What Motivates a 4 Year Old?

We have always known that Josiah needed was the kind of child that needs strong boundaries and consistent reinforcement (what kid doesn't?). The trick has been to figure out what would motivate him enough to listen, obey and stick to it. We have tried so many different things, but recently started a new system with him that so far is working very well. While we were in WI for Thanksgiving we attended our old church. During the Bible Study hour we watched a video on parenting. The one thing that stuck with me from that video was to make contracts with your kids. I thought that it was worth a try, but also thought that Josiah would be too young to do this with.
I went out and bought poster board and fun colored cards to make charts. We sat down as a family and decide to make house rules. We asked Josiah what the rules should be and low and behold we discovered the kid has been listening to us for the last 4 years. He came up with several things that were right on target to addressing his own personal discipline issues. The first one was: No hitting, punching and kicking. Another he came up with is: Use kind words and no whining. How appropriate. We also came up with consequences for violating a house rule. Josiah wanted to get a spanking for all violations. I think for him that was quick and easy. He definitely did not like a consequence of loosing toys or screen time.
Several other things we have implemented are cards for 30 minute blocks of screen time. I Have never known him to be selective with what shows he wanted to watch or how much Wii he wanted to play. Now with the cards he will ask, "How many shows do I have left?" and then will decide if a particular show is worth watching or not. We gave his what we thought was too much screen time per day and he has not had a day where he has used it all up yet. We also have the Mommy Toy Box thanks to Tracy. Clean up time has become a breeze in my house. Josiah gets 20 minutes on the clock to clean his room and anything left out or on the floor when the timer goes off goes into Mommy's Toy Box and no one knows when they will come back out. This is a great motivator. The last thing we are doing is for every 3 days of obedience reflected by a card system Josiah gets to pick a fun activity to do that we would not ordinarily do. The time frame for this will be increased periodically until we reach a week of obedience. The last week and a half we have had home made cinnamon rolls for breakfast, a trip to the Science museum and gingerbread house decorating. We have had a very happy house lately. I would highly recommend these techniques to anyone.