They lack strength and i can't control specifically my ring and pinkie on my left hand- they move, when i make a fist, etc, but just as an example, I took pottery lessons a few years ago hoping it would be a good and satisfying therapy, and it was! But, every time I was at the pottery wheel, trying to hollow out a form, you use one hand (dominant hand, my right) to push down and your other hand to push in at the side. Well, my two non-cooperative fingers on the left hand would flip right into and under the centered clay and splat the whole situation at speed into the workroom mirror haha