Why Smart People Buy Bad Insurance

Losses loom larger than gains. — Daniel Kahneman and Amos Tversky, prospect theory (1979)

Sensible, numerate people routinely make the same insurance mistakes: they insure the trivial and skip the catastrophic. The reason is not stupidity but wiring. Psychologists Daniel Kahneman and Amos Tversky showed that the mind does not weigh risk the way a spreadsheet does, and a few of their findings explain most insurance errors.

Loss aversion means a loss hurts about twice as much as the same-sized gain feels good. So we overpay to avoid small, certain losses — the cracked phone, the cancelled trip — buying cover we do not need. The certainty effect means we place an outsized value on removing a risk completely, which sellers exploit with riders that promise to take a cost "to zero." Probability neglect means we badly misjudge rare events — either ignoring them or, once vivid, over-fearing them — which is exactly why the rare-but-ruinous risks get under-insured. And present bias makes us delay cover we will need later, because the cost is now and the benefit is distant.

The remedy is not willpower but a rule that sidesteps the wiring: insure by size of loss, not by feeling. Cover what you could not afford to lose, ignore what you could, and let a simple framework — not your gut — set the priorities.

Illustrative example: four traps, four mistakes

The list pairs each mental bias with the insurance error it causes — loss aversion, the certainty effect, probability neglect, and present bias. Knowing the trap is the first step to not falling into it.