Are spiritual beliefs an inevitable consequence of evolution? In the second article in a two-part series, Brandon Ambrosino examines the ways that spiritual beliefs emerge from ancient psychological tendencies.

When I was in grade school, there was an anti-drug commercial that regularly came on television. There were a few different versions of it but the gist was, an egg would be shown to the camera as a voice said, “This is your brain.” And then the egg would be smashed by a frying pan and the voice would say, “This is your brain on drugs.” We all got the point: drugs did something to your brain.

At my Pentecostal Church, drugs were talked about somewhat differently. We didn’t need them, we were told, because we could get high from God. God could do the same thing to our brain – give us a rush, a sense of euphoria – but our brains wouldn’t end up scrambled. God provided all the “positive benefits” of heroin with none of the damaging side effects. (Of course, when we consider the amount of religious violence throughout history, it’s impossible to claim that there are no damaging side effects to some beliefs in God. More on that later.)

I long ago left my childhood church and often feel embarrassed about the “God as a drug” theology. But the more I think about religion as an emerging phenomenon, the more I wonder if, for all their sloppy Pentecostal vocabulary, my youth leaders were onto something: God does something to your brain.

“This is your brain. This is your brain on God.”

Andrew Newberg, a neuroscientist who studies the brain in light of religious experience, has spent his career following this hunch. “If you contemplate God long enough,” he writes in How God Changes Your Brain, “something surprising happens in the brain. Neural functioning begins to change. Different circuits become activated, while others become deactivated. New dendrites are formed, new synaptic connections are made, and the brain becomes more sensitive to subtle realms of experience. Perceptions alter, beliefs begin to change, and if God has meaning for you, then God becomes neurologically real.”

Read the first part of this essay, which examines the deep origins of religion in the animal kingdom, here.

Religious experiences, he tells me in his Pennsylvania-area office, satisfy two basic functions of the brain: self-maintenance (“How do we survive as individuals and as a species?”) and self-transcendence (“How do we continue to evolve and change ourselves as people?”).

Newberg and his team take brain scans of people participating in religious experiences, such as prayer or meditation. Though he says there isn’t just one part of the brain that facilitates these experiences – “If there’s a spiritual part, it’s the whole brain” – he concentrates on two of them.

There is a deactivation of the parietal lobe during certain ritual activities

The first, the parietal lobe, located in the upper back part of the cortex, is the area that processes sensory information, helps us create a sense of self, and helps to establish spatial relationships between that self and the rest of the world, says Newberg. Interestingly, he’s observed a deactivation of the parietal lobe during certain ritual activities.

“When you begin to do some kind of practice like ritual, over time that area of brain appears to shut down,” he said. “As it starts to quiet down, since it normally helps to create sense of self, that sense of self starts blur, and the boundaries between self and other – another person, another group, God, the universe, whatever it is you feel connected to – the boundary between those begins to dissipate and you feel one with it.”

The other part of the brain heavily involved in religious experience is the frontal lobe, which normally help us to focus our attention and concentrate on things, says Newberg. “When that area shuts down, it could theoretically be experienced as a kind of loss of willful activity – that we’re no longer making something happen but it’s happening to us.”

Newberg thinks all the brain scans he’s collected might beg the question about why the brain is built in such a way as to facilitate spiritual kinds of experiences.

“If you’re spiritual or religious, the answer is obvious,” he says. But even if we leave aside any talk of God, we still have to wonder why the brain developed in ways that not only facilitate but seem to promote the kinds of experiences Newberg is studying. These are experiences that seem to be an inescapable part of human existence.


“The explanation for religious beliefs and behaviours is to be found in the way all human minds work,” writes Pascal Boyer in his book Religion Explained. And he really means all of them, he says, because what matters to this discussion “are properties of minds that are found in all members of our species with normal brains”.

Let’s take a look at some of these properties, beginning with one known as Hypersensitive Agency Detection Device (HADD).

Say you’re out in the savannah and you hear a bush rustle. What do you think? “Oh, it’s just the wind. I’m perfectly fine to stay right where I am.” Or, “It’s a predator, time to run!”

Well, from an evolutionary perspective, the second option makes the most sense. If you take the precaution of fleeing and the rustling ends up being nothing more than the wind, then you haven’t really lost anything. But if you decide to ignore the sound and a predator really is about to pounce, then you’re going to get eaten.


The cognitive scientist Justin Barrett has spent his career studying the cognitive architecture that seems to lend itself quite naturally to religious belief. One of our cognitive capacities Barrett is interested in is HADD. It’s this property, he writes in The Believing Primate, that causes us to attribute agency to the objects and noises we encounter. It’s the reason we’ve all held our breath upon hearing the floor creak in the next room, which we assumed was empty.

Barrett says this detection device causes us to attribute agency to events with no clear physical cause (my headache was gone after I prayed) and puzzling patterns that defy an easy explanation (someone must’ve constructed that crop circle). This is particularly the case when urgency is involved. “A hungry subsistence hunter will find HADD registering more positives than a well-sated recreational hunter,” he writes.

HADD is what Barrett calls a non-reflective belief, which are always operating in our brains even without our awareness of them. Reflective beliefs, on the other hand, are ones we actively think about. Non-reflective beliefs come from various mental tools, which he terms “intuitive inference systems”. In addition to agency detection, these mental tools include naive biology, naive physics, and intuitive morality. Naive physics, for example, is the reason children intuitively know that solid objects can’t pass through other solid objects, and that objects fall if they’re not held up. As for intuitive morality, recent research suggests that three-month old “infants’ evaluations of others’ prosocial and antisocial behaviours are consistent with adults’ moral judgments”.

Barrett claims that non-reflective beliefs are crucial in forming reflective beliefs. “The more non-reflective beliefs that converge the more likely a belief becomes reflectively held.” If we want to evaluate humans’ reflective beliefs about God, then we need to start with figuring out whether and how those beliefs are anchored in non-reflective beliefs.

But how do we go from non-reflective beliefs like HADD and Naive Biology to reflective ones like a God who rewards good people and punishes bad ones? It’s here that Barrett invokes the idea of minimally counterintuitive (MCI) concepts, which are often strong candidates for cultural transmission. MCI concepts are basically intuitive concepts with one or two minor tweaks. In a different paper, Barrett gives the example of a flying carpet, which “behaves” like a regular carpet in every way except one. “Such ideas combine the processing ease and efficiency of intuitive ideas with just enough novelty to command attention, and hence receive deeper processing.”

It’s not surprising, then, that cross-cultural studies have shown that MCI concepts are easily recalled and shared. There are two reasons for this, says Barrett. First, MCI concepts maintain their conceptual structure. Second, MCI concepts tend to stand out from among an array of ordinary concepts. “What captures your attention more,” he writes, “a potato that is brown, a potato that weighs two pounds, or an invisible potato?”

Religious beliefs are shared – and they’re shared by human animals with a shared neural anatomy. Our mental toolkit contains built-in biases, such as HADD, which is responsible for a number of false positives. (Most of the time it is just the wind!) For brains that seem wired to find agency and intention everywhere, religion comes very naturally.

As Daniel Dennett points out, our adoption of the intentional stance is so much a part of who we are that we have a hard time turning it off – especially after someone dies. A loved one’s death, he writes, “confronts us with a major task of cognitive updating: revising all our habits of thought to fit a world with one less intentional system in it”. And so we talk about our deceased loved ones as if they’re still around, telling stories about them, reminding ourselves that they would approve of our decisions.

In short, we keep them around. But not physically because, as Boyer points out, dead bodies are a problem. “Something must be done” with them. Indeed, “religion may be much less about death than dead bodies”. For this reason, some suggest that the earliest forms of supernatural agents were the departed, the ghosts of whom are minimally counterintuitive: like us in almost every way, except for the disappearing through the wall thing.

Closely related to the idea of agency is what Dennett refers to as a cards-up phenomenon. Agency detection carries with it certain risks: do you know about that bad thing I did? How can I be sure you know, and how can I be sure about what you think about me because of it? These are complex questions and human beings aren’t good at managing all the options. What’s needed for learning how to navigate these muddy waters is for everyone to be taught the rules of the game by placing all of our cards face up on the table. The teacher, then, is something of a full-access agent: they see everything and can instruct us accordingly.

The original full-access agents, says Dennett, were our dead ancestors. But eventually, the seeds of this idea became more formalised in various theologies.

“Humans are not very good at behaving just because you punish them for not behaving,” says evolutionary psychologist Robin Dunbar, “otherwise we would all be driving well under 70 on the motorway.” The real problem isn’t how bad the punishment is, but how risky it is to be caught. If the risk is low, he says, we’re prepared for the punishment.

This would have been a major issue in prehistory. As hunter-gatherer groups grow, they need to be able enforce a punishment mechanism – but the greater the size of the group, the less chance there is of being found out.

Enter full-access agents: “We don’t see what you do on Saturday night, but there is somebody who does, so beware,” as Dunbar puts it.

This idea was consonant with the intuitive mental tools such as HADD and intuitive morality, so it was well-received by our ancestors’ evolved brains. Plus it had the added bonus of regulating behaviour from the bottom up.

“You always get better behaviour from individual commitment,” says Dunbar, “not coercion.”

As I argued in the first part of this series, morality predates religion, which certainly makes sense given what we know about the very old origins of empathy and play. But the question remains as to why morality came to be explicitly connected with religion. Boyer grounds this connection in our intuitive morality and our belief that gods and our departed ancestors are interested parties in our moral choices.

“Moral intuitions suggest that if you could see the whole of a situation without any distortion you would immediately grasp whether it was right or wrong. Religious concepts are just concepts of persons with an immediate perspective on the whole of a situation.”

Say I do something that makes me feel guilty. That’s another way of saying that someone with strategic information about my act would consider it wrong. Religion tells me these Someones exist, and that goes a long way to explaining why I felt guilty in the first place. Boyer sums it up in this way: “Most of our moral intuitions are clear but their origin escapes us… Seeing these intuitions as someone’s viewpoint is a simpler way of understanding why we have these intuitions.” Thus, Boyer concludes, religious concepts are in some way “parasitic upon moral intuitions”.


We tend to think of religious beliefs as the result of individual minds, but they’re actually quite social. This isn’t surprising since, as I’ve been arguing in both parts of this essay, religion emerges from an evolutionary process that pressured apes to become more social.

But the problem created by increased sociality is its maintenance, as Dunbar explains. Before our ancestors settled into villages, they could simply “move from the Joneses to the Smiths’ group when tensions arise”. After settlement, however, they faced a very serious problem: “how to prevent everybody from killing each other”. Enter grooming.

The bonding process is built around endorphin systems in the brain, which are normally triggered by the social grooming mechanism of touch, or grooming. When it comes to large groups, says Dunbar, touch has two disadvantages: you can only groom one person at a time; and the level of intimacy touch requires restricts it to close relationships.

Recent data caps wild primates’ daily maximum grooming time to about 20 percent of their activity. Dunbar calculates that this cap limits group size to fewer than 70 members, which is significantly less than the group capacities of modern humans, at about 150. The problem, then, was to find a way to trigger social bonding without touching. Laughter and music were good solutions, which Dunbar says create the same endorphin-producing effects as grooming by imposing stress on muscles. Language works, too, a theory Dunbar has explored at length in his book Grooming, Gossip, and the Evolution of Language. Because these effects can be achieved sans touch, social bonding can happen on a much larger scale.

Dunbar’s argument is that religion evolved as a way of allowing many people at once to take part in endorphin-triggering activation. Many of the rituals associated with religion, like song, dance, and assuming various postures for prayer, “are extremely good activators of the endorphin system precisely  because they impose stress or pain on the body”.

One ritual Dunbar says was involved in shamanistic religions – the earliest types of doctrine-less religion – was trance dance, which Dunbar says was about restoring social equilibrium.

“It works specifically as social bonding,” he says. “They do it as things are getting tough, until they annoy each other enough, and then they say, ‘Let’s do a trance dance.’”

In effect, he says, the same pharmacological effect of grooming is achieved: many individuals feel powerfully bonded together, at the same time. But maybe they don’t know what it all means…

“You come out of these states feeling relaxed and at peace, and bonded with the people you’re doing it with,” says Dunbar. “Then you start asking what it’s all about. How is it I feel good after these? Then after that maybe you have a few Einstein theologians who can make sense of it. ‘I can tell you what it all means!’ Then you’ve got the capacity for more doctrinal religions.”

But these sporadic dances only worked until our ancestors began to settle down. Once hunter-gatherers began to form more permanent settlements, around 12,000 years ago, something more robust was needed to encourage populations to behave prosocially towards each other. Especially given the enormous newfound stress that comes with living in such large and inescapable groups. Trance dances could happen in these larger communities with some regularity – say, monthly – but what is needed are more regularised rituals to encourage social cohesion.

The formation of permanent settlements corresponds with the advent of farming. The agricultural, or Neolithic, revolution, began in the Fertile Crescent in the Middle East, which is sometimes referred to as the Cradle of Civilisation. Dunbar says it’s in these settlements where history’s first ritual spaces appear, the oldest of which is Gobekli Tepe in south-east Turkey. First examined in the 1960s, the site was excavated from 1996-2014 by a team led by German archaeologist Klaus Schmidt. In a 2008 Smithsonian Magazine feature, Schmidt referred to the site as humanity’s first “cathedral on a hill”. Gobekli Tepe, which means “belly hill” in Turkish, is a non-residential space that seems to have housed various temples made of pillars. It is estimated to date to about 10,000 BCE.

As historian David Christian writes in Origin Story: A Big History of Everything, farming was a mega-innovation, like photosynthesis. That is, farming was a major threshold that, once crossed, set off our ancestors on a whirlwind journey that ran headlong into the complex societies that have dominated our species’ recent history. As population growth surged, mega-settlements saw increased social complexity, and large-scale political, economic, and military networks, says Christian. To accommodate such large groups, earlier ideas about kinship had to be modified “with new rules about properties, rights, ranking, and power”. The result of this ranking was the concept of specialisation, which led to different the stratification of classes. Some were rulers, some were merchants, some were priests.

In contrast to hunter-gatherer religious experiences, the religious rituals of Neolithic humans “focuses above all on one person, the divine or quasi-divine king, and only a few people, priests or members of the royal lineage, participate”, writes the late sociologist Robert Bellah. Importantly, it was during this period that “king and god emerged together… and continued their close association throughout history”.

Eventually that association came to be challenged in what some have called the Axial Age. Originally coined by the philosopher Karl Jaspers, the term refers to a time of sweeping changes that occurred in the first century BCE in China, India, Iran, Israel, and Greece. It was then, claimed Jaspers, that “man becomes conscious of Being as a whole” and “experiences absoluteness in the lucidity of transcendence”. It was then that our species took “the step into universality”.

The concept of axiality, as Jaspers framed it, is controversial. Not only is there disagreement about the what and the when, but as Bellah has noted, Jaspers’ history looks a lot like his existential philosophy. “In discussing the Axial Age,” says Bellah, “it is all too easy to read in our own presuppositions.”

Still, Bellah thinks the concept is worth holding onto, albeit with qualifications. If we set Jaspers aside, it’s still impossible to deny that huge transitions in thought happened very quickly in the first century BCE. When I ask Dunbar if he buys the Axial Age hypothesis, he says, “If by that you mean a phase transition in which suddenly and quickly you have the emergence of religions with rituals and doctrines, the answer is yes.”

So what was axial about the axial age? First, all of the so-called axial breakthroughs occurred outside imperial centres. Bellah says an increased competition between states “created the possibility for the emergence of itinerant intellectuals not functioning within centralised priesthoods or bureaucracies”. Axial figures were able to criticise the centre from the margin. In fact, one historian has called the Axial Age “the age of criticism”.

Bellah says the question that was key during this breakthrough period was, “Who is the true king, the one who truly reflects justice?” So, for example, in Greece, Plato instructs people to look not to the aristocrat Achilles but to Socrates. In India, the Buddha was the one who gave up his claim to kingly succession. And in Israel, the God/king unity was decisively broken with the prophetic tales about YHWH rejecting and installing kings at will. In short, Bellah argues, axiality consists in the ability to imagine new models of reality as preferential alternatives to the ones already in place.

The key to this transition to criticism was the capacity for graphic invention and external memory, without which a bridge from Neolithic to modern humans might never have emerged, according to Bellah. Without the ability to store information outside the human brain, humans would not have been able to develop second-order thinking. And without that, we would never have been able to codify our religious experiences into elaborate theologies.

Surely there were theory and analysis before writing, as Bellah admits. Nor should we overlook the fact that orality and literacy overlap in ways that make it difficult to say that something is only the effect of literary culture. Still, as Bellah notes, we shouldn’t downplay the importance of the written word, which allowed narratives to be written down, studied, and compared, “thus increasing the possibility of critical reflection”.

The kind of thinking that he sees emerging in the Axial Age is theory about theory, thinking about thinking. It’s second-order thinking that leads to a religious and philosophical breakthrough: “not only a critical reassessment of what has been handed down, but also a new understanding of the nature of reality, a conception of truth against which the falsity of the world can be judged, and a claim that truth is universal, not merely local”.

The historian Antony Black, who has taken major issue with Jaspers’ notion of an Axial Age, nevertheless agrees that in roughly the same period described, there develops “an approach to the self and to the cosmos that is more reasoned, brooding, reflective, self-conscious, and at the same time more articulate… What was involved was nothing less than a new interpretation of our experience and a new set of goals.”

In short, what makes the Axial Age axial is that it is still with us today. The “fundamental categories with which we still think, and the beginnings of the world religions, by which human beings still live, were created”, writes Jaspers. Of course these religions and philosophies have undergone some changes, but they represent the something from which all of our contemporary institutionalised religions emerge.


The words “This is my body” spoken at Mass set my mind off on this two-part journey into the origins of religious being. The focus is always on embodiment – ours, Jesus’s, his followers’, their ancient Jewish ancestors’, hunter-gatherers’, or that of other hominins, chimpanzees, bonobos, apes. Our bodies can feel and act and be in religious ways because the embodiment that eventually became our embodiment was responding to environmental pressures (biological and cultural) to flourish. Many of these developments occurred as nature pressured our ape line to become more social, and the unprecedented numbers of members living together in close proximity. Social cohesion had to be maintained and promoted, but the tried-and-true method of grooming was no longer possible because it was time-prohibitive. Certain rituals, like dancing, were capable of producing the same pharmacological effects in its practitioners, and hunter-gatherers eventually began to practice them with more regularity, especially as their group sizes grew.

Eventually hunter-gatherers set down roots in permanent settlements, which required even more prosocial behaviour management to alleviate the stresses of group living. Given the human brain’s evolved ability for agency detection and intuitive morality, quasi-formal religion quite naturally emerged. These seeds became institutionalised throughout the Neolithic Revolution, which laid the groundwork for the so-called Axial Age to occur. The major ideas of this period – from Confucianism to Judaism and Ancient Greek philosophy – are still with us today.

At least that’s one way to tell the story. There are others, and perhaps some of these get the story more correct. Human knowledge – especially about our past – is constantly evolving, and therefore our theories are constantly being confirmed, fine-tuned, or left behind. No matter what we learn about religion’s past, though, we can be sure that our religious way of being has deep historical roots in our evolutionary lineage.

But what about religion’s future? Some people argue that since we know how and why religion evolved, we’re now able to leave behind such childish, primitive things.

Some even argue that it’s in our best interest to do so because religion, like a virus, has infected our species and caused us to enact horrible atrocities the world over. Better to leave it to science and rationality to help us forge our way ahead. But this perspective is shortsighted. For one thing, science itself is not neutral, and it has facilitated some of the worst modern phenomena, including eugenics, the atomic bomb, and drone warfare. Should we also leave science behind because of its checkered history? Of course not.

Our criticisms of human institutions shouldn’t blind us to the positive contributions those institutions have made across the globe. None of us should deny either the ugliness or nobility found in the deep history of religion. Instead, we should acquaint ourselves with that history, appreciate it where can, interrogate it where we ought, and, with both eyes open, trek on toward the future opening up before us.

Whatever that future ends up being, at the moment it looks like humans will be there, at least in some form. And we’ll be there with our hopes and our fears and our feelings and social norms and our bouts of play and our questions – all of the same capacities that came together in just the right way to allow religion to emerge and replicate and flourish across the entire planet. Religion is so bound up with everything we know about our species that it seems near impossible to imagine a future human without any religious sensibilities.

“I’m sceptical that religion will disappear,” says the primatologist Frans de Waal. “I don’t think that’s a realistic option for the human species. Maybe it can be replaced by something better, but it cannot disappear.”

One of the better somethings, for many people, seems to be religion sans doctrine or hierarchy. Many researchers have noted that at the same time Church attendance in the West has declined, there’s been a noticeable increase in spirituality. Hence, the so-called Spiritual But Not Religious (SBNR) phenomenon.

Spirituality in this sense has been defined by one researcher as “a personalised, subjective commitment to one’s values of connection to self, others, nature, and the transcendent”. In a 2017 survey across 15 Western countries, for example, 64% of SBNRs said even though they didn’t believe in God as described in the Bible, they believed in a higher power.

Some have referred to the SBNR trend as yet another example of DIY culture: practice whatever helps you achieve a sense of union with the transcendent. It’s not surprising, then, that yoga, meditation, and crystal healing have been gaining in popularity.

It’s also worth noting that the majority of American Christians hold at least one “New Age belief” (for example, a belief in reincarnation or astrology), according to another Pew study. Which means even those who participate in traditional religions may go about it non-traditionally. Without a doubt, these syncretistic trends attest to the processes of globalisation. 

Paul Tillich, one of the most famous 20th Century theologians, developed a theology of correlation: the answers religion has to offer should correspond to the questions that a culture is asking. If it fails at this endeavour, then it becomes irrelevant. Much of the loudest theology preached by the loudest practitioners of religion seems to have failed in precisely this way. So many people have decided to take their questions elsewhere.

But the questions remain. As do we – human animals whose brains “have been designed to blur the line between self and other”, as de Waal puts it. We’re always going to seek out activities – trance dance, prayer, communion – that remind us of and enhance this blur.

At the centre of religion, says Dunbar, is a mystical concern with belonging – a concern that predates and will outlive Homo sapiens, who will, in the end, be said to have occupied a narrow sliver of time and space in the great cosmic story of the universe.  


Brandon Ambrosino has written for the New York Times, Boston Globe, The Atlantic, Politico, Economist, and other publications. He lives in Delaware. This is the second of a two-part special examining the evolutionary roots of religion.

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