Critical Thinking: Confirmation Bias

In the last post in this series I posed the following question:  four cards with a drink on one side an age on the other, indicating the patrons at a bar. In USA the drinking age is 21. Which cards must you flip over to see whether or not the bartender is breaking the law?: 16, ginger ale, beer, 28

The answer is 16 and beer.

Now for an experiment a sheet of paper has the number sequence 2, 4, 6, and a rule written on the opposite side. Let’s say I asked for numbers, to which I’d either reply “Fits the rule” or “Doesn’t for the rule”, and then, based on my answers, let you guess the rule. (If no one guesses it, I’ll give it in the next post in this series.)

This puzzle illustrates something called the confirmation bias, which is the tendency to pay attention to evidence confirming our notions while ignoring anything that contradicts them. Smoking is an example: there is a lot of evidence on the health risks of smoking. However, for smokers (particularly those who choose to pick up smoking), there are a number of ways of ignoring the data. Many probably just don’t think about it. For others, they cite their mistrust of the mainstream media (which is actually a genetic fallacy, to be covered later); some even go as far to say the link between lung cancer and smoking is bogus.

Examples of confirmation bias include conspiracy theories, punditry, purchasing trends, reading material, and the culture wars. In other words, people tend to read newspapers, magazines, articles, and blogs that are in line with what they already believe. The same goes with the radio shows they listen to, the pundits they watch, and the books they buy. Remove confirmation bias, and conspiracy theories collapse like a Jenga Tower.

Confirmation bias also plays a role in perpetuating prejudice and stereotypes. If a white person stereotypes black people as lazy and criminally prone, (s)he will notice black people on welfare, on drugs, or crime committed by someone black. Perhaps the person will even be more afraid if they see a black person. This white person will ignore the fact that there are more white people on welfare or that most crime is committed by white people. In fact, white people are more likely to be victims of another white person. (S)he will ignore the possibility that a black person might not be on welfare to freeload off the system, but might have just faced hard times. (The same is true with any other kind of ethnic, racial, religious, or national stereotyping or prejudice.)

Now, for fighting confirmation bias. To quote Rolf Dobelli’s book The Art of Thinking Clearly, “If the word ‘exception’ crops up, prick up your ears. Often it hides the presence of discomfirming evidence.”(p. 20). Charles Darwin is an example of someone who fought confirmation bias, by writing down anything he found that contradicted his theory. Nowadays in science theories are proven by trying to disprove them. Another suggestion of Dobelli is to write down your beliefs and to seek out discomfirming evidence.

Why should we do this? First of all, as I noted above, it helps us out of our prejudices and provincialism, which decreases the chances of our supporting destructive policies. Recognizing and attempting to avoid the confirmation bias fosters humility, as we recognize our biases and the fact that we can be wrong. On a smaller scale, we each have choices we make each day. When people try to sell us things or convince us to make life choices, they tend to present all the good points, while ignoring the less flattering aspects. So, challenging the confirmation bias helps us make better decisions in our personal lives as well.

My mention of only paying attention to the good points makes me think of the Texas Sharpshooter Fallacy; however, I think I’ll talk about over thinking next, as we need to be balanced.


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Christian, freethinker, believer, skeptic, seeker.

3 thoughts on “Critical Thinking: Confirmation Bias”

  1. Hello, Kevin, this will be my first comment here. Thank you for granting me permission to post on your blog. I’d continue the conversation at LJF but I seem to have caused a dreadful firestorm and I’m a little worried the mods might delete some of my comments, especially as I didn’t go there to cause problems. I’m also a little worried that I might have just fired facts at people and not really listened to where they were coming from, and I say that as someone who, while being fairly certain of my facts and beliefs on this matter, also wishes to be someone that communicates my thoughts in a non-condemning and respectful manner.

    Now here’s the comment I promised; it didn’t go through last night so I’ve decided to try again; my response is below:

    Thank you for being willing to have this discussion with me. Before we get into this topic, I’d like to emphasise – if I haven’t done so before – that I totally sympathise with your struggle for spiritual and emotional liberty from the controlling church environment you grew up in, and wish you well on that journey, as I also am going through a similar sort of process in my own life. I very much hope that, if you are agreeable, that we can encourage and strengthen one another on our prospective roads to freedom. Please feel free to tell me anything about your church that you found positive or negative anytime. Would you mind if I asked you to share a little about your church life, what you thought about it at one time, and what you believe about it now, and why?

    I wondered about what you believed because I have read some of your comments about Islam (the religion) and, while I strongly disagree with certain aspects of your viewpoint, I’m also willing to discuss why I disagree with you civilly. One reason is I can understand that you want to have a rational and reasonable opinion on the issue; because I think you have heard a lot of wild and irrational comments about the topic of Islam and Muslims, would that be correct? Something I’d really like to know, if you wouldn’t mind sharing, is what did your church teach about Islam, who gave the lectures (and by this I mean ex-Muslims, white people, etc) on it, and what their motivations were for what they believed. Also did your church encourage you to study the koran for yourself?

    “I have read a number of sources on Islam over the years: most recently I’ve started reading Allah, Liberty, and Love by Irshad Manji.”

    I’ve never really heard of Irshad Manji, but I’m curious to know how liberal this person is? Also what is your opinion of him/her, and what sorts of causes does s/he advocate for?

    “Other sources are the V-Pod The Deen Show, a Muslim talk show; I have also listened to Debt Free Muslims(but this is a finance podcast based on Islamic principles). Religion and Ethics has done a number of reports on Islamic matters, in which Muslims tell their own stories.”
    I see, okay. You mention the finance podcast; could you tell me what sorts of subjects dealing with finance the Debt Free Muslims discusses?
    Also I’d like to know about the range of issues the V-Pod The Deen Show talks about, and what sorts of stories from Muslim perspectvies Religion and Ethics covers?

    “I haven’t read the entire Quran and Hadith(differing sects have different collections; but a collection by Bukhari is cited a lot. The collection I have was compiled by an Ahmadi[a sect many Muslims consider heretical and whose adherents must fight for their rights], and he quotes Bukhari a lot.)”

    From what I know, I think Bukhari is one of your best shots you’ll ever get when it comes to hadiths. As for the koran, if I were reading it, I’d want to read a variety of translations from the most literal interpretations of the classical Arabic and compare the different translations with each other, plus read the Ahmadi collection so I could learn more about the beliefs of my friends. I mean, doesn’t it make sense to try to learn about what your friends believe by really reading and studying their religious books? In other words, the best way to learn about the koran isn’t to rely on secondhand information from either your friends, other Muslims, your church pastor, me or anyone else – because any one of us could be wrong – but rather to read and study a literal interpretation of the koran so that you can see the intentions of the founder of Islam for yourself.

    Despite the Ahmadi being severely persecuted as they are not considered as believers by their counterparts, there have been Ahmadi Muslims who have contributed significantly to Islam and are used by many of their non-Ahmadi counterparts, such as Ahmed Deedat; have you ever heard of him?

    “This is the first I’ve heard of Reliance of the Traveler.”

    I strongly urge you to read Reliance of the Traveler. It is one of Islam’s most trusted Sharia manuals. You can get it from Amazon, at this link:

    “Anyway, concerning Islam’s being a literal interpretation of what the Quran says and following what Muhammad said, like with Christianity, there are a number of schools of thought on what that exactly means.”

    That might be so, but from what I understand there is very little room for nuance in Islam, because all the schools and Islamic scholars agree with Mohammed’s claims regarding the koran, and that all Muslims must obey its central tenets and books – koran, hadiths, surat, without question. Would you mind if I asked you to list out for me the schools of thought and their interpretations on literalism?

    “I recently read an article called “Innovation and Creativity in Islam” by Umar Faruq Abd-Allah. In it he mentions the early Muslim requirement of itjihad, or using one’s capacity in search of the right ruling; it’s Islam’s tradition of questioning and searching. It’s been out of vogue for centuries; nowadays people like Manji appeal to it in their attempts to reform Islam. (I have read some that claim the literalism was a reaction to things like colonialism and other circumstances.)”

    Which Muslim tradition required ijtihad? Was it Sufi, Shia, Sunni, Ahmadi, Wahabbi, Salafi or any of the others?

    As for the claim that literalism became a reaction to colonialism, what do you believe about it? Do you think it’s true, or false, and why?

    I believe in taking my opinions of Islam not from white people who know nothing about it but from the koran itself. I say that because people can say either positive or negative stuff about a subject without knowing very much of what they are talking about, and I don’t believe in being one of those people. I’m sure you don’t either.

    I have a lot more thoughts but I don’t have the time to put them down. I’m sorry for firing such a bunch of questions at you but I’d rather seek to understand your viewpoint than condemn you. Furthermore, I hope I’ve come across as reasonable and rational in my reply to you and if I haven’t please let me know.


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