Dr. Alan Hirsch is a Chicago neurologist who is the founder of the Smell and Taste Treatment and Research Foundation.
In 1995, Hirsch wafted a pleasant smell into an area of slot machines at the Las Vegas Hilton. He checked the revenues for the weekend before and the weekend after and, verifying that there hadn’t been any casino-wide increase in revenue, determined that people plunked 45 percent more change into the slots in the scented area.
Scent appears to have encouraged gamblers in the scented area to continue inserting coins for longer periods than usual. As scent is know to increase dwell time, it explains that as staying longer gamblers spent more money.
When someone feel comfortable in a place this person will want to stay more and scent greatly contribute to someone's comfort. It makes perfectly sense. Just think of the last time you were in the tram and ther was a bad smell, I bet that you only wanted to escape.
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 scent is a "blend with no well-defined high notes."
Different scents can make people more alert or more relaxed or even induce "olfactory-invoked nostalgia," the way smelling fresh-cut grass sometimes reminds people of their childhoods.