The Sweet Smell of Success : Aromas: In a test, gamblers put more money into slot machines in a pleasantly scented area. Will Las Vegas gain a new sense of power?


Las Vegas casinos have long played to the senses. They’re virtually synonymous with the sound of jingling coins, the taste of free-flowing alcohol, the sight of glittering lights and the touch of forearms on green felt-covered tables.

And the sense of smell? If anything, casinos are known for the scent of cigarette smoke, Aqua Velva men and Aqua Net women.

That could change. A study by Chicago researcher Dr. Alan Hirsch found that Las Vegas Hilton gamblers dropped 45.1% more coins into slot machines in an area that was scented with a pleasant odor.


What’s more, dollar figures supplied to Hirsch by the Hilton showed that the slot machines in fragrance-free areas had no decrease in revenues.

That finding, says Hirsch, is important because it suggests that the pleasant odor did not draw gamblers away from other areas. Rather, it appears to have encouraged gamblers in the scented area to continue inserting coins for longer periods than usual.

Hirsch, a psychiatrist and neurologist who is an assistant clinical professor of neurology at the University of Illinois, won’t say what particular odor created the change in income. He’ll only say that the smell has received the Food and Drug Administration’s GRAS (generally recognized as safe) rating and is a “blend with no well-defined high notes.”

He’s not sure why the fragrance increased gambling. But he speculates that it may have made people more alert or more relaxed--or it may also have worked by inducing “olfactory-invoked nostalgia,” the way smelling fresh-cut grass sometimes reminds people of their childhoods.

Although Hirsch doesn’t know why the odor worked, he does know that higher concentrations of it were more effective than lower ones, a significant finding in that critics of scented environments fear that fragrances may be used subliminally to manipulate behavior.

Says Hirsch: “We have done tests in the past where we found we could actually affect brain-wave frequency with odors in such low concentrations that they could not be detected, but I think it’s really unethical for a retailer or any sort of merchant to use odors subliminally.” He adds that odors used in the Hilton study were strong enough for patrons to detect.


The study was conceived and funded by the Smell & Taste Treatment and Research Foundation in Chicago, an organization founded by Hirsch.

The foundation, which employs 24 physicians who treat patients and research the effects of odor on moods and behaviors, derives its income from patients’ fees and from drug companies requesting research on specific substances. The Hilton study was conducted independently of commercial or academic organizations, although Hirsch jokingly reveals that he and others from the foundation accepted complimentary lodging from the Hilton.

But, now that the results have been tallied, will the casino permanently scent its gaming areas?

“We’re looking at this, but I don’t know that we’re necessarily going to do anything about it in the near term,” says Mark Grossman, Hilton Gaming Division’s vice president for communications.

“Our view was as long as the study was not going to be disruptive or interrupt anyone from playing, it was not a problem,” he says. “And, we thought, better us (to participate in the study) than our competitors.”

For the experiment, special free-standing devices that diffused the scent were placed in the casino for one weekend near the end of last year.

Slot machine revenues from the preceding weekend and the following weekend were compared to those from the weekend during which the area was scented. Earnings from previous years were also studied to make sure that seasonal or holiday factors did not influence the results.

Grossman says that Hilton executives were initially surprised by the study’s findings, adding, “But maybe, in retrospect, you shouldn’t be surprised, because if you look at casinos generally, they’re set up to appeal to the senses of sight and sound. Smell is the next logical step.”

Although diffusing fragrance into the air of public places is rarely done in the United States, it is more widely practiced in Japan. There, the Shimizu Construction Co. has built office buildings that use computers to pump scent into work areas via ventilation ducts.

In the United States, scented boutiques like Victoria’s Secret are commonplace. Hirsch says little is known about the effects of particular odors used in such shops, although his research suggests that fragrance may help boost sales.

“I would say that the Japanese are probably 10 years ahead of us. I know that in Japan there are alarm clocks that put out a smell 10 minutes before you wake up to make you more alert. Japan appears to be leading the way in odor research. We are really just at the tip of this.”

The possibility that aromas may be used commercially in public places concerns Dr. Roger Fox, chairman of the American Academy of Allergy and Immunology’s committee on environmental control and air pollution.

“I would not recommend diffusion of fragrance in public places unless there was more medical research to substantiate that these odors are not harmful to humans.

“People who have allergies or are sensitive to odors that cause nasal congestion, coughing or headaches may be at risk of developing these symptoms in a scented environment. Olfactory stimulation of the nose may have neuro-endocrine implications that we don’t understand yet,” Fox says.

He also argues that just because a substance is on the FDA’s GRAS list does not mean its safety has been adequately researched; he points to MSG as an example of a controversial food additive on the list.

Hirsch doesn’t see a health problem in scenting public areas without further study.

“Odors are already there, whether they’re from the carpet cleaning the night before, something in the air conditioning or a fluid used to clean the counter. The question is whether we use smells to enhance our environment or not.

“There’s nothing absolutely safe. . . . To withhold using smells because of risk is to suggest we should withhold using air conditioning because some people might get pneumonia. The risk, although it’s clearly there, is on a level that approaches the absurd.”

Whether Nevada’s Gaming Control Board would regulate the use of fragrance in casinos has not been determined.

“In my opinion this is clearly outside our scope,” says spokeswoman Joanie Hammack. “But if there were allegations that (people were being manipulated by odor), we might look into it. We have a regulation that allows us to look at the total scope of an operation.”

Most of the Smell & Taste Treatment and Research Foundation’s 24 researchers also treat patients for symptoms associated with the loss of senses of smell and taste.

The casino study has not yet been published, but Hirsch says he is applying to present it at an upcoming meeting of the Assn. for Chemoreception Science, an organization of researchers in the area of smell and taste. He expects to submit an article on the study to the journal published by that organization.

Several olfaction researchers were asked to comment on the study. Many of them said they were familiar with Hirsch and his work in general but they declined to comment on the casino study, saying either that they had not read it or that they preferred to wait for more studies.

Duke University Medical School’s Susan Schiffman, whose work has shown that people can become less depressed when exposed to pleasant odors, said, for instance, that she would “reserve judgment until the study is replicated by several other researchers connected to universities with strong backgrounds in the field.”

It appears that Las Vegas casinos are similarly not rushing to action. Phil Cooper, a vice president at Caesars Palace, says the casino has made no decision to on whether to look into scenting, “but it’s amazing the marketing techniques that are available.”

Bob Stupak, owner of Bob Stupak’s Vegas World, is a bit more eager.

“I’d like to know more about it,” he says. “I know what happens if you add something that smells awfully bad. I know what dumping horse manure in a room would do. Maybe they have something that works in reverse. Have you ever smelled bacon cooking in the morning? It makes you hungry.”