Clay Shirky on the four primary factors motivating participation
Fragment of a discussion from Talk:Task force/Community Health
That makes a ton of sense.
It also explains why there is friction when two competing visions of an article (let alone the whole encyclopedia) collide. Working with others can threaten autonomy. The hope is that there is enough mutual respect and feedback to get you through the friction. I think those little acknowledgments can get you through the tough times.
So there's probably a lot of leverage in improving our reward system. I'm more and more convinced that will be one of our top recommendation areas, if we can figure out what exactly we should reward and how.