We are the only species on the planet known to practice religion. This behavior is universal: there is no nation on Earth that does not practice one or another form of spiritual belief.
The question is what makes our brain different so that we practice spirituality? Does religion serve any purpose in terms of benefiting our survival and progress? These questions are very philosophical. Many thinkers believe that religiosity is what distinguishes Homo sapiens from the rest of the animal kingdom, and brought our species to dominate this planet. On the other hand, a large numbers of thinkers believe that religion impedes progress and keeps our society in a barbaric state.
There is no doubt that religion played a very important role in early human history: providing the first explanations for the existence of the world around us. The need for such explanation highlights an important step in the development of the brain and cognitive processes.
Behavioral traits might become strengthened by evolution if they bring survival benefits. Researchers think that altruism, for instance, is this kind of behavioral trait: it might be disadvantageous for a particular individual at a particular instance, but it brings advantages to the species in general. Altruistic behavior is promoted by the majority of the world’s religions. Therefore, religious practices might have provided evolutionary advantages for early humans in terms of survival, too.
Some people are so deeply religious that the system of beliefs they practice shapes their whole life. It would be reasonable to assume that something interesting should be going on in their brain. It is also quite likely that these brain processes are different from the processes in the brains of nonbelievers. This is what the new science of neurotheology seeks to study. Neurotheology investigates the neural correlates of religious and spiritual beliefs. Such studies may help to uncover why some people are more inclined towards spirituality, while others remain deeply skeptical about the whole notion of God’s existence.
There are already some interesting findings from the field of neuroscience that can help to open the window into the spiritual brain.
First, there is no single part of the brain which is “responsible” for an individual’s relationship with their God/s. Like any emotionally intense human experience, religious experiences involves multiple brain parts and systems. Several experiments with the use of brain scanners confirm this. In one study, Carmelite nuns were asked to remember their most intense mystical experience while neuroimaging of their brain was conducted. The loci of activation in this experiment were observed in the right medial orbitofrontal cortex, right middle temporal cortex, right inferior and superior parietal lobules, right caudate, left medial prefrontal cortex, left anterior cingulate cortex, left inferior parietal lobule, left insula, left caudate, and left brainstem.
Similarly, an fMRI study on religious Mormon subjects found areas of activation in the nucleus accumbens, ventromedial prefrontal cortex, and frontal attentional regions. The nucleus accumbens is the brain area associated with reward. It is also involved in emotional responses to love, sex, drugs, and music. One recent study also identified a number of changes in regional cortical volumes that are associated with several components of religiosity, such as an intimate relationship with God, and fear of God.
It appears likely that life-changing religious experiences may be linked to changes in brain structure. For instance, one study demonstrated that the brains of older adults who reported such experiences feature a degree of hippocampal atrophy. Hippocampal atrophy is an important factor in the development of depression, dementia, and Alzheimer’s disease. It remains unclear exactly how structural changes in the brain and the level of religiosity relate to each other.
It is well known that some drugs simulate spiritual experiences. For instance, psilosybin, the active ingredient in “magic mushrooms,” stimulates temporal lobes and mimics religious experiences. This implies that spirituality is rooted in neuronal physiology. It is no wonder that psychoactive compounds are often used in ritualistic and shamanistic practices around the world.
All studies that involve brain imaging of people in specific states suffer from one major limitation: it is hard to be sure that people are actually in that particular state at the time of measurement. For instance, if we measure the brain activity when a subject is supposed to solve a mathematical task, we can’t be 100% sure that his or her mind is not wondering around instead of focusing on the task. The same applies to the measurement of any spiritual state. Therefore, the patterns of brain activation obtained through brain imaging should not be viewed as ultimate proof of any theory.
Various religious practices have the potential to influence our health, in both positive and negative ways. It was noted that religious people, in general, have a lower risk of anxiety and depression. This, in turn, is linked to a stronger immune system. On the other hand, people engaged in religious struggles might experience the opposite effects. Research into the brain’s response to religious practices might help to develop further our understanding of the connection between health and spirituality.