Confirmation bias: we seek evidence to confirm existing beliefs while ignoring contrary evidence. Our emotional brain filter allows confirming information but disallows contradictory information. We react emotionally, not logically, to conflicting data. We then rationalize away evidence that does not fit our preconceived beliefs. When we do this, moreover, our reward centers of the brain are activated, thus reinforcing the process. Evidence that conforms to our beliefs is well founded, useful.  Evidence that contradicts our beliefs is discounted or ignored. Moreover, reading information that goes against our own view makes us even more attached to our beliefs.  Likewise, the absence of evidence is seen as evidence for our beliefs, e.g., they’re hiding evidence. Opposing evidence actually enhances our attachment to our original position. What’s more, MRIs show our reasoning area shut down in the brain when dissonant information is revealed, but activated again when confirming evidence is shared. The bias often takes this form: “Just what I always said!”  We interpret evidence in the light most favorable to our client or theory, thus ignoring blind spots and weaknesses.

This might also explain our commitment to our belief after making an important decision: post hoc rationalization to maintain consistency and to reduce cognitive dissonance.  Especially true when our decisions are irrevocable or when unmaking decisions that will cost money, e.g., study of gamblers who just made bets at track showed their confidence much higher than those in line, even though nothing had changed except for bet being made.  Works too with unconscious decisions when we make up reasons later.

Because of the adversarial nature of our legal work, we lawyers are especially prone to confirmation bias. First, our worldview is often predicated upon positional argument, during which we characterize evidence to fit the legal framework most likely to yield the desired result. We categorize and pigeonhole to stake out positions. The hallmark of lawyering is advocacy, in which arguments are generated and tested in the heat of controversy. The litigator’s ethos, in particular, promotes a stalwart resistance to the opponent’s contrary position. Research shows that the more our beliefs are challenged, the more strongly we adhere to them.

Second, evidence is usually incomplete, contradictory and ambiguous, allowing the confirmation bias plenty of room to weed out evidence that conflicts with our theory of the case.

Third, we often over-identify with our clients and our cases, imbuing each with a sense of ourselves as integrally tied to the person whose cause we advocate and the legal position we advance.  Both the people and the ideas become an extension of our professional selves.

Fourth, many legal decisions pose great risk and result in irrevocable outcomes, which further enhances the confirmation bias.  We are more likely to confirm that which can’t be undone without difficulty (related to the “sunk cost” fallacy we explore in later posts).

While there is no cure to confirmation bias, we lawyers must always look – as counter-intuitive as it feels – to disprove our case at the earliest stage and continuously thereafter! Only if we know intimately how our case should lose on the evidence can we understand how to win. And we should also try to impart the wisdom of the confirmation bias to our clients and opposing counsel. Explaining the bias as an unavoidable feature of all minds will help loosen its grip on us. Be wary of what confirms. Look for what falsifies.