Luc Arnal

But what makes screams so special and unpleasant and how the brain processes these sounds was not clear.

Normal speech patterns only have slight differences in loudness, between 4 and 5 Hertz (sound wave cycles per second), but screams can modulate very fast, varying between 30 and 150 Hertz.

In terms of potential applications, our findings could be used to improve the way we design alarm sounds. 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.

I started being interested in screams when a friend of mine told me that the sound of his newborn's screams was literally hijacking his brain, and I wondered what makes screams so efficient as an alarm signal.

Everyone is familiar with those lights that flash superfast in clubs, screams could be considered as strobophones, since they are modulating very fast in an analogous way in the auditory domain.

We even saw that this observation remained true when we compared screaming to singing and speaking, even across different languages.

Roughness refers to fast sound changes in loudness (in a 30-150Hz frequency range) of a sound that can be high-pitched or not.

We found that the rougher the sound, the stronger the response in the amygdala, the part of the brain involved in fear reactions.

Well yes, our results definitely show that rough screamers are the best candidates to make great horror movie actresses and actors.