Attention Span and Testing

It's really hard to pay attention to all of a long presentation; back when I was a brand-new (and really bad) asst. prof of computer geekery at the University of Delaware, the Center for improvement in teaching (or some such name) explained that typical lecture retention was 17% -- I remember the number, more than thirty years later, but not the experimental support for it. One way to improve, which I never really mastered, was simply to break up the lecture into small chunks for which retention would be at least a bit higher -- and ask questions in between. Good teachers do that, they don't get lost in their lecture thoughts. Today I see Harvard psychologists saying that the questions-in-between pattern also works online: I admit that I don't see that it's all that different, but they say Online learning: It's different

in both experiments, students who were tested between each segment -- but not the others, even those who were allowed to study the material again -- showed a marked drop in mind-wandering and improved overall retention of material.
"It's not sufficient for a lecture to be short or to break up a lecture as we did in these experiments," Schacter said. "You need to have the testing...." Those tests...act as an incentive for students to pay closer attention to the lecture because they know they'll have to answer questions at the end of each segment.
Another surprising effect of the testing, Szpunar said, was to reduce testing anxiety among students, and to ease their fears that the lecture material would be very challenging.

I'm filing this under "Independent experimental evidence that the Khan Academy is doing it right."


Or then again, maybe not.