Posted by: Jeremy Fox | October 28, 2011

On changing your mind in science

In the previous post I asked readers if a post of mine had changed their minds about whether the intermediate disturbance hypothesis is true or even useful. I was gratified to see I did completely change a few minds, and caused many others to at least doubt their previous views.

Which raises the broader question: What’s the biggest scientific claim about which you’ve ever changed your mind? I don’t mean that your views became more nuanced or sophisticated, or that your views shifted because at first you didn’t completely understand the idea, or that you never really had a strong view in the first place so changing your view didn’t actually amount to much of a change. I mean, some claim that you were familiar with, and fully accepted–only to later decide that you were mostly or totally wrong. I ask about the biggest claim because I think everyone changes their mind about all sorts of small, unimportant things.

And why did you change your mind? Was it gradually, over a period of years, due to long accumulation of experience and evidence? Or was it suddenly, perhaps thanks to a single paper (or zombie joke-based blog post) that opened your eyes and caused you to see the world in a new way?

Were you consciously trying to change your mind? For instance, did you decide (for whatever reason) “I really need to rethink my views on X”, and then do so? Or did you wake up one day and realize “You know, I used to believe X, but now I believe not-X”?

Did you feel any external pressure to change your mind, for instance frequent interactions with peers, teachers, or mentors holding a different view? What about internal pressure, either to change your mind or perhaps not to change it? (few people like to admit when they’re wrong)

Looking back, can you still understand why you held your previous view? Or is your view now so altered that you can’t understand how you could possibly have believed what you used to believe?

And if you’ve never changed your mind about any big scientific claim, why do you think that is? Do you think you ever will? Does it bother you that you haven’t? Or conversely, are you proud that you haven’t?

Looking forward to your responses in the comments.

p.s. Would you stop changing your mind, or at least admitting that you’d done so, if you knew that it would make your views much less likely to take hold in the broader scientific community? As David Hull has pointed out, drawing on the history of evolutionary biology for examples, scientific theories succeed when their adherents change their minds without admitting that they’ve done so. Perhaps not even to themselves…



  1. [Arriving from Evolving Thoughts]

    Good questions.

    Although I think you’ve specified them to the point where you’re not going to be getting many answers. I can think of several instances where I’ve changed my mind, but to do so some learning had to occur, which implies that “at first [I] didn’t completely understand the idea” and thus that wouldn’t count for the purposes of your question.

    If we relax that particular constraint to something along the lines of “I really thought I understood the idea, but turned out to have no clue”, then I do have one particular example in mind:

    “The best way to evaluate a model is by looking at the error bars.”

    I had spent years trying to wring the last bit of error out of a particular model and my long-suffering adviser finally got through to me that this wasn’t the point. The details of that conversation are etched in my brain: I was on my cellphone pacing around the patio of the EEB building at UArizona because I couldn’t get any reception in the basement lab I was borrowing (a fact I would use to my advantage from time to time). A half hour in to the conversation he mentioned that Culler’s LogP was a terrible predictive model and yet it had been cited 1,537 times (as of 9:54a this morning), and maybe they knew what they were doing.

    At that moment my world shifted: models ought to predict /and/ explain, and the explanation was far more important than the prediction. That was the point I stopped making my models complex enough to be error-free and started making them simple enough that I could understand them.

    But this didn’t quite answer the question you were asking: it’s more a claim about scientific practice than a proper scientific claim. Perhaps I thought of that example first because I tend to be much more passionate about “ought” questions than “is” questions. I can’t bring to mind any review where I questioned the accuracy of a set of measurements, but I have questioned whether the measurements ought to have been done at all, or if a particular set of conclusions ought to have been drawn from those measurements. Those are the positions where it much harder for me to change my mind precisely because they can’t be settled by appealing to facts.

    So I think I’ve managed to avoid your question entirely.

    • Interesting thoughts, Barry. And I don’t think you managed to avoid the question entirely–I’m fine with reading “scientific claim” broadly, so as to include normative methodological claims like “you ought to try to make your error bars as small as possible”.

      My phrasing of the question was intentionally narrow, and yes, I don’t expect to get many answers. But I’m hoping the answers I do get will be very interesting, as opposed to “At first I didn’t understand the idea, but then I learned more about it,” which is surely a universal experience.

    • “If we relax that particular constraint to something along the lines of “I really thought I understood the idea, but turned out to have no clue”…”

      Ah, been there. Actually, lived there for a while, and still go back frequently for visits.

  2. I liked Barry’s response and mine, were I to undertake one, would be along the same lines. That is, mistaken beliefs about what constitutes a good analysis of a particular problem, rather than a yea to nay shift on any particular topic (probably there have been some such, but I can’t think of any right now).

    I used to think that the scientific literature was pretty much entirely free from major errors, and that when those rare errors that did occur were spotted and pointed out in the literature, that the original authors would duly acknowledge same, admit mistakes and move on.
    Negative; insert sound of game show failure buzzer here.

    • “insert sound of game show fail buzzer here.”

      You have no idea how intensely I wish I could do that in this blog. 😉 Or indeed in my everyday life. 😉

  3. […] while back I asked what was the biggest scientific claim that you had changed your mind about? At the time, I wasn’t aware that hundreds of very prominent scientists had already answered […]

  4. Dunno whether this can count as a scientific claim but I’ve been disenchanted about ecology. Might seem naive now, but there was a time when I thought that ecology as a science was about to get unified and that thereafter it would live up to (my) expectations for solving environmental problems. Now I think that ecology will never by unified the way evolutionary biology is and that most environmental problems require political, economic, or social solutions/change.

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