The part of your brain that processes smell is closely tied to the part of your brain responsible for memories, according to Jason Fischer and Sarah Cormiea of the Dynamic Perception Lab at Johns Hopkins University in Baltimore, Maryland.

[...] The popularity of pumpkin spice comes from both the scent of the spices -- the familiar cinnamon, ginger and nutmeg that are commonly used in many fall desserts and drinks -- and our previous experiences smelling, tasting and even just being aware of the aroma.

"Your brain fills in the gaps between the scent of the spices and the memories associated with the smell," Cormiea, a doctoral candidate in the department of psychological and brain sciences, said.

— Read more in Pumpkin spice really does give you the warm fuzzies — here's the science of why at WTVA.