Possibility effect

Biological Parallel

Organisms overweight small probabilities when consequences are fatal—the possibility effect made flesh. Meerkats maintain 20-minute sentinel shifts (2024 study) despite predator attacks occurring in under 1% of shifts; the rare event justifies constant overhead. Vervet monkeys evolved three distinct alarm calls for leopards, eagles, and pythons—each predator type rare (<5% annual encounter rate) but one mistake ends your genetic line. Ground squirrels dedicate 15-20% of active time to vigilance scanning despite predation accounting for only 11% of adult mortality annually. The pattern is universal: rare catastrophes (predation, drought, starvation) shaped evolution disproportionately because frequency-weighted decision-making loses to tail-risk weighting. Your fear of unlikely plane crashes or shark attacks reflects millions of years encoding 'rare but fatal' deeper than 'common but minor.' Businesses exhibit the same bias: insurance markets price tiny probabilities of catastrophic loss far above expected value; Y2K spending reached $300B globally for a low-probability event. Probability weighting isn't a cognitive bug—it's evolutionary design.