When people watch movies together, they oftentimes blink in unison and their brain activity is almost mirrored. That came out in a study back in 2004.

Well, now the researcher at the head of that project is looking at the impact of movies have on the human brain, again, by using his knowledge to track audience engagement in films. Whether this'll be put to the actual test during screenings is another story.

Princeton psychology professor Uri Hasson says this research could be used for screenplay writers who are trying to get a specific reaction from viewers or, on the flip side, hoping viewers will have different interpretations of the same movie.