How do you document encounters with the Holy Spirit?

It's a tough question: Religious experiences are intensely personal, and people have different frames of reference for understanding transcendence. It's possible that a devout Christian might report an experience that's qualitatively similar to that of an atheist standing atop Mount Fuji: an ephemeral feeling of otherness, connectedness, existential clarity. For the Christian, that experience might be interpreted as evidence of God's existence; for the atheist, it might be interpreted as a neurological quirk. Trying to track and chart transcendence with quantitative social science is definitionally fraught: transcendent, that which is beyond what we can know or comprehend.

But within certain communities, in which people might share or be open to similar beliefs about the metaphysical nature of the universe, it is possible to track the behaviors that those people associate with transcendent experiences. In the vocabulary of evangelical Christianity, these might be seen as "being filled with the Holy Spirit," or direct encounters with God. This often includes things like spontaneously jumping, shouting, or singing, speaking in tongues, or perhaps waving hands in the air. This isn't anything new; in his book, The Varieties of Religious Experience, the social scientist William James paraphrased one man's experience of this at a tent revival 1829:

I began to feel my heart beat very quick all on a sudden, which made me at first think that perhaps something is going to ail me, though I was not alarmed, for I felt no pain. My heart increased in its beating, which soon convinced me that it was the Holy Spirit from the effect it had on me. ... I could not very well help speaking out, which I did, and said, Lord, I do not deserve this happiness, or words to that effect, while there was a stream (resembling air in feeling) came into my mouth and heart in a more sensible manner than that of drinking anything, which continued, as near as I could judge, five minutes or more, which appeared to be the cause of such a palpitation of my heart.

In recent years, this kind of experience has become more common in American churches. The National Congregations Study, created by Duke professor Mark Chaves, released new data this week that shows an increase in behaviors that are typically associated with spiritual encounters. Since Chaves and his team started tracking these trends in 1998, the portion of congregations that see hand-waving during services has increased by 11 percentage points; spontaneous jumping, shouting, or singing has increased by 9 percentage points; and speaking in tongues has increased by 5 percentage points.


Spiritual Experiences in American Congregations

The data are based on interviews with clergy at a nationally representative sample of congregations from a number of religious denominations, including some outside of Christianity. In each wave of the survey, between 1200 and 1500 congregations were represented. (Data: The National Congregations Study)

What's behind the surge in this expression of spiritual experiences? Chaves says "there is a trend in American religion towards ... a certain kind of experience for people, away from just religious teachings—to make it more emotionally engaging, not just intellectually engaging."

Historically, this type of worship has been associated with evangelical Christianity, particularly Pentecostalism. As mainline Protestant denominations like Presbyterianism and Methodism continue to lose members, Chaves says, this evangelical style of worship has "diffused across the spectrum." Hand-waving and dancing and singing might be encouraged by ministers in a bid for better attendance—"congregations are kind of mimicking what they think is a successful worship style," he said. That perception may or may not actually be true, though: Even though Pentecostal-style churches make up a greater proportion of American congregations than they did ten years ago, "it’s a little bit of a myth that Pentecostal and evangelical churches are growing," he added.

More broadly, this finding seems to hint at a particular quality of one kind of contemporary American worship: It's direct, and personal, and visceral. Historically, this has characterized Protestantism more than Catholicism and Orthodox Christianity, which involve routinized liturgies and priests that act as intermediaries between people and God. As attendance at mainline churches has shrunk, the proportion of independent congregations has grown somewhat—15 percent of American churches weren't affiliated with any particular denomination in 2012, as compared to 10 percent in 1998. Although these churches aren't specifically associated with Pentecostal organizations like the Assemblies of God, they are very likely to involve these kinds of "spiritual encounters." Non-denominational congregations were more than twice as likely as denominational congregations to have members spontaneously jump, dance, or sing during worship services—nearly 40 percent said this happened in 2012. In the latest wave of data, these congregations were also twice as likely to have members speak in tongues—nearly 45 percent saw this. And although hand-waving is generally more common across congregations than these other "spirit-filled" behaviors, it's even more in non-denominational churches: 70 percent said this was part of their worship in 2012, compared to a little over half of affiliated congregations.

There is no way for an observer to fully know the experience of someone who is moved to raise her hands and get up and dance and speak in tongues in the middle of religious worship. As fascinating as it is to track the behavior of people in religious settings, it's also inherently limited: The chain of events that leads someone to lift her hands in prayer and experience a feeling that she identifies as "grace" could be psychological, neurological, social, or, perhaps, metaphysical in nature. Some people might see speaking in tongues as an act of mass psychosis. Some might see it as a direct communication from God. And this is the nature of peering into faith: Observing what we can, then recognizing the inadequacy of observation alone for understanding humanity's variety of religious experience.