When scientists present in an informal setting where questions are expected, I always have an internal bet with myself as to how long until some daring person asks the first question, after which everyone else joins in and the questions rapidly start pouring out. This usually happens around the 10 minute mark. This phenomenon has gotten me wondering what this means for how best to structure a scientific talk.
I think this “dam breaking” phenomenon can be best thought of in terms of “refusal of the call”, which is a critical part of the classic hero’s journey in the theory of storytelling. The hero typically is leading some sort of hum-drum existence, until suddenly there is a “call to adventure”. Think Luke Skywalker in Star Wars (Episode IV, of course) when Obi Wan proposes that he go on an adventure to save the galaxy, only for Luke to say “Awww, I hate the empire, but what can I do about it?”. (Related point, Mark Hamill sucks.) Usually, shortly afterwards, the hero will “refuse the call” to adventure—usually from fear or lack of confidence or perhaps just from having common sense. This refusal involves some sort of rejection of the premise of the proposed adventure, which then needs to be overcome.
I think that’s exactly what’s going on in a scientific talk. As Nancy Duarte says, in a presentation, your audience is the hero. You are Obi Wan, presenting the call to adventure (an exciting new idea). And, almost immediately afterward, your audience (the hero) is going to refuse the call, meaning they are going to challenge your premise. In the context of a scientific talk, I think that’s where you have to present some sort of data. Like, I’ve presented you with this cool idea, here’s some preliminary result that gives it some credibility. Then the hero will follow the guide a little further on the adventure.
The mistake I sometimes see in scientific talks is that they let this tension go on for too long. They introduce an idea and then expound on the idea for a while, not providing the relief of a bit of data as the audience is refusing the call. The danger is that the longer the audience's mind runs with their internal criticism, the more it will forever dominate their destiny. Instead, spoon feed it to them slowly. Present an idea. Within a minute, say to the audience “You may be wondering about X. Well here is Y proof.” If you are pacing at their rate of questioning, perhaps a little faster, then they will feel very satisfied.
“You may think drug resistance in cancer is caused by genetic mutations and selection. However, what if it is non-genetic in origin? We did sequencing and found no mutations…”