Each fall, as leaves turn golden and the crisp autumn air carries the scent of pine, Catherine Franssen waits for her husband to bring home the latest pumpkin spice-flavored concoction he has discovered at the grocery store.
"My husband -- whose favorite pie is pumpkin; he'll eat it year-round -- thinks the pumpkin spice craze is funny and brings home all sorts of odd pumpkin spice items to try," said Franssen, assistant professor of psychology and director of the neurostudies minor at Longwood University in Virginia.
"I think I ended up eating the entire box of pumpkin-spiced Cheerios last year after the rest of the family tasted and rejected," she said. "They were pretty good."
Franssen called the current trendiness of pumpkin spice "a fantastic example of the psychology of consumer behavior and fads." She knows that the sweet smell and tantalizing taste of pumpkin spice can trigger a nostalgic emotional response in her brain and the brains of many other consumers, she said.
After all, "this spice blend has been used in popular baked goods for quite some time, but mostly in home-baked goods," said Franssen, who wrote a 2015 blog post in the Huffington Post about the science behind pumpkin spice.
"Since these are popular spice combinations, it's very likely we would have encountered some or all of them combined in a favorite baked good in a comforting situation, like a family gathering, early in life," she said. "It's not just the pumpkin spice combo but that we've already wired a subset of those spices as 'good' very early in life."
In other words, if the pumpkin spice blend -- or a synthetic version -- that has been added to your favorite food item reminds you of a baking pumpkin pie at grandma's house, then it probably did its job.
What is pumpkin spice anyway?
Most pumpkin spice mixtures don't involve an actual pumpkin. Typically it contains ground cinnamon, nutmeg, dry ginger and clove or allspice mixed together, said Kantha Shelke, a food science communicator for the Institute of Food Technologists and a scientist at Corvus Blue, a Chicago-based food science and research firm.
When many food companies use a pumpkin spice flavor, they often develop a synthetic version with various compounds and aromas designed to trick your brain into thinking you actually consumed a mix of cinnamon, nutmeg and other spices.
Included in many of these synthetic pumpkin spice flavors are top notes that mimic the aroma of butter browning with sugar, which creates an olfactory illusion of a freshly baked pumpkin pie, Shelke said.
Nonetheless, "history shows that pumpkin spice-like combinations have been used for millennia in various cultures," said Shelke, who is also an adjunct professor of regulatory science and food safety at Johns Hopkins University.
For instance, similar mixtures of spices are used in Indian masala chai and Middle Eastern baklava, she said. These mixtures are often used in celebratory occasions -- most often to ease the digestive impacts of overindulgence, Shelke said.
Yet "in the Western world, the aroma of pumpkin spice immediately transports people to all the warm and friendly times associated with pumpkin pie, holiday gatherings, families, celebrations, treats, sweets ... things that childhood memories are made of," Shelke said. "This is why pumpkin spice latte is trendy."