The Verplanck Effect:
For this one, you need to get a bunch of classmates in on it, it can be tough to pull off. I believe it was an experiment done originally by a bunch of Harvard kids.
Go to lecture one day whenever the lecturer goes to one side of the room have everyone in the class smile. When the lecturer goes to the opposite side of the room, have everyone frown. Ideally, you can have a sort of “gradient” of smiles. More people smile as the lecturer gets closer to the area you want them in. By the end of lecture, the lecturer will be pinned to the side of the room that everyone was smiling at and not even realize it.
Not only is it a funny little trick to pull on your professor, but is is an important experiment and has some interesting implications on behavior.
The reason that this experiment works is that behavior can be governed by feedback.Feedback is an important concept to grasp when thinking about psychology, the nervous system, or computer science and robotics.
Consider a pendulum clock. A pendulum clock works using feedback:
The pendulum wants to be hanging straight down, perpendicular from the x axis of the clock due to gravity/normal force. As the pendulum swings to one direction, the restoring force becomes stronger.
In this instance, the restoring force acts like an error signal. The varying strength of error signals is a huge part of the basis of how our nervous system, as well as our “psych” operate.
Here is the feedback “circuit” for our current experiment.
In this case, the error signals are the frowns. As the frowns become more in number, the lecturer is receiving negative feedback, higher error signal.