What role does cognitive dissonance play in religious belief?

Cognitive dissonance can be a type of glue that keeps some religious adherents "in the fold," so to speak, when their interaction with competing belief systems of scientific understanding would otherwise undermine their faith in a particular dogma.   Your comparison wouldn't normally apply to atheists because there is no competing belief systems that they have to contend with...which is the definition of this term. Despite the rhetoric from religious advocates who like to set up a strawman argument of the "hostile" and "fundamentalist atheist" (that hates god, and yet has a "belief system" of their own), the reality is most people that identify as atheist do not have firmly held "faith" in their atheism. It really is a simple matter of not believing in something that doesn't have any apparent proof. It is the default position for those that are uninterested in religion or have not been indoctrinated into a particular faith (or have deprogrammed themselves from one). For example, I would have no problem believing in a god if I saw evidence of it. I simply do not. And there is no cognitive dissonance involved in this position.   I'd suspect the level of cognitive dissonance will vary within the religious population. For example, perhaps a majority of religious adherents in the middle of the bell curve have less cognitive dissonance than those on the sides - who follow less traditional or classic tenets of an origanized religion. The latter group may not accept the more literal aspects of their religion and are more open to non-religious understanding of existence (e.g. most of the natural and applied sciences) but they may have further to go to reconcile these competing beliefs. Those found in the mid-bell curve might simply reject - outright - all kinds of accepted scientific truths or explanations of natural phenomenon. So, there is little cognitive dissonance for them. I think this term inherently means that an individual has to accept some fact/knowledge and some level, and yet ignore the full context where it clashes with other belief systems or compartmentalizes them. How adherents reconcile these competing belief system will vary. Then again, if we are looking at a bell curve of a reglious population the extreme outliers may be all over the charts with their levels of cognitive dissonance. They might be so extreme that they need astounding levels of cognitive dissonance to still consider themselves part of the religion, or others might have such an esoteric or unique version that they are hardly part of the recognized religious community and they are content to do their own thing with no apparent internal psychological conflict. I suppose the level of cognitive dissonance could run the whole gambit and would depend on a lot factors.   But, here is a straight foward example: classic Young Earth Creationism. This has been utterly demolished by just about every natural science discipline out there. So, ignore these damning implications requires either a "doubling down" and digging in your heals in a form of spiritual Ludditism....or, creating a stop-gap measure like that of "Intelligent Design." This latter approach is a recalibration or re-entrenchment, whereby the broad principles of the religions (e.g. that the world was still created by God) are left intact, while at the same time there is an acknowledgement that the Biblical description is more allegorical or "beyond our comprehension." This re-formatted belief system still requires a deity to create matter, He put in place all of these laws of the universe, this is part of His plan/design, etc.   If I had to point to one of the most extreme displays of cognitive dissonance and the power of self-delusion and adherence to a dogma it would have to be Mormonism and the Book of Abraham.   This entire religion is predicated upon the word of one person that claims to have been visited by angels and translated magical texts from an ancient Semitic population that settled in the Americas and had knowledge of Jesus! Conveniently, the original texts Joseph Smith "translated" were taken by angels (conveniently) and none of the original texts exist for comparison or study. But, after he had "translated" and published the Book of Mormon and developed a bit of a following he got a bit over-confident. He bought some papyrus scrolls from a traveling oddities show which happened to contained Egyptian funerary texts. He immediate proclaimed them to be a description of Abraham's life, the nature of god, pre-mortal existence, creation, etc. Convenient! Of course at that time, the field of ancient Egyptian linguistics was not all that advanced. Unfortunately for Smith, experts were steadily working on decyphering the heiroglypics system and eventually the texts could be read with complete accuracy. Smith had the Book of Abraham cannonized as part of Mormon dogma and a literalist belief in this "translation" was accepted by adherents of this religion. Unlike the so-called Golden Plates that magically dissappeared and could not be studied, some of original Book of Abraham papyri did survive. They initially were passed to Smith's mother, then his ex-wife. She then sold them to a private collector...and after changing hands a few more times, some of the texts ended up in the Museum of Chicago.   After the 1871 Chicago fire damaged the museum it was assumed that all of these texts had been lost. However, in 1966 fragments of the papyri were found in the New York Museum of Metropolitan Art (some texts having been kept in private hands and eventually sold to the MMA) and could be then be compare with the Book of Abraham translation and the printed fascimiles. The bottom line is the Book of Abraham is a complete fabrication and it can be rather easily demonstrated as such. But, the level of apologetics is astounding. And the cognitive dissonance is overwhelming. Adherents would rather dismiss overwhelming evidence or accept the most convoluted rationalisations than to admit the truth that this religion was made up whole-cloth by a charlatan. The other aspect that exacerbates cognitive dissonance is our demand of using kid-gloves when it comes to religious belief...as if it is of such a sacred nature that it is outside the bounds of rigorous debate. Often, simply stating aspects of a religion are bogus or contrived is seen as rude. So, even in the case where a relatively new cult can be debunked definitievely, it is see as impolite to point out these facts. Thus we get to the negative aspect of religions: that there is a willful ignorance of facts and any evidence that would discredit the belief system itself.    However, I don't think extreme cognitive dissonance is a requirement in all religions. Human cultures have always had religious beliefs and they reflect the need to understand reality and make sense of the world. The more scientific knowledge expands our understanding the more religions may shift internally. The Intelligent Design belief which started off with its root in cognitive dissonance (e.g. former literalists looking to make sense out of a body or knowledge that conflicted with the earlier dogma) will eventually evolve into a more moderate strain of belief, which may well become a new religious norm. All religions shift and evolve. Perhpas a less vengeful, less anthropomorphic concept of god may emerge...that will look nothing like the god of the Puritans of the ancient Hebrews. However, while it can get expressed in more esoteric and vague terms, we can also see the rise of more extremist dogma that delves into deeper pools of cognitive dissonance. This is especially apparent when there are fundamental flaws built into the tenets of a particular religions which cannot adapt to modern science and/or societal shifts.   Actually, this phenomenon can be found outside of the realm of religion. A spouse that stays with an abusive partner can often display a level of cognitive dissonance. Particularly, in cases where there is abuse of the children, a spouse often intuitively "knows" it but chooses to ignore the signs and willfully donwplays the facts.   In other words, this is a human trait. But, I think religious dogma probably just exacerbates this phenomenon.

This is an interesting question on a number of levels. The theory of Cognitive Dissonance owes its existence to religion. In this sense religion is the mother of Cognitive Dissonance, but perhaps not in the sense assumed by the question. Cognitive Dissonance theory flew into the scene of sociology and psychology in the mid 1950's under the study of a strange, small apocalyptic UFO cult based in Chicago. The theory was that people will seek to alleviate the inner turmoil of evidently discrepant beliefs and expectations in their lives. The mind will seek to justify tensions between their expectations and beliefs and the reality of disproven events by renegotiating the terms of their expectations/beliefs. This was not presented as some kind of proof text for agnosticism or atheism, nor was it an apologetic for skepticism. Rather, Cognitive Dissonance was a descriptor of behavior in extreme cultic settings, which had ramifications into the psychological profiling of people strongly committed to causes and beliefs, which collapse or fail in front of them. The theory was that the most committed, and most connected people in a group would retain their beliefs in the face of clear disconfirmation. The book When Prophecy Fails was published after Leon Festinger embedded his sociology students into a the small Flying Saucer cult during a season of apocalyptic pronouncements in 1953. This was an extremely unorthodox sociological study, because it demanded that the students pose as believers, while studying the subjects. Yet, the study has provided some of the great psychological/sociological insights in the 20th century. Festinger and team reference general belief in religion within the book, but make a clear point of delineation between faith in God, and the more obvious and clearly refutable beliefs such as the fact that the "spacemen" did not come to pick the group up on Christmas Eve, while 200 people stood watching, and the newspaper and news reporters were gathered around them. The prediction of results in the aftermath of the non-event by Festinger was based upon observations from the history of religion. The apocalyptic pronouncements of the Seventh Day Adventists in 1840's, which did not come to pass was followed by a redefining of the apocalyptic prophecies, and a renewed evangelistic vigor. Although unmentioned in the book, a similar thing occurred in 1914 with the Watchtower organization (Jehovah Witnesses). Indeed, as Festinger's team predicted, the UFO cult's closest, most committed followers reformatted their apocalyptic prophecies to the conclusion that the "spacemen" were offering mercy and giving the earth another chance. These followers then felt compelled to spread the message that the people of earth needed to learn to care for the earth properly, or they might be eradicated by the spacemen at some future, undisclosed time for the sake of saving the planet. Festinger was careful not to connect a generic belief in God to this same phenomenon of clear and public disconfirmation. Yet, there is some connection of this theory to general beliefs. I feel pretty confident in saying that it cuts both ways. Whether atheist, agnostic or religious believer, we are all stuck in some form of Cognitive Dissonance. I am not necessarily saying that everyone has kooky beliefs that have been publicly disproven, rather I am saying that we all are struggling with the tension of believing, or expecting things which we cannot prove. For the sake of identifying with the predominant culture around me I will place this in the setting of Christian/atheist comparison and contrast. The Christian, like myself, holds a belief in an unseen, immaterial, unmeasurable God. We often believe that a relationship can be had with this illusive Being. We believe that this God is the source of all things, and therefore we reference the Universe as "Creation." Yet, by the very nature of being supernaturalists, we cannot recreate the processes of our miraculous faith in a lab setting, and are left with mystery, and unproven theories for the initiation of things like time and matter. Our beliefs remain unproven, but unlike Dorothy Martin's UFO cult in 1953 Chicago, there is no news crew standing around watching the moment of solid evidence that what we say did not happen. Our Cognitive Dissonance is not of the same degree as those who stood firm against the laughing crowds on a cold Chicago Christmas Eve in 1953. At least for most of us this is true. Occasionally, someone rises up and declares another silly apocalypse like Harold Camping did on May 21st, 2011, or Hal Lindsey did back in 1981. Now the atheist has a similar albeit uniquely different Cognitive Dissonance to struggle against. In the search for the answers to the mysteries of the universe, science seeks for resolution to the internal dissonance of justifying such things as the eternality of matter (now, considered a somewhat passe belief in the advent of  Quantum Physics), or searching for a discovery to find the source of that singularity event setting up the Big Bang. Justifying a belief that nothing comes from nothing is as complex and internally dissonant as justifying that there is an immaterial, knowable Being Who is the source of all things. So, Stephen Hawking can write the books positing and attempting to describe the moment of singularity, yet the causation remains unproven, untestable and illusive. On one hand, theories lead in the direction of a great event 13.7 billion years ago that exploded like a blast of light and a sudden emergence of matter and time establishing what we all experience, but what lies before (sorry, I realize that before is probably a poor choice of words here, and the French word "sans" might be more accurate) is completely unknown. Mathematics slouches away from theories of evolutionary origination of life, while other disciplines appear to slouch toward it, and the Cognitive Dissonance mildly settles in us all. Of course, Cognitive Dissonance plays a role in religion, but it plays a role in irreligion as well. Perhaps the role it plays for the average seeker of truth is a good one. It may be the cause for hungry search for truth. Each us has chosen a resolution in our own unique and perhaps self-justifying ways. One of us can blame God for our resolution and another may blame science, but we are all living with the tension of unknowing, and at some point what we believe can be compellingly argued against. The mysteries of life are too great to not leave us hanging. So, debate on debaters, preach on preachers, teach on teachers, and study on students of life.

It's usually not an issue.  Believing the world works by scientific laws does not preclude miracles if you beleive that God can suspend/alter/rewrite these laws.

In a way it addresses the 'cognitive dissonance' of your existence. Religion tries to be a reconciling element, which solves contradictions that you observe and have within yourself. Some might say it does it clumsily against better knowledge, with premises that it can't support, but that is still what it does.

Compartmentalization.   Think of  a theoretical physicist who knows a great deal of how the world really works and at the same time a devout communicant of his religion.  Example.  John Polkinghorne who was a student of Diract in quantum physics and is now an Anglican Priest.   I could not manage that.

Cognitive dissonance occurs only under certain reasonably well-defined conditions, as described in the scientific source material, and as I explained in http://www.dailykos.com/story/2014/08/04/1306714/-Grokking-Republicans-Cognitive-Dissonance. Deep conviction, not only that something is true but that it requires some particular action. Commitment, that is taking an action that is difficult or impossible to undo. Specificity, so that disconfirmation is unequivocal when it comes. Disconfirmation, failure of the prophecy, is obvious and admitted. Believers have strong social support for maintaining their beliefs. Conversely, this implies that the supporters would cast them out and shun them if they wavered. This was initially observed directly in a flying saucer cult, and set out in When Prophecy Fails, by Festinger, Riecken, and Schachter. We observe it in a number of Religious Right issues in the US, and in some other cases around the world, but not in religion generally. It is a general feature of cargo cults.We also have historical evidence of many episodes of Cognitive Dissonance concerning the time for the Second Coming and the end of the world, from early Christian times, when it was generally understood that the book of Revelation referred to the Roman Emperor, and specifically the Emperor Nero. The Millennium was a particularly strong example.The key point is that it is not Cognitive Dissonance that a belief is not widely shared, or even that it has been historically debunked. There must be a prediction such as the end of the world that a cohesive group commits itself to, and that then fails utterly and obviously.We also observe it in politics, for example in the decades of disconfirmation of Supply-Side tax cut policy, which has always greatly enriched the already rich, but has never once given a boost to the economy, increased tax revenue, or "trickled down" to the middle class or the poor, "lifting all boats" like the tide, all promised with the greatest air of certainty over and over. Nevertheless, it remains an Article of Faith and a recruiting tool on the Right.The belief in WMD continuing even after the Iraq War is another clear case.I can cite dozens more from the political Right. We used to get the same from the Loony Left in the days of the Soviet Union, when the genuine Communist workers' paradise was going to emerge out of Stalinism any day now, or at worst at the end of the next Five-Year Plan.Many other phenomena that are popularly called Cognitive Dissonance are actually instances of other psychological phenomena, such as Authoritarian Personalities (including dogmatism, hypocrisy, racism, non-cooperation, and other ills) and the Dunning-Kruger effect (in the worst case, the belief that one knows better than all of the experts). All of these effects are observed from time to time in particular religious groups, but by no means all of them, and also in politics.