As of 2015, 84% of the world’s population is religiously affiliated, and that percentage is expected to grow in the next 30 years. That high percentage begs the question: Why are so many people religious? Scientists, philosophers, and religious leaders have posited that the reason most human civilizations have developed some form of organized religion or spiritual practice is because humans are biologically hard-wired for religion. And we all know what it means when people use computer metaphors to talk about humans—they mean the brain! So, let’s examine this premise and look at some of the cognitive processes that might or might not be involved in religious experience in order to see if we can find some neural explanations for its prevalence.

Looking for the Promised Land

One of the first questions we wonder about when we talk about the neuroscience of religion is whether some brain area or process is responsible for religious experience. As early as the mid-1800’s, clinicians started noticing that patients with epilepsy concentrated in the right temporal lobe were having religious, ecstatic experiences prior to their seizures. In fact, when scientists used transcranial magnetic stimulation (TMS) to induce activity in the right temporal lobe, they found that healthy participants felt a “sense of presence”, which was sometimes accompanied by reports of supernatural beings or a God-like aura. This led scientists to speculate that the right anterior temporal lobe was responsible for religious experiences via micro-seizures or some kind of enhanced activity in religious individuals (some, like the neuroscientist V.S. Ramachandran, even called it the “God Module“). The thought that all religious experience could be boiled down to misfiring in one region was, of course, exciting and controversial.

However, given that these results were difficult to replicate, it’s more likely that this area is responsible for experiences of a sense of presence which individuals interpret as religious based on assumptions and prior beliefs, not that stimulation of the area induces religious experience itself. For example, work by Granqvist et al (2005) found that TMS results of induced religious experience could be explained by high participant suggestibility. By high suggestibility, researchers mean high “absorption” of mind-altering experiences, a “new-age” lifestyle, and signs of abnormal temporal lobe activity, all of which contributed to reports of induced religiosity. Participant suggestibility could explain 10-25% of the variability, indicating that results could be explained by a predisposition to certain religious beliefs and tendencies, instead of temporal lobe activity itself!

Instead of focusing on one region, other research has investigated other possible mechanisms, such as weak magnetic field disruption and an alteration of the default mode network, but this research isn’t yet conclusive. So let’s move on to some of the more general issues and challenges in this field.

Isolating Constructs

Universally, most systems of religion, faith, and spirituality have some commonalities (e.g. they include a set of moral values, they provide a creation/origin story, they give a purpose of existence, they utilize rituals). But part of the difficulty in looking for a single brain region which might hold the key to assessing the involvement of neural differences in religious experiences is that religion entails a host of cognitive, emotional, and perceptual constructs. This makes it highly improbable that only one region or function is responsible. For example, the brain regions discussed above in the experience of a “sense of presence” are completely different from those involved in the production of glossolalia (i.e. “speaking in tongues”).

Multiple regions and processes are involved in the experience of religion, even if we examine only one construct at a time. For example, one experiment measured changes in blood flow using single photon emission computed tomography (SPECT) to measure meditation-induced neuro-metabolic changes in experienced Tibetan Buddhist meditators and Catholic nuns. Results showed a pattern of increased activity in frontal areas and decreased activity in right parietal areas during meditation, which was interpreted as a decreased sense of self, i.e. “oneness”. However, replications of the study by Azari and Spezio using functional magnetic resonance imaging reported the involvement of adjacent, but distinct brain networks in spiritual meditation (for more on meditation, click here). Not only has no one area or process been implicated in religious experience; even pinpointing specific activity involved in any one construct (e.g. spiritual meditation) has turned out to be misguided.

The truth is that while aspects of religion like glossolalia, religious rituals, and mystical experience have been correlated, they are not the same thing and employ different brain regions and networks.

The Bottom Line

In fact, there may not be a neural or genetic explanation for the prevalence of religion at all. Some researchers have suggested that studying possible neuroscientific causes of religious experience is futile, either because religion is the byproduct of neural mistakes or because it is something that arises out of environmental factors during development and is too complex for us to pick up in a scan just yet.

Ultimately, most humans have the neural capacity for religion; that is, we are all capable of moral decision making, deep contemplation, the interpretation of perception, and the use of ritual and routine to guide our behavior (among many others). Faith-based worldviews utilize all of these natural processes and put them into a complex framework using the history, values, and circumstances of a group. In all likelihood, any predisposition for religion in humans is just a byproduct of other cognitive abilities we have. Until the field of neurotheology progresses further, all we can say for now is that the interpretation of phenomena as spiritual, religious, or mystical is likely based on prior assumptions and expectations. On the upside, at least we know that the “God Module” is only a myth.