The Columns

Making Sense of Holiday Scents

— by on December 9th, 2008

What would the holidays be without those familiar scents — the fresh spruce tree, peppermint candy canes, mulled cider?

The absence of those particular odors in the context of the holidays would create a puzzle for the senses, says Washington and Lee neuroscientist Tyler Lorig, who specializes in the study of the olfactory system.

Our sense of smell is central to our ability to make sense of a particular experience, says Lorig. If, for instance, you walk into a room with a nice, fresh evergreen tree and there is no odor to it, or the odor is not what you expect, that experience will not make as much sense to you.

“You might not be able to put your finger on what’s wrong, but you would know that something about this scene wasn’t quite right,” he says. “There is a whole constellation of stimuli that are part of our sensory world, especially at the holiday season. We put those things together in context automatically.”

But Lorig says that while smell plays a central role in helping us understand our experiences, we are actually trained to ignore odors in most settings. “You can be in a room that is full of books and computers and telephones and all these things that emit odors, but you probably don’t notice,” he says. “Despite the fact that the air around us is full of molecules that we can smell, most of the time we don’t. We tend to smell only those things when specifically ‘looking’ for a smell or when something isn’t quite right.

“So when we do encounter smells, especially those closely associated with emotion like the good times of the holidays, we tend to have very strong feelings about those smells, and we actually seek them out.”

Lorig’s research looks at how the brain responds to smells and, recently, has focused on how the timing of that information can lead to knowledge about what someone has just smelled. Using coffee as an example, Lorig says that the smell is composed of many molecules, some of which bind to receptor sites in the nose very quickly, some more slowly and even others more slowly, up to as long as two seconds. That pattern, that whole matrix of individual receptors being activated at different times, is what allows you to know that you’ve smelled coffee.

One thing that Lorig says is especially misunderstood about olfaction is that smelling is not a passive activity. “We have the illusion that it is quite passive, that the odors just come to us and we smell them,” says Lorig. “The reality is that we are out there seeking them, changing our expectations and even our breathing patterns to put those odors into our nose in a way where we can make more sense of them–where they provide information about the richness of our world.”