At the beginning of the study period, about half the comments expressed an extreme anti-immigrant view. By 2009, the extreme views had retreated to about 30 percent of the comments.
"You kind of feel like it would go in the other direction," said Benjamin Gibbs, a BYU professor. "In the end, my conclusion is that people want to be, or at least appear, reasonable."
The study was published in the journal New Media & Society. The Deseret News is owned by The Church of Jesus Christ of Latter-day Saints, which also owns BYU.
Researchers found the moderation effect also happened on a smaller scale as commenters on a single article thread became more moderate over time.
The findings run counter to the thinking among some scholars that the Internet is the "anti-commons," driving more extreme views and polarization in discussions and opinions. It remains to be seen, though, whether the results are applicable on other websites, issues or regions.
The Mormon church came out publicly in favor of a moderate approach to immigration in 2011, after the test period. The newspaper implemented a stricter comment moderation policy, focused on civility, in 2010; during the study period moderators filtered out primarily "profanity, links, and certain types of formatting," according to the study.
Gibbs and his colleagues call newspaper websites an "emerging public sphere" where people of differing opinions can join in a discussion, and the anonymous, somewhat de-centralized nature of the forums means people feel comfortable saying things they might not face-to-face.
"To me, this is a kind of unfiltered reaction to important news," Gibbs said.
The results of the study could be different if they had examined more polarized news or opinion pages.
The researchers looked at immigration because it is a contentious issue but the religious and moral lines aren't as sharply drawn as they are on issues such as abortion, Gibbs said.
And with a generally conservative population combined with a rapidly growing number of immigrants, Utah has a unique place in the debate. While it remains to be seen whether the results are reproducible, it's a subject that warrants further discussion, he said.
"We've got some work to do to see if it's really applicable anywhere else," he said. "I hope we encourage other scholars out there ... to study more of this."