At an international conference not so long ago, I saw a talk by a Distinguished Professor. The talk consisted of figures that he cut and pasted from papers he published decades ago when he was a hot young scientist doing cutting edge work. There was nothing new in the talk: not the images, not the science, even though this was not supposed to be a review talk. I suppose it was accepted as a talk at the conference because of the Distinguishedness of the professor, in honor of the contributions he made to his field in his academic youth.
OK.. I thought, as I listened to the boring talk, this is weird, and there are several possible explanations, some of which could probably be eliminated if I knew the Distinguished Professor personally (but I do not):
Hypothesis #1. He does have new results to present, but he just didn't have time to write them up by the abstract deadline, and between the time his abstract was accepted and the conference, he also didn't have time to prepare a new talk, so he thought he'd present his 'classic' work (which is indeed classic and much-cited) because it remains the best work he has done to date and he figured the audience wouldn't mind seeing it again.
Hypothesis #2. Similar to Hypothesis #1, but with the additional factor that he didn't think it was worth spending the time because most of the scientists in the audience were not native English speakers and he figured his old work was good enough for this particular conference venue.
Hypothesis #3. He actually hasn't done much that is worth speaking about since his classic work. He didn't want to present the results of his recent work because that would definitely be boring. So he had an idea! He decided to relive the glory days of his best work.
Hypothesis #4. Although by no means ancient, the DP has lost his mind, has impaired judgment, has been ill, or has some other tragic reason, beyond his control, for being unable to prepare a presentation of new (or at least more recent) results.
Whatever the reason, if it related to hypotheses #1, 2 or 3, it was a miscalculation. Oh, I am sure that his distinguishedness has not lost much, if any, of its luster, but there was quite a bit of murmuring at the conference about the boring, recycled talk, and some people were a bit insulted that he would present something so completely old for a non-review talk.
I kind of forgot about this recycled talk incident for a while, but a colleague (who was not at the international conference) recently told me that he went to a US conference and heard a talk by this same DP. My colleague was dismayed that the talk had consisted of nothing but recycled slides and description of old work.
This colleague knew nothing about the previous conference, and spontaneously mentioned his opinion when we were discussing what we might want to present at a future conference. My colleague had joked "We could just show the figures from our 1993 paper." What?? Then he explained, and I was amazed that the DP had re-recycled his talk.
But: At least I could eliminate Hypothesis #2 based on this new data point. The DP was equally willing to bore people at home and abroad.
It's impossible to know what motivated the re-recycling, or to know whether the DP was at all aware that his audience might not be fascinated by these presentations, but this incident relates to the general issue of how much 'old' material we can/should present in our conference talks.
When presenting new results from a long-term project, I sometimes worry about how much of the 'old' work to present as context for the new -- when you only have a short time to present complex results, every minute counts and you (should) want to highlight the new, but perhaps the new can't be understood without also presenting some of the old results. At the same time, perhaps a significant fraction of the audience isn't aware of the old work, and it would be a mistake to assume otherwise. (Note: A couple of years ago, I discussed a similar issue regarding invited non-conference talks and the eerie similarity between professors and rock stars).
From now on, I will probably have this DP re-recycling incident circling my head whenever I prepare a talk that consists of at least some old material. Getting the balance right can be challenging, but it is well worth thinking about during talk preparation.
8 years ago