Bjork: I think the study that I shared in the TEDx talk was from a researcher named Deloriae and colleagues, but also from Harvard. In both conditions were a standard lecture of a physics concept by individuals who had had extra training in making the content engaging and using visuals on the whiteboard to explain themselves. So they all preferred that approach where this engaging lecturer explained things to them and did a think-aloud protocol and used visuals for example. The test of learning had almost the opposite results where they performed better in the conditions where they had to stop and do this problem solving and have that kind of difficulty.