Evangelicals are leaving the church because they are angry.
Roman Catholics are leaving because they feel betrayed.
And mainline Christians? They're leaving because they're bored.
Those are the findings of Elizabeth Drescher, author of a new book about why people are leaving their churches.
Drescher, who teaches religious studies and pastoral ministries at California's Santa Clara University, grew interested in the subject after seeing a jump in the number of Americans who identified themselves as not affiliating with any religion.
According to the Pew Forum on Religion and Life, a record 20 per cent of the U.S. population now say they are "nones" when asked what religion they belong to.
Since 70 per cent of this number once were part of Christian churches, Drescher wanted to know: Why are they leaving?
Over the past 20 months, while interviewing nones, she discovered some interesting things.
Evangelicals told her they left because they feel they were misled by church teaching about science, evolution and the environment.
"They feel they were tricked," she says. "It makes them really angry."
Roman Catholics left because they feel betrayed by the clergy sexual abuse scandals, and the church's attitude towards women.
"This is a big deal," she says of their decision to no longer call themselves Catholics. "It used to be that Catholics said they were former or non-practising or recovering, but now they are saying they aren't Catholic at all."
As for mainline Christians, they left because there's nothing new to learn at church.
"They're saying, 'we got the ethical lessons -- be nice, don't be a jerk. We don't need to hear that every Sunday. We have better things to do with our time'."
Although these "nones" no longer attend church, they haven't become atheists, she says. More than two-thirds believe in God, and over half pray on a regular basis.
Instead of seeking spiritual fulfillment in church services, they are finding it in what Drescher calls the "4Fs of contemporary spirituality: family, friends, food and Fido."
"People feel most connected to whatever they understand as God, the divine, a higher power when they're deeply engaged in the fabric of everyday life, spending time with family, with friends, preparing and sharing food, enjoying their pets," she says.
Interestingly, these are the same things that church-goers list as spiritually meaningful, she notes, adding that members of both groups rank attending worship services "as the least important way to experience God."
What can churches do to win back these "nones?"
First off, Drescher points out that the most of the "nones" she interviewed have no desire to return to church. But if they were to do so, they would be interested in churches that found new and unique ways to help them deepen their experience of God, and "connect to the world in meaningful ways."
By way of example, she points to how some churches are now taking services outside of their buildings to places like pubs and parks and doing things like "liturgical hikes" -- group hikes in nature that conclude with communion.
Practical involvement in the community and around the world is also important, she says, noting that a number of the "nones" said they admire Jesus.
"For half of the people I interviewed, the Jesus of radical compassion and justice remained spiritually and ethically significant, regardless of religious identification, affiliation or practice," she says, adding that some "nones" may be "yearning for a more ethically engaged, prophetic Christianity."
Drescher's research echoes similar studies by Reg Bibby of the University of Lethbridge, who has been studying religion in Canada for over three decades.
Although about eight million Canadians, or 25 per cent of the population, say they have no religious affiliation -- up 12 per cent since 1991 -- Bibby has found that a majority of Canadians still engage in personal religious and spiritual practices whether or not they go to worship services. Many also say that spirituality is important to the way they live their lives.
Drescher's findings will be published in her new book, titled Choosing Our Religion: The Spiritual Life of America's Nones, due out in fall, this year.