Confirmation Bias

“The moment a person forms a theory his imagination sees in every object only the traits which favor that theory.” (Thomas Jefferson)

Last night a reader of this site took the time to send me a link to an article I had somehow missed reading. It was written by Dr. Albert Mohler and discussed the subject of “confirmation bias.” Dr. Mohler traces an article written by Michael Shermer of Scientific American as he discusses a study based on this topic. Schermer discusses “A recent brain-imaging study [that] shows that our political predilections are a product of unconscious confirmation bias.”

As a fiscal conservative and social liberal, I have found at least something to like about each Republican or Democrat I have met. I have close friends in both camps, in which I have observed the following: no matter the issue under discussion, both sides are equally convinced that the evidence overwhelmingly supports their position.

This surety is called the confirmation bias, whereby we seek and find confirmatory evidence in support of already existing beliefs and ignore or reinterpret disconfirmatory evidence. Now a functional magnetic resonance imaging (fMRI) study shows where in the brain the confirmation bias arises and how it is unconscious and driven by emotions. Psychologist Drew Westen led the study, conducted at Emory University, and the team presented the results at the 2006 annual conference of the Society for Personality and Social Psychology.

During the run-up to the 2004 presidential election, while undergoing an fMRI bran scan, 30 men—half self-described as “strong” Republicans and half as “strong” Democrats—were tasked with assessing statements by both George W. Bush and John Kerry in which the candidates clearly contradicted themselves. Not surprisingly, in their assessments Republican subjects were as critical of Kerry as Democratic subjects were of Bush, yet both let their own candidate off the hook.

This is no great surprise, as experience shows all of us that we are much more willing to grant clemency to people whom we like and support than those with whom we disagree. What is particularly interesting about this study, though, is the source of the brain activity that formed these judgments. “The neuroimaging results, however, revealed that the part of the brain most associated with reasoning—the dorsolateral prefrontal cortex—was quiescent. Most active were the orbital frontal cortex, which is involved in the processing of emotions; the anterior cingulate, which is associated with conflict resolution; the posterior cingulate, which is concerned with making judgments about moral accountability; and—once subjects had arrived at a conclusion that made them emotionally comfortable—the ventral striatum, which is related to reward and pleasure.” What the researchers saw “was a network of emotion circuits lighting up, including circuits hypothesized to be involved in regulating emotion, and circuits known to be involved in resolving conflicts.” In other words, when people assessed the statements made by President Bush and John Kerry, they reacted with emotion rather than reason.

Like Dr. Mohler, I am “suspicious of all efforts to reduce human consciousness and cognitive activity to measurable or observable studies of the brain. There is a connection there, no doubt, but biological reductionism (and its close cousin, biological determinism) is a woefully inadequate explanation for human thinking and behavior.” To reduce human cognitive function, thinking, feeling and believing to mere imaging results is clearly inadequate in explaining the intricacies of the brain, the will and the heart. I don’t believe that we can ever neatly map out human reason or that we can ever solve how and why humans love, feel and believe. And yet there is likely some truth in the results of this study, for we are no doubt prone to make judgments based more on emotion than reason. Michael Shermer says, “The implications of the findings reach far beyond politics. A jury assessing evidence against a defendant, a CEO evaluating information about a company or a scientist weighing data in favor of a theory will undergo the same cognitive process.” In other words, confirmation bias can show itself in any number of situations.

Dr. Mohler writes, “We are unquestionably inclined to seek evidence that confirms our bias and to discard or discount evidence to the contrary. There may be biological evidence of this fact (indeed I assume there must be such evidence), but the main factor behind this problem, from a human perspective, is the Fall. The corruption of the race involves the corruption of our cognitive abilities. Confirmation bias is just one more evidence of the Fall; one more reminder that we are fallen creatures whose minds are not only finite, but corrupted. The human mind is truly amazing, but we all have to deal with conflicted thinking, limited knowledge, fragile memory, and emotional influences.”

When we affirm the doctrine of the fallenness of man, we affirm that through the Fall we have been corrupted in every way. The depravity of man extends to every area of his being so that nothing remains untouched. We are unable to use our minds without allowing emotion to interfere with reason. Clearly this poses a threat to intellectual integrity. “The reality of confirmation bias and its threat to intellectual integrity is one reason that Christian thinkers must read widely and think carefully.” Christians bear the responsibility of knowing their sin and thus knowing their proclivity for all manner of sin—even the sin of confirmation bias. For if we are able to admit that confirmation bias is a result of the Fall, we must also admit that it likely comes naturally to fallen men and women and that we are all likely to slip into it from time to time. I did not have to think long or hard before seeing areas where I am prone to make snap judgments and to allow emotion to override more measured reason. And, as the subject of discernment has been much on my mind in recent days, I also see how people to seek to be discerning may be particularly prone to this bias.

Here is an application Dr. Mohler drew from his reflections on the subject: In order to avoid confirmation bias “We must not limit ourselves to reading material from those who agree with us, fellow Christians who share a common worldview and perspective. Instead, we have to ‘read the opposition’ as well — and read opposing viewpoints with fairness and care.” If we are to avoid this bias, we must deliberately stretch ourselves. As I read this I thought back to the review I posted just a couple of weeks ago about the book While Europe Slept which was written by a homosexual. When I posted that review, several people questioned the validity of reading and reviewing such a book. These questions arise often when I read and review books that are written by unbelievers or by those who write from a liberal Christian perspective. Yet I think these books are important, for it is all too easy to delude ourselves, sometimes deliberately and sometimes inadvertently, into thinking that we are fair and unbiased when the reality may be far different. I believe, like Dr. Mohler, that it is important that we read the opposition. I believe that there is nothing to fear in doing so, provided that a person is well-grounded in the truths of Scripture.

John Calvin, in his Institutes wrote “If we regard the Spirit of God as the sole fountain of truth, we shall neither reject the truth itself, nor despise it wherever it shall appear, unless we wish to dishonor the Spirit of God.” We can look outside the Christian bookstores for truth. We would not look outside a Christian worldview to find eternal truths, but we may still find truths outside the church and perhaps even truths to which Christians are oblivious. To ignore or to reject these truths, especially on the basis of confirmation bias, would be to dishonor God, the very source, the fountain, of truth.