Researchers have also looked at the impact of social pressure on voting behavior. Not surprisingly, fear of public exposure can motivate people to get to the polling place. A political scientist named Donald Green mailed out letters to about 90,000 Michigan households before the 2006 primary election. An additional 90,000 households received no letters. Four different letters were sent out. One letter simply reminded people of their civic duty to vote, the second letter reminded the recipients that voting records (whether or not people voted) were publicly available. The third letter included information on recipients’ previous voting behavior and the fourth letter listed the past voting behavior of recipients’ neighbors. It also stated that the recipients’ own voter turnout would be reported in another letter sent out to their community. Recipients of the fourth letter showed the greatest increase in voter turnout (8.1 percent), followed by recipients of the third letter (4.9 percent), and the second letter (2.5 percent). Recipients who were simply reminded of their civic duty to vote only increased their turnout by 1.9 percent.