Jazz Kat, isn't "knowing the tune in your head" what memorization is?
Just trying to figure out what you're saying. My original point was that if it is a tune you don't know, how can you "figure it out during the first four bars", when you haven't heard the whole form yet?
If it's a tune you do know, what's left to figure out? Or are you talking about remembering the tune by hearing the first four (or so)bars?
I think when one develops one's ears it is possible and common to play well on unfamiliar tunes by just listening to the changes once or twice. Ever hear that recording of Bird sitting in w/Woody's band? He plays on Four Brothers (which is not your run-of-the-mill chord progression) and you can tell he's feeling out the tune, and on each subsequent chorus he nails it even more.
Allright.
I dont have any memorized on my instrument. But they are in my head! Like if someone says to me play Satin Doll, I dont know if it starts on a friken A or Z, but I know it in my head! So I try to bring it out on the guitar, piano, vibes, whatever I am playing.