[pmjordan]

I think the effectiveness of lectures might depend on the student as much as the lecturer.

I can remember some lectures (6-10 years ago) and their content quite vividly, even if they were fairly unidirectional and to large audiences. I find that if I start looking up something that was explained in a lecture, it will trigger the memory of the lecture, even if I couldn't recall it previously. This almost never happens for things I learned from books or the internet - if I've forgotten them, I have to relearn them. It also seems to take me much longer to understand something from a written explanation.[1]

I can only assume it's to do with multi-sensory input having easier access to long-term memory. And maybe there's an emotional element, too: reading a (factual) book is an emotionally neutral experience. That's not the case when you're watching and listening to a human.

And I'm sure the effect is more pronounced in some than in others. Many other students in my year did very well despite missing lots of lectures; I think I missed about 5 of what must have been about 2000 and would have needed to do vastly more revision to pass exams. I suspect I would have dropped out of university if it hadn't been for lectures. As it turns out, I had essentially zero intrinsic passion for my subject (physics), but the good lecturers made it interesting.

[1] I realise this is anecdotal and hard to verify. The most direct comparison I can think of is this: I remember that when trying to catch up after a lecture I missed, it took me much longer than the 50 minutes to understand the covered subject matter using the blackboard notes and reference books.