When I tell people that I’m a part of an improv group, they assume that I do stand-up comedy and immediately ask me to tell them a joke. I then have to do the brief explanation that improv is a group “sport” where we create scenes on the spot based on a suggestion from the audience and the funny comes from the situations, characters, and/or unplanned dialogue that occurs with my scene partners. Then with confused looks on their faces they ask me why we rehearse.
I understand the logic that
if our show is made up on the spot then why should we rehearse. The misconception is that we are rehearsing what we will be saying and doing at our show but I can assure you that there is no prior preparation for that. We are rehearsing basic scene work. When you are a part of a play you are given the script that already has all the lines that your character will be saying. But during the rehearsal process for the play you are not only memorizing those lines but exploring how your character walks, talks, thinks, reacts, etc. You also start to focus on how your character feels and reacts to different characters and situations. You get props to practice using them. The scenes get blocked meaning that you know where and when you will be walking and what area of the stage will be used for each scene. All of those things combined gives you a play.
But for improv we have a few seconds to make all those decisions. We are making up our lines as we go along while figuring out our character and how we want to walk and talk. We don’t have any props so we need to find clear ways to convey our environment/location to the audience. We have to figure out our blocking on the fly. And we need to figure out what the scene is about. We have to be able to communicate all of this with one glance or one phrase to our scene partners. And we have to do all that while, hopefully, being funny.
So when we rehearse we are trying to work on our skills to be able to do all the above and more while making it look flawless. If we do it right then it looks like we rehearsed it exactly that way.