There's something about the smell cinnamon, apple cider, pumpkin and fallen leaves that just screams fall. That association is no accident. According to a Canadian neuroscientist, there's science behind the smells of fall that you associate with the season.
There's a mix of chemistry, biology, and psychology that can play a big role in how you interact with scents of the season depending on what kind of memories you have associated with it.
So if you have fond memories of eating apple pie at Thanksgiving, smelling that combination of apple and cinnamon can have a mood-boosting effect on you.
But in turn, that means if you don't have the best memory associated with the smell of pumpkins, for example, then it might trigger sadness or anxiety.
"When it gets cooler and drier, specific scents tend to stand out more — we're able to kind of pull out the scent of leaves, the scent of bark, the scent of grass in more distinct ways," said Rachel Herz, a Canadian neuroscientist, to the CBC.
In the summer scents tend to blend together since you can smell a lot more things.
Since your nose can pick out more specific scents when the weather gets colder, fall smells can impact you more.
And that impact comes without you even thinking.
"With smell, it's the emotion first and then we try to figure out, 'Why am I feeling like that? Why am I feeling wistful or nostalgic or excited?'," said Herz.
There's a split second response when a scent molecule meets a memory as you're smelling something that is familiar to you. That response happens in the parts of the brain that store emotional memories and associations.
"Sometimes we can get back to [thinking first], but other times we just have the feeling and even we don't quite know why," said Herz.
Egan Davis teaches horticulture at the University of British Columbia and remembers the maple trees that dumped sweet-smelling leaves every October at his home as a child.
"When I kick my feet through raked maple leaves now, I am back to that moment when I was four or five, and I'm wooshing my boots through maple leaves," he told the CBC.
So it's not a coincidence when you catch a whiff of those fallen leaves or apples and cinnamon that your mind jumps to fall. Your brain is working way before you can even think about making the association between the season and the smell.