Go on. Do it. Let all of the angst, fear and anger out. Just open your mouth and scream at the top of your lungs. Feels kind of good, doesn’t it? I’ll give you a moment to phone your neighbors (at least the ones who care) and let them know you’re not in harm’s way. Now let’s get into the science of screaming.
A scream of frustration or relief is a different animal than a scream of terror. Researchers from the University of Geneva, New York University and elsewhere have recently released a report on Current Biology detailing how “roughness” affects the human brain’s response to what a layperson might describe as a horrifying scream. “Roughness” can be defined as the speed at which the volume of a particular sound alters over minute portions of time. It turns out that screams, the really attention-grabbing ones, aren’t just high and shrill (that could just be a loved one asking you to take out the trash) — they’re also a lot rougher than other sounds. In other words, they change volume significantly over short time slices.
By measuring the modulation power spectrum (MPS), a “recently developed, neurally informed characterization of sounds,” researchers discovered that the roughness of a sound (like a scream) in human beings and artificial alarm systems stabs right into the amygdala area of the brain. The amygdala is a grouping of neurons dealing with a variety of emotions, but for the purpose of a blood-curdling scream, it processes fear and fear response. The swift volume spikes (30 to 150 hertz) in a “killer” scream (hopefully the screamer isn’t actually being murdered) cuts through sound traffic, letting the listener locate the direction of the scream in short order while jolting the mind and body into an alert status, ready for immediate action.
By testing roughness on study participants, the team was able to determine how a rough signal affects the brain, which in turn helped them gain insight into this primal form of communication. A good scream — as well as someone’s reaction to said scream — “confers a behavioral advantage to react rapidly and efficiently,” the report states.
In Jerry Seinfeld’s web series “Comedians in Cars Getting Coffee” (bet you didn’t see that twist coming), Jerry describes pain to Trevor Noah as “knowledge rushing in to fill a gap.” Stubbing your toe on the foot of the bed (which really hurts), he points out, was a “gap in knowledge” that a shot of quick pain quickly corrects. A scream of terror — as far as the brain and body response are concerned — it seems, is another biological mechanism that floods the brain with vital information almost instantaneously.
The information a scream of terror communicates is simple: You need to be ready for flight or fight right now — irrespective of the fact that you might not be clear of the danger coming your way. If you wait a few seconds to react, it could be too late. So thank you, terror screams, for all of those evolutionary advantageous heads ups you’ve given us over the years.
Carl Pettit is a contributing journalist for TheBlot Magazine.