The Science Of Scary: 10 Reasons Why You Love Being Scared
9. Why Are Screams Scary?
Nothing makes the blood run cold quite like a piercing shriek of terror, but what is it about screams that make them so blood-curdling?
Well, scientists reckon its because there's nothing else like it in all of human communication. A lot of our communication is pretty similar, it's quite easy to mistake friendly banter for an argument if you can't heart what's being said, but there's no mistaking a scream.
David Poeppel of New York University conducted a study in which he analysed the qualities of different human sounds and found that the frequency of a scream varied wildly compared to normal speech, fluctuating between 30 to 150 hertz, giving it a quality that Poeppel calls its "roughness". Turns out, the rougher the sound, the scarier it is.
It was found that people listening to screams with more modulation had more activity in their amygdala, a portion of the brain activated by fear and danger.
This is the same reason why sirens and alarms modulate up and down, it makes them unsettling and difficult to ignore. Evolutionary biologists are beginning to wonder why this "roughness" makes us feel so uneasy, it could be something to do with the warning calls of primates, signalling when danger was near, which are basically the alarms of the animal kingdom.
Either that or, you know, something bad is usually happening when somebody screams.