A new study examined the science of screaming, investigating why human take notice when they hear someone yell out. The Swiss university research team discovered that the root causes are human evolution and a certain brain structure linked to dangerous situations.
The study was conducted by the University of Geneva. They learned that humans' reaction to screaming is related to a brain part called the amygdale, which has a key role when people are in harm's way.
The amygdale is almond-shaped. It is located deep inside the medial temporal lobe of the human brain, according to IOL.
University of Geneva's neuroscientist Luc Arnal stated that the loudness of regular speech patterns range from 4 to 5 Hertz (cycles per second), while loud screams can alternate between 30 to 150 Hertz, according to Daily Times Gazette.
However, Arnal noted that it was not crystal clear why screams are unpleasant and unique, and how brains process the sounds. The research team discovered that the "roughness" or fast change in loudness, made screams different from all other sound waves.
They used functional magnetic resonance imaging (fMRI). This brain imaging method allowed the researchers to observe brain activity as a person yelped.
Researchers already knew that the auditory cortex and other brain regions were linked to speech processing. They also knew which sfrequencies speech signals used.
During their research the scientists learned that a person's screams can cause a bigger response of the amgydala, located in the cerebrum. It has an important job in motivation and emotional behavior.
Arnal shared that possible applications of his research team's study on human screams include the design of alarm sounds. A harsh noise could be added. It would be like the process of adding a bad smell to natural gas so it can be easily detected.
The study's findings were published in the journal Current Biology.