From the comments on a conference-themed post last week, it is clear that there are various opinions, some of them fierce, about the use of laptops by audience members during a talk. I wonder if one's opinion for or against syn-talk laptop use by the audience depends on the specific situation. For example:
Does it matter whether the laptop is being used to take notes about what the speaker is saying or whether it is being used for activities unrelated to the talk being given at the time?
Does it matter whether the talk is interesting or extraordinarily dull and/or poorly presented, or is it always impolite?
Is the issue the distraction of the type type type sound of a keyboard or the flashing graphics of some websites or would it be OK if someone just stared silently at a screen of unmoving text?
Does it matter where the laptopper is sitting? Even if you think that laptop use by someone sitting in a prominent place at the front of the room would pose a distraction, but would it be OK if someone sitting at the back of a large-ish room quietly read something on their laptop?
I personally prefer to take notes on paper, so I don't use my laptop for taking notes during talks, and I don't take out my laptop if I am sitting in a crowded room or near the front of a room. If I am in a long session and can't zip in and out of the room easily, however, I have been known to sit in the back, take out of my laptop during a talk of little interest to me, and do some quiet work, mostly reading and perhaps some editing, in what I hope is a non-obtrusive way.
During one conference this year, two of my grad students who were not at the conference sent me frequent emails and things to read for a looming deadline. During spare moments, I read, edited, and sent comments back to them so that I would not delay their progress despite being away. Some of these spare moments were during conference sessions.
In each case, I was sitting near the back of the room and did not have people sitting next to me. Perhaps any form of lack of attention is disrespectful to a speaker, but at a big meeting in a large room, the audience will be composed of individuals whose attention will wax and wane depending on the specific topic of each talk. It is unreasonable to expect that there won't be some people flipping through the schedule (if there is one..), closing their eyes, making brief whispered comments, and, as long as it is done reasonably quietly so as not to disturb the speaker or others in the audience, I think this is acceptable behavior. You cannot expect every member of an audience to give every talk their full attention; you can, however, expect a respectful and reasonably quiet audience in which speakers and listeners are not disturbed by ancillary activities.
2 months ago