Screams have an unique property that creates fear.
By Raif Karerat
WASHINGTON, DC: New research from New York University, published in the journal Current Biology, finds that among the sounds made by human beings, screams have an unique property that activates not only the parts of the brain involved in auditory processing, but also the brain’s fear response, designed to snap us to attention.
NYU psychology and neural science professor David Poeppel and his colleagues collected screams from YouTube, films, and 19 volunteers who screeched in a sound booth. The team measured sound properties, volume, and people’s responses to the screams via brain scans, then compared the data to that of normal speech, reported Time.
They found that screams, unlike regular conversation, up the activity in the amygdala, “a nucleus in the brain especially sensitive to information about fear,” Poeppel says, meaning screams are processed as a kind of alarm.
“There’s a part of the soundscape that’s reserved for screams, which is cool and weird — but it makes sense, because you want that sound to be specialized,” Dr. David Poeppel, a professor of psychology and neural science at NYU and one of the study’s authors, told The Huffington Post. “You want the signals you use for alarm purposes to be really unique, special and easily identifiable.”
While normal speech varies in loudness between 4 and 5 hertz, screams range between 30 and 150 hertz, reported USA Today. How fast that variation occurs is referred to as a sound’s “roughness.” The more roughness that a scream had, the more it activated the amygdala.
The findings might pave the way for more effective alarms — a rougher alarm signal might provoke more fear and be harder to ignore.
“You can make more effective alarm signals and scarier movies,” Poeppel told the Huffington Post. “[Using this research], you can modulate sounds in a very specific way.”