Special Part of Brain Registers Screaming, Scientists Find
The "acoustic roughness" of screaming selectively activates the amygdala, involved in danger processing, concludes the study. A rough sound is not how people typically describe a scream, though.
"If you ask a person on the street what's special about screams, they'll say that they're loud or have a higher pitch," says study senior author David Poeppel, PhD, head of the speech and language processing lab at New York University.
"But there's lots of stuff that's loud and there's lots of stuff that's high pitched, so you'd want a scream to be genuinely useful in a communicative context."
There was no repository of human screams, the researchers found, so they used recordings from YouTube and popular films, as well as volunteer screamers in the lab's sound booth.
The team plotted the sound waves "in a manner that reflects the firing of auditory neurons," and they noticed that screams activate a range of acoustic information that scientists had not considered to be important for communication.
"In a series of experiments," explains Prof. Poeppel about the uniqueness of the sound, "we saw [that] this observation remained true when we compared screaming to singing and speaking, even across different languages.
"The only exception - and what was peculiar and cool - is that alarm signals (car alarms, house alarms, etc.) also activate the range set aside for screams."
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