Jarring music such as Jimi Hendrix's rendition of The Star-Spangled Banner works because it evokes primitive distress calls, say scientists.
"Music that shares aural characteristics with the vocalizations of distressed animals captures human attention and is uniquely arousing," says Daniel Blumstein of UCLA.
Blumstein teamed up with Peter Kaye, a Santa Monica–based composer of movie and television scores, and Greg Bryant, an assistant professor of communication studies who's also a musician and recording engineer.
Using synthesizers, they composed a series of ten-second music pieces of several types or 'conditions'. "We wanted to see if we could enhance or suppress the listener's feelings based on what's going on with the music," says Blumstein.
In the control condition, the music was generic and emotionally neutral, without noise or abrupt transitions in frequency or pitch - elevator music, in other words. This was compared with music that began in an easy-listening manner but then suddenly broke into distortion, much as Hendrix famously did at Woodstock.
After listening to both types, students were asked to ratem based on two factors: how arousing they found the music, and whether the emotional feeling in the music was positive (such as happy) or negative (such as fear-inducing or sad).
And when the music featured distortion, subjects rated it as more exciting, and were more likely to describe it as charged with negative emotion.
The researchers believe the effect of listening to music with distortion is similar to hearing the cries of animals in distress. Thisdistorts animals' voices by forcing a large amount of air rapidly through the voice box.
"This study helps explain why the distortion of rock 'n' roll gets people excited: It brings out the animal in us," says Bryant.
"Composers have intuitive knowledge of what sounds scary without knowing why. What they usually don't realize is that they're exploiting our evolved predispositions to get excited and have negative emotions when hearing certain sounds."