This is a subject that has been studied quite a bit, as there are a bunch of jobs where people have to monitor for rare emergencies, and react fast if an emergency should arise. Things like pilots on flights with autopilot; lifeguards watching for swimmers in distress; CCTV monitoring; operating airport X-ray machines, and so on.

One such study is "Performance consequences of automation-induced 'complacency'" (Parasuraman, Molloy & Singh, 1993) https://www.pacdeff.com/pdfs/Automation%20Induced%20Complace...

Previous studies had found that a human and a computer performed markedly better than either a human alone or a computer alone - but in those studies failures were quite common, so they didn't give the humans time to get bored or distracted.

When researchers got test subjects to perform a simulated flying task, monitoring a system with 99%+ reliability, they found the humans were proportionally much worse at stepping in than they were on less reliable systems.

Swimming pool lifeguards will often change posts every 15-20 minutes and and get a 10-15 minute break every hour, to keep things interesting enough that they can pay attention. Good luck getting drivers to do that.

> Things like pilots on flights with autopilot;

Funny, I was going to mention exactly that. I'm a private pilot with a modern autopilot and flying is exhausting. Partly because the piston engine is rattling your brain the entire time but also because you're on high alert the entire time. You're always making sure the autopilot is keeping the plane on the blue (or green) line and is being predictable. And my smartwatch shows my heart rate is usually more elevated on autopilot than not.