It’s hard for moviegoers to forget a scream like Janet Leigh’s in the shower scene from Alfred Hitchcock’s “Psycho” movie. Now, a new study has unraveled the mystery behind these effective hair-raising screams. According to the research, carried out by a team of experts from the University of New York (USA), there are voices whose vocalization has special acoustics, with auditory qualities that our brains recognize and to which they react by making our speech system jump. alert or possible danger.
“If you ask a person on the street what is special about screaming, they will tell you that they are loud or have a higher pitch. But there are a lot of things that are noisy and there are many other things that have a high tonality, so more input is needed for a shout to be really useful in a communicative context ”, explains David Poeppel, leader of the study.
To find out why there are screams that frighten us in such a particular and conspicuous way, the researchers traced the sound waves of various screams in a similar way to how auditory neurons behave , discovering that screams occupy a reserved space of the hearing spectrum that it is not used during normal speech, a “privileged place” in human-to-human communication.
What happens is that the screams have a unique vocal characteristic: harshness . But what is “rough” in a scream ?; A shrill voice, perhaps? “Roughness refers to the rapid changes in the volume of a sound (in a frequency range of 30 to 150 Hz) that may or may not be high-pitched,” clarifies Luc Arnal, co-author of the study.
In the next part of the experiment, the scientists asked the participants to listen to different human screams, alarms, bells, car horns … and to compare them with the control sounds. The results revealed that the screams and sounds classified as the “harshest” were the most terrifying for the participants .
“We found that the harsher the sound, the louder the response in the amygdala, which is the part of the brain involved in fear reactions. These findings suggest that the design of red flags can be further improved . In the same way that an unpleasant odor is added to natural gas to make it easily detectable, adding harshness to the sound of alarms could improve and speed up processing, ”concludes Poeppel.
