I had an interesting thing happen to me last night.  I have been experimenting with moving my Magnepan speakers different distances from the wall.  The various positions effect the soundstage in different ways.  I was wearing my contacts while listening and changed to glasses.  When I wear my glasses, things seem farther away for a while until my eyes adjust.  

What is interesting is that I perceived a difference in the way my system sounded when I came back and listened to the same track.  The difference in what I heard was consistent with the differences I heard when the speakers were further back.  I changed back to contacts and everything sounded like before.  It seems that there is some type of "past experience" learning that effects current sonic perceptions.  I'm sure everyone's senses don't have the same degree of interaction, but they obviously effect one another.  

I wasn't really a huge proponent of blind testing, but I'm now coming around to it.  I always thought I could detect the subtlest of changes, but I'm going to be a bit more caucious going forward.  I'm experimenting a bit now with turning off the lights when listening and waiting a day or two to evaluate setup changes, giving time for my sense to "clear" and reevaluate.