There’s an article in Seed entitled “So” and subtitled “The anatomy of a scientific staple” which purports to discuss the use of the word as a preface to scientific pronouncements in the classroom and, I presume, in conference talks as well. I thought perhaps the author was overanalyzing things, but there is this observation:

In the 1990s, Columbia University psychologist Stanley Schachter counted how often professors said “uh” and “um” in lectures and found that humanists said them more than social scientists, and natural scientists said them less frequently of all. Because such words mark places where a speaker is choosing what to say next, Schachter argued, natural scientists’ low hesitation rate underscored the hard facts they were communicating. “So” can be said to have the inverse relation for exactly the same reason. It relays a sense of accuracy and rigor. One doesn’t have to worry about what to say as much as when to say it. “So” is the organizing device for a logic-driven thought process.

I don’t fully agree with this. The delay does help you organize your thoughts; I’m not sure if the observation from the article is necessarily a fair comparison. Does a scientist use “um” rather than “so” when discussing topics in the humanities or social sciences?

Anyway, just a few days ago the Quantum Pontiff gave some empirical data on this; I had been tempted to comment on that but it kinda slipped away from me, but now I shall do so. It was my favorite word as well, when I started teaching. My experience lecturing was in the navy, and since the military is all about training, I was afforded the opportunity (if mandatory training can be considered an opportunity) to acquire and then improve my lecturing technique.

The lecture training was somewhat orthogonal to the subject-matter training; you had to qualify for them separately, but that didn’t mean you could be technically incorrect in lecture or use atrocious boardwork in technical Q&A. You lectured to a small group of qualified instructors (who were impersonating enlisted students, though we refrained from calling them by the generic “Petty Officer Schmuckatelli” that was bandied about elsewhere when discussing lecture techniques), and they gave feedback on things like spatial use of the board, handwriting, the ability to face the class and write and talk at the same time (and this was all chalkboard work — no powerpoint or transparency slides). Classroom distractions were added in as you became more proficient; things like talking and sleeping, and some navy-specific issues (a favorite was the “foot-up chit” from sick call, allowing the student to have his shoe off and foot up on the desk).

After just one or two practice lectures, I was informed that my favorite word was “so,” and I was not alone in its use. I observed this myself, because we videotaped some lectures to reinforce the feedback we were getting. Once I was aware of this, the next stage was to internally wince whenever I said it, and then to eventually reduce how often I said it, either by eliminating it or occasionally replacing it with “Now” or “OK” or something else. I’m sure that having been out of the classroom for a while, I would be back where I started, or close to it, in this habit.

I think part of the use of this (or a substitute) word is similar to the issue of the voice-activated speakers you run into in speakerphones, where the first word is often clipped because the system hasn’t started up yet. It’s a throwaway word that gets the attention of the class, but contains no information that would be lost to inattentiveness. IMO it’s almost the equivalent of ¶, the new paragraph symbol, and an instance of phonetic punctuation (as comically portrayed by Victor Borge in the link).