There are a few immutable laws of instruction that I try and uphold. Intrinsic learner motivation is critical (i.e., learners with high motivation on a topic will learn from any informative instruction, no matter how poorly designed). Human beings can only process one source of language at a time. Instruction that lacks realistic examples is unlikely to be applied in the real world. Never get involved in a land war in Asia. And, listening is an inefficient way to learn.
Or, stated positively, interactivity significantly aids learning.
I was challenged on this point recently. The argument was two-fold. One, experts have a richer knowledge base and can therefore more easily absorb new information related to their expertise. Two, experts tend to have greater demands on their time which leads to a greater likelihood that they will use time reserved for, say, working with a case study in small learning groups to instead return calls to clients.
My initial reaction is to argue that even experts in a topic are not immune to human limits on attention. While I’ve never seen a study that tried to systematically determine typical attention spans under different circumstances, the usual guidance I see is ten to twenty minutes for a typical lecture. It’s hard to pin down this number, though, because it depends on a number of factors, such as inherent interest in the topic. I imagine that one factor that influences interest is expertise; the more you know about a topic, the more interesting it is (or, perhaps, you know more because you find the topic interesting). Therefore, perhaps it is reasonable to surmise that being an expert can increase attention span (though not infinitely), at least related to his or her topics of expertise.
So, the case here is plausible, it seems to me. More to come.