If you prefer the second theory, then you might consider grades a useful instrument of positive or negative reinforcement, but the only thing that matters is what students actually learn.
What I complain of is not only that this theory in its various forms has unduly usurped the central place in monetary theory, but that the point of view from which it springs is a positive hindrance to further progress.
Mr Davies said it was part of what is known as "nudge theory", which is based on a belief that groups and individuals can be influenced by positive reinforcement and suggestion.