Overcoming Bias has this great post about a professor who used to lie in his lectures. I liked the post so much that I’ve “excerpted” pretty much the whole post (because I know you are too lazy to click on the link):
Now I know some of you have already heard of me, but for the benefit of those who are unfamiliar, let me explain how I teach. Between today until the class right before finals, it is my intention to work into each of my lectures … one lie. Your job, as students, among other things, is to try and catch me in the Lie of the Day.” And thus began our ten-week course.
This was an insidiously brilliant technique to focus our attention – by offering an open invitation for students to challenge his statements, he transmitted lessons that lasted far beyond the immediate subject matter and taught us to constantly checksum new statements and claims with what we already accept as fact. Early in the quarter, the Lie of the Day was usually obvious – immediately triggering a forest of raised hands to challenge the falsehood. Dr. K would smile, draw a line through that section of the board, and utter his trademark phrase “Very good! In fact, the opposite is true. Moving on … ”
As the quarter progressed, the Lie of the Day became more subtle, and many ended up slipping past a majority of the students unnoticed until a particularly alert person stopped the lecture to flag the disinformation. Every once in a while, a lecture would end with nobody catching the lie which created its own unique classroom experience – in any other college lecture, end of the class hour prompts a swift rush of feet and zipping up of bookbags as students make a beeline for the door; on the days when nobody caught the lie, we all sat in silence, looking at each other as Dr. K, looking quite pleased with himself, said with a sly grin: “Ah ha! Each of you has one falsehood in your lecture notes. Discuss amongst yourselves what it might be, and I will tell you next Monday. That is all.” Those lectures forced us to puzzle things out, work out various angles in study groups so we could approach him with our theories the following week.
Brilliant … but what made Dr. K’s technique most insidiously evil and genius was, during the most technically difficult lecture of the entire quarter, there was no lie. At the end of the lecture in which he was not called on any lie, he offered the same challenge to work through the notes; on the following Monday, he fielded our theories for what the falsehood might be (and shooting them down “no, in fact that is true – look at [x]”) for almost ten minutes before he finally revealed: “Do you remember the first lecture – how I said that ‘every lecture has a lie?'”
Exhausted from having our best theories shot down, we nodded.
“Well – THAT was a lie. My previous lecture was completely on the level. But I am glad you reviewed your notes rigorously this weekend – a lot of it will be on the final. Moving on … “
Found: here.
For those amongst you who give lectures and presentations, do you think this technique would be useful in your presentation?