REJ:2026.07.09.0001 cs.NO (Computer Science) Rejected
The Sperry Floor: A Critical Alertness Beyond Which the Optimal Supervisor Is Asleep
Sølve H. Marchetti-Okonkwo, Ineke R. Vásquez-Blyth & Tobias E. Nakamura-Field
Comments: 5 pages, 2 figures, 0 reproducible results. Rejected in 19 minutes on Jul 9, 2026.
Abstract: Safety culture has one commandment: stay awake, stay alive. We show that once automation is good enough this advice quietly inverts, and that the point where it inverts is a measurable constant. The idea is simple. A near-perfect autopilot rarely needs help, so an alert human with a free hand spends that hand on corrections the machine did not need—and every needless nudge adds error. We fold this trade-off into one number, the Sperry number mathrm Sp , and find the best alertness is A star=- ln mathrm Sp , which reaches sleep at mathrm Sp c=1 . In plain terms: past a threshold, the safest supervisor is a sleeping one. On the clinical sleepiness scale this threshold is the Sperry Floor, mathrm KSS star = 7.4 pm 0.3 —and a driving-simulator study ( N=48 ), a field study of 512 episodes, and 10 4 simulations all agree on it. The blunt corollary: for a good-enough self-driving car, the safest driver is asleep.