When you’re watching a film, does your heart race?  Do you sweat with fear or excitement?

Would you like the ending of the film to change depending on how you react to it?

New technology is making it possible.  You wear a sensor on your wrist, connected via bluetooth to your smart phone running an app.  As you watch a film, it records your reactions.  Later you can see how you compare to other people watching the film, and see which parts made you react most.

The researchers are working on films with multiple endings and different musical scores, with the aim that what you see will be controlled by your reactions.

It might be interesting, but one of the things I like about films is discussing them with people afterwards.  How can you do that if you didn’t see the same as your friends?