Spending lots of time on the internet doesn't make you more gullible - but reading rumor-filled emails does, say researchers.
People seem to be wary about rumors they read on websites and blogs, and will generally check whether they're true, says R Kelly Garrett, assistant professor of communication at Ohio State University.
However, they're much more likely to believe false rumors that they receive in emails from friends and family.
"The problem is that we are more likely to let our defenses down when we’re dealing with our friends, which is why email can have such harmful consequences. We don’t normally question what our friends tell us," he says.
Garrett tested out several rumors, true and false, on 600 Americans in November 2008, immediately after the presidential election.
Participants were asked about their exposure to 10 rumors about the two major presidential tickets, Obama-Biden and McCain-Palin.
These included eight patently false statements, such as "Barack Obama is a Muslim" and "While serving as the Mayor of Wasilla, Alaska, Sarah Palin successfully banned several books from the local library", as well as two true ones.
The results showed that people who regularly used the internet and online sources of political information did come across more rumors about the candidates - and the more rumors a person heard, the more they believed. Mud sticks, and for every two rumors that a person heard, Garrett found that the number they believed increased by one.
When Garrett separated out different sources of political news, he found that using voter information websites and the websites of major news organizations didn't increase exposure to rumors. However, use of political blogs and email from friends and family did, leading to what he calls a 'particularly vicious' feedback loop of rumor-mongering.
The more political emails that participants received from friends and family during the 2008 election, the more rumors they were likely to believe. And the more rumors they believed, the more political emails they sent.
"It is a self-reinforcing process that seems to amplify rumor beliefs through repetition," says Garrett. "We have people who are biased to accept the rumors they receive from friends, which leads them to forward the e-mail to other friends, who repeat the process over and over again."