The Certainty Bias

Over at Mind Matters, I've got an interview with Dr. Robert Burton on the danger of certainty and its relevance during a presidential election:

LEHRER: To what extent does the certainty bias come into play during a presidential election? It seems like we all turn into such partisan hacks every four years, completely certain that our side is right.

BURTON: The present presidential debates and associated media commentary feel like laboratory confirmation that the involuntary feeling of certainty plays a greater role in decision-making than conscious contemplation and reason.

I suspect that retreat into absolute ideologies is accentuated during periods of confusion, lack of governmental direction, economic chaos and information overload. At bottom, we are pattern recognizers who seek escape from ambiguity and indecision. If a major brain function is to maintain mental homeostasis, it is understandable how stances of certainty can counteract anxiety and apprehension. Even though I know better, I find myself somewhat reassured (albeit temporarily) by absolute comments such as, "the stock market always recovers," even when I realize that this may be only wishful thinking.

Sadly, my cynical side also suspects that political advisors use this knowledge of the biology of certainty to actively manipulate public opinion. Nuance is abandoned in favor of absolutes.

Why are people so eager for certainty? I think part of the answer is revealed in an interesting Science paper by Colin Camerer and colleagues. His experiment revolved around a decision making game known as the Ellsberg paradox. Camerer imaged the brains of people while they placed bets on whether the next card drawn from a deck of twenty cards would be red or black. At first, the players were told how many red cards and black cards were in the deck, so that they could calculate the probability of the next card being a certain color. The next gamble was trickier: subjects were only told the total number of cards in the deck. They had no idea how many red or black cards the deck contained.

The first gamble corresponds to the theoretical ideal of economics: investors face a set of known risks, and are able to make a decision based upon a few simple mathematical calculations. We know what we don't know, and can easily compensate for our uncertainty. As expected, this wager led to the "rational" parts of the brain becoming active, as subjects simply computed the odds. Unfortunately, this isn't how the real world works. In reality, our gambles are clouded by ignorance and ambiguity; we know something about what might happen, but not very much. When Camerer played this more realistic gambling game, the subjects' brains reacted very differently. With less information to go on, the players exhibited substantially more activity in the amygdala and in the orbitofrontal cortex, which is believed to modulate activity in the amygdala. In other words, we filled in the gaps of our knowledge with fear.

I'd argue that it's this subtle stab of fear that creates our bias for certainty. Not knowing makes us uneasy, and we always try to minimize such negative feelings. As a result, we pretend that we have better intelligence about Iraqi WMD than we actually do, or we make believe that the subprime debt being bought and sold on Wall Street is really safe. In other words, we selectively interpret the facts until the uncertainty is removed.

Camerer also tested patients with lesioned orbitofrontal cortices. (These patients are unable to generate and detect emotions.) Sure enough, because these patients couldn't feel fear, their brains treated both decks equally. Their amygdalas weren't excited by ambiguity, and didn't lead them astray. Because of their debilitating brain injury, these patients behaved perfectly rationally. They exhibited no bias for certainty.

Obviously, it's difficult to reduce something as amorphous as "uncertainty" to a few isolated brain regions. But I think Camerer is right to argue that his "data suggests a general neural circuit responding to degrees of uncertainty, contrary to decision theory."