Scientists have found that people give off chemicals when they watch movies. It's not something (as you a person reading this knows) people consciously do. All living organisms from the smallest bacteria to the largest elephants emit chemicals into the environment. In many instances, those chemicals are used to send messages to nearby organisms.
These chemicals are less specific than pheromones. In the movie research study, ninety‑five hundred German moviegoers watched sixteen films which included comedy, romance, action, and horror movies.
The researchers classified scenes from the movies using labels such as suspense, laughter and crying. They also measured the concentration of over one hundred trace gases during the movie.
They found that many of the chemicals varied over time. They focused on carbon dioxide and isoprene which peaked at suspenseful moments. They attributed the spikes in carbon dioxide to increased pulse and breathing rate. The spikes in isoprene, a chemical associated with muscle action, were probably due to tense movie moments.
Scientists predict that future studies will measure heart rate, body temperature, and other physiological measurements during movies.
Williams, J. et al. Cinema audiences reproducibly vary the chemical composition of air during films, by broadcasting scene specific emissions on breath. Sci. Rep. 6, 25464; doi: 10.1038/srep25464 (2016).