I wish I had more of an explanation than that for you, but it's a very new study of mine.
But this I can discuss. Contrary to its name, a pumpkin spice latte contains no pumpkin (the thought of a buttered gourd dipped in coffee was enough to put me off the stuff entirely, but then it was explained to me that it was simply the spice associated with this world's traditional pumpkin pie. So think - hot, sweet, slightly spicy, generally with a whipped topping. The very definition of cozy and comforting.