Does critical thinking depend on intelligence?

One purpose of formal education is to teach critical thinking skills. Critical thinking is the ability to collect and integrate information to form knowledge. An important piece of critical thinking is the ability to divorce emotions, prior beliefs, and personal opinions from the evaluation of evidence and arguments which can often get in the way. In psychology, this is called myside bias. Myside bias is a term that describes how people evaluate evidence, generate evidence, and test hypotheses in a manner that is biased toward their own prior beliefs, opinions, and attitudes. For example, if you love dark chocolate, you look for articles that support the premise that dark chocolate is good for your health. That's ok, our biases, beliefs, and values are what make us who we are, who we love, and what we accomplish. That being said, sometimes these biases are based in fears instead of experience, blind intuition instead of evidence, or worse, faulty logic. It's at these times, that myside bias can keep us from our goals or lead to poor decisions.

Given that myside bias can lead to poor decision making, some psychologists have attempted to describe what individual characteristics, situations, and social norms predict myside biases. One individual characteristic that has become a big topic of interest is intelligence. Given that critical thinking is often associated with basic intelligence, one might expect intelligence to be related to the ability to put aside your personal biases in order to generate better arguments and make more informed decisions.

Recently, Dr. Keith Stanovich of the University of Toronto conducted several cognitive experiments to test whether individuals with above average intelligence engaged in myside bias more often than individuals with below average intelligence. To do this, he and his colleagues had a group of undergraduates read a a paragraph about the safety ratings of a specific type of car, and then asked whether that car should be banned. Half of the participants received a version of this paragraph describing an American car and were asked whether it should be banned from Germany, while the other half read the same paragraph where the car was German and asked whether it should be banned from the U.S. They then assess each participant's intelligence. 

They found that 78% of participants thought that the German car should be banned while only 51% of participants who read the other version thought that the American car should be banned on German streets. Thus, these participants were vulnerable to myside bias, given that the same statistics led to different answers depending on the potential risk these statistics pose for the reader. North Americans used those statistics to defend a position that would protect them as drivers, while those statistics were not convincing enough to convince them that citizens of Germany needed protecting from the car. However, they found no evidence that participants with below average intelligence were more susceptible to this effect than their above average peers.

In another study, they were interested in whether this effect depended on whether the task instructed the participant to divorce their responses from their previous beliefs and attitudes. To do this, they asked another group of undergraduate participants to complete reasoning tasks. For example, participants were given two independent premises, such as "All things that are smoked are good for the health," and "Cigarettes are smoked," and a conclusion, "Cigarettes are good for the health." Participants are then asked explicitly to decouple their previous attitudes and beliefs from their reasoning in the task, and decide whether the conclusion logically follows from the premises. Participants who were successful would answer that yes, this conclusion follows logically from the premises, despite their pre-existing belief that cigarettes are not actually good for health. Individuals who were vulnerable to myside bias would answer no because the conclusion is inconsistent with their beliefs. They found that individuals with higher intelligence were less likely to be vulnerable in this task. Thus, more intelligent individuals may be more skilled at engaging in objective, critical thinking, that is divorced from their pre-existing biases and beliefs than their lower intelligence peers, but only when explicitly instructed to do so. 

Why is this interesting and important? I work with children and teens who often use the excuse that they are not smart enough to engage in some sort of critical thinking activity. Fortunately for me and other adults who are trying to help them, these excuses are exactly that; excuses. Critical thinking, including the ability to put aside your own beliefs and attitudes is a skill rather than an innate capacity that can (read: must) be practiced an cultivated just like any other skill. For me, that skill has been cultivated in graduate school, where you are constantly being asked to document every piece of specific evidence to support or refute your theoretical position and explain your findings. It is a skill that is pursued in law school almost ad nauseum, and is central to any professional where observation and objectiveness are crucial.

Another important question is whether you want to cultivate critical thinking and reduce myside bias. In some ways, being able to make snap judgments based on your own intuition must be adaptive. For example, not walking through a dark, abandoned alley alone would create a bias against walking down that alley. However, this same bias explains the reasoning errors made by members of the Nazi Party during WWI and WWII, as well as individuals who stay in relationships with someone who is physically or verbally abusive.

Thus, I end this post, and coincidentally this year, with an exercise for improving your ability to think critically in 2014. Spend a few minutes thinking about the beliefs you hold, or more importantly, the decisions you have made lately that are driven by beliefs you hold. In the article, Dr. Stanovich uses controversial political examples such as organ donation, criminal rehabilitation, and abortion. I think this can be extended to even more daily beliefs about what foods are healthy to eat, or what areas of your community are safe to frequent. Take stock of the objective evidence that you have to support those beliefs. Take stock of all of the objective evidence that you have to refute those beliefs. Do you hold any beliefs where there is no evidence to support them? Are those beliefs affecting your relationships with others, your mental or physical well-being, your financial stability?

My expectation is that 9 of 10 beliefs will be reaffirmed after going through this exercise, but you will have practiced thinking critically about your core beliefs anyway. That remaining one belief however may be holding you back or may be driven simply by hearsay, so why not reconsider? What is it about that belief that helps you be who you are and can you be the same person, or a better and happier person, without it? 

Stanovich, K. E., West, R. F., & Toplak, M. E. (2013). Myside bias, rational thinking, and intelligence. Current Directions in Psychological Science, 22(4), 259-264.