Theories of voter turnout pay increasing attention to ethical and social motives of voting, yet the empirical foundations of such perspectives are still scarce. In this chapter, we present the results of a laboratory experiment, conducted in two different countries, in which we manipulate the social conditions under which the elections take place. We find that both visibility and the possibility of administering and receiving sanctions boost voter participation by seven or eight percentage points. We also show that voters are willing to punish non-voters at a cost to themselves one third of the time and that receiving a sanction for non-voting increases the likelihood of voting in the next round by about eight percentage points. Overall, the results are consistent with a social norm model of voting.