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Infectious Diseases

A Mistake About Making Mistakes

Most of the people reading this blog have some knowledge of chemistry and/or biology. (Not everyone, though – I get email from readers with no formal training who just stop by to hear what’s going on, and I’m very happy to have them). But if you do know a lot about a subject, any subject, you’re almost certain to have trouble picturing what it’s like for someone who doesn’t. That includes trying to anticipate what sort of misconceptions they might have, or errors that they might make. It’s almost impossible to pretend to unlearn something in a way that’ll let you do that.

This is a well-known problem in teaching, naturally enough, and one part of being a successful teacher (at any level) is knowing what sorts of conceptual mistakes students are most likely to make and recognizing them when they show up. Even those of us who didn’t go into academia got a taste of this while being teaching assistants in grad school. I remember doing a lab lecture about thin-layer chromatography, with illustrations on the board, before handing out those aluminum-backed TLC plates for the sophomore organic lab section to use. I was baffled when two of the guys in the class couldn’t get any spots to show up. They tried again – no spots, and these samples were the sorts of organic compounds that will give you bright, well-defined spots by TLC. Finally, I watched them apply the test mixture to the TLC plate – to the aluminum side of it, rather than the white powdery silica gel side. After I got through rolling my eyes, I had to admit to myself that I hadn’t anticipated that one; it was an error that it had never occurred to me that anyone could make. But there it was, right in front of me. After that, when I told anyone how to do TLC for the first time, I always worked in a quick mention of the difference between the two sides of the plate.

This article by Ed Yong over at The Atlantic got me to thinking about these sorts of errors. He’s summarizing a recent survey (PDF) in the UK by the Wellcome folks about antibiotic use. They found, of course, that the general public doesn’t have much idea how antibiotics work, and are mostly lost on the difference between antibiotics and antivirals. Those I already knew (discussions with relatives and so on). But this survey turned up another misconception that falls into the same category as my TLC plate one above, something that I never would have thought of on my own. It turns out that when asked about antibiotic resistance, many people thought that the problem was that their own bodies were becoming resistant to the effects of antibiotics. Therefore, you know, not finishing a prescription course of one wasn’t such a bad thing, because it probably kept your body from becoming resistant to it. (This, of course, is the opposite of what you should actually do)

The survey people tried various ways to get across the actual situation, that it’s the bacteria themselves that are becoming resistant, and had some success. The Wellcome Trust itself now says that they’re not using the phrase “antibiotic resistance” now, and they refer to “drug-resistant infections”, for example, to make the causality more clear. Showing people pictures of actual bacteria also seemed to help them connect the ideas, probably because bacteria in general can be a sort of invisible abstraction if you’ve never spent much time in front of a microscope (or reading articles by people who have).

That by itself is not going to turn the public health problem around, although it certainly won’t hurt. The larger point, though, remains the same – that we don’t always get the scientific messages across that we’re trying to, because (1) most people aren’t scientists, and (2) because we are. Something to keep in mind.

51 comments on “A Mistake About Making Mistakes”

  1. Anon E. Moose says:

    To say it with the words of the great Douglas Adams:

    “A common mistake people make when trying to design something completely foolproof is to underestimate the ingenuity of complete fools.”

    1. Hap says:

      I don’t think people are (necessarily) being fools here, though – anyone can be a fool outside of their realm of expertise, and if you don’t know much about something, it’s hard to know what you’re misunderstanding and what questions you should be asking to clarify your mental model.

      Though, I guess if stuff could be separated on aluminum, then keeping food in aluminum foil might not work so well, because you don’t know exactly what you’d get (or what it would look like) when you opened the foil.

  2. b says:

    I think you’re missing a link to the article.

  3. Mark Murcko says:

    One of the (many) reasons I love teaching a course on fundamentals of drug discovery (20.201) is because it forces me to sharpen my own understanding of basic concepts, as well as the ability to explain them effectively. Very hard to do, but quite satisfying when it works well (as occasionally happens!).

    1. Anon says:

      Glad to hear it’s a beneficial relationship for both of us, then.

  4. Mary says:

    So, it’s like the inverse of Dunning-Kruger?

  5. John Beutler says:

    There are a couple of good books on communicating science written by Randy Olson: “Connection” and “Don’t Be Such a Scientist”. Randy was trained as a scientist but is now a screenwriter, and has a lot of good ideas about how to communicate science both to other scientists and the general public. Highly recommended!

  6. steve says:

    It reminds me of a story my brother told me about his daughter. They were sitting in their dining room on a bright, sunny day and she asked him what does the word “filter” mean. He looked at the window with the sun shining through and said, “A window is a type of filter. It blocks one thing, the wind, but let’s something else through. What does it let through?” His daughter thought for a second, brightened and said, “A brick?”.

  7. Andy says:

    Once in teaching lab the manual instruction was to charge a flask with 10 g propionic acid.
    A kid came over to me and asked if there was a mistake in the script, I said I didn’t think so.
    “It says 10 grams of propionic acid”
    “Is that a problem?” I asked
    “It’s a liquid, does it mean milliliters?”
    “It still has mass though, right…..?”
    “Well that’s a bit weird, but I suppose so…..”

    1. dearieme says:

      Full marks for suspecting a typo.

      1. NJBiologist says:

        I would have given bonus points for articulating the weirdness of not specifying concentration–an ambiguity that has been known to kill patients.

      2. chemical says:

        In my line of work, specifying a volume measurement for a liquid to be used in an experiment will make me ask “At what pressure and temperature?” Is it atmospheric pressure and room temp? You should have specified that. I frequently have to prep a fluid with gas dissolved in liquid, and the liquid and gas are compressed to increase the gas solubility. So I like the fact that the liquid measurement was provided in grams here.

        1. Robert L Bell says:

          This is why parts per million (ppm) is commonly used to specify water chemistry in steam generator plants. While frustrating for the classically trained chemist, the method is unambiguous when specifying working fluids under conditions that vary quickly from cold condensate to superheated steam.

  8. luyii says:

    The problem with teaching is that once we know something we forget the difficulty we had learning it when everything was new. Many things just seem so obvious that they aren’t worth talking about. I once wrote an article about neurology and neuropharmacology and gave it to a very intelligent, nonscientifically trained woman to read. She asked me ‘where is the brain in the head’? This is not a dumb question, but I forgot to put in a diagram.

    1. Mary says:

      I had this conversation with my nephew once:

      Me: So, Pete, what do you want to be when you grow up?
      Pete: I think I want to be an engineer.
      Me: Wow, that’s great. [I ponder asking what kind–electrical, civil, chemical…I am so psyched someone else in the family turns to a STEM path]
      Pete: And you can ride on my train anytime.

  9. Ash (Wavefunction) says:

    To mirror what Mark said, one of the reasons I love talking to laymen about my field (and science in general) is so that I can constantly have a reality check on how clearly I understand and am able to communicate basic concepts. It’s surprising – but also sobering – to realize how hard it can be to communicate concepts which you think you have been familiar with for ages.

  10. Nick K says:

    I’ve often been astonished at the huge gulf between the scientists and non-scientists in their worldviews. I once had an argument with a relative who was absolutely convinced that heavy objects fell faster than light objects, Galilieo notwithstanding. She was also concerned that the Apollo rockets were going to perturb Earth’s orbit.

    1. tangent says:

      Well, who normally has the opportunity to see how masses fall in a vacuum? Everybody has seen a brick fall faster than a feather. Natural to learn that’s how it works.

      1. Nick K says:

        Er, no. Even someone without scientific training ought to understand that the density and shape of an object are the factors which control its rate of descent in air, not its mass. A simple thought experiment would have solved the problem (does the mass of a parachutist change when the parachute opens?)

        1. Martin Brummell says:

          Non-scientists don’t know what the word “mass” means. It’s a vague term to a lot of people that kinda-sorta means how big something is. It’s not a quantity, it’s a quality – “massive” things are big and ponderous and move slowly and can’t hide behind the furniture.

          I have had to tell people that water does not change mass when it freezes to ice. Your simple thought experiment with the parachutist will be anything but simple.

          1. Nick K says:

            Sadly, you’re probably right. Scientifically trained people have real difficulties even imagining the viewpoint of someone who thinks water changes mass on freezing.

  11. Gogoosh says:

    Another problem is how often scientists use common words in a specialized way, and forget that students think of the common meaning. As a TA for an introductory org class, the students were doing an exercise using CPK models. They were supposed to build t-butylcyclohexane and satisfy themselves that the equatorial conformation was more stable than the axial due to clashes between tBu and the other axial protons. A disagreement arose between two students; one insisted that the axial tBu was more stable because when you set it down on the table the axial protons on the other side make a nice tripod and the molecule doesn’t fall over, whereas with the equatorial tBu it falls over and is therefore less “stable”. I had forgotten not thinking of stability in the thermodynamic sense and regrettably laughed believing the student was joking.

  12. James Cook says:

    I am an engineer, but I spend a large part of my time training people to use the equipment my company makes, industrial robots. I tell my fellow engineers, if you want to test your mastery of a subject try to explain it to someone who knows nothing about it.

  13. Ted says:


    This comes second hand….

    Student: “Mr. TA, I can’t get the phosphorus oxychloride to dissolve in the solvent, it just floats on top!”
    TA: “Huh? How much did you add?”
    Student: “One point two grams, just like the procedure said. I opened a fresh can and everything!”
    TA: “Let’s take a look”

    Both walk over to the hood. A freshly opened golden can labelled ‘phosphorus oxychloride’ sits to one side. Next to it is a round-bottom flask, half full of solvent and vermiculite, busily bobbing about.

    As the TA’s mouth drops agape, the student comments “It was tough to get all that stuff through the neck of the flask, but the syringe really helped in poking it though!”


    1. J C McKeown says:

      … and everyone survived allright?

  14. bacillus says:

    Once worked for a not-for-profit where each year we’d give lay talks to our richer benefactors and their trophy wives. My friend gave a short talk on B cells. Later in the day a trophy wife approached him and asked where he kept the bees!

    1. Victor says:

      Reminds me of a Shaw joke:

      Shaw is at a dinner seated next to a Pretty Young thing. After trying various topics and failing, he finally asks,”Do you like Kipling?”

      “Well,” says the PYT,”I don’t know. I have never kippled before.”

  15. David Cockburn says:

    I couldn’t write a very good essay about the impact of the Tirpitz navy law on the origins of the first world war. I know far less about about Wittgenstien’s philosophical ideas and recongise that this points to weaknesses in my education.
    I do find it curious however that intelligent, well educated people who do understand something about philosophy are so incurious about what is going on just below their own skin as not to understand the meaning of ‘antibiotic resistance’ and indeed to believe that homeopathy works.

  16. vermiculite says:

    Another vermiculite story, told to me by a post-doc. There’s a guy in lab, and he’s surprised since he only ordered a gram of cmpd, and they sent him more than 5g. There’s still more cmpd in the box. He can’t believe how much they sent him. He shows the overflowing beaker of cmpd to his labmate, as he is amazed that they sent him so much. This was expensive cmpd, will the professor be mad? The postdoc, then a grad student, reaches into the box full of ‘cmpd’, and pulls out a little bottle from all the vermiculite that has yet to be weighed out.

  17. LabMaus says:

    Despite several attempts, a group of grad students were unable to grow anything from their bacterial cultures following serial dilution. After watching them repeat the whole process again, the reason became clear – they were flaming their already-sterile plastic pipette tips in the bunsen burner, thus sealing the tips and preventing the pipette from picking anything up…

  18. David Bush says:

    Clearer communications won’t stop hypochondriacs, or those who are just willingly ignorant and desperately seeking any perceived remedy for their ailment. I had a friend in my dorm in college who had a cold and was furious that the doctor wouldn’t prescribe him an antibiotic. I explained to him that if it was not a bacterial infection (the doctor said the cultures were negative) that antibiotics wouldn’t help, but could aggravate the cold, make him unnecessarily uncomfortable, and contribute to global resistance. He didn’t want to hear it; the doctor was a jerk because it was his job to give people medicine when they’re sick and he wasn’t doing it.

  19. Anonymous says:

    Yet there is a bit of paradox in the popular account of the development of antibiotic resistance from failing to complete a prescribed course, isn’t there?

    If the infecting bacteria have antibiotic resistance in significant numbers in the first place, the antibiotic will fail to eradicate the infection whether the course in completed or not, yet once the antibiotic is stopped midway through, selective pressure to develop antibiotic resistance disappears, so in order to argue that stopping midway produces antibiotic resistance, we have to postulate that antibiotic resistance already exists among the infecting bacteria at that point, or that the bacteria go on to develop it subsequently by some mechanism and for some reason (since the metabolic cost of having it at that point becomes a negative selective factor).

    But if the bacteria already have resistance when the course is stopped prematurely, why would finishing it get rid of the infection? Perhaps the numbers of bacteria haven’t been reduced sufficiently at this point for the immune system to complete the job, but this answer still depends on a fairly low level of antibiotic resistance at the stopping point, or finishing the course wouldn’t have helped anyway. Resistance in this scenario would develop as the bacteria repopulated despite the best efforts of the immune system from a reduced number in which the proportion of resistant bacteria had been increased, but once again, except in the presence of the antibiotic, possessing antibiotic resistance is a negative selection factor, though presumably a relatively minor one.

    1. b says:

      This statement relies on the assumption that bacteria are either resistant or not. It isn’t a binary system. Some bacteria may have a mutation or two that aid in acquiring resistance. The idea is to kill the entire population so that those which have beneficial mutations don’t survive and reproduce. Evolution at its finest.

    2. z says:

      You’re assuming that both the antibiotic and resistance act like on/off switches.
      Stopping the medication short could A) leave a sizeable portion of bacteria that could still reinfect/evolve and B) still leave some lingering, but diluted (thus nonlethal) antibiotics in the system and thus giving them a pressure to build resistance.

      It is very possible that some bacteria could already contain either partial resistance or “sleeping” segments that when activated could build resistance. However, that doesn’t mean they are immune to it yet.

  20. Mark Thorson says:

    How much would it cost to add a notice to the label “Compound is contained in a small bottle within this can. The large brown particles are packing material. Do not eat.”

  21. Phoobahr says:

    Over dinner I was describing my career path (such as it’s been) to an intelligent, articulate non-scientist collaborator, when she stopped me, interested to know more about confrontational chemists, and what made them that way. I hesitated before clarifying, it was as though the universe was expressing a Freudian slip through her, but ultimately out of consideration I had to correct the misunderstanding. But, I did go on to intimate that some of us had also referred to practice as molecular muddling.

  22. DrSnowboard says:

    We used to cross interview at a small company I worked for, a couple of chemists would interview the potential biology candidates and vice versa. A really good discriminating question was to ask the candidate to describe their thesis/last project to me as if I was their parent (assuming their parents were not science qualified). The people who were really good at this question were invariably some of our best hires.

  23. David Kroll says:

    A somewhat related anecdote: I taught in two semesters of pharmacology at the University of Colorado School of Pharmacy (1992-2001). In the first, I did about 45 lectures on CNS pharmacology, far from my area of expertise in anticancer drugs (see, I made an assumption – CNS is “central nervous system,” drugs like antidepressants, general anesthetics, epilepsy drugs, drugs for pain that work on the brain and spinal cord, recreational drugs, etc.). In the second, I’d teach about 12 lectures on anticancer and antiviral drugs, much more allied with my training and research.

    Invariably, I’d receive better teaching evaluations for the lecture block on the topics where I am least an expert. When I taught about anticancer drugs, I was told that I’d assume too much and go into too much detail without adequate orientation. So even in the same environment with the same students, I learned that I was unaware of how my expertise made me a less effective teacher. I was at my best when I had to approach my lecture material like a student.

  24. Young Padawan says:

    Does any reader here have any experience with Rosewell Industry Co., Limited
    (, a Shanghai and CA based company. The sell some organic building blocks but also some transition metal catalysts, one of which I am interested in. Thanks for any feedback.

  25. Sam Adams the Dog says:

    This is one of the few times when the responses have been as good as the original posting. So here’s another anecdote, told to me by a fellow grad student, who was an organometallic chemist. His lab had to handle quite a few air-sensitive compounds, some of which were dangerous.

    A new grad student arrived in the lab from a country where they received only the most minimal lab training. He also didn’t speak English very well, and everyone was scared of him, because he would handle these dangerous compounds on the desktop, rather than in the hood, without a safety shield or any protection. One day the whole lab ganged up on him and said “You have to do this reaction in the hood. Understand? In the hood. IN THE HOOD!”

    Later, they couldn’t find him. They looked around for him. He had climbed up into the hood and was in there running the reaction….

    1. Andrew says:

      Well it’s a good thing you didn’t give him anything to do in the glovebox.

  26. Andrew Goff says:

    I’m one of those curious outsiders (I came for the descriptions of explosions and bad smells and I stayed because there’s a genuine risk of learning and understanding things from this blog) – so thank you for everything you do.

    My anecdote to add is passed on to me from my mum, an artist who ran courses in many forms among which was a course in street art. Spray paint is toxic stuff (by non-lab standards anyhow) with Xylene and Toulenes and other goodies, so an important part of teaching this is the safety precautions. In an effort to make sense of “respirator mask” to teenagers she said that “you’ll need a mask, like Walter White from ‘Breaking Bad'”. Well… 13/14 kids understood. And one kid showed up with a latex costume mask of Walter White.

    Sometimes “everyone knows” is just not quite enough.

  27. pyridone says:

    It has been always confusing to explain to other people( common people without bakcground of science) what is organic synthesis, and the simple answer will be “we make new drugs”, not exact but it works. When I was TA of freshman’s chemistry, two students came to me and told me the magnetic stirrer was not working, as nothing happened while they put the starting materials in and turned on the power. I took a look, and it turned out there was not a stir bar inside the flask. We just can not imagine how difficult it is to think in the laymen’s shoes as we are already kind of “expert”.

    1. paperclip says:

      That reminds me of an experience of my own: I hate to say that I wasn’t the baffled TA but the clueless undergrad. The instructions said to stir the solution with a magnetic stir bar. Hmm, what in this room is magnetic and looks like a bar? Well, that thing stuck to the fume hood is more like a stick, but it is certainly thin enough to stir with. So I started to manually stir my solution with the magnetic wand, like a spoon.

  28. David Antonini says:

    I run into this problem all the time, in phys/chem and history where I do have some tertiary experience, and medical ideas, that I have a highschool education in. It astounds me on a daily basis, particularly living in the US compared to Australia.

  29. Anon says:

    Every time I have written on this blog asking some of the very smart chemists here for some basic instruction, I have a very kind, helpful information. Thank you in advance.

    Given the nature of this blog topic I thought it would be ideal to ask a question I have been considering lately, namely how to make hydrogen enriched water.

    Why might one want to make such a beverage?
    http://www.ncbi.nlm….pubmed/25936373 etc.

    Here is one method to make it.

    So a pop bottle and run this reaction:
    2Al + Ca (OH)2 + 6H2O → Ca [Al (OH)4]2 + 3H2.

    No sweat, The chemicals might be a little messy. Would there be an alternative
    approach that would use nicer chemicals?

    Or perhaps simply hydrolysis of water?
    No messy chemicals. The details for the setup of such a process would be appreciated.
    Perhaps just a sealed pop bottle?

  30. Edgar Carpenter says:

    As an outsider, the way antibiotics are treated by the medical profession seems odd. On the one hand, we read that among the many microorganisms which live in and on most of us are quite a few which are potentially dangerous, but which our immune systems usually protects us from – staph, strep, pseudomonas etc.

    We also read that bacteria exchange genetic defenses against antibiotics with other like and unlike bacteria, accelerating the spread of resistance.

    And yet, dosage advice to physicians for antibiotics is dependent only on a patient’s presenting infection, and the amount and duration of antibiotic treatment can vary wildly depending on what is being explicitly treated.

    Dosages are determined as if there were no other potentially pathological bacteria present in the patient’s microbiota, and no potential for creating resistance in bacteria which are, in fact, present, but which are not part of the infection for which the person is being treated.

    How much research has explored the development of bacterial resistance in non-targeted but present bacteria when the targeted infection is treated with low antibiotic dosages? And how does this affect the spread of resistance?

  31. Rich Lambert says:

    I’m an engineer and once testified in court about an issue that had to do with the tightness of a bolted connection. The case was dismissed, but at the end the judge asked me to explain what torque was since I had been using the term to try to explain bolt tightness. Boy, did I feel dumb.

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