Michael Shermer of Scientific American offers an interesting column on confirmation bias. Mr. Shermer is prone to biological reductionism (as evidenced in this article) and his primary interest in this article is politics, but his column raises a basic question of intellectual integrity.

Here is how he sets up his argument:

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.

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.

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.

Nevertheless, the issue of confirmation bias is real. We are unquestionably inclined to seek evidence that confims our bias and to discard or discount evidence to the contrary. There may be biological evididence 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.

The reality of confirmation bias and its threat to intellectual integrity is one reason that Christian thinkers must read widely and think carefully. 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.

This does not come easily, but Christians bear a particular responsibility to be watchful for confirmation bias and its effects.