Two Cultures At Meetings

For some reason, I was forwarded a link to an old article from the Chronicle of Higher Education about how to give a scholarly lecture. (It's a time-limited email link, so look quickly.)

As with roughly 90% of all Chronicle pieces, it's aimed squarely at the humanities types. The advice given thus ranges from pretty good advice even for science types ("Remember that people who show up to hear you want to believe that you're smart, interesting, and a good speaker"; "Rehearse, rehearse, rehearse. Then stop"; and "Prepare yourself in advance for questions.") to horror-show glimpses of how the other half does conferences ("Even if your talk is only 20 minutes, you could be seated on a dais for a three-hour panel"; "Don't read aloud subheads or part numbers that may divide up bits of your lecture"). I think I can safely say that I'd rather hit myself in the head with a brick than sit through a three-hour session in which people read prepared papers aloud. Of course, most English faculty would probably rather brain themselves than listen to the ten-minute PowerPoint talks that are the staple of physics meetings.

As it turns out, I have an old post about different types of talks that I'll schedule for a Classic Edition a little later, but for those not up on physics conferences, I'll give a quick run-down of the basic structure of APS meetings below the fold.

The big meetings in physics, or at least my field of physics, are the ones run by the American Physical Society. There are also some Optical Society of America meetings that I've sometimes gone to, and those are broadly similar, but it's the APS meetings that I'm most familiar with.

At these meetings, talks are generally grouped into sessions lasting two to three hours. The number of talks in a session varies depending on exactly what sort of session it is (more on this below), but all the talks will be about related topics. The overall topic can be pretty broad ("Bose-Einstein Condensation I" tends to be a popular session title), but some effort is put into grouping them so that people doing similar work give their presentations close to each other. Each talk in the session is generally intended to be a wholly independent presentation, though-- you'll sometimes see a group with two back-to-back talks that build on one another, but that's the exception rather than the rule.

There are two types of sessions, divided by the amount of time allowed for each talk. "Invited" sessions generally feature speakers who are either prominent in the field, or the students or post-docs of prominent people (I've given a few of these, back when I was a post-doc and my boss wasn't travelling). These speakers are given half an hour (the talk slots are 36 minutes, usually considered to be 30 minutes of talk followed by 6 minutes of question-and-answer time), and expected to present either an in-depth discussion of ground-breaking results, or a broad overview of their field of expertise. Invited sessions usually consist of four, maybe five speakers, but each speaker does their own question-and-answer session immediately after their talk. After they're done, they sit down in the general audience (nobody is up on a dias), and it's tacky but not unprecedented for speakers to leave after they're done.

The other type of session is the "contributed" session, featuring people who are less prominent in the field talking about their very latest results. Contributed talk slots are 12 minutes long, generally interpreted as ten minutes for the talk, and two for questions. The time limit is fairly strictly enforced (invited speakers get a little more slack than contributed speakers). Contributed sessions will feature something like fifteen speakers, and again, nobody is on a dias. For sessions at inconvenient times, or about unpopular topics, the audience for a contributed session may consist primarily of people giving talks in that session.

("How can you possibly do your research justice in ten minutes?" you ask, horrified. You can't, really. The information transferred in a random ten-minute talk is nearly zero. You can get enough of the idea across for somebody who already knows more or less what you're doing to understand new results, and if you're good, you can suggest enough of the basic idea for people who don't know the field to know that it's interesting enough to ask you about after the talk. I'm not a big fan of ten-minute talks.)

There are always several sessions running in parallel-- five or six different sessions going at once is pretty typical, though they try to avoid having two closely related sessions running at the same time. People will wander from one session to another in search of the most interesting talks. It's not unusual for the number of people in a given room to double leading up to a talk by a particularly good speaker, or for the number to drop by two-thirds when a Big Name speaker finishes talking. There are session chairs who are charged with enforcing time limits and directing traffic during the question-and-answer periods, but very little in the way of introductory or summary remarks. It's rare for anyone who isn't a speaker to stay for all of a given session.

The other key difference between science meeting and humanities meetings is in the area of visual aids. Absolutely every talk at a scientific meeting will have some sort of visuals associated with it-- mostly PowerPoint these days, though overhead transparencies used to be the rule-- even if they're just pretty pictures put up on the screen while the speaker natters on about something else. Scientists expect pictures. If you're a humanist asked to give a presentation to scientists, bring some pictures. They don't even have to be all that relevant, but the audience will get very antsy if you don't put something on the screen or chalkboard.

Why do we do things this way? Beats me. I have no idea who decided that 12 and 36 minutes were the appropriate lengths for contributed and invited talks, but that's the way it's done, so that's the way we do it. I realize this is somewhat different from the way things are done even in other sciences, but it's pretty standard across the American Physical Society meetings, and the time slots for big meetings run by other societies differ by no more than a minute or two.

It's kind of strange, I know, but at least nobody stands up and reads prepared papers...