Word of the Day: Confirmation Bias

Christianity and atheism, does God exist?Sandy beaches often have a line of debris left by the last high tide. These lines look different on different beaches, reflections of the local environment. They might contain rocks, shells, seaweed, jellyfish, flotsam or garbage, egg cases from skate or conch, and so on.

When I was about 11, I spent a week at a beach on which amber occasionally washed up. After a little training, I got pretty good at seeing the amber. On a different beach, the prize was fossilized shark’s teeth, and again I got good at spotting them amid the pebbles.

Given a little training and motivation, the mind pulls out interesting things from the background chaos. What is the wheat and what is the chaff changes based on your needs.

Suppose you’re an emergency room nurse and comment on what a crazy night it’s been and a coworker says, “That’s always the way it is with a full moon.” Now that your mind has been primed, you may notice this coincidence often. But seeing this as more than just a coincidence without good evidence is confirmation bias. Confirmation bias becomes a problem when you sift through the evidence that you come across and select only those bits that confirm what you already believe. You don’t seek information but confirmation.

The hypothesis “God answers prayers” can also be supported by confirmation bias—those prayers that more or less come true within some broad time range are counted as successes, and those that don’t are either ignored or repositioned with, “Sometimes, God says no.” Psychics and horoscope watchers will similarly list successful predictions and ignore or forget the failures.

I listened to the weekly Reasons to Believe podcast from Creationist Hugh Ross for a while. It was little more than a selection of the few bits of evidence from the thousands of scientific articles that week that could be interpreted to support his old-earth Creationist views. Seeing this for what it is—an answer to the question, “What in this week’s news would support my Creationist preconceptions?”—would be fine. It’s when we imagine that this is objective science that we delude ourselves.

So that we evolution-accepting atheists don’t get too smug, Sam Harris proposed the Fireplace Delusion, a chance to have our own preconceptions challenged. It’s a good exercise by which to see your mind being offended and the defenses it puts up to maintain its initial position.

The mind is built to favor evidence that confirms an existing opinion over disconfirming evidence, and to combat this bias, science tries to disconfirm theories rather than confirm them. You can’t prove a scientific theory right, but you can prove it wrong. This reversal—testing our opinions with disconfirming challenges rather than selecting confirming evidence—is a good example to follow.

We can prime our mind, like we’re looking for shark’s teeth on the beach, to pull in only what we want to see, but we delude ourselves when we do so.

Photo credit: Wikimedia

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32 thoughts on “Word of the Day: Confirmation Bias

  1. To Bob S,

    So maybe you should stop thinking that Christians are hopelessly weak thinkers. If you devote all your time arguing against nutty fundamentalists found on the net or on TV, of course that you will win cheap victories. The real challenge may be to read liberal theologians that can actually challenge the way you see the Bible, Christianity and God.

    • Cheap victories? Those idiots are still out there, fleecing their sheep with idiotic promises. I’ll take any victory I can get, but I don’t see any victory over these charlatans.

      You seem to imagine that my blog has absolutely nothing to say to a liberal theologian or Christian. Sure, let’s imagine that liberal Christians are on the same page as me with respect to social issues. That still leaves maybe half of my posts that attack belief in the supernatural. No?

      If there are specific liberal ideas that I should find compelling or convincing, I’d like to hear what you have in mind.

      • Hi Bob,

        Well, ok, some of your posts are relevant to all Christians and even to all believers.

        In fact your blog seems primarily concerned with ethical/political/legal issues revolving around religion, and more specifically Christianity in America. That’s your choice and I won’t deny it does some good. But the broader question “Is Christianity true?” has not so far been given a fair hearing, mainly because of your lack of acquaintance with liberal theology.

        • Well, I’m not done yet! Hopefully future posts will make additional relevant arguments.

          Yes, my focus is almost exclusively on Christianity (as opposed to, say, Islam) in the US. Both social issues (homosexuality, abortion, etc.) and apologetics are interesting to me.

          I may indeed be unacquainted with certain tenets of liberal theology. If you want to sketch out the key points that come to mind for you, that would be great.

          But where I’m attacking extreme positions that you too disagree with, then isn’t that worth kudos? I’m not groping for praise here, just trying to understand where you’re coming from. If I slap something that needs slapping, why complain? I’m guessing we agree.

  2. Just because you were trained to find shark teeth and were therefore able to do so does not discount the fact that what you found were actually sharks’ teeth. You were not deluded by your bias, if I read the article correctly, when you found amber or teeth on the beach.

    While it is always good to recognize our biases and try to avoid being swayed unduly by them, the fact is that training sometimes helps us to see the truth that may actually be there. In the case of your article, this helped you to see the amber and sharks’ teeth.

    In the case of DNA, it might similarly help you to see a creative influence in the information content. Unless your atheist confirmation bias causes you to impose on that information content a far less likely scenario, of course. (Accidental random undirected chance acting over time.)

    • The beach example may not be perfect. My point was simply that an unfocused mind will take in the junk along the high tide line equally but that you can train it so that a particular subset jumps out at you more.

      You’re right that there were indeed sharks’ teeth. I didn’t just invent them. But there were also pebbles, seaweed, and shells that I trained myself to ignore. If these were all facts, I deliberately focused on the sharks-teeth facts at the expense of the others.

      Unless your atheist confirmation bias causes you to impose on that information content a far less likely scenario, of course. (Accidental random undirected chance acting over time.)

      You’re saying that evolution is the less plausible explanation? When the scientific consensus says that, I’ll definitely pay attention. Until then, why would I?

      • The first part of your response indicates you trust your ability to discern facts from fiction. The second part says you are unwilling to do so, and instead will only trust your alleged science popularity contest. We have been over this before. When the emperor has no clothes, you don’t need a cheering section to tell you the truth. Don’t be afraid to use your intellect when it makes sense to do so.

        I am still researching the mutation consensus we discussed earlier. Alas, time is short for such pursuit in the midst of life’s required tasks these days. But I trust my ability to discern and that the science will back this up as well.

        • The second part says you are unwilling to do so, and instead will only trust your alleged science popularity contest.

          The second part says that it’s a laughable enterprise for a layman to look at the evidence and conclude that those who actually are in a position to know–the scientists–are wrong.

          I typically avoid flying commercial aircraft or performing appendectomies since I’m not qualified to do so. This is the same thing.

          The focus needs to be on humility when my ability isn’t enough, not trust in my abilities.

          We have been over this before.

          Yes, many times.

          Don’t be afraid to use your intellect when it makes sense to do so.

          Give me the logic behind my saying that the consensus within a group of which I am not qualified to be a part is wrong.

        • Bob, Reference “Give me the logic behind my saying that the consensus within a group of which I am not qualified to be a part is wrong.”

          I don’t need to. You are qualified as a software expert, and we are talking about information content. You are qualified to see intelligence in code. Your confirmation bias simply allows you to sheepishly hide behind your alleged biologist non-qualification. But information content is your baby. You don’t need biology to see intelligence in DNA. Go with what you know.

        • ??

          Yeah, I think it’s a bit more complex than that. This is “information” in living things, about which I know pretty much zilch. I am truly unqualified to jump into biology and critique the consensus. When I apply my understanding of computer software and hardware to DNA, I’m like a doctor from 1800 teleported into the present who can’t even properly wash his hands.

          You want to declare yourself King of All Science and point out that the bumpkins who call themselves “biologists” are a bunch of idiots? That they can’t see the plain and beautiful logic in your argument? Go ahead, but don’t think this makes any sense to the observers on the sidelines.

          You realize that this has all the hallmarks of someone following, not the evidence, but a religious agenda, right? You’re cool with all of science … except for that bit that steps on your theological toes. Hey, you want to rein in a bunch of scientific hooligans? Go slap some sense into those quantum physics guys. That stuff is completely ridiculous.

        • Reference, “You realize that this has all the hallmarks of someone following, not the evidence, but a religious agenda, right?”

          And you have all the hallmarks of one following only the scientists in your preferential line of thinking, without even considering the evidence provided by the other side. Whose head is in the sand here? I’m looking at both sides and saying one makes more sense. You look only at one because you claim it has a majority. Most of those could care less about this issue, and simply voice as much support as needed to publish their research on issues not affected by philosophical debates such as this one.

          A Wikipedia article shows the fallacy of blindly accepting the scientific community’s assertions without using common sense:

          “Also, the current scientific community consensus is no guarantee of truth. The history of science shows many examples where the scientific community consensus was in error, was scientifically unsound, or had little or no empirical basis. For example, bloodletting was practiced from antiquity and still had many practitioners up until the late 1800s.[214] In his essay, A Paradigm Shift: Are We Ready? , Niranjan Kissoon, M.D. wrote the following: “…history is rife with examples in which our best medical judgment was flawed. The prestigious British Medical Journal begun in 1828 chose the name Lancet to signal its scholarly intent and cutting edge therapy.”[215] Also, in regards to modern medical science, in a 1991 BMJ (formerly called the British Medical Journal) article, Richard Smith (editor of BMJ at the time) wrote the following: “There are 30,000 biomedical journals in the world…Yet only about 15% of medical interventions are supported by solid scientific evidence, David Eddy professor of health policy and management at Duke University, told a conference in Manchester last week. This is partly because only 1% of the articles in medical journals are scientifically sound and partly because many treatments have never been assessed at all.”[216] Next, alchemy was at one time considered to be a legitimate scientific pursuit and was studied by such notable individuals as Isaac Newton, Robert Boyle, Roger Bacon, and Gottfried Leibniz.[217][218] Given the aforementioned weaknesses in the evolutionary position and given that the history of science shows there have been some notable paradigm shifts,[219][220][221] the scientific consensus argument for the macroevolutionary theory certainly cannot be called an invincible argument.”
          http://conservapedia.com/Evolution#Scientific_Community_Consensus_and_the_Macroevolution_Position

        • And you have all the hallmarks of one following only the scientists in your preferential line of thinking

          Correction: I have all the hallmarks of someone who follows the scientific consensus without exception.

          It’s really quite simple: I know my limitations, and I declare myself superior to scientists in no field.

          … without even considering the evidence provided by the other side.

          What?? You have a far, far higher estimate of my abilities than I do. I’d be flattered if you didn’t sound like you’re from Wonderland. Do you truly not get it? I am not qualified to evaluate and judge the evidence. And y’know what? Neither are you.

          I’m looking at both sides and saying one makes more sense.

          With all due respect, who cares what you think? You’re not a biologist. I care not for your evaluation and neither should you.

          Also, the current scientific community consensus is no guarantee of truth.

          Obviously! So what?!

          Do you truly not understand what we’re even talking about here? What does this have to do with it?

          The scientific consensus may not be correct, but what do we have that’s better??

          (And you need to be clear in your own mind whether you’re referencing Wikipedia or Conservapedia. They’re not really the same. 🙂 )

    • In the case of DNA, it might similarly help you to see a creative influence in the information content. Unless your atheist confirmation bias causes you to impose on that information content a far less likely scenario, of course. (Accidental random undirected chance acting over time.)

      Or, your bias may cause you to see supernatural agency where there is none.

      How likely you feel the scenario seems is also part of this bias.

    • Explained 4,000 years ago (a bit before PNAS data) as the fall of man and its consequences. See Genesis 3.

      • The fall of “man” never happened. When I see how violent chimpanzee societies are, I understand that I don’t need a divine curse to account for moral evil. Besides, there is no shred of paleontological evidence for fall.

    • RF2:

      Great stuff, thanks.

      I do think, however, that the conclusion (“the science of evolutionary genetics should rightly be viewed as an ally (not an adversary) of mainstream religions because it helps the latter to escape the profound theological enigmas posed by notions of ID”) won’t be widely accepted within religious circles.

      It’s good advice, but those who need to hear it have their hands over their ears. (Which perhaps gets back to your point of the sensibility of liberal Christianity.)

      • Reference: “And you need to be clear in your own mind whether you’re referencing Wikipedia or Conservapedia. They’re not really the same.”

        Duh. I was very conscious. The Conservapedia link took you to Wikipedia to the specific place in the long article that I was trying to reference. I saved you some time. You’re welcome.

        Reference: “Do you truly not understand what we’re even talking about here? What does this have to do with it?”

        I get it. Scientific consensus can be wrong. And folks with common sense questioning it are what helped uncover the wrongs. You clearly don’t get THAT.

        Reference: “I care not for your evaluation and neither should you.”

        Thanks for your honest evaluation and assessment that you don’t care a whit about folks who comment on your blog, unless they agree with your position, which is in agreement with your alleged consensus, which turns out to be part of the holy ground of “scientific consensus,” which though frequently wrong, can’t be questioned unless one is ordained as an official priest within that community. Whew. What logic? Right. WHAT logic. At least you don’t sugar coat it with tact.

        I will be careful to avoid making efforts to communicate with clarity and logic, because you really don’t care unless it agrees with your position. Somehow, I missed that part of the scientific method.

        • I was very conscious. The Conservapedia link took you to Wikipedia to the specific place in the long article that I was trying to reference.

          Huh? The Conservapedia link takes you to a Conservapedia page. Conservapedia (“a conservative, family-friendly Wiki encyclopedia.”) and Wikipedia are two very different wikis.

          Scientific consensus can be wrong. And folks with common sense questioning it are what helped uncover the wrongs. You clearly don’t get THAT.

          Correct. Scientists, not “folks with common sense” have corrected the scientific consensus. Perhaps you’re thinking back to the days of gentlemen scientists. Back then, when today’s scientist didn’t exist, ordinary dabblers could indeed become important contributors. That time is long gone. A bit sad, perhaps, that we laymen can no longer participate in science, but very much for the better IMO.

          Thanks for your honest evaluation and assessment that you don’t care a whit about folks who comment on your blog, unless they agree with your position, which is in agreement with your alleged consensus, which turns out to be part of the holy ground of “scientific consensus,” which though frequently wrong, can’t be questioned unless one is ordained as an official priest within that community.

          Perhaps you’ve taken your thin-skinned pills today. That’s not what I said.

          What I said might well have been inflammatory, but let’s deal with it directly and accurately instead of me responding to complaints about what I didn’t say.

  3. Dialogue at a physician’s clinic.

    Physician: you are seriously ill. You need to take these pills.
    Patient: why should I? Maybe they will kill me instead of healing me.
    Ph: no, they won’t. Scientists did tests and their conclusion is that it is beneficial.
    Pa: maybe this is what they think now, but everyone knows that scientists have often been wrong.
    Ph: true, science is self-correcting, but we cannot afford to wait till we find absolute truths.
    Pa: still, why should I trust the scientific consensus since it turns out that it is often mistaken?
    Ph: well, listen, no one can compel you to take those pills. But all the clues we do have show that you should take them to be healed.
    Pa: No, I won’t trust a group of fallible scientists that cannot even prove what they say. I need certainties, because it is my life that is at stake and nothing matters more to me.
    Ph: (sigh)

    (And the patient did not take the pills and was reported to have died a few weeks later)

    • Nice parable. Totally different from what we have with lots of evidence in conflict with the alleged consensus on evolution and naturalism. Nice try though.

      I’ll take the pills. But I won’t swallow Darwinism with all of its legitimate scientific challenges.

      • Did you read the PNAS article that RF2 sent a link to?

        The author of that article wrote a book on the subject: Inside the Human Genome: A Case for Non-Intelligent Design (2010) by Avise.

        You’ve said what a slam-dunk argument DNA is in favor of the ID/Creationist position. What do you think Avise–someone who actually understands the biology–would say about it?

        • I haven’t read it carefully. When the author mischaracterizes ID in the opening salvo, it is a bit off-putting. In skimming the material, I saw a lot of “could have,” “might explain,” “may have been able to account for” sort of language that is not the stuff of convincing evidence. I will look at it more carefully when time permits, but initially my reaction is that it is a lot more “just so” stories knit together with rigorous sounding but insufficiently explanatory scientific terms.

        • Certainty would be great, wouldn’t it? And yet when there is uncertainty, the careful scientist points it out. And all this “could have” apparently builds to a scientific consensus.

          Back to my question, how do you think your DNA-proves-design argument would fare against someone (like Avise) who actually understands this stuff?

  4. Reference: “And you need to be clear in your own mind whether you’re referencing Wikipedia or Conservapedia. They’re not really the same.”

    You are correct. I thought it was linking to Wikipedia—they clearly imitated the look of Wikipedia. I should have known though. It was too objective and balanced. My bad! But you were correct about the reference.

  5. Reference “Back to my question, how do you think your DNA-proves-design argument would fare against someone (like Avise) who actually understands this stuff?”

    Well, if he is open to facts and not encumbered with a deeply invested position, I would expect him to acknowledge the significant challenges raised by the ID scientists. If he is not, I would expect him to minimize but not seriously address them. I haven’t gone through the material thoroughly enough to know if he is objective or deeply biased. Which do you find to be the case? I will save my analysis until I have time to do it more carefully. It’s a long article, and other irons in the fire are more pressing today…

    • Take your time, but it doesn’t sound like we’re going anywhere here. The author is a smart guy, honorably upholding the title “scientist,” only if he acknowledges your position?

      I wonder if another possibility is your position being flawed and him correctly rejecting it.

      • Hmm. “The author is a smart guy, honorably upholding the title ‘scientist,’ only if he acknowledges your position?” I’m sure that must be it. That’s not what I said, of course. But I’m used to dissenting ideas being ridiculed and recast in the least favorable light.

        And as for “I wonder if another possibility is your position being flawed and him correctly rejecting it…” As usual, you only acknowledge the possibility of error on the other side, never on your own. Clear thinking?

        • But I’m used to dissenting ideas being ridiculed and recast in the least favorable light.

          What else can I do except deliberately misrepresent your position? It’s not like I have any intellectual ammunition.

          As usual, you only acknowledge the possibility of error on the other side, never on your own. Clear thinking?

          I was simply suggesting the addition of another possibility. Seemed to me that it was you who acknowledged only error on the other side.

          You said: “Well, if he is open to facts and not encumbered with a deeply invested position, I would expect him to acknowledge the significant challenges raised by the ID scientists. If he is not, I would expect him to minimize but not seriously address them.” The two options are: (1) he says, “Wow–you’re right. I never considered that, but I really need to go back and rethink some fundamentals here” or (2) he’s closed minded and refuses to consider your arguments. Sounds like this is “heads I win, tails you lose” from your standpoint.

  6. Or option 3, which you left out, was what I was suggesting. He could, without ad hominem attack, respond to the genuine scientific content of the ID claims. I don’t know yet if he does that. But starting out by derisively, dismissively sniffing a summary of the ID camp as “the latest incarnation of religious creationism,” (which it decidedly is not) is not encouraging for your side being objectively open to evidence.

    But this clarification will not be good enough for you either, so please correct me. I’m sure I got it wrong again. Silly me.

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