clipped from www.newyorker.com

Americans may want to buy the biggest and most environmentally damaging vehicles available, but polls show that, given an option, some three-quarters of them vote for dramatic increases in fuel-economy standards

Back in the nineteen-seventies, an economist named Thomas Schelling, who later won the Nobel Prize, noticed something peculiar about the N.H.L. At the time, players were allowed, but not required, to wear helmets, and most players chose to go helmet-less, despite the risk of severe head trauma. But when they were asked in secret ballots most players also said that the league should require them to wear helmets.

The players wanted to have their heads protected, but as individuals they couldn’t afford to jeopardize their effectiveness on the ice. Making helmets compulsory eliminated the dilemma

Without the rule, the players’ individually rational decisions added up to a collectively irrational result. With the rule, the outcome was closer to what players really wanted.