A carrot in the right place makes all the difference, the issue here is this is not the place that the carrot needs to be. Most thought-work, learning in this case, is intrinsically motivated. We can classify this motivation as being one or more of the following needs: autonomy, mastery, and purpose. In order for that kind of motivation to function, basic needs must be met. A teacher can have as many carrots dangled in front of them, but you’ve given them an impossible task in a large number of cases.