We instinctively know that a scream can make us feel frightened, but exactly how this happens is less well-known. Reporting in Current Biology, neuroscientist David Poeppel and his team found that “roughness”—an audio quality not found in speech—determines the scare factor. Of his research, Poeppel says, “We wanted to go through a whole bunch of sounds to verify that this area is unique to screams.”