Scent is a bizarre thing. Have you ever smelled something and immediately thought of something in your past? As I was installing Windows 2000 on my computer at work, I was browsing a binder with a collection of plactic folders, which contained the cd-roms with the software I needed to install. Anyhow, as I was turning the pages I caught the smell of thick plastic. It was the same as the inflatable rubberboat I used to share with my brother when we were vacationing in France. We used to go to the beach, my brother and I and my parents. And because we had a lot of stuff to move from the parkinglot to the shoreline, we used to inflate the boat and load in all the food, towels, toys, books and other necesseties for a day at the beach. Isn't that strange, I hadn't thought about that for ages, yet after a brief smell I almost felt as though I was on the parkinglot in France again.
Read more on scent and the development of scent tracking here. Or take a look at this page at Britannica.com on Human sensory reception | Smell (olfactory) sense | Effects on behaviour.