No man or woman is an island, not even in that sacrosanct chamber of democracy known as the ballot box. That’s because the nature of an assigned polling place can, without people knowing, sway how they vote — enough to swing a close election, a new study indicates.

In a 2000 statewide election in Arizona, a greater proportion of people who voted at schools supported a school-funding initiative than did people who voted at churches or other polling places, say marketing professor Jonah Berger of the University of Pennsylvania in Philadelphia and his colleagues.