Daniel A. Cox at the Survey Center on American Life:
The widening gap in social connectedness between those with a college degree and those without may also be explained by the decline in religious participation and membership in the US. Past research has shown that Americans who are involved in a local congregation tend to be more active in their communities and participate more often in civic and political life.[18] Those who attend religious services more often have been found to have more extensive social connections than those who do not attend services.[19]
For many Americans, particularly those without access to other sources of social capital, religious communities serve as a crucial way of establishing enduring social bonds and providing a sense of belonging. And Americans without a college education have experienced a much more precipitous decline in religious membership than college graduates have.
The relationship between religion and educational attainment is complicated. College-educated Americans tend to express greater doubts about the existence of God, but they are much more likely to be formal members of a religious congregation.[20] According to Gallup, a majority (54 percent) of Americans with a college education report belonging to a religious congregation, compared to less than half (44 percent) of those without a degree.[21]
But the education gap in religious membership is a relatively recent phenomenon. In 1998, the gap in membership rates between those with a college degree and those without one was far smaller. Roughly seven in 10 (69 percent) college graduates and approximately two-thirds (65 percent) of those with a high school education or less reported being members of a local church or place of worship.[22]