A while back, when I was doing some research into motivation by means of awards for a paper I was working on, I did find that there wasn't (yet) that much research on badging. There was, however, a lot of psychology related research on motivation, intrinsic and extrinsic motivation, and the affects that rewards and reward mechanisms had on motivation, and specifically motivation to learn. There were some pretty cool findings (must find articles to post references at some point). While I don't remember everything off the top of my head, I do remember that motivation is quite a complex thing. There is no silver bullet that will work for everyone when it comes to motivation and reward mechanisms. What I do remember, from a video-game perspective, is that game designers do award some limited badges for certain things like completing the tutorial (this way players have gotten some instruction on how to play the game), and for certain check-points in the game (like reaching the end of a chapter or module and completing it with a satisfactory performance). Other than that, rewards tend to be more specific in that the gamer has to go out of his way to pursue and complete that goal, like putting 100 enemies to sleep with a tranquilizer dart.
If you over-indulge games (and learners) in really basic rewards, they get hooked on easy rewards, and they don't necessarily want to pursue harder to reach goals, which give them a reward. Thus some easy targets at the beginning mean that rewards wet the pallet of the gamer (or learner) to want to continue to pursue certain goals. I'm thinking that the way Hyperlinked Library has implemented the badging system might mean that badges may lose some value because of the over-saturation of easily accomplished tasks. I would be quite curious to know what learning design parameters were for the design and implementation of these badges.
That said, I am quite curious to see people experimenting with alternative credentialing and badges. I really hope that people support the Mozilla Open Backpack and we get some interesting data to work with. In some cases we will have a glut of badges, for no good reason, but it's a learning experience. What are your ideas for badge-worthy tasks in a course? [Tasks that can be done in any course]