So when am I going to have a hundred simple 400 Mhz processors on a super fast bus all churning away in parallel, rather than a big complicated CPU spitting out heat and not really doing anything?

Yep. I’ve never heard this done, but it would be cool if in post-production an editor’s voice would interrupt briefly and say: “For those listening, it’s a picture of a pony” … or whatever. Wouldn’t that be a nice touch?

Saying that, I do think about what I may be missing in the learning process when just listening to audio. Missing in that additional symbol auto-association probably happens in my head when I’m watching something like Dr Quantum or getting the essence of someone like you mention. Video potentially associating more than just words and sounds together with my existing knowledge in ways that help me remember it. I tend to think of it as firing multiple sensory stimuli together, and having it wire together forming stronger memory associations. I think it really depends on the context in which your learning though. I find it’s easier to switch off visually than it is audibly. I do know audibly; research has shown faint indistinguishable background noises are more distracting than obvious noises. Earbuds tend to block a lot of that out and help me concentrate. Earphones tended to let in noise and distract me more. On the other hand audio with video has the advantage that if you miss one, the other may fill-in the gap.

GrammarGirl, another of the podcasts I listen to occasionally includes a mneumonic to help listeners learn grammar tips. Occasionally she’ll include a cartoon on site to help listeners remember. Having a picture to associate with the process helps immensely. Someday I just hope she remembers my suggestion to add the cartoons as the podcast cover art. But then I may never visit her website and the other offers on display there…

I understand what you mean, and in general I agree.

In this case, the video does add value in two ways. First, it’s full of equations and charts that Brian refers to. It’s not necessary to see those in order to follow the presentation, but it’s helpful. Of course they do boil down to a set of slides (plus some video clips) that you could review before or (as I did) after listening.

Second, there’s emotional bandwidth. If you were to simply read a transcript of what Brian said, you could get through it quicker than by listening. But voice adds a lot of emotional content. It conveys who Brian is, and how and why he is passionate about the topic, and that counts for a lot. In the same way, video adds even more of this emotional content. That said, once you sample 10 seconds of video, you’ve absorbed the essence of how he looks and acts. Now you can project that onto the voice.

“radio Mathematics instructions in Nicaragua”

I looked that up and it sounds interesting. Wouldn’t you say, though, that if they could have done what Tim Fahlberg does with his mathcasts (http://weblog.infoworld.com/udell/2006/09/29.html) back in the 1970s, they would have preferred to? In this case, you really do want to watch the equations being solved while you hear a narrative about the process.