Actors love improvising their dialogue. It makes them feel more in touch with the character. Directors tolerate improvisation: a chance to cut loose now and then keeps the actor fresh and engaged through multiples takes of the same scene. (Which sometimes leads to actors convincing themselves they improvised the dialogue for the entire movie: they remember than they improvised in this scene and that scene, and forget that the improvised take wasn’t actually the one that was used…)
So, if improvisation is so good for the on-set process, why isn’t it universally used? Why do writers bother writing dialogue at all?
Mainly because writers and actors have different instincts when it comes to dialogue.
When writing dialogue, a writer’s instinct is to BURY the true meaning under a layer of words. A character says “I heard you got the promotion”, but he means “You butt-kissing bastard, that job should have been mine.”
The actor’s instinct, as you might have guessed, is to EXPOSE meaning through dialogue. They pick up the script containing that line, and they use the tools at their disposal – voice, facial expression, phrasing, body language and sheer belief that they are that character – to bring the buried meaning back to the surface of their performance.
When the writers write the lines and the actors perform them, the two techniques are a perfect fit, and the script is given life. But what happens when the actors are writing the lines as well as saying them – that is, improvising?
Their instinct is still to expose character and meaning, not to bury it. So they tend to improvise lines that have all their meaning right on the surface, lines that say exactly what they mean. That’s pretty much the definition of melodrama – and without realizing it, they’re also making it impossible for themselves to do what they do best, excavate hidden meaning, so their performance becomes shallow and unconvincing.
There are a few exceptions: improvisation works well in comedy, but comedy is a form that thrives on surface meaning, on characters saying exactly what they’re thinking. There’s Mike Leigh – but even he eventually pins down a script that the actors stick to, and he selects his casts very carefully. And there are a few actors who understand the difference in the writing and acting processes and can switch between them.
But on the whole, when writers baulk at the idea of an actor improvising all their dialogue, we’re not being precious about our contribution to the film. We’re recognizing those two complimentary processes. So, let’s think of improvisation as a valuable tool for rehearsal, not a process to create filmable work…