So it turns out sitcoms can erase bigotry.

That’s the bottom line of a study recently presented before a conference of the Society for Personality and Social Psychology. And it doesn’t even have to be a particularly good sitcom.

To judge, at least, from a screening of its first two episodes, the Canadian sitcom on which the study is based was earnest, amiable, and about as funny as Schindler’s List. Apparently, however, Canadian television viewers liked it well enough. Little Mosque on the Prairie, a culture clash show about life at a Muslim worship house in small town Canada, premiered in 2007 and ran for five years. Here in the United States, it’s available on Hulu.

Sohad Murrar, a doctoral candidate in social psychology at the University of Wisconsin at Madison, used the show to test whether entertainment media can reduce prejudice. She gathered a representative sampling of white men and women between the ages of 18 and 60, first testing them to establish a baseline measurement of their prejudices. Then they were divided into two groups. One was assigned to watch episodes of Friends. The other watched Little Mosque.

Afterward, when Murrar again tested the groups for prejudice, she found that while the Friends group showed no movement, there was a reduction in anti-Muslim bias among those who had watched Little Mosque. Nor was this a fleeting thing. Four to six weeks later, the Little Mosque group still showed less bigotry.

The study participants, she says, “were identifying with the characters. Just seeing these characters, these Muslims, go through everyday life situations that they themselves could imagine themselves in or they themselves could relate to . . . kind of led our participants to feel like, ‘Hey, yeah, that’s something I myself could experience.’ ”

Prejudice, she notes, derives from the identification of an “in” group and an “out” group and the social distancing of the former from the latter. It’s a process some have dubbed “otherization.”

For all that academia and news media might do to combat that process, entertainment media are uniquely positioned to neutralize it. It is one thing, after all, to read statistics or hear arguments on the humanity and equality of, say, African Americans. It is quite another to have Anthony Anderson in your den every week giving you belly laughs or to root for Denzel Washington shooting it out with bad guys on the big screen.

Murrar’s study is only the latest to quantify this. And mind you, some of us didn’t even need a study to know it. Some of us have always regarded the likes of Sidney Poitier and Diahann Carroll, Ellen DeGeneres and Will and Grace, Mary Tyler Moore and Cagney and Lacey as the unsung heroes and secret weapons of the movements for African-American, gay and women’s freedom.

Still, Murrar’s study underlines a truth often overlooked when the talk turns, as it has with this year’s snow white Oscar nominations, to Hollywood’s dubious track record on diversity. Namely, that inclusion is not some enlightened sop to political correctness. Nor is it just good business, though it is that.

Rather, inclusion changes the society itself. It lessens fears, opens eyes, unsticks hearts, makes people better. What exclusion otherizes, inclusion normalizes.

In a nation that has seen Islamophobia rise with the inexorability of floodwaters and racial animus spike to levels not seen since Jim Crow, a nation where Holocaust survivors say a leading presidential contender actually reminds them of Hitler, that’s no trivial thing. There is a great power here and those of us who have been too long defined as “other” must use every form of pressure we can to ensure that that power includes us in the circle of what America deems “normal.”

Or else find more constructive uses for our money and our time.