Talking heads may or may not improve presentations, but they do add to conversations

MOOCs and other online classes give us an opportunity to learn what works in presentations. For example, I've proposed studies of the effect of playback speed or including a talking head in a presentation on comprehension, retention and engagement.

I'm not sure how these studies would turn out (though I have my suspicions), but I am sure that talking heads are important in coversation.

My certainty is based on a single anecdotal experience (of no scientific value). Some friends and I meet for a weekly podcast bull-session on technology (Yet another tech show). We do the podcast using a Google Hangout.

As you see here, video thumbnails of all the participants are shown under a larger head-shot of the person who is speaking. (Switching is automatic). But, check the thumbnails and you see that the second from the left is blank. That is because one of us had a slow Internet connection that night and could not stream video. We could hear what he said, but not see his face.

If you had asked me before we did that podcast whether not seeing him while he spoke would matter, I would have said "no" -- figuring that the audio conveyed all the information in a technical discussion.

If you ask me now, my answer is "yes, for sure." It had nothing to do with information or content. We understood what our invisible colleague was saying and he participated fully, but it felt weird.

Talking to disembodied people on the phone feels natural because there is no point of reference. But, in a mixed conversation, where you can see some, but not all of the participants, the difference is palpable. I don't know if it is because of subtle clues as to who gets the floor next, some primitive fear or something else, but it feels more natural to talk with someone you can see.

Two researchable questions: do talking heads and moving hands improve learning?

I would like to see studies testing the hypotheses that seeing a talking head or a hand writing on the screen improves student comprehension and retention.

I've developed a collection of modules for my digital literacy course. Each module contains an annotated PowerPoint presentation and other material. As I find time, I record videos of the PowerPoint presentations, using the annotation as a script.

To conserve bandwidth and storage space, I only use still images of the PowerPoint slides in my videos. There is no video of me speaking. I reasoned that my students knew what I looked like, and viewers who were not in my class could see what I looked like in a photo.

But, I notice that Google (left), Coursera (right) and others include video of the speaker's face during their presentations.

Is there evidence that talking heads improve comprehension and retention?

We see a similar contrast in the screencast videos produced by Udacity (left) and the Khan Academy (right}. Udacity videos are screencasts with superimposed video showing the teacher's hand and pen while drawing and writing on the screen (with noticeable parallax). Khan produces screencasts in which only a cursor is shown.

Does seeing the hand and pen improve comprehension and retention?

(If these research questions sound interesting, see a proposal for a related study of the effect on comprehension and retention of varying playback speed and bullet point images).