Charles (Chuck) Bryant

Like that's the only sound a human can make that's like that.

The only other sounds are all artificial alarms.

So the human screen lives in the rough disc domain alongside sirens and car alarms and, you know, just other, like a klaxon maybe.

Yeah, I mean, because that's the sound that happens when a nuclear facility is melting down.

Yeah, so thanks NYU for that, right?

Yeah, so then they said, all right, we got all this collection of sounds.

Neutral sounds is what we'll call the ones that aren't screams.

And then the screamy things.

And they brought in some other volunteers, other NYU students for sure, and said, all right, we want you to rate the scariness, like maybe on a 1 to 10, 1 to 5, who knows what they used.

Maybe a Yelp star system.

Okay.

And they said, rate the scariness of the sounds.

All the sounds in the roughness domain are,

this is pretty obvious, were rated as scarier than the neutral sounds.

Sure.

And the sounds that were rated the scariest were the ones that were highest on the roughness scale.

All makes sense.

So the upshot, to borrow a term from Josh, is that it seems like humans are specifically attuned and our amygdala is specifically activated by the sound of a scream to say like, hey, it's time to panic or it's time to kick into high gear.

They found that this works if you're awake or asleep.

The rough vocalizations in that rough domain that we were talking about penetrate human sleep cycles more than neutral vocalizations.