Stress seems to be detectable in air

Rigging a mass spectrometer into the outflow vent of the theater, the Kino Cinestar in Mainz, Williams had a sense that the experiment as something of a lark. “I thought, we’re probably just going to get a big mixture of popcorn and perfume,” he said. But, nonetheless, to measure relationships between scenes and gases, his team meticulously mapped out and labeled every scene in 16 films—from beginning to end. In 30 second increments, the team labeled each by its quality (kiss, pet, injury), as well as its emotional elements using a finite set of descriptors.

Their efforts were not entirely wasted. They published the findings this month in Scientific Reports, an open-access journal published by Nature. After measuring more than 100 chemicals in the theater air from 9500 filmgoers, the team saw some changes that stood out—at the same points, in almost every showing of some films.

In Hunger Games: Catching Fire, for example, during the “suspense” scenes—when Jennifer Lawrence was in particular danger—the carbon dioxide, acetone, and isoprene levels in the theater air predictably increased. The researchers speculate that this may have something to do with breath-holding, or stress hormone production—but it is all speculation. The important point was that the signals occurred at exactly the same time in all four screenings of the film. They also found the reproducible changes in the air chemistry during “humor” scenes in other films.