Are teachers cursed with knowledge?

//Are teachers cursed with knowledge?

The Curse of Knowledge: when we are given knowledge, it is impossible to imagine what it’s like to LACK that knowledge. Chip Heath, Made to Stick

How much do teachers need to know? In my last post I proposed that an effective teacher – one who is warm, friendly and a great speaker – is minimally effective if they have nothing to teach. The Dr Fox – or Ken Robinson Effect – shows that even though we love charismatic teachers, we don’t learn much from them unless they are also knowledgeable about the subject they’re teaching.

Following a prolonged and protracted debate with headteacher Jonathan Taylor I’ve accepted that images (1)the relationship between teachers’ subject knowledge and student achievement is probably ‘curvilinear.’* That is to say, although there’s a minimum level of subject knowledge teachers need to have in order for their students to be successful, increases in subject knowledge appear to lead to declines in students’ outcomes. This is probably similar to the findings of Inverted U Theory: that while some stress is desirable, too much will adversely affect performance.

This kind of curvilinear relationship makes intuitive sense for stress, but why should it apply to teachers’ subject knowledge? Well, try the following experiment for size: tap out the melody to a number of popular song and estimate how many will be recognisable to a listener. In a study by Elizabeth Newton, it was found that subjects overestimated the ability of another person to recognise the melodies by a factor of 20. When you know something it is very difficult to think about it from the perspective of someone who doesn’t know it. As physicist Carl Weiman puts it, “well intentioned physicists are achieving poor educational results because the “curse of knowledge” makes it very difficult for them to understand how physics is best learned by a novice student, or to accurately evaluate that learning.”

Recent advances in neuroscience have demonstrated that experts’ and novices’ brains actually think differently. A study from Nicole Hill and Walter Schneider confirms that as we learn, our brain architecture changes and thoughts are processed differently; as we move to mastery, our brains form different links it’s possible to observe different activation patterns during problem solving. Not only do experts and novices think differently, it may be that the very knowledge which makes us experts acts to prevent us from understanding how novices perceive and process the material we’ve already mastered. This may cause us to make mistakes about how students are likely to learn. In Ouroboros, Greg Ashman points out that, “people think that authentic, real-world projects will be motivating …  teachers routinely underestimate what is required to complete a task because they are suffering from the curse of knowledge.”

The ‘curse of knowledge‘ is a real and pernicious cognitive bias; the more expert teachers become the less empathy they may be able to have with their students. So, how much do teachers need to know to be optimally effective? After all, it may be that most teachers are not yet at the point where the relationship between what they know and how their students learn has reached the point of the curve where their knowledge has become a curse. Before you get too excited about all this, it really won’t help students for their teachers to know less.

In order to best understand the relationship we would be well to unpick the differences between ‘mere’ subject knowledge and pedagogical content knowledge. I’d argue that the latter must include the former but, added to the wealth of understanding a great teacher ought to have about the subject they’re teacher, they also need to know about how novices learn the subject. Teachers’ subject knowledge ought to include knowledge of the threshold concepts of their subject and a thorough knowledge of common misconceptions and how to help students suppress them.

Ironically perhaps, this is a call for teachers to know more, not less about their subjects. We need to need to become experts in how our subjects are learned as well as taught.

* This proves once and for all that Twitter really can be an effective tool for debate if all involved are prepared to be reasonable and learn from each other.

2016-09-05T12:58:17+00:00September 5th, 2016|Featured|


  1. Harry Fletcher-Wood September 5, 2016 at 4:48 pm - Reply

    This is fascinating, but I find the curvilinear idea tricky… probably because, as you rightly conclude, there are two different factors at play, subject content knowledge and pedagogical content knowledge.

    I’d be interested to know where you mass most teachers on this. I would suggest that almost anyone with a degree in the subject they are teaching is on the right-hand side of the curve: they’ve forgotten they ever held many of the misconceptions the average Year 7 holds.

    But it’s also impossible to develop your pedagogical content knowledge unless that’s within a strong body of subject content knowledge… So I’m envisaging two axes, subject content knowledge on one, pedagogical content knowledge on the other. A novice teacher with a degree is cursed until they start moving along the other axis too…

    • Glen Gilchrist September 5, 2016 at 7:25 pm - Reply

      I wonder if this x (content) and y (pedagogical) could be divided into quadrants just like we used to plot cats NV against V scores for example??

    • Grumpywearymathsteacher September 5, 2016 at 10:09 pm - Reply

      Totally agree with this.
      Great subject knowledge is not a curse, we just need the pedagogical knowledge to go with it.
      A properly planned curriculum/scheme of work is also essential: it’s impossible to teach a more advanced skill or concept if the student’s previous teachers have not taught the building blocks effectively (either because they lacked ‘advanced’ subject knowledge so didn’t know which bits would be really important later(#), or because they lacked the pedagogical knowledge, or both) or if those building block skills or concepts didn’t have enough time/skilled instruction invested in them during previous years because the curriculum was not structured carefully enough….

      (#) and this is where you get the student who did great at GCSE with the not-really-a-subject-specialist teacher (the recently-deceased Maths GCSE setup, for example, rewarded teaching to the test with proper understanding optional (thank goodness the new one looks better designed)), who then falls off the cliff at A level (with the highly knowledgeable teacher, who can see there are massive problems which are ingrained and there’s no time to fix them)
      …and whose results look bad now? Oh yes, the teacher with the great subject knowledge…

  2. Glen Gilchrist September 5, 2016 at 7:23 pm - Reply

    What’s interesting here about the “curse of knowledge” is also how this applies to those of use operating from outside the classroom.

    Having grafted for 12 years inside the class rooms both as a teacher and latterly as HoD, I can claim to have developed both subject content and subject pedagogical skill / knowledge. Now looking into other’s classrooms, often in the guise as support / coach for struggling teachers, it it always pertinent to remember that the solution to what I perceive as obvious (say behaviour issues) is far from trivial and I am “cursed with knowledge” and at times, it can be difficult to frame advice in a manner that is actionable by the teacher being coached.

    One thing that we are exploring more of in the region is direct school-school knowledge, where support is teacher – teacher, without an external agency so encumbered by “knowledge” — in this model, both parties are learning from each other.


  3. Neil Williams September 5, 2016 at 10:34 pm - Reply

    You can really ‘know’ a subject without necessarily knowing how to teach it… So our subject knowledge needs to be used to carefully structure learning to develop ideas in a coherent way.

  4. […] The Curse of Knowledge: when we are given knowledge, it is impossible to imagine what it’s like to LACK that knowledge. Chip Heath, Made to Stick How much do teachers need to know? In my last post I proposed that an effective teacher – one who is warm, friendly and a great speaker – is  […]

  5. @SteveTeachPhys September 8, 2016 at 4:12 pm - Reply

    “Following a prolonged and protracted debate with headteacher Jonathan Taylor I’ve accepted that the relationship between teachers’ subject knowledge and student achievement is probably ‘curvilinear.’”

    What a engrossing battle it must have been, two titans of the educational world hurling research papers and thought experiments across the aether at one another, and all conducted on Twitter so that mere tyros in educational thought could observe and admire. What a shame I missed it.

    “Curvilinear” was the conclusion, not linear, not curved, but curvilinear – which means – oh – curved.

    Excellent, no doubt it will be an exponential growth curve, just an extra hour reading a fraction more about your subject could have huge gains for all your pupils. You don’t have to feel guilty in taking pleasure in reading about your subject instead of wading through some impenetrable pedagogical tome, every bit of subject knowledge matters.

    But no those hopes are dashed. The great Learning Spy steps in with a graph. We don’t have to wonder about curvilinearity we can see it in all it’s upside down U glory. Now the only question I have is where am I on that graph? In a subject knowledge sense am I optimally aroused, or am I – god forbid – overaroused (let’s not even whisper the wake up in cold sweats worry that I’m underaroused)?

    The great David with his licence to slay Edumyths will help. All I need do is follow the helpful link. Mmmmmm 20 dull pages on why it might be a good idea to model education processes to identify areas for improvement, and the proposed model doesn’t even explicitly include teacher subject knowledge!?

    Perhaps it was just all bunkum in the first place.

  6. […] a teacher, labouring under the curse of knowledge, the meaning behind our intentions is clear. But to students, standing at the threshold, not […]

  7. […] certainly think with them. This lack of insight into the source of expertise is sometimes called the curse of knowledge, and can lead us into neglecting the teaching of the vital nuts and bolts on which expertise […]

  8. Gabs July 20, 2017 at 8:08 pm - Reply

    This is key for leaders to recognise when recruiting. It’s all good wanting the best graduates and academics to work in schools but if those individuals don’t know how to transfer that knowledge effectively and correctly at the right place and with the right quality, it’s fruitless having those individuals (especially if they are resistant to feedback, due to the ego of too much knowledge). In fact I would go as far as saying it might be better to have a teacher who can communicate and transfer knowledge effectively with a directive to develop their knowledge. From experience this is easier that trying to get a teacher with incredible knowledge and poor transfer skills to teach. I see this often and its upsetting as both the kids and staff lose out.

  9. […] recognize the importance of knowledge among teachers. It is easy for teachers to suffer from the ‘curse of knowledge’ and forget what it was like to not know something. When we see what knowledge our students need, […]

  10. […] Students, as novices in geography, find it difficult to manage such change – Rapid change of content is difficult for students to process and meaningfully engage with. This references the ways in which experts (teachers) think differently about content to students (novices). Even now, my mind boggles at the extent of the background geography I would need to teach to ensure students could even effectively comprehend such an event. As geographers, we have already built an extensive bank of geographical knowledge, and so managing these transitions is not problematic for us. Excellent stuff on the ‘curse of knowledge’ by David Didau found here. […]

  11. […] Once skills has been acquired, we stop being able to see the joins between all the knowledge that went into its creation. The more expert we become, the more invisible and automatic are skills become. Eventually, we may start to believe the skill which for us has become so natural and straightforward can be taught to others as a complete edifice. This is like giving someone a cooked meal and telling them to prepare a meal out the ingredients. It’s easy for another expert to see how this could be done, but very difficult for a novice. The idea that skills can be taught is an illusion born from the curse of knowledge. […]

  12. […] expert like’ model, but a model closer to the novice than I could likely produce. David Didau’s discussion of the ‘curse of knowledge’ encourages this theory, suggesting that with […]

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