Psychophysical numbing
Each additional life saved feels less valuable as the numbers grow.
What it means
The diminishing emotional and evaluative response to increases in the number of people affected by a harm or helped by an intervention, so that the felt difference between saving 0 and 100 lives dwarfs the felt difference between saving 100,000 and 100,100. Modeled on the psychophysics of sensation — where the just-noticeable difference grows with the baseline stimulus — it implies that human value for lives follows a concave, compressive curve rather than scaling linearly with the count. The phenomenon is a key mechanism behind scope insensitivity and compassion fade, and it has unsettling implications: it can make a single death feel weightier than a distant catastrophe and can blunt response to mass suffering. It matters for humanitarian appeals, public-health triage, and policy, where decisions ideally scale with magnitude but human feeling stubbornly flattens as the numbers climb.
Examples
People are willing to spend roughly the same to save lives whether the at-risk group numbers in the thousands or the millions, because the larger figure does not feel proportionally worse.
Lifting a screening programme from 100 lives saved to 200 feels like a breakthrough; lifting one from 10,000 to 10,100 feels like a rounding error, though both add 100 people.
A safety fix that spares ten workers a year is fought for in the meeting; the same fix bolted onto a scheme already sparing ten thousand barely gets mentioned.
First described in Fetherstonhaugh, Slovic, Johnson & Friedrich (1997).