> we often mistake the speed of initial understanding with a students’ capacity for mastery This is one of those assumptions that I didn't notice I was making

> we often mistake the speed of initial understanding with a students’ capacity for mastery This is one of those assumptions that I didn't notice I was making till it was pointed out. It is hard to predict capacity for mastery. It seem natural to adopt initial understanding speed as a heuristic, but I think it is the kind of heuristic that while effective, also tends creates a significant overestimation of it's own effectiveness through confirmation bias.