ACHIEVING Utopia might require a stick rather than a carrot. Punishment seems to be a necessary evil in the pursuit of a common good.
Participants in an investment game each received 20 tokens to invest over 30 successive rounds. Payments were made into a central fund and investors had to rely on the goodwill of others to swell the common fund. Players could choose between two groups: in one, they were able to punish those who did not contribute.
Although two-thirds of the 84 participants opted initially for the non-punishing group, players flocked to the punishing group when it became…
