Probability Neglect
Focusing on the magnitude of a possible outcome while disregarding how likely it is.
How it is identified
Test: the decision responds to the size of a payoff or loss but is insensitive to changes in its probability
Unit
qualitative
In depth
Vivid outcomes crowd out probability, which is why people overpay for lottery-like payoffs and overinsure against dramatic but rare events while ignoring likely but dull ones. In markets it is why far out-of-the-money options attract buyers on the size of the possible multiple rather than the probability of expiring worthless, and why a story about a hundredfold return outweighs the base rate. Prospect theory's probability weighting function captures the pattern: small probabilities are overweighted and moderate ones underweighted. The correction is to compute the expected value explicitly, which forces the probability back into the arithmetic.
Worked example
An option costing ₹3,000 that could return ₹90,000 is attractive on the multiple. At a 3% probability of paying anything, the expected value is 0.03 x 90,000 = ₹2,700, below the ₹3,000 paid.
Illustrative figures, chosen so the arithmetic is easy to follow. Not a live price and not a valuation of any company.
Educational reference only
This entry explains what “Probability Neglect” means. It is not investment advice and not a recommendation to buy or sell any security. Any numbers above are illustrative, not live prices, and nothing here predicts price direction or rates a stock. Consider your own circumstances and consult a SEBI-registered investment adviser before acting.