I think certain movies work and that is part of the magic of it all. We can't truly define why something succeeds.

If you test Iron Man and that audience doesn't respond well, you can be damn sure that there is something wrong with the movie that you have to address. Because they're expecting a certain amount of action, right? They want a hero. There are certain things that have to be compatible with the way the audience is thinking about it. If you take some other film, like No Country for Old Men, you can end up with all kinds of crazy reactions.

I think we are seeing a radical shift in the business in general. The studios are making much more of the real big extravaganzas and there are other kinds of films that are coming out. I think you are going to begin to see more diversification that we've seen in the past.

Different reactions while film test screening doesn't mean even the audience thinks ambiguity is a bad thing. But if you're asking them right away to start checking things off, they don't know what to do. I think at their best, it applies to when the audience knows what it is. Then, when they say, "Oh, well, I thought it was too boring in blah-blah-blah part," then you better pay attention to it. It's like going for the hamburger. Better be the good hamburger I went for.

I play around with human things, human relationships and that, and allow that kind of talk to work in that way, on that level.

You don't always have to have the ending, but you want to have a satisfactory conclusion.

I got a chance to work with Mel Brooks on two of his films: Silent Movie and High Anxiety.