Answered by Evan DeFilippis
Evan DeFilippis 的回答：
Nodding your head up and down while asking a question substantially increases the likelihood that someone will answer affirmatively. When other people nod in response to something you say, you are likely to be perceived as an expert on the subject.
If your friend is giving a lecture and you want to produce contagious agreement in the room, vigorously nod your head at a rate of one bob per second, and you can independently alter the opinion of the entire audience.
Answered by Zaira Sheeren Khan
Zaira Sheeren Khan的回答：
If a song stuck in your head...
There's something called the Zeigarnik effect which explains that your mind tends to think of things left unfinished.
Think of the end of the song, this will allow your mind to close off the loop.
Answered by Aseem Agrawal
In high school and university. When there was about 10-15 minutes left in class I would zip my bag up, loudly a couple of times, up and down. What resulted was a cascading effect—everybody starting to put their things away. This would oftentimes lead the prof or teacher to let the class out early as everyone is clearly packing up. The sound of the zipper triggered something in everybody—Pavlovian conditioning in action.
Edit: To clarify. I would just do the two zips. Then I'd settle back with my pen in my hand and look intently at the professor and take notes while the rest of the class packed up. It was never obvious who started it. In retrospect it was a shithead thing to do but I felt like a wizard every time it worked.