It's September and we all know what that means. 

Back-to-school time? Sure. The unofficial start to fall? OK. 

The REAL reason for the season? IT'S PUMPKIN SPICE TIME. 

Lattes, candles, muffins, dog treats, even your favorite breakfast cereal – we're looking at you, Cheerios – are available in the ubiquitous fall flavor and scent. And we love it. 

It turns out there are reasons that so many of us are obsessed with PS, pumping more than $500 million into sales of pumpkin spice items just in 2019, according to data from Nielsen.  

WellSpan psychiatrist Dr. John Shand sheds some light on the topic. 

It's the association: The cinnamon-y, pumpkin-y smell and taste reminds us of cozy Thanksgiving holidays with family, makes us think of walking in rustling fall leaves, and even prompts memories of going back to school. In the recent uncertain times of the pandemic, this is a reassuring reminder of good times and good things. "Who does not want to be comforted by the thought of simpler times, perhaps when we were children or when we spent a warm holiday with family or loved ones," Shand says. "Sure, we romanticize it sometimes, but that's why it feels so good." 

It's the smell: An important component of the pumpkin spice experience is actually the smell, which is wired into our brains in a particular way. Our sense of smell can actually induce nostalgia and other complex emotions. Just like when you get a whiff of chocolate chip cookies and automatically think fondly of your beloved grandma – or conversely when you smell a certain cologne or perfume and think not so fondly of a certain ex – when you smell pumpkin spice, it triggers a whole host of emotions. Smell is transmitted directly to the emotional center of the brain. Therefore: Pumpkin spice + amygdala = nostalgic happiness. 

It's the taste: Pumpkin spice items tend to be sugary. Sugar is addicting. The more you consume, the more you want. "Do you find yourself in the drive-through line for that latte a few times a week?" Shand asks. "There's a reason for that. Our brains are wired to love sugar." 

It's for a limited time only: Many of us know that our favorite coffee shop offers that pumpkin spice latte only for a certain time. Or we know when we see pumpkin spice baking mixes or cookies at the grocery store, we better scoop them up quickly before they are gone. Scarcity increases value in our brains. Think of Shamrock Shakes at McDonald's or roses on Valentine's Day. Lots of people want them because lots of other people want them, Shand says. "We feel like we NEED pumpkin spice because we know it will only be around for a certain time frame," he says. "We look forward to that 'season' when we can access it."