In response to mass shootings, some schools and hospitals are installing microphones equipped with algorithms.

Jack Gillum and Jeff Kao:

Ariella Russcol specializes in drama at the Frank Sinatra School of the Arts in Queens, New York, and the senior’s performance on this April afternoon didn’t disappoint. While the library is normally the quietest room in the school, her ear-piercing screams sounded more like a horror movie than study hall. But they weren’t enough to set off a small microphone in the ceiling that was supposed to detect aggression.
A few days later, at the Staples Pathways Academy in Westport, Connecticut, junior Sami D’Anna inadvertently triggered the same device with a less spooky sound — a coughing fit from a lingering chest cold. As she hacked and rasped, a message popped up on its web interface: “StressedVoice detected.”
“There we go,” D’Anna said with amusement, looking at the screen. “There’s my coughs.”
The students were helping ProPublica test an aggression detector that’s used in hundreds of schools, health care facilities, banks, stores and prisons worldwide, including more than 100 in the U.S. Sound Intelligence, the Dutch company that makes the software for the device, plans to open an office this year in Chicago, where its chief executive will be based.