The big problem is that Roscoe doesn't realize this and he has a different agenda about what should happen. Here's Alisha trying to pacify him with the monkey pacifier that he got from UCSF. It's a back-and-forth battle of wills.
Lately I've started playing games with him to stimulate his mind. When he moves his hand to touch my finger, I'll say "fingers" each time he does it so that he learns cause and effect. We've noticed that he'll flop his hand around when he knows something is nearby until he's able to grab onto it, then he locks on and doesn't let go. Sometimes his little finger tips turn white because he's holding on so tight!
Another game I have started playing with him has to do with proximity (but he doesn't know that word yet). I will bring the pacifier out about 10-12" in front of him, then say "Here it comes" and bring it in closer and closer until it touches his lips. I am hoping that he starts being able to predict that the pacifier will touch his lips before it gets there, just based on it visually getting bigger as it gets nearer. If not, I can just show him this video from my youth where I learned the concept: