I just finished a book by C. Russell Brumfield called Whiff! It is basically about the use of scent to trigger and enhance customers' emotions, perceptions, and brand loyalty resulting in increased sales. He is world renown and gives insider tips on how to use this technology to get a step on the competition.
One of the tips that he shares:
"When scent scripting a product or brand, you need to know two things: What's happening in your story line? And what actually happens when the consumer encounters your product, opens it, or uses it? Here is the simple formula that you will be able to attract and hold the attention of your target audience. . .Anticipation, Progression and Surprise (APS). Anticipation builds emotion. Progression keeps it coming. Surprise triggers a rush of adrenaline."
A good example of this is the holiday, Christmas. The smells of baking treats, the tree, visit to Santa Claus, presents wrapped under the Christmas tree, and the family dinner. All are triggers to the anticipation of the wonderful day.