It certainly seems counterintuitive that students should learn better from a recording than from interacting with a live professor

It should not seem so. It should be very intuitive. We are talking about lectures here (a technology that was deprecated by the invention of writing), not interactive discussions. In a lecture, you cannot rewind the parts that you do not understand. You cannot turn up the volume. If you miss something, it is gone forever. In a lecture, if taking notes and listening interfere with each other, there is no second chance. In a lecture, if you think too long about one concept, you miss the next. If someone talks or your cellphone rings or any of a thousand other distractions occur, there is no way to review what was said.

Visual aids can also be enhanced with lectures — substituting animated images for a professor’s crude drawings, for instance. Compare what you learned watching Nova as a kid to what you learned from your teachers, and the difference should be obvious.

If that is coupled with the fact that one has more freedom to choose the time and place of learning, the advantages are even greater. You might be more interested in listening to those words when they become entertainment to help you not to realise the time spent on public transportation, or they could even be combined with music you like so that you are excited about listening. With recordings, the possibilites are really limitless.

All interaction in the classroom should be debate and discussion. Professors should spend time helping students over hurdles that are inevitably encountered in their learning. Professors should never lecture. With today’s technology — and even the technology of 1000 years ago — lectures waste both teachers’ and students’ time. One way communication is better left to media more suited for that purpose. And two way communication should be the norm for human interaction. If teachers do not help students to understand, what is their job exactly anyway?