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. Those who attend religious services more often have been found to have more extensive social connections than those who do not attend services.
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. 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.
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.