You smell fresh popcorn, and somehow you’re transported back to that old movie house where you had your first date. Or you smell the signature odor of books, and you’re wandering the stacks of your hometown library in your mind…what is this wizardry? Oh, just your sense of smell tapping into the part of your brain responsible for memory and emotion. Our sense of smell is most closely tied to memory and emotion because the olfactory bulb—the organ that translates chemical content in the air to sensations of smell—has the most direct line to the amygdala and hippocampus, two parts of the brain that play a big role in processing memory and emotion. Our visual, auditory, and tactile senses don’t pass through these brain areas, so they don’t have such close ties to distant memories and powerful emotions. Evolutionarily speaking, the amygdala and hippocampus are primitive parts of the brain in that we share them with our earliest mammal ancestors. This helps explain why certain smells trigger powerful associations that you can’t quite put your finger on—they’re ancient associations with instinct as compelling as the call of the wild.