Does the smell of a Christmas tree help brighten your day? Or how you can feel so much better by simply walking around a forest? Turns out there is a reason for that… But it might not be the reason you think! 

Pine is one of those scents that can change a room, and your mood, in an instant. One whiff, and suddenly you’re transported to a world of woodsy snowscapes, twinkling lights, a fresh-cut tree shedding needles in your childhood living room. The scent feels soothing and joyful…but why? Turns out the answer has less to do with what’s inside the tree, and everything to do with what’s inside us. 

“There is nothing that is in pine that has any specific, inherent pharmacological influence at all on humans,” says Dr. Rachel Herz, a neuroscientist at Brown University and an expert on the psychological science of smell.

“The way it works is through learned associations. If I have associated the smell of pine with relaxation, then it’s going to relax me. If, for whatever reason, I associate pine with anxiety, that’s how it’s going to affect me. If I have never smelled pine before, and have no clue as to anything about it, there’s going to be no effect.”

Humans, Herz explains, are “generalists,” meaning we can thrive in many different environments. Unlike species that are born knowing exactly what certain smells mean (like which scent signals a predator or poison), humans have to learn what a smell signifies. 

“It wouldn’t make sense for us to gravitate toward pine smell willy-nilly,” she says. “In certain circumstances, it could actually signify danger.”

For example, if a person’s first whiff of pine occurs while being chased through the woods by a ravenous coyote, the scent is unlikely to awaken a cozy vibe later on.

Herz maintains that although pine scent might not have inherent mood-boosting compounds, its effects on well-being should not be dismissed.

“It’s not pharmacology: It’s psychology,” she says. “But emotions are real, and they have real physiological consequences.”