Prepare to cringe. Nails on a chalkboard has company.
Researchers from Newcastle University endured the most spine-tingling sounds to determine the five worst offenders to the human ear. Based on the way our brains and bodies react, the scientists found that nails on a blackboard is only the fifth-worst sound in existence, according to a study published in the Journal of Neuroscience.
And while chalkboards are no longer commonplace in our society, the worst transgressors—a knife and a bottle—certainly are.
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Following up that screeching sound of horribleness that is a knife scraping a bottle is something similar, a fork on glass. Ouch! Beyond that we have chalk on a blackboard in third and a ruler on a bottle in fourth. Fingernails on a blackboard is fifth.
But all the noises have one thing in common: the sounds falls within the frequency range of 2,000 to 5,000 Hz, the same range that includes human screams. Our brains don’t like that much.
As the paper’s author Dr. Sukhbinder Kumar notes, that’s the range where our ears are most sensitive, so the findings weren’t all that surprising. In the study, Kumar and Newcastle researcher Tim Griffiths brought volunteers into the Centre for Neuroimaging at University College, London. From there, the volunteers were subjected to excruciating noises while their brains underwent MRI scans, according to The Guardian. The worse the sound, the more heightened of a response the auditory cortex gave to the amygdala, the area of our brain that regulates negative reactions, the paper says.
“It appears there is something very primitive kicking in,” Kumar writes. “It’s a possible distress signal from the amygdala to the auditory cortex.”
Of the 74 different noises tested out, volunteers got a reprieve when met with babbling water, the most well-adjusted of the sounds.
Want to listen yourself? Here they are — if you dare.
Knife on bottle:
[soundcloud url=”http://api.soundcloud.com/tracks/62796068″ iframe=”true” /]
Fork on glass:
[soundcloud url=”http://api.soundcloud.com/tracks/62796143″ iframe=”true” /]
Chalk on blackboard:
[soundcloud url=”http://api.soundcloud.com/tracks/62796176″ iframe=”true” /]
Ruler on bottle:
[soundcloud url=”http://api.soundcloud.com/tracks/62796238″ iframe=”true” /]
Nails on blackboard:
[soundcloud url=”http://api.soundcloud.com/tracks/62796264″ iframe=”true” /]
(Audio courtesy of the study’s funder, Wellcome Trust.)