Nearly a century of opinion polling attests that 70–85 percent of Americans profess not merely a belief in a generic God, but a belief in highly specific, religious propositions: that the Bible is the word of God (whether literal or “inspired”), that Jesus Christ will physically return to earth at some point in the future, that Satan exists and leads people to sin, that prayers actually get answered, etc. The failure to subject such beliefs to rational criticism may be one reason for their survival. But, as Boyer 
points out, the failure of reality testing cannot explain the specific character of religious beliefs. According to Boyer, religious beliefs and concepts must arise from mental categories and cognitive propensities that predate religion—and these underlying structures might determine the stereotypical form that religious beliefs and practices take. These categories relate to things like intentional agents, animacy, social exchange, moral intuitions, natural hazards, and ways of understanding human misfortune. On Boyer's account, people do not accept implausible religious doctrines because they have relaxed their standards of rationality; they relax their standards of rationality because certain doctrines fit their “inference machinery” in such a way as to seem credible. And what most religious propositions may lack in plausibility they make up for in the degree to which they are memorable, emotionally salient, and socially consequential; all of these properties are a product of our underlying cognitive architecture, and most of this architecture is not consciously accessible. Boyer argues, therefore, that explicit theologies and consciously held beliefs are not a reliable indicator of the contents or causes of a person's religious outlook.
Boyer may be correct in saying that we have cognitive templates for religious ideas that run deeper than culture (in the same way that we appear to have deep, abstract concepts like “animal” and “tool”). We may, in fact, be what Bloom 
has called “common sense dualists”—that is, we may be constitutionally inclined to see mind as distinct from body and, therefore, will tend to intuit the existence of disembodied minds at work in the world. This could lead us to presume ongoing relationships with dead friends and relatives, to anticipate our own survival of death, and to generally conceive of people as having immaterial souls.
A variety of experiments suggest that children are predisposed to assume both design and intention behind natural events—leaving many psychologists and anthropologists to believe that children, left entirely to their own devices, would invent some conception of God 
. The psychologist Margaret Evans has found that children between the ages of eight and ten, whatever their upbringing, are consistently more inclined to give a Creationist account of the natural world than their parents are 
Because our minds have evolved to detect patterns in the world, we may tend to detect patterns that aren't actually there—ranging from faces in the clouds to a divine hand in the workings of Nature. Hood 
posits an additional cognitive schema that he calls “supersense”—a tendency to infer hidden forces in the world, working for good or for ill. On his account, supersense generates beliefs in the supernatural (religious and otherwise) all on its own, and such beliefs are thereafter modulated, rather than instilled, by culture. Hood likens our susceptibility to religious ideas to our propensity to develop phobias for evolutionarily relevant threats (like snakes and spiders) rather than for things that are far more likely to kill us (like automobiles and electrical sockets). Barrett 
makes the same case, likening religion to language acquisition: we come into this world cognitively prepared for language; our culture and upbringing merely dictate which languages we will be exposed to.
And yet, however predisposed the human mind may be to harboring religious beliefs, it remains a fact that each new generation receives a religious worldview, at least in part, in the form of linguistic propositions—far more so in some societies than in others. Whatever the evolutionary underpinnings of religion, it seems unlikely that there is a genetic explanation for the why the French, Swedes, and Japanese tend not to believe in the God of Abraham while Americans, Saudis, and Somalis do. The importance of religious doctrines that purport to be true, and their subsequent acceptance as true by great numbers of human beings, seems indisputable.
Recent attempts to study the neural correlates of religious belief have either suffered from a lack of a nonreligious control condition 
or were not designed to isolate the variable of belief at all 
. To investigate the neural correlates of belief for both religious and nonreligious modes of thought, we asked Christians and nonbelievers to evaluate statements of both types while in the MRI scanner.
The data reported above present statistical tests of the reliability of signal changes occurring throughout the brain as a function of the stimuli and their associated behavioral responses. However, these data are of greater value when interpreted against related results in the neuroscientific literature. Such a discussion necessarily entails “reverse inference” of a sort often considered problematic in the field of neuroimaging 
. One cannot reliably infer the presence of a mental state on the basis of brain data alone, unless the brain regions in question are known to be truly selective for a single state of mind. As the brain is an evolved organ, with higher order states emerging from lower order mechanisms, very few of its regions are so selective as to fully justify inferences of this kind. Nevertheless, our results appear to make at least provisional sense of the emotional tone of belief. And whatever larger role our regions of interest play in human cognition and behavior, they appear to respond similarly to putative statements of fact, irrespective of content, in the brains of both religious believers and nonbelievers.
The contrast, belief minus disbelief
, revealed greater BOLD signal in the VMPFC (see , ). The medial prefrontal cortex is known to have a high level of resting state activity and to show reduced activity compared to baseline for a wide variety of cognitive tasks 
. BOLD signal in this region has often been associated with self-representation, particularly for verbal stimuli 
: for instance, one sees smaller decreases in activity from baseline when subjects make judgments about themselves than when they make judgments about others 
. This region has also been implicated in reward-related processing 
. The smaller decrease in activity for belief compared to disbelief could reflect the greater self-relevance and/or reward value of true statements.
Our study was designed to produce high concordance on nonreligious stimuli (e.g.
, “Eagles really exist”) and high discordance on religious stimuli (e.g.
, “Angels really exist”). The fact that we found essentially the same signal maps for belief minus disbelief
in both groups, on both categories of content, argues strongly for the content-independence of belief and disbelief as cognitive processes. Despite the fact that religious believers and nonbelievers accepted and rejected diametrically opposite statements in half of our experimental trials, the same neural systems were engaged in both groups throughout. This would seem to rule out the possibility that these results could be explained by any property of the stimuli apart from their being deemed “true” or “false” by the subjects in our study. The involvement of the VMPFC for belief is consistent with our earlier findings 
In our earlier study of belief, we found anterior insula signal to be associated with the contrast disbelief minus belief
. Kapogiannis et al. 
also found signal in the insula to be correlated with the rejection of religious statements deemed false. The significance of the anterior insula for negative affect/appraisal has been discussed above. Because Kapogiannis et al. did not include a nonreligious control condition in their experiment, they interpreted the insula's recruitment as a sign that violations of religious doctrine might provoke “aversion, guilt, or fear of loss” in people of faith. Reducing the statistical thresholding in our present study did nominate the insula as a region of interest for disbelief, in both groups and on both categories of stimuli. However, these areas of signal did not survive our cluster thresholding.
Our previous study of belief, in which we explicitly modeled uncertainty, revealed greater signal in the ACC and adjacent regions of the superior frontal gyrus in the uncertainty condition. Given that our signal maps in the contrast religious minus nonreligious elicited this same pattern, we speculate that both groups experienced greater cognitive conflict and uncertainty while evaluating religious statements. In support of this conjecture, we also note that our religious stimuli, while semantically and grammatically well matched to our nonreligious stimuli, incurred longer response times for both groups. This contrast also showed bilateral signal in the striatum and the anterior insulae. It is perhaps not surprising that the evaluation of religious statements would more fully engage regions of the brain responsive to emotional salience, both positive and negative.
The contrast religious minus nonreligious also showed increased signal in the medial parietal regions regularly associated with self-referential tasks. We note that a possible difference between responding to our religious and nonreligious stimuli is that, for both groups, a person's answers could serve to affirm his or her identity: i.e. for every religious trial, Christians were explicitly affirming their religious worldview, while nonbelievers were explicitly denying the truth-claims of religion.
The opposite contrast, nonreligious minus religious, showed increased signal in left hemisphere memory networks. Thus, judgments about the nonreligious stimuli presented in our study seemed more dependent upon those brain systems involved in accessing stored knowledge.
Finally, there were several regions that showed greater signal in both groups in response to “blasphemous” statements (i.e. those that ran counter to Christian doctrine). The ventral striatum signal in this contrast suggests that decisions about these stimuli may have been more rewarding for both groups: Nonbelievers may take special pleasure in making assertions that explicitly negate religious doctrine, while Christians may enjoy rejecting such statements as false.
There is, of course, no reason to expect that any regions of the human brain are dedicated solely to belief and disbelief. Nevertheless, our work suggests that these opposing states of cognition can be discriminated by functional neuroimaging and are intimately tied to networks involved in self-representation and reward. Despite vast differences in the underlying processing responsible for religious and nonreligious modes of thought, the distinction between believing and disbelieving a proposition appears to transcend content. These results may have many areas of application—ranging from the neuropsychology of religion, to the use of “belief-detection” as a surrogate for “lie-detection,” to understanding how the practice of science itself, and truth-claims generally, emerge from the biology of the human brain.