The crunch of leaves underfoot, bare branches and colorful canopies of auburns, yellows, and fading greens: Fall is here—pumpkin-spice lattes and all—and we don’t just see it and feel it in the temperature drop. As it turns out, we also smell the changing seasons. Some may associate fall with the scent of harvest, or melancholy; for others, October brings to mind cinnamon and campfires. All are hardwired into our memories, and combined with our other senses, fall is more than a season; it’s a feeling. And no, it’s not a nostalgic figment of your imagination.