Some people have a little problem with their third and fourth finger always wanting to try and move together.  I learned an exercise to help get over that back over 30 years ago from a bassist named Paul.  He probably isn't among the living anymore, but I still use the exercise as a "fidget" to keep the fingers limber after all these years.

 I'm going to try uploading it as video, since it is super simple to understand once you've seen it, but explaining it clearly with just text would be less sure.  I don't know if this video will work, since it is shot with the little camera built in to my pocket media player.  The quality is craptastic in any case.  If it doesn't work, I will take some pics and explain the moves. 

It is a super easy "baby" sort of exercise.  Doesn't take any gear, and it doesn't make any sound, which can be good.  Especially at first, tensing your hand will make it harder to do, so try and keep the hand as relaxed as possible.

Fiddlestix said
Nope,,, nothing happened, Dannyboy…. it opened but no vid or aud. 

Yeah, I was afraid that might happen.  Been having a heck of  time with getting uploaded video to work.  It will run fine on my system, but not on other people's systems when I send or upload it.  Oh well..

The exercise is simple. 

1.)You have your hand with the palm turned up and the fingers relaxed against the palm. 

2.)Then you lift the first and third fingers as in the second pic. 

3.)Drop them back to the palm as you raise the second and fourth fingers. 

Alternate between step 2 and step 3 until you get bored or have something better to do.  Try and keep the hand as relaxed as possible and the movements easy and smooth as you speed up. 

I can say it does help with independent finger movement not just for the 4th or 3rd finger, but all of them somewhat.