Milton Becknell, Michael Firmin, Chi-En Hwang, David Fleetwood, Kristie Tate, and Gregory Schwab, students at the University of Alabama, put together an experiment in 2008 designed to test the effects of rock and roll music on college students. Unlike many social experiments that examine behavior before and after listening to the music, they wanted to go a step further and see if rock and roll directly affected brain patterns. For this, they needed an electromyograph (EMG, a device used to study muscle activity) and some high-quality silver/silver chloride sensors.
Using, among other devices, an EMG and pre-gelled silver/silver chloride sensors attached to the skin at the frontalis (between the eyebrows) and masseter (above the turn of the jawbone) muscles, the scientists had the subjects listen to five minutes of generic heavy metal music, then five minutes of silence, then five more minutes of heavy metal. Their hypothesis was that heavy metal music would cause small physiological changes in the listeners, as compared to the control group, which listened to classical music.
Indeed, the EMG and the silver/silver chloride sensors did their jobs well: the subjects showed a distinct increase in muscle activity in the frontalis and masseter muscles of the group that was subjected to heavy metal, even though they were asked to relax and be still. More interestingly, the increase occurred strongly during the first music phase, and then again but more weakly during the second music phase, as though the physiological response had some become ‘inured’ over repeated exposure.
The scientists were aware of the potential of this effect, and they screened their subjects with a music preference survey prior to the study. They chose only subjects that didn’t list rock and roll as their music of choice, believing that frequent exposure to rock and roll would diminish the response to the music.
Perhaps the most striking finding: women’s physiological responses to rock and roll music are dramatically more profound than men’s, particularly in the masseter muscles. The scientists theorized that this may have an indirect relationship to women being more prone to grinding their teeth.