Religion and neuroscience are not an obvious pairing. But a 2016 study published in Social Neuroscience demonstrated that spiritual feelings activate the neurological reward systems of devout Mormons. The study used fMRI scans to show that the nucleus accumbens—an area associated with reward—is activated when Mormons who have a strong sense of spirituality carry out religious activities. The same area can also be activated by love, sex, drugs, and music.

In this particular paper, the study, with a sample size of just 19, has serious limitations. But it’s part of a young and fast-growing new field that examines the relationship between our brains and religion, called neurotheology.

Jordan Grafman, head of the cognitive neuroscience laboratory at Rehabilitation Institute of Chicago and neurology professor at Northwestern University, says that neurotheology is important in part because early religious practices helped develop our brains to begin with. “Religion has played an incredibly important role in human evolution. It’s funny, people want to separate the two but in fact they’re intertwined,” he says.

Of course, it’s a two-way relationship between the brain and religion. Our brains had to develop the capacity to establish social communities and behaviors, which are the basis of religious societies. But religious practice in turn developed the brain, says Grafman. “As these societies became more co-operative, our brains evolved in response to that. Our brain led to behavior and then the behavior fed back to our brain to help sculpt it,” he adds.

For example, frontal lobes are necessary to future planning and controlling compulsive behavior, and therefore to the social arrangements within organized religion. But consistently practicing religious social behaviors likely strengthened those areas of the brain: “If we end up using more of one region, it will try to take up greater shape. It will expand a little bit. That’s no doubt what happened to the frontal lobes,” says Grafman.

But there’s no part of the brain, nor neurological response, that’s distinctly religious. Andrew Newberg, a neurotheologian and professor of emergency medicine and radiology at Thomas Jefferson University was one of the first to study the connection between neurology and religion, in the 1990s. Back then, his work was highly unusual, but he says the field has grown massively in the past 10 to 15 years. Newberg’s work has identified key neurological responses to spiritual experience, but he points out that the field “is about understanding ourselves as human beings,” not simply in connection with religion.

“No specific part of the brain is the religious self,” he says. “Many parts of the brain are part of our religious and spiritual practices. I think that makes sense because religious beliefs involves our thoughts, actions, and behaviors.”

Studies suggest that the reward system activated in the Mormon study would also be activated whenever subject experience an equivalent secular experience: for example, when a subject reads an opinion—whether it’s political, scientific, legal, or any other field—with which they strongly agree. “We’ve seen it with political beliefs, donating to charities they believed in—after all, that’s why we repeat our behaviors,” says Grafman.

“What makes religious studies interesting is they’re uniquely human traits and belief systems. If you do find a set of brain areas that are active during a religious task, by reverse inference you can make a judgment about what cognitive processes—social or emotional—underlie that particular activation that’s there in the religious task,” he says. If you ask people to think about God, for example, the brain areas that activate turn out to be the same as brain areas activated in empathetic tasks, like imagining a situation from someone else’s perspective.

Some academics resist certain neurotheology practices, arguing that religion is far too nuanced and subtle an experience to study using brain scans. Evan Thompson, philosophy of mind professor at the University of British Columbia, says that studies such as the recent Mormon paper are simply too blunt. “The brain has to be understood as a complex series of networks in which the meaning of anything going on in it is always dependent on the context,” he says. “When we study the brain, we’re interested in how it enables human cognition generally. And if we want to understand religion, we need something like anthropology.”

Some work in neurotheology does work to incorporate anthropology, and researchers say that neuroscience is, at the very least, a crucial area of study within the larger conversation around understanding religion. “There’s the argument that religion has benefited human beings by helping to create cohesive societies and morals and help us to determine our behavior and interact with the world more effectively,” says Newberg. “The ability to think about this from a neuroscience perspective is part of that discussion.”

As Grafman points out, the history of every human society involves religion. “There’s nobody who’d say it’s not important,” he says. “It’s just been understudied from a neuroscience point of view.”