You will often hear people spout the virtues of critical thinking. Ironically, they can often be the people who are least likely to exhibit it themselves in certain situations. The reason is the Primacy Effect, or when you become biased toward the first explanation you hear about a topic and only then display critical thinking of information afterwards.
A famous example of this is when people hold one political position and then, in a man-on-the-street interview, are told of a policy that their political leader supports—they almost always agree with it, and then the interviewer reveals that it was actually the opposing party’s policy. I saw this myself, when someone who hated a specific politician asked me what the politician proposed, and what he did propose was exactly one of the things that the opposite party was fighting for. This politically-biased person immediately shouted, “That won’t work!!!” Lo and behold, just a couple of months later, a major bill passed with a majority of his party with that exact kind of clause put into the bill (that he undoubtedly would support). So critical thinking against anything the opponent proposes; blind support for anything the supported party proposes—even if it’s the exact same proposal.
So what is going on here? There is something called The Primacy Effect in psychology, which is the idea that you are more likely to take on an initial belief or idea you hear about a topic as true and then hold it for much longer when new information comes because a lot more evidence is required to overturn a belief than form it. The idea is that the less information you have, the more that you are influenced by new information than once you have an established set of beliefs based on information.
An example of this is if someone read Karl Marx and read his Labor Theory of Value that states that the value of a product or services is derived from a combination of the labor it took to make the product and the capital invested in it. That sounds like a bullet-proof calculation, right? So now you think of a pair of underwear costing $5 and think that (for example) $4 of value came from manufacturing the product and then $1 of value came from the capital—e.g., the factory. It sounds like a flawless calculation, correct? You confirmed (rather than failed to disprove) the theory and now believe it to be true. But now I can sarcastically say, “Okay, I have a used pair of my underwear in my drawer right now. I make $50/hour. It’ll take me 10 hours to drive it to you right now. Based on the labor theory of value, I should price that pair of underwear at $500. Do you want to buy it?” Of course you wouldn’t—the value of a product is based on how much someone is willing to pay for it, and basic economics demonstrates that the price is ideally set at the point at which supply and demand meet—i.e., you can sell every item you have because exactly that number of people want to buy it at that price. If the price is set higher, you have excess inventory and have to lower the price; if you set it lower, you run out and have people who would have bought the product at a higher price who now can’t buy it at all. So, for misinformed people, they would accept the Labor Theory of Value and then immediately exhibit critical thinking against the retort by saying something like, “Yeah, but that’s product was already made…” (etc.). The point isn’t about whether the Labor Theory of Value is a good or bad theory; it’s about the fact that readers with less information won’t question the original theory but, once they accept it, will immediately dismiss the retort via critical thinking.
So when people teach critical thinking, they really need to teach critical thinking both ways: when you are learning something new and when you are testing your existing beliefs against new information. When facing conflicting information, you can ask, “What would need to be true for this information to be disproven?” for both sides. So, in my Labor Theory of Value, for example, there is truth in the theory that is what misleads people: it is 100% true that a business for a product cannot exist unless the price exceeds the cost required to produce it, which is made up of staffing costs, capital investment, and other costs (arguably, it’s more complex than “labor” and “capital”, which are terms to create division between workers and owners, but we’ll give Marx that his categorization isn’t wrong per se but simplified). Therefore, I can’t have a used-underwear business because no one would buy it at any price, and it’d take my time and effort plus advertising, etc. to sell it. However, that doesn’t determine a product’s value; it determines the minimum price that people would be willing to pay for the product to be profitable and, therefore, created. If I became a famous rockstar, however, that underwear might have value to someone and, therefore, I might actually be able to start a business wearing underwear once and selling it on the internet (many women and famous people already sell used clothing like this). If I sell it for $1,500, there is no way that the value of that can be derived from how much it cost me to buy the underwear, wear it once, and then sell and ship it. So the value is not tied to the labor + capital—clearly, the theory is not correct.
But it’s just as important to test the “it’s worth whatever people are willing to pay for it” hypothesis. To test that, you’d have to find an instance where a product or service was not “worth” what someone was willing to pay for it. Now, people complain all the time about things not being “worth” what they’re charging; however, the two results of people saying that are they either don’t buy it or are just complaining about how much they had to pay for it. However, the assertion being made is that, by definition, something can’t not be “worth” the price charged if someone was willing to pay said price. If it wasn’t worth it, the person wouldn’t pay the price. Therefore, the idea holds. Note, however, that some people do buy products before they get to use it and find out that it was not what they were expecting in terms of quality, value, etc.—at which point they either return it or don’t buy the product again. That is the risk inherent in any purchase of a product or service, recently exacerbated by the internet, but the theory would hold because the person bought it believing that the product was worth the price. Hence, the term “what someone is willing to pay for it” is the language used and not, “what someone is happy paying for it” or “what someone was glad to have bought“ or some other permutation that would be inaccurate. This definition acknowledges the subjectivity of value, and now the overwhelming majority of people agree that value is, in fact, subjective and not an objective, absolute calculation of labor + capital.
So any time you face new information, you want to think critically—whether you have information already or not. If you don’t, test it against “nothing”—i.e., assume the null hypothesis (science term for assuming that your assertion is not true) and you will now create a “primacy effect” of your own of not believing anything without testing it or being willing to test it as you get new information. Then, once you gain more information, you can treat both sides with some skepticism, understanding that your initial information might’ve been incorrect. Yes, it might be ridiculous to give any credence to a “flat Earther”, for example, when you know the Earth is round, but for every one of those where testing both sides would be a waste of time (though flat Earthers have tested it and disproven their own hypotheses with various experiments, so if only they were open to changing their mind they would’ve been doing a great job of testing their own beliefs), there are instances where you, say, heard from one source that a movie star abused his wife and then heard from another that, actually, she was the abuser. Your bias about the data around abuse (i.e., the assumption that men commit the overwhelming majority of domestic violence is untrue; men and women both hit their partners) would immediately get you to side with the wife and then, only through long recordings of the wife admitting to her abuse of him do you change your mind—and some people never will. (Yes, I’m referring to a real-life case but will leave their names out of it since I don’t want to oversimplify the events)
So critical thinking is important, but it is a double-edged sword: some people will only exhibit critical thinking against things they disagree with and not toward things that they agree with morally or factually. The idea is to not dismiss ideas out of hand if you can: always be open to new information but have criteria by which you would evaluate both the new information and your knowledge to see which will hold up better to scrutiny. It’s a lot easier when it’s something innocuous like thinking a show starts at 10:30 and then you are told that the event starts at 10:00. You check the ticket, and you confirm which information is correct. If you are incorrect, you change your belief to fit the truth.
It’s a little more difficult with an ethic you hold, though. If you believe, for example, that guns are bad and then someone shows you the official government statistics that guns prevented 500,000-3,000,000 crimes from occurring, that information will be immediately dismissed as, “Well, those people would’ve just lost property, so it’s worth saving lives.” Again, the point is not to get you to have one opinion or another on guns; the point is that your initial moral belief would immediately cause you to accept or dismiss information based on whether it supports or contradicts your belief. The more intelligent response would be, “Interesting; there are trade-offs to any legal decision, and I will take this information and see how that might change what I already believed about policies.” Maybe you change your mind, or maybe you don’t—but if you don’t, you should now say, “I do understand the advantages of gun ownership for self-defense, but I still believe that the costs outweigh the benefits.” Blindly stating, “There’s no reason why anyone needs a gun,” when there are 500,000-3,000,000 examples of reasons why people chose to arm themselves for self-defense is, however, the primacy effect in action where the person likely lived a sheltered life and never experienced life in the middle of nowhere without police just a few minutes away protecting them. Dismissing accurate information that doesn’t support your belief is just as dangerous as blindly accepting new information. (Similarly, if someone supported gun ownership, hearing that statistic should trigger a “yes, and it is acknowledged that there are also times when guns are used for harm” reaction to show that all data is considered and not ignored)
As a final point, this brings up the ideas of argument and persuasion as it comes to understanding truth and life. One of the biggest examples of people dismissing new information is in a debate when trying to persuade. As Jim Carrey famously said in Liar Liar, “I object! . . . Because this is really damaging to my case!” Yes, if your goal is to “win”, dismissing an opposing point out of hand is a great tactic to belittle your opponent and look like you have a stronger case. I won’t deny that—as I’ve said in other posts, people don’t care about truth, they care about what benefits them. In this case, the benefit is “winning” and the truth is that the opposing point is possibly valid but might be overweighted by the audience and so the debater has to belittle it. But if your goal is optimal understanding and decision making, your reaction (in your mind, at least) should be, “Hmmm, is that true? If it is, how does this information affect my position on the matter? Should it change it?” The same might be true in instances of mediation or political compromise: if you need to play well with others, it might be best to hear the other person out so they’ll hear you out and then you can figure out how your information can come together to reach an amicable resolution. If you dismiss their information, then they will dismiss yours. Reciprocity is a biologically-engrained ethic, so you’re not going to overcome that easily if you want others to listen to you when you haven’t listened to them.
In short, critical thinking is important, but if you wanted the most accurate understanding of the world around you, you would exhibit critical thinking on both a brand-new topic and then with new or additional information on a topic that you believe that you are familiar with. Most people tout the idea of critical thinking and then go about confirming their own beliefs and dismissing all conflicting information or beliefs. That is not critical thinking, though it seems like it since you are being critical of those other opinions. In truth, however, that is straight-up denial or dismissal—not critical analysis. If you want to understand the world in the best way possible for your life, don’t confuse critical thinking with being able to dismiss out of hand anything you don’t agree with.