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A media alert for the journal Current Biology.
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Media Contact: Joseph Caputo | Cell Press
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STRICTLY UNDER EMBARGO UNTIL 12:00PM NOON ET (US) ON THURSDAY, JULY 16, 2015
Region(s) of Interest: United States, New York; Switzerland, Geneva; Germany, Frankfurt
Institution(s): New York University, University of Geneva, Frankfurt Max Planck Institute
The Emerging Science of Human Screams
Our noisy world is no match for a screaming infant.
An airplane could be flying by as a house party
rages on downstairs while a literal cat fight takes
place outside, and still a wailing baby will win your
attention. One possible explanation, published July
16 in the journal Current Biology, is that human
screams possess a unique acoustic property found
to activate not just the auditory brain but also the
brain's fear circuitry.
"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, who heads a 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."
Humans make a variety of meaningful noises. Part of what makes us human is how our ears can
distinguish speech patterns made from vowels and consonants, which is a step above being able to
identify whether a sound is made by a male or female, or by our species or another species. Where in
the brain we process this information is known, but there was one area that scientists assumed didn't
have much to do with human communication. This is where screams come in.
After noticing how little research had been done on human screams, Poeppel's post doc Luc Arnal,
now at the University of Geneva, led a series of studies to analyze the properties of screams.
Because there is no repository of human screams, the researchers used recordings taken from
YouTube videos, popular films, and volunteer screamers, who were asked to give their all in the lab's
sound booth. The researchers 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 hadn't
considered to be important for communication.
"We found that screams occupy a reserved chunk of the auditory spectrum, but we wanted to go
through a whole bunch of sounds to verify that this area is unique to screams," says Poeppel, who
also directs the Frankfurt Max-Planck-Institute Department of Neuroscience. "In a series of
experiments, 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."
What sets screams and alarms apart from other sounds is that they have a property called roughness,
which refers to how fast a sound changes in loudness. Normal speech patterns only have slight
differences in loudness (between 4 and 5 Hz), but screams can modulate very fast (varying between
30 and 150 Hz). When Arnal and his team asked people to judge screams on how frightening they
were, those with the highest roughness came across as the most terrifying. Modifying the sound wave
of a non-scream to be rougher can also make it scream-like. The researchers then confirmed that
increases in roughness correspond to more activation of the fear response in the human amygdala.
The finding is also evidence that acoustical engineers have been tapping into the property of
roughness just by trial and error. Alarms and movie shrieks do their job of getting our attention, but
perhaps they can be better. "These findings suggest that the design of alarm signals can be further
improved," Arnal says. "The same way a bad smell is added to natural gas to make it easily
detectable; adding roughness to alarm sounds may improve and accelerate their processing."
The researchers plan to continue investigating human screams in the lab, particularly those of infants,
to see if their screams are particularly rough. The researchers would also like to apply their analyses
to animal screams to learn how much this trait is conserved across species.
"Screaming really works," Poeppel says. "It is one of the earliest sounds that everyone makes--it's
found across cultures and ages--so we thought maybe this is a way to gain some interesting insights
as to what brains have in common with respect to vocalization."
###
Your readers are invited to ask further questions by tweeting senior author David
Poeppel @davidpoeppel
This work was supported by the National Institutes of Health, the Fondation Fyssen, the Philippe
Foundation, and the Fondation Louis Jeantet.
Current Biology, Arnal et al.: "Human Screams Occupy a Privileged Niche in the Communication
Soundscape" http://dx.doi.org/10.1016/j.cub.2015.06.043
In online coverage, please mention the journal Current Biology and link to the paper
at http://www.cell.com/current-biology/abstract/S0960-9822(15)00737-X
Related Files: https://www.dropbox.com/sh/3jkz0zvaq1pg2yc/AABX_qnijGrOgeAwd-SwYzsSa?dl=0
This Dropbox contains:
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
A PDF of the paper proof.
A conceptual image of roughness (Credit: Luc Arnal)
Author Contacts:
David Poeppel
New York University and Max-Planck-Institute
Mobile (US): +1 347 407 4447.
Work (Germany): +49 151129 6-142
Secretary (Germany): :+49 69 8300479-301
[email protected]
Note: Dr. Poeppel is at the Max-Planck-Institute through July 19
Luc Arnal
University of Geneva
Mobile: +33 6 38 61 46 90
[email protected]
Media Contacts:
James Devitt
New York University
212.998.6808
[email protected]
Victoria Monti
University of Geneva
+41 (022 37) 94 158
[email protected]
IMAGES:
Image 1:
Caption: A conceptual image of roughness
Credit: Luc Arnal
AUDIO:
Audio 1:
Artificial alarm rough
Audio 2:
Human scream rough
Audio 3:
Human voice not rough
Audio 4:
Instrument flute not rough