The 15-minute short film, Many Worlds, described as a bizarre physics experiment, has an alternate ending for every viewing, and decides between its endings based on how the audience reacts during the screening.
Before the film airs, audience will be strapped with small sensors to help measure their heart rate, muscle tension, brainwave activity, and how much they’re sweating. These data help the movie identify the interactivity level and mood so the film can select upcoming scenes accordingly. If an audience is feeling restless, the movie may insert intense, slow music to induce fear. If an audience is bored, an exciting action sequence may appear to keep their attention. It’s basically a Choose Your Own Adventure-type film, except all the choosing magically appears according to the way your body reacts.
In Plymouth, U.K, movie watches you (and changes endings depending on your reaction)
by Natt Garun
http://www.digitaltrends.com/international/in-plymouth-u-k-movie-watches-you-and-changes-endings-depending-on-your-reaction/