The answer is last week some time. I don't know which day precisely but one day he just started to LISTEN. The first time I noticed it was when he saw a garbage can across the street (a yucky, if you will) and he ran forward to go see it. I yelled, "Stop! Wait for Mama!" and he DID. In the face of a yucky, he stopped and waited. He also started holding our hands and putting away toys without throwing a fit. His favorite chore of all is taking something to the garbage can. He does that when we ask him. He also started bringing us things we ask for. All this in the space of one week. What a good boy! Oh, and he's also started folding his arms and won't throw a fit as long as the prayer is a short one.
And because everyone likes pictures, here they are. You'll never guess what he's doing in all of them.