"The best way to ensure that the learned information is retrieved from memory in an on-the-job situation is to prompt learners to practice retrieving that information during the learning event. It's not the interactivity that facilitates learning--it's the retrieval practice.
This explains why questions about nonessential information actually hurt learning. They provide practice on retrieving the wrong information. It also explains why feedback is useful, but not always necessary. When the correct retrieval routes are practiced, feedback is redundant."
:: comment :: . . . have always intuited (and have sought empirical, written and practised evidence) that you must live the questions . . . but what is nonessential information . . . too easy or simplistic criterion will deny too much . . . the search for the essential to distinquish from the nonessential is a art in itself . . . & what is 'art' . . . and as Paul Celan wrote (in his speech on the occasion of receiving the Georg Buchner Prize, Darmstadt, 22 October 1960) :
"Art, you will remember, is a puppet-like, iambic, five-footed thing without - and this last characteristic has its mythological validation in Pygmalion and his statue - without offspring."