We show in a public goods experiment on three continents that conditional cooperation is a universal behavioral regularity. Yet, the number of conditional cooperators and the extent of conditional cooperation are much higher in the United States than anywhere else.

We show in a public goods experiment on three continents that conditional cooperation is a universal behavioral regularity. Yet, the number of conditional cooperators and the extent of conditional cooperation are much higher in the U.S.A. than anywhere else.

We show in a public goods experiment on three continents that conditional cooperation is a universal behavioral regularity. Yet, the number of conditional cooperators and the extent of conditional cooperation are much higher in the U.S.A. than anywhere else.

We show in a public goods experiment on three continents that conditional cooperation is a universal behavioral regularity. Yet, the number of conditional cooperators and the extent of conditional cooperation are much higher in the United States than anywhere else.