A new study has found that Catholics now have the lowest proportion of "strongly affiliated" followers among America's major religious traditions, while evangelicals are growing stronger in their devotion to their faith.
Philip Schwadel, a sociologist at the University of Nebraska-Lincoln, whose findings rely on a survey conducted among a cross-section of Americans on an annual or bi-annual basis since 1974, notes that from about a 5-percentage-point difference in the 1970s in how strongly Catholics and evangelicals felt about their religion, it has increased to around 20 percentage points today.
Roughly 56 per cent of evangelicals now say they're strongly affiliated with their religion, as opposed to 35 per cent of Catholics who say the same. Mainline Protestants also have a higher level of religious devotion (39 per cent) than Catholics.
"Sociologists have been writing about declines in mainline Protestantism for the last few decades," Schwadel is quoted as saying in the Autumn 2012 issue of the journal Sociology of Religion.
"The tremendous decline in Catholics' strength of affiliation, though, was somewhat surprising."
However, the change took place gradually over time, Schwadel says. "When it's that rapid and not really generationally motivated, it may be possible to reverse people's views."
Mass attendance by younger Catholics remains unaffected, he adds. "That could be seen as good news and bad news for the Catholic Church. Younger Catholics are not being driven away from going to church, but they do still feel less strongly committed to their religion than they did a few decades ago."
Schwadel analysed about 40,000 responses over the decades.
The study did not attempt to know why their devotion had increased or decreased, but Schwadel says priest sex abuse scandals in the Catholic Church could have been a factor. On the other hand, he adds, evangelicals became more visible during the 1990s, as well as more politicised. It's possible that their role in the public square encouraged more people to identify strongly with the faith, he suggests.
The study also shows that the total number of strongly affiliated people has remained at around 37 per cent, with a brief rise to 43 per cent in the mid-1980s. Schwadel also found that African-American Protestants reported almost the same level of religious intensity (57 per cent) as white evangelicals in 2010.
