Hodge alerted me to this article and I found it really interesting. The most intriguing part to me was that in trials, people could identify the "real" smell among "mirror" smells if they were first exposed to it in emotionally charged situations (electric shocks). So often I am confused that I get flashbacks from a certain kind of smell, but not similar ones. This explains, perhaps, why. And it makes me feel less strange about being so sensitive to certain smells! It's a documented phenomena.