Five Reasons Why Studying Psychology (Might) Make You More Skeptical of Religion

Academics and professionals from the fields of psychology[1] and psychiatry[2] were found more likely to be irreligious compared to their counterparts in a variety of other disciplines. Here are five reasons why studying psychology might nudge you to think more skeptically when it comes to religion:


# 1- The brain is a product of evolution


To the untrained eye, pictures of our brains and the brains of dolphins or chimps are practically indistinguishable.  Someone trained in comparative neuroscience could tell them apart, of course, but she or he could also tell you a lot more about the shared characteristics that are fundamental to the function of brains. The same fundamental building blocks in our DNA, including the genes responsible for building our brains, are found in the DNA of all living organisms. This means the same genes that are key to building the electrical wiring in your brain are also key to building the electrical wiring in a koala’s brain—pretty cool, eh? (Same for a fly’s brain though…)

Figure 1. I think even experts mistake manatee brains for testicles, though. Figure from PNAS, Herculano-Houzel (2012).

Perhaps I shouldn’t denigrate the fly’s brain—it’s actually pretty impressive when pitted against that of a bacterium. Ancient microscopic bugs like bacteria have tiny brain-like structures in the form of ion channels. Incredible as it sounds, the very same genes that are responsible for building these ion-channel bacterium “brains” are also responsible for building the ion channels that power our brains’ neurons!


It’s not just similar genes and brain structures that we share, but also an apparent addiction to sugar and ice cream (watch till the end)

The fundamental structural similarities in the genes and brains of different species, along with many, many, many other bodies of evidence, constitute strong evidence for the fact that we’re all related in one epic tree of life (according to Dawkins, there are 12 independent lines of evidence). Admitting that we are evolved is for obvious reasons incompatible with most religious stories about creation. Seeing this evidence from comparative genetics, neuroanatomy, and neurophysiology may prompt psychologists to move away from creation myths and closer to this evolved view of life.

Figure 2. My favorite illustration of the tree of life – you can find an interactive version here. From “Tree of Life”.Copyright by Leonard Eisenberg, 2008, 2017.


# 2- There’s no soul in the brain


Introductory psychology courses typically have a full chapter dedicated to the brain, and students of psychology often take subsequent courses in behavioral and cognitive neuroscience. What you learn in neuroscience is that, first, the brain does not appear to have room for anything “extra” in it: there is no seat for any soul, nor is there room for any non-physical spirits. Second, there is no indication of a top-down command center—that is, one place where all the “essence of you” comes together. Right now, your conscious experience is the result of the orchestra of millions of parts in your brain. When these parts eventually stop working, that’ll be the day your brain’s music dies!


Ultimately, studying psychology makes it extremely difficult to be a dualist. Dualists (like Descartes) believe that we have brain stuff and non-physical spirit stuff, and these two substances can co-exist and even interact. Most genuinely religious believers are dualists because it would otherwise be difficult or impossible to believe in a soul or in an afterlife. Even though neuroscience is still a young field with certain  issues it needs to overcome, discoveries about the brain (such as the absence of a command center and widespread consensus that your mind and behavior are a product of your brain) seem to corrode one’s faith in spirits, souls, or immaterial substances that somehow live on after you die.


# 3- Our beliefs are predictably untrustworthy


Cognitive psychologists have discovered many biases that distort our thinking. Confirmation bias, for example, is the tendency to interpret new evidence as confirmation of one’s existing beliefs; and boy do we love confirming our beliefs. We tend to selectively look for, attend to, and remember information that confirms our existing beliefs . This bias gives our beliefs inertia—the tendency to stay in their active states. All you really need is for a baby belief to be born, and then the confirmation bias helps the baby grow and become entrenched as a belief. You don’t need to do much; your mind will take care of it for you.


Confirmation bias is joined by error management biases that seem to push us toward religious belief. In any decision-making scenario, there are two types of mistake you can make: a false positive or a false negative (also known as Type I and Type II errors respectively). Sometimes, one of these errors is costlier or more dangerous than the other. In such situations, it is better to err on the side of caution. This is why we purposely build smoke alarms to be biased toward false positives: we are willing to tolerate the occasional nuisance of a false alarm (safer error) when we’re cooking as long as the smoke detector never fails to detect a real fire (much more dangerous error). As a result, we purposely build our smoke alarms NOT to be maximally accurate, but rather to be biased toward the less costly error. Error management theory (EMT) suggests that the same principle applies to animal brains: when animals face decision-making situations characterized by a recurrent asymmetry in the costs of the two types of errors, they evolve decision-making mechanisms in the brain that are “adaptively biased” toward the less costly error (Haselton and Buss, 2000). Some have noted that this bias might push people toward belief in supernatural entities, not unlike Pascal’s wager (e.g., Johnson, 2009).



Imagine this: You’re peeing in the savannah when you hear rustling in the grass. Do you shrug it off as the wind? No, you typically jump to the conclusion that it might be a hungry lion that is ready to pounce on you. The cost of being lion-paranoid when there’s no actual danger is minuscule compared to the cost of failing to realize that a lion is lurking when, in fact, the lion’s about to pounce and kill you! Because of these kinds of situations, the reasoning goes, our ancestors would have evolved error management biases that pushed them toward belief in invisible entities and hidden agents. Such beliefs may be wrong, but as with the smoke alarm example, it is better to err on the side of caution. Decision-making mechanisms in the brain don’t evolve to be maximally accurate; they evolve to be maximally safe. While this bias (which is similar to the animistic fallacy) might lead to a higher number of errors, overall it leads to less costly errors. Bottom line: we appear to be endowed with cognitive biases—known as error management biases—that push us toward belief in hidden agents and supernatural entities, even if such beliefs are factually incorrect.


# 4- The beliefs of the devout can be worryingly untethered to reality


When psychology students begin studying abnormal psychology and clinical psychology, they often realize that it can be difficult to tell apart religious beliefs from the kind of delusional beliefs you see in schizophrenia and schizotypal personality disorder. There are actually cases where clinicians weren’t sure whether someone was schizophrenic or fervently religious.


The king of France was afraid of being shattered because he believed that he was made out of glass. Most agreed that there was something wrong with his mind. But when Catholics believe that consecrated bread and wine are really the flesh and blood of Jesus Christ (i.e., the Eucharist), few worry that something is equally wrong with the Catholics’ minds. If it weren’t shielded by its attachment to a well-known worldwide religion, a Eucharist-belief would sound just as worrisome and schizophrenia-like as the mad king’s made-out-of-glass belief.


If we’re being honest and consistent, why would we make exceptions for beliefs attached to famous religions? Isn’t that arbitrary? The bottom line is: there doesn’t appear to be a solid, principled dividing line distinguishing religious beliefs from false beliefs. Perhaps we shouldn’t be surprised then if we find that psychologists and psychiatrists are wary of fervent religiosity and the false beliefs it engenders.


# 5- Conformity and its grip on the faithful


Imagine being asked to pick out the obviously shorter line out of a few longer lines. Easy, right? Now imagine you were asked to repeat the same picking-out-the-shortest-line task, only this time it was right after witnessing a bunch of strangers confidently pick out one of the longer sticks as the shortest one. I’ve just (more or less) described Asch’s famous experiment on conformity.  The results of the experiment? Many participants chose the longer line, conforming to what the majority was saying even though it was obviously wrong. What psychology students take away from this and related studies on conformity is a sense of just how much we care about conforming to the majority around us. Can’t imagine this kind of situation ever fooling you? I’m sorry to break it to you, but the odds aren’t good—more than two thirds of the participants in Asch’s famous experiment conformed and selected the line that was obviously incorrect. Similar experiments confirm this general finding.


If you study psychology, one of the things you will discover is that religiosity’s benefits include the sense of belonging and sociality it offers its hosts. The social rule seems to be: (1) be a good member of your family’s or community’s favorite religion and, voilà, (2) get the benefits of being accepted in that community. It’s like having an extended family where you recognize each other’s goodness and belongingness on the basis of your specific god-related beliefs. Imagine an introspective psychology student who, moments after learning about this, wonders: “Well, gee, do I believe in my religion partly because of social pressure and the benefits of communal belonging?”


You can imagine that learning about these findings, peppered with some introspection, might begin to shake one’s religious faith. Those familiar with the psychology of religion might come to view their own religious behaviors as a combination of virtue signaling and a bid for social cohesion and group belonging. Coming to grips with the fact that many people believe in religion because of social reasons, not because of airtight logical arguments or empirical evidence, may very well implant a seed of doubt in the psychology student’s mind.


Before we wrap up, a quick caveat: even if it turns out to be true that students of psychology are more skeptical of religion, we still wouldn’t know anything about the direction of the causal arrow driving this relationship. Could it be that those of little faith are more inclined to major in psychology in the first place? Yes, that’s also possible. The two causal arrows could be there, to varying degrees, or only one, or neither. I’d personally bet on both. The point of this post is merely to answer a question I have been asking myself for a few years: does studying the nature of the mind tend to make people more skeptical of religion?


[TLDR] In short, studying how the mind works could push you toward skepticism about religion by forcing you to ‘face the facts’ about: (a) how the brain evolved over millions of years, (b) how everything modern neuroscience reveals about the brain points to the absence of an immaterial soul, (c) how cognitive biases make some of our beliefs untrustworthy, (d) how religious beliefs do not appear to be fundamentally different from clinical delusions, and (e) how our strong tendency to conform to our group’s beliefs and traditions is an important factor in why we adopt their religious beliefs.


[1] The data re: psychologists’ relative religiosity come from a 2006 survey  where the researchers surveyed nearly 1500 full-time uni/college professors teaching in the United States.


[2] The data re: psychiatrists’ relative religiosity come from a 2007 survey  where they found that psychiatrists were the least religious of physicians.

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I recently got my MSc. in evolutionary psychology from the UK. I'm currently in Colorado gearing up to launch a study on the psychology of conspiracy theories. I love all life forms, but not equally.