 His study found that stress could be induced by cinema in segments of the general population, and "Jaws" specifically caused stress reactions in its viewers.While Johnson could not find an exact cause for the stress response in viewers, whether it be the suspense, the gore or the music production, a 1986 study by G. Sparks found that particularly violent films, including "Jaws", tended to cause the most intense reactions in viewers.Universal spent $1.8 million marketing "Jaws", including an unprecedented $700,000 on national television spot advertising.