Why smelling a pine tree can instantly lift your mood
The scent of pine is more than just a pleasant aroma; it has the power to evoke vivid memories and emotions, transporting us back to cozy winters and festive celebrations. According to Dr. Rachel Herz, a neuroscientist at Brown University, the magic of pine scent lies not in any inherent qualities of the tree itself, but in the associations we have formed throughout our lives. For many, the smell of pine may conjure images of twinkling holiday lights and fresh-cut Christmas trees, creating feelings of comfort and joy. However, Herz emphasizes that these effects are psychological rather than pharmacological. “There is nothing that is in pine that has any specific, inherent pharmacological influence at all on humans,” she explains. This means that our emotional responses to pine are shaped by personal experiences rather than the chemical composition of the scent itself.
Aromatherapy often promotes pine essential oils as stress-relieving and mood-enhancing, attributing these effects to the terpenes found in the tree, such as α-pinene and limonene. However, Herz argues that the perception of scent is processed in the brain’s amygdala-hippocampal complex, which triggers emotional memories connected to specific smells. This process occurs almost instantaneously, allowing a person to experience feelings of nostalgia and happiness without consciously recalling past experiences. For instance, someone may find joy in the smell of pine while hiking in the woods or decorating for the holidays, but the same scent can evoke negative feelings if associated with less pleasant experiences, such as cleaning a bathroom with pine-scented products. Herz’s research illustrates that context plays a crucial role in how we interpret scents, reinforcing the idea that our emotional responses to smells are deeply personal and dependent on our individual histories.
In a fascinating study, Herz demonstrated how the same scent could elicit completely different reactions based on the context in which it is presented. Participants were exposed to a scent they were told was parmesan cheese, which they found pleasant and appetizing. However, when the same scent was framed as vomit, their reactions turned to disgust. This highlights the power of psychological associations in shaping our perceptions of smell. While the scent of pine may not contain mood-boosting compounds, its ability to evoke strong emotional responses should not be underestimated. “It’s not pharmacology: It’s psychology,” Herz concludes, reminding us that the emotions tied to our sensory experiences can have profound physiological effects, making the simple act of inhaling a pine scent a powerful trigger for joy and relaxation.
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.”
Aromatherapy works, but not the way it’s advertised
Pine contains compounds called terpenes, like α-pinene and limonene, which are touted in wellness circles for their stress-reducing and
mood-boosting properties
. Aromatherapy brands frequently promote pine essential oils with terms like “refreshing” and “uplifting,” suggesting there’s something inherently calming in the chemistry of the tree itself.
But that idea doesn’t hold up scientifically, according to Herz. She says the perception of scent occurs in the amygdala-hippocampal complex, otherwise known as the primary olfactory cortex. It is this mechanism that drives pleasant experiences around particular scents.
Your sense of smell is the first sense you use when you’re born.
Video: How do we smell? – Rose Eveleth /
TED-Ed
“What I always like to say is that aromatherapy works, but not in the way people think it does,” she says. “If I have an emotional association around a certain smell, that’s going to be instantly activated upon smelling a particular scent. It’s actually more immediate than if there was a drug-like mechanism that would take time to metabolize.”
She added that a person would not need to consciously think about their pleasant associations with pine to experience the uplifting feelings. “You
could
consciously experience that nostalgia, but what’s going to happen first is you’re going to have that mood boost, and that happy feeling,” she says. “Then you might reflect on a memory of a time you went camping as a child, for example, but that is not necessary.”
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.
Festive wreath vs. floor cleaner: the importance of context in pine smells
Sure, you might experience a happiness spike when you take an invigorating hike through the forest, or hang a holiday wreath on your front door. But what about when you’re using pine-scented cleaning products to scrub the bathroom, or hanging one of those pine tree air fresheners to mitigate a friend’s chain-smoking in your car? Does it make a difference?
It depends on your overall perception of the experience, Herz says. “Let’s say you have an essential oil, or a real tree or a chemical fabricated for a cleaning product. If a person is blindfolded and smells each of these samples, the perceptual experience would be the same,” she says. “Where context really comes into play is in the interpretation. If I’m standing in the bathroom opening a bottle of pine cleaner to clean the toilet, that pine smell is going to have a completely different connotation for me.”
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In fact,
Herz and colleagues conducted a study
in which they presented a mixture of two chemicals to participants. The chemicals were placed in identical white jars with black lids, and consisted of pellets underneath cotton. Participants unscrewed the lids and sniffed the cotton.
In one instance, Herz said she handed the participants the jar and told them they were smelling parmesan cheese. She then asked a series of questions about the smell and the feelings it evoked.
“They would say it was very pleasant, very familiar, and that they would eat it,” Herz says.
A week later, when the participants came back to do the study again, Herz presented the jar containing the same scent—only this time, she told them they were smelling vomit.
“People were saying, ‘Oh that is disgusting,’ and ‘I would never eat that,’” she says. “They could not believe me when I told them it was the exact same scent. It’s like doing a magic trick.”
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.”
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Why smelling a pine tree can instantly lift your mood
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