First, by improvisation, I mean dramatic improvisation within a framework. For example, you are given a situation to play -- a doctor telling Character B she has cancer. You don't have a series of lines. Your job as an actor is to pursue an objective. In this case, it might mean to comfort her or it could be to scare her -- to shock her so she takes care of herself during treatment. Either way, you follow your objective as you would in life, by making stuff up that you hope will get you what you want.
These exercises are pretty common in acting classes here in the U.S.
But my teacher in the Russian version of the Stanislavski system said they used a similar approach when rehearsing plays. Generally, the practice here is that you're given a script. You read through it, seated. After discussions of motivations, actions, obstacles and given circumstances, you get the play up on its feet. That is, you start exploring movements that support the meanings of the text while you have the script in hand. In the meantime, you're memorizing the text by rote. The next step involves getting the actors off book and completely into the movement, or blocking on stage. The directors and other actors make adjustments and refinements. This is an oversimplified version of a complex process, but you get the picture.
How Some Russians Rehearse
In the System, though, the rehearsal process is radically different. First, the director reads through the play himself, out loud. Then the actors learn the beats or the actions of the play. Once they get those down, then they stand up and improvise their pursuit of those actions on stage, without the script. The actors are working to achieve their goals as set by the script, but without the lines in place, instead using their own words and physical actions. As the most juicy or most moving or most effective strategies are tried out and tested, the play develops. Then, the lines -- the playwright's text -- come into play. The actor, having worked with her guts and brain to pursue the objectives set in the text can now make use of it as an ally.
Again, this is a crude over simplification, and my apologies go out to the very sophisticated teacher who gave me this lesson.
I understand the rationale behind the first, more common method. It's fast, it's easier in many ways, and a set of professionals can get a whole play in shape in four weeks. Individual scenes can be done in hours, as in most television and movies, and made presentable. But I also wonder if that practice isn't responsible for a lot of the superficial work we see. Actors want to please and tend to rush to solutions. Reading text lends itself to "funny voices" -- to actorly readings that get ingrained.
This current acting class has reminded me of how difficult it is to act and deal with text at the same time. Training and practice can make that juggling act easier. But a fundamental split happens. The work isn't organic; it has less of a chance to come from the actor's own imagination and pursuit of her needs in the given circumstances.
I plan on using the latter method -- the method of action analysis -- the next time I rehearse. It places much higher demands on the director and on the actors' creativity. It may not work with actors who haven't been trained in the Russian version of the system, but I am going to experiment with it.
(Then there's the Mike Leigh/Cassavetes method of development which I purposely am not getting into here. For now.)