I found an exercise at one web site, forget which, you lift the index and ring finger at the same time, while keeping the "finger" finger and pinky on the frets. Then switch. Lift the "finger" (what is that one called?) finger and the pinky at the same time, while leaving the index and ring fingers on the frets. Repeat over and over. I guess it helps build independence. All I know is it's not very easy.