The power of scent

I am always astonished by how strong the memories are that accompany certain scents.  When I was very young (we're talking very young!) my mother wore Tweed perfume whenever she went out somewhere, and to this day if I stumble upon that fragrance I can feel her bending over my bed to kiss me goodnight.  Love's Baby Soft puts me back into my early teens with jeans and shirts and does-he-like -me concerns.  Upon smelling a combination of sizzling bacon and cool air, I am in our summer holiday tent trailer with a cold nose, burying myself deeper into my cozy sleeping bag and listening to my dad cooking breakfast out at the picnic table.  The mix of diesel fumes and early spring air instantly transports me to France -- happy trip! -- to the times I accompanied students on an exchange and we spent a lot of time around buses.  (Kinda neat that a basically negative smell could have such positive connotations for me!)  The list goes on and on.  What strikes me is the force with which the memory returns; I am there, reliving that moment viscerally.

I wonder why scent has such a strong association for us -- we, who are usually such visual creatures.