OK, rewards do work if the only thing you're rewarding is reptative mechanical tasks. Watching this made me think of traditional education. Most students see grades as both a carrot and a stick. Luckily most education seems to boil down to "reptative mechanical tasks" and so it seems to work quite well (yet another time I wish there were a sarcasm font, I know how to YELL, but how do you express sarcasm?).
Unfortunately many educators, me included want more than just the traditional approach. We want students to express themselves creatively in the class. We want them to think critically when solving problems. We want them to be intrinsically motivated. However we are forced to use a carrot/stick reward system. How do we move past this to foster authentic education? I wish I had answers.