Unless you were the runner, how do you know that the runner was trying to distract the pitcher and not touch the ball?
It comes down to umpire judgment. Did whatever the runner was doing impede or hinder the fielder's ability to make a play? If it did, then it's probably interference. If not, then maybe it's not. It might hinge on what exactly the runner did with his had, where he put it, or his proximity to the pitcher when he did whatever he did.
Don't forget that a player can attempt to interfere, but if his attempt is unsuccessful it might not be interference.
And then there's the old umpire axiom: Punish stupidity whenever you find it!
Probably not the answer you're looking for, but being a judgment call it's impossible to know what the umpire saw and how he judged it. This is potentially interference, but not automatically interference.
