin' approach; but they're minimized. Sound plus scent plus situation equals sales. Which is in part why the "hard smell" approach won the Bronze Lion award at Cannes this year -- for "best use of ambient media."