Are Grades Necessary for Learning?

I found this shortened video of Dan Pink on a Washington D.C. television show from Larry Ferlazzo's blog.  As most of you read Pink and I am extremely interested in the concept of learning versus grades (as we have discussed in class), I thought you all might find this interesting. . .





So my question for the class is this:  What would happen if we took grades out of the equation? Would kids learn more or less than they do now? Explain.