In a 1992 survey by W. H. Desvousges and colleagues, people were told that birds were dying because they became mired in uncovered pools of oil at refineries. This (fictitious) problem could be solved by putting nets over the pools. The experiment asked participants to indicate how much they would be willing to pay for nets to save the birds The researchers tried telling different groups that 2,000 birds were being killed a year — or 20,000 birds, or 200,000 birds. The answers didn’t depend on the number of birds! In all cases, the average dollar amount was $80. Evidently, all that registered was A lot of birds are being killed. We should do something about it.
Excerpt from: Priceless: The Myth of Fair Value (and How to Take Advantage of It) by William Poundstone