How the Neurosciences Explain Religion or Not
In the last lecture1, we learned how humans evolved as hunter-gatherers and how our genetic, mental, and behavioral nature was conditioned by and for this kind of life, even as we now live in a very different environment of our techno-cultural creation. We considered how evolution had shaped our predispositions for religion and what functions and dysfunctions religion might have played in our species’ history. We were introduced to the idea that the human mind was modular, that there were instinctive dispositions that then developed in conjunction with social and environmental factors into various inference systems in our brains. Religion, we were told, could be understood as a potent combination of these different inference systems in our evolved brains – agency detection, ontological categories, intuitive physics, intuitive psychology, pollution-contagion templates, memory-recall patterns, and so forth, all assembled and accessed as independent mental modules (Boyer 2001).
In this lecture, we are going to examine the human brain directly to see how the cognitive neurosciences try to understand and explain religious and spiritual experiences. And we note first that there has been a tremendous amount of new research and new insights into the working of the human brain in the last few decades. Powerful new tools also allow us to examine the function of healthy human brains and these tools have recently been used to study the brain functions of Buddhist monks, Catholic nuns, Pentecostals speaking in tongues, and others.
Inside the Brain
Now if you look inside the human brain, you do not actually see these mental modules previously referred to. There is no piece of the brain that one could label the “agency detection module” or the “pollution-contagion module”. In dissecting a human cadaver, we first see large-scale structures. On the outside is the cerebral cortex, or neocortex, including areas labeled the Frontal Lobe, the Parietal Lobe, the Occipital Lobe, and the Temporal Lobe, and of course, these are divided into two hemispheres, right and left, with a broad band of nerve fibers know as the Corpus Callosum connecting the two halves. If we peal away the neocortex, we discover the mesocortex and subcortical structures in the limbic system, including the Thalamus, the Amygdala, the Hippocampus, and the Cerebellum, all connected to the brain stem and the spinal cord. This much you probably already know. Images of the human brain have become iconic in our 21st century culture.
A lot of what we know about the specialized functions of different areas of the brain comes from observing survivors of traumatic brain injuries or stroke victims. In both cases neuroscientists correlate the destruction of certain brain regions due to hemorrhaging or injury with the loss of particular mental functions, for instance the loss of motor-control, speech, or even particular parts of speech or sets of word concepts, the latter known as Aphasia.
Curiously, memory seems to be distributed throughout the brain and is not located in any particular region. I recall a colleague at Oxford University, who I visited in the hospital shortly after he had had a stroke. He could point to Paris or London on a map, but he could not say the word “Paris” or “London”. Nor could he speak the names of any number of other common items and places, though he certainly knew what they were and could directly point to any of them. When I said “wallet,” he reach into his back pocket, pull out the wallet, he just could not himself say the word “wallet”. Our brains are strange, indeed, though we take them for granted until something goes wrong. Fortunately, my friend was able to fully recover his speech, but did so by training new regions of the brain to compensate for the loss of the one region destroyed by the stroke. This is an example of another curious characteristic of the brain called neuro-plasticity.
When we examine brains under powerful microscopes we see that the brain is made up of neurons, lots and lots of neurons. There are different types of neurons in the brain, and throughout our central nervous system in the rest of the body, but they all share a basic structure. The cell body contains the nucleus and organelle. Extending out from the cell body are lots of dendrite “trees” and axon “arms”. These connect to other neurons. This maze of connections end in synapses, linking each neurons with hundreds or thousands of other neurons. The neurons fire electrical charges in the form of chemical ions, which are mediated by a variety of neurochemicals that are produced endogenously by the brain. The chemicals produced and present in different areas of the brain are very important.
There are a lot of neurons in the human brain, estimated at 1011 (one hundred billion). Now each neuron has on average about 7*103 (seven thousand) synaptic connections. A three-year old child has about 1016 synapses (10 quadrillion), but this happily decreases with age to a more manageable number between 1015 to 5*1015 synapses (1 to 5 quadrillion).
Here are a few comparisons to help you remember these big numbers. The number of neurons in your brain is approximately the same as the number of stars in our Milky Way galaxy, which turns out to be conveniently also the number of galaxies in the observable universe, i.e., one hundred billion. Or if you prefer, there are more neurons in your brain than the number of hamburgers served by McDonalds (before they stopped counting).
And it takes a lot of hamburgers, or other food, to keep our neurons firing. The 1.5 kilograms of your brain, give or take, represents only 2 percent of your body weight and yet it consumes 15 percent of your cardiac output, 20 percent of your body oxygen, and about 25 percent of your body’s glucose consumption. Just sitting around the brain needs about 0.1 calories per minute. With intellectual activity this can increase to as high as 1.5 calories per minute. From a biophysical and evolutionary point of view, the human brain is an expensive item. In birth, it is difficult to pass through the female pelvis, too often resulting in the death of the infant or the mother. In life, it requires a lot of extra food and care.
The brain is best understood as a kind of Rube Goldberg machine. Rube Goldberg (1883-1970) was an American cartoonist who was famous for depicting complex devices that performed simple tasks in convoluted ways. One such cartoon depicts a man eating his soup. The spoon is attached to a string which flips a cracker to a Parrot which then activates water pouring into bucket which pulls a string which activates a lighter which launches a rocket attached to a knife which cuts a string that turns on a clock with a pendulum which swings back and forth moving a napkin that now wipes clean the soup-eating man’s mustache. The entire contraption is worn on the head of the mustached man as a kind of hat. Our brains are like this Rube Goldberg machine, except that the complex machine is worn inside our heads instead of outside. Neuroscientists today are developing algorithmic flow charts that map out neural processes. Something simple like engaging in meditation sets off an impossibly complex series of actions, reactions, and feedback loops (Newberg 2006). Thankfully, we do not need to be the least bit aware of any of these processes to have wonderfully functional brains allowing us to mindlessly perform lots of simple and complex mental activities everyday. It is worth stopping a moment, however, to reflect that the most complicate object in the known universe is sitting right here between our ears.
The Explanatory Gap
It is hard to recognize ourselves – our subjective experiences, thoughts, emotions, and daily activities – in this neurological description of our brains. Normally we have no conscious awareness of the cognitive modules and Rube Goldberg machines in our head. Cognitive neuroscientists and philosophers of mind refer to this the “Explanatory Gap”. Our physical descriptions of the way the brain works at the level of neurons, brain anatomy, and neurological processes bear no resemblance to our subjective experiences as people with brains having complex mental and emotional states. Nor is there any neurological definition of consciousness. We have no device that can measure presence or absence of consciousness. This is also referred to as the “Hard Problem” in consciousness studies. We can study brains and learn all kinds of interesting and practical things about brains, their functions and dysfunctions, but this does not get us near to understanding what subjective conscious experience is or how the brain creates it. We know that a diseased or damaged brain may lose function or consciousness, ultimately resulting in death, but we do not know what consciousness per se is at the level of the “neural code”.
Some are optimistic that we are closing this Explanatory Gap, that we will soon come to understand the “neural code” and be able to translate the “machine language” of the brain into the “software applications” of human consciousness. Indeed, a lot of progress has been made in understanding how the brain functions. Scientists have probed, prodded, tested, measured, dissected, and scanned lots and lots of brains, both human and animal. Scientists have also developed a remarkable pharmacology of new drugs to treat depression, schizophrenia, and other disorders.
Progress in the neurosciences raises lots of other interesting philosophical questions, which necessarily overlap with religious and theological concerns. First, there is the question of reductionism and how far it can go? If we can reduce certain mental phenomena, say mystical experiences of enlightenment, to neurological processes, does that mean that we have adequately explained the experience and can dismiss it? What happens if we invent ways to stimulate these peak experiences at will? If the brain is a deterministic system, then how can we talk about free will, moral responsibility, and creative choice? If personality is intrinsically linked to brain chemistry should we reject the dualism between brain and mind, body and soul? In treating mental illness should we “waste time” with talk therapy or simply treat these illnesses with medications? Do the cognitive neurosciences import assumed values and perspectives that are more ideological than empirical? And what of bioethical issues that arise in the context of neuromedicine? This is just a short list and we are going to revisit some of these questions below and in the discussion to follow. The Hard Question remains: what is consciousness? Can we fill in the Explanatory Gap between the neurosciences and subjective experience? And what in particular is the nature of religious experience from the perspective of the neurosciences?
Science does not need to solve all of these philosophical problems. That, I would argue, is not the job of science, but rather the task of scientifically informed philosophers and theologians. Science can and does continue to plod along in its methodical manner. The neurosciences move ahead by formulating small questions and then constructing experiments to try to answer them. The neurological basis of religious and spiritual experiences is certainly an interesting question and it has recently been the subject of a lot of fascinating research in laboratories and debate in the academe and in the media. There are a number of ways to tackle the question:
- Disease and injury based studies
- Surgical studies
- Functional Imaging studies
- Psychotropics drugs studies
- Developmental studies
1) Disease and Injury Based Studies
As already mentioned, many insights about the brain are derived from the study of brain disease and injury. For instance, there may be a link between mental illness and religiosity, for instance in the case of schizophrenia, in which psychotic episodes often have religious content. Indeed, for many decades the psychiatric community classified all religious content as delusional or neurotic in its Diagnostic and Statistical Manual of Mental Disorders (DSMMD) (Larson 1993). That is happily no longer the case. The psychiatric community has slowly come around to recognizing that religious manifestations among patients may be a sign of strength, a resource in healing, and not necessarily pathological (Hufford 2005).
There is a lot of interest in the role of the frontal lobes in religious experience. Traumatic injuries to the frontal lobes have a profound effect on a person’s personality, impulse control, and complex thought processes. The seat of cognition, however, does not work alone. It is part of a complex network, left, right, inside out, and all around. V.S. Ramachandran, a neuroscientist at UC San Diego, has focused on Left Temporal Lobe epilepsy, which is frequently associated with religious visions during seizures and a preoccupation with religious issues between seizure episodes. Ramachandran speculates that Saint Paul, Mohammad, and other prophets and sages were afflicted with Left Temporal Lobe epilepsy (Ramachandran 1998). Ramachandran notes that “God may be the ultimate confabulation of the Left Hemisphere of the brain” (Ramachandran 2006).
There are other mental defects that manifest themselves in otherwise mentally healthy individuals. For instance, with Charles Bonnet Syndrome, people have complex visual hallucinations of people, animals, or objects not actually present. With Capgras’s Syndrome, otherwise mentally healthy individuals have delusions that people around them have been replaced by imposters.
Another, much more common mental disorder is known as Sleep Paralysis or Agoraphobia. Probably many of you have had the experience of waking up at night with an inability to move and the strong sense of someone else in the room with you. This is not a pleasant experience. The presence-in-the-room is typically perceived to be a demon of some sort and the experience is generally terrifying. This is such a common experience that it has many names, folk stories, and mythological explanations in diverse cultures around the world. Neuroscientists now have an etiology for sleep paralysis, but one could easily imagine how this experience or others would help give rise to religious beliefs in demons, ghosts, or the devil (Hufford 1982).
There is one other neurological disorder that is worth mentioning. Synesthesia is a condition that might be thought of as metaphoric thought on steroids. It typically involves things like hearing sounds and seeing colors, reading numbers and seeing colors, seeing colors and hearing sounds. Perhaps one in a thousand humans have some form on synesthesia in varying degrees. It is not necessarily unpleasant. Indeed, far from being a disorder, it can be seen as a mental strength. As we would expect, many creative artists have synesthesia.
Synesthesia may be linked to a much more common mental functions that all of us employ everyday, the ability to make and use metaphors, of which religion is an important subset. A metaphor is the combination of two unlike things to create a new meaning. Shakespeare writes that “time is a beggar” and now we have a new insight into time. You may have noticed that I have used several metaphors from the computer sciences to illuminate the neurosciences – neural “code”, neural “machine language”, mental “software”, neural “networks”, etc. Science also uses metaphors. In some sense, all human language is derived from metaphors (Ricoeur 1976). Religion can be thought of as something like the metaphoric confabulations of synesthesia, seeing nature and hearing the voice of God or the Buddha-nature in all things (Ramachandran 1998).
2. Surgical Studies
Surgical studies are much more limited, because doctors cannot ethically open up someone’s brain and start poking around, say like fixing a car or a computer. The occasion to do surgery on live humans is typically to remove a brain tumor and these are risky operations. Because the brain has no sensory nerves and cannot feel pain, brain surgery is typically done on conscious humans, which means you can ask them questions during the surgery. In the 1950s, Wilder Penfield, a Canadian neurosurgeon, electrically stimulated different regions of patients’ brains during surgery and asked patients to describe any sensations. Stimulation of the right temporal lobe caused patients to hear voices and see apparitions. Around the same time, Robert Heath of Tulane University induced intense pleasure in psychiatric patients with electrodes implanted in the septum, a minute region just above the hypothalamus. He also induced multiple orgasms in a female patient by injecting the neurotransmitter acetylcholine directly into her septal region. These kinds of studies would not be allowed today by the Internal Review Boards at medical schools, and rightly so, but they were certainly illuminating and suggestive. Certainly, every neuroscience course and textbook today still presents the work of Penfield and Heath.
Based in part on these kinds of studies, Julian Jaynes proposed a unique theory of religion in his 1976 book, The Origin of Consciousness in the Breakdown of the Bicameral Mind. Jaynes speculated that there were structural changes in the human brain some 10,000 years ago. He suggested that the bundle of nerves connecting the two hemispheres of the brain, the corpus callosum, may not have been as developed as it is today. In our ancestors’ brains, the left hemisphere, acting as the primary seat of language and identity, would misattribute signals originating from the right hemisphere to an external source, and thus imagined ghosts or gods (Jaynes 1976).
Brain surgery research continues on nonhuman animals, but alas lab rats, dogs, and monkeys cannot report to us on their subjective experience. Nevertheless, we learn a lot about how the brain functions, which is then correlated with human brain function. We are also embarking upon a new era of electrical implant machines to help patients with Parkinson or other brain disorders, as well as brain implants to help quadriplegics to control computers with their thoughts alone. All of this will have implications for our understanding of religious and spiritual phenomena, some of which may have been best prefigured in science fiction novels.
3. Functional Imaging Studies
New non-invasive technologies now allows us to look inside the brains of humans without adverse risks to the patient. Improvements in these technologies allow us measure actual brain functions while performing limited tasks or experiences and compare these states to some base-line image. These are referred to as functional brain imaging studies. The earliest form of such techniques was involved using electroencephalographs of brain waves, as well as measures of autonomic activities such as heart rate and blood pressure changes, for instance, as used in early meditation studies. You are probably familiar with the term “bio-feedback device,” which were popular in the 1970s. This approach, however, has been compared to trying to understand human speech by listening to the sound of a sport stadium. The new technology is much more powerful, but not without its limitations. There are three new techniques for functional brain imaging and each has different strengths and weaknesses.
PET scans, or positron emission tomography, uses a radioactive tracer injected into blood stream of the subject to measure oxygen flow, glucose consumption, blood utilization, or neurotransmitters in different regions of the brain. This then indicates which areas of the brain are most active in any given experience or activity. The injection provides a freeze frame at a particular moment and then is followed by the actual scan of the brain. The problem with PET scan is that the tracers are only present for a few minutes, so the patient needs to be already in the scanning device before the injection occurs. Hospital scanning devices are not particularly conducive to having profound mystical experiences.
Another category of imaging technology is fMRI, which stands for functional magnetic resonance imaging. The advantage of fMRI is that it does not involve injecting radioactive tracers into the blood stream of the patient. The disadvantage is that it involves placing the patient inside a claustrophobia-inducing machine that makes loud banging noises, only slight more tolerable than listening to a jackhammer. Again, this is not an atmosphere particularly conducive to contemplative practice or religious devotion.
The functional imaging technology most suited to the kind of research proposed is SPECT scan, which stands for Single Photon Emission Computed Tomography. This involves using a longer lasting radioactive tracer. Typical research design has the patients outfitted with an IV and a button so they can self inject the tracer at what they subjectively consider to be the peak experience in meditation or prayer. This can be done in a comfortable room in the hospital near the SPECT scan machine and can involve the use of ritual objects, incense, chanting, prayer, etc. After the peak experience and the tracer’s “snapshot” record of brain activity at the time of injection, the subject can then be put into the scanning machine to measure brain metabolism from the tracer “snapshot” some minutes earlier.
Andrew Newberg and his deceased colleague Eugene D’Aquili pioneered this research with religious subjects. Their first study involved eight American Buddhist trained in the Tibetan meditation and three Franciscan nuns. They observed increased neural activity in the prefrontal cortex and decreased activity in the posterior superior parietal lobe. The latter is connected with the ability to navigate the physical self in an external world. They hypothesized that the decreased activity in posterior superior parietal lobe was linked to the experience of non-duality described by the subjects. They call this experience “Absolute Unitary Being” (Newberg 1999; Newberg 2000). They maintain that “mystical experience is biologically, observably, and scientifically ‘real’ rather than ‘wishful thinking’ (Newberg 2001) and go on to speculate:
[We] saw evidence of a neurological process that has evolved to allow humans to transcend material existence and acknowledge and connect with a deeper, more spiritual part of ourselves perceived of as an absolute, universal reality that connects us to all others (Newberg 2001)
4. Pharmaceutical Interventions
Psychotropic or psychedelic drugs have long been part of human religious practices in diverse parts of the world. The authors of the Hindu Vedas received inspiration from the drug soma, which is thought to be derived from psychedelic mushrooms, psilocybin or fly agaric, perhaps in combination with cannabis or other substances. The ancient Greek Eleusinian Mysteries also involved the use of some kind of psychedelic drug. Tribal shamans from Africa, Asia, and the Americas use psychotropic drugs as part of their rituals. The Native American Church in the United States won a Supreme Count case to ensure their right to use peyote in their religious observances. The urge for intoxication is not limited to humans. Chimpanzees, elephants, parrots, and other species ingest fermented fruit and other intoxicants. UCLA psychopharmacologist Ronald Siegel speculates that the desire for intoxication is “the fourth drive” after hunger, thirst, and sex (Siegel 1989). The suggestion in this line of research is that perhaps religion is founded on this desire to get high.
Ergot, a fungus that contaminates rye, wheat, and barley, also has psychotropic properties and is probably used intentionally as part of the Eleusinian Mysteries. It has also caused many accidental poisonings in human history. Ergot epidemics were known as St. Anthony’s Fire in the Middle Ages and may be linked to incidents of mass hysteria and hallucinations. The synthesis of LSD in 1942 by the Swiss chemist Albert Hoffman was based on an Ergot derivative.
In addition to LSD, modern science has synthesized a great number of new psychotropic and psychedelic compounds. Some prefer to use the term Entheogens, meaning “God-inducing”, to describe this class of chemicals, because of their ability to induce intense mystical experiences. The most common and quite potent drugs are:
- Mescaline –– 3,4,5-trimethoxyphenethylamine,
- LSD -- lysergic acid diethylamide,
- DMT - 5-methoxy-dimethyltryptamine, and
- MDMA (3,4-methylenedioxy-N-methylamphetamine),commonly known as Ecstasy
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