ISIS is all over the news, climate change is a hot political topic and outbreaks of diseases like Ebola and Swine Flu have caused mini-panics in the last few years. These threats to our society have received extensive popular attention, and rightfully so, because the dangers they pose can be devastating if left unchecked. While we have been preoccupied with these external threats, however, we have ignored an even more dangerous internal threat.

A threat that impacts virtually every aspect of our lives, including our ability to address all of the aforementioned challenges. It is called confirmation bias. Anyone who has taken an introductory psychology course has probably heard the term before. Confirmation bias is defined as "the tendency to search for, interpret, favor, and recall information in a way that confirms one's beliefs or hypotheses, while giving disproportionately less consideration to alternative possibilities." I am certain that this bias is responsible for stymieing the success of and occasionally wrecking personal lives, careers, companies and even countries.

Until the 1700s, the Catholic Church believed that the earth was the center of the universe, and cited the movement of celestial bodies across the sky as well as certain biblical passages to corroborate its claim. When Galileo published his observations supporting the idea that that sun was at the center of the universe in 1610, he was met with strong opposition from the Church. In 1616, the Inquisition decided to declare heliocentrism to be formally heretical and banned heliocentric books. The Church also ordered Galileo to refrain from holding, teaching or defending heliocentric ideas. It was quite some time before the Church altered its stance.

What caused the Catholic Church to react the way it did to Galileo? Why did it so strongly reject scientifically sound information? Put simply, it was confirmation bias. The Church’s bias was particularly potent here because it was strongly invested in its pre-existing belief. Admitting that it was wrong about the solar system could have opened the door for people to question the Church’s positions on other issues. Hence, the Church was strongly inclined to reject Galileo’s discoveries, in spite of their scientific merit. The Papal authorities’ confirmation bias held back scientific and societal progress for many years.

Unfortunately, this cognitive slant is not something we left behind in 18th century. The Vietnam War demonstrates that. In Barbara W. Tuchman’s book "The March of the Folly: From Troy to Vietnam" she describes how “[o]nce a policy has been adopted and implemented, all subsequent activity becomes an effort to justify it" (p. 245). She discusses this form of confirmation bias in the context of the United States’ involvement in the Vietnam War.

The U.S. entered and remained in the war for 16 years despite considerable evidence that it was a lost cause. This was, at least in part, due to the fact that top U.S. officials were subconsciously trying to make the information they had compatible with conclusions they wanted to reach. I am sure that this drive to justify already-made policy decisions has had major implications before and since the Vietnam War as well.

Confirmation bias also played a role in the financial crisis of 2008. Hersh Shefrin, an economist best known for his pioneering work in behavioral finance, argues that psychological factors compelled prominent, Wall Street firms to misread the housing market and take greater risks. Between 1997 to 2006, the price of homes in the US increases by approximately 85% adjusted for inflation, making it the largest housing boom in American history.

Wall Street, blinded by excessive optimism, overconfidence, extrapolation bias, groupthink and of course confirmation bias, assumed that this trend would continue. A lack of safeguards against cognitive bias in the financial services sector allowed these firms to make the mistakes that ultimately led to the recession.

Do not think though that confirmation bias needs to come from a papal authority, a government official or a Wall Street broker in order to wreak havoc. The confirmation bias of regular people, like you and me, can have widespread consequences as well. One way in which it can is through the political process.

Politicians often tell people exactly what they want to hear. They craft ads and give speeches that confirm people's deep-seated beliefs and let them go home thinking their worldview is spot on. Yes, immigrants are the problem. Yes, the wealthy are evil. Yes, they are plotting against you. Yes, they are trying to destroy the country. Rarely will you hear a politician tell his audience no, and with good reason: It could hurt his/her chances of getting elected. It is more beneficial to pander than to challenge.

Additionally, once an individual has made up his/her mind about a political party or a politician, it can be very difficult to change it. The individual — like the Papal authorities persecuting Galileo, the government leaders managing the Vietnam War, or the Wall Street brokers pre 2008 — will interpret and/or selectively read information in a way that reaffirms their pre-existing opinions.

In a 2006 Scientific American article, Michael Shermer talks about a study conducted by psychologist Drew Westen that demonstrated this. In the run up to the 2004 presidential election, Westen asked 30 men — half of whom were “strong democrats and the other half of whom were “strong republicans” — under a functional magnetic resonance imaging (fMRI) machine to evaluate statements made by George W. Bush and John Kerry in which they both very clearly contradicted themselves.

Unsurprisingly, the test subjects were very hard on the presidential candidate from the other party, and very soft on the presidential candidate from their party. What was somewhat more surprising was what the neuroimaging results revealed. They showed that the part of the brain responsible for reasoning was dormant while the test subject were assessing the candidates statements. Instead, the parts of the brain involved with emotional processing, conflict resolution, and judgements about moral accountability were the active ones. And once the test subject reached a conclusion that made them feel emotionally comfortable the part of the brain involved with reward and pleasure was active too.

All this is to say that we need to be conscious of our psychological flaws because they can affect everything you do. Confirmation bias is always right around the corner looking to sabotage your efforts. The only way to combat it is to constantly challenge your beliefs. Go out of our way to listen to opposing points of view with an open mind. Try to evaluate evidence from a neutral standpoint. I know how difficult this can be, I try my hardest to do it all the time and it is a struggle, but I guarantee that if you do do it, you will be more successful in all of your endeavors and you will be a significantly better member of our society.

In order to stop ISIS, end climate change, prevent pandemics, or improve our world in any capacity, we must fight for reason and rationality, because we stand no chance of fixing the world if we don’t see it clearly.