Active Versus Passive Learning
It is the discomfort in active learning that probably pushes the student to work harder and learn. On the other hand, it is the comfort in having the solutions handed to them that perhaps leads students to overestimate how much they know and how much they can really do on their own. And the interesting result of the study is that scores are indeed inversely proportional to feelings:
Traditional classes that make use of chalk boards and lectures in colleges should not be confused with the "passive" version of learning in the study. What makes learning "passive" is when "a smooth-talking professor lulls students into thinking they've learned more than they actually have."