Threshold Concepts (and troublesome knowledge)

4 December 2017

Author: Niki Kaiser

I have been interested in Threshold Concepts, and how they might help me support students to understand Chemistry, for a while now. I’ve read and blogged about them, used research literature to inform my teaching, and analysed student answers to try and identify them. Threshold Concepts fascinate me, because they conjure up those satisfying “lightbulb moments”, when a whole host of ideas that you’d been struggling to understand suddenly fall into place.

So when I found out that Stuart Kime had interviewed Ray Land (who wrote a seminal paper with Jan Meyer on Threshold Concepts), I was rather excited (to say the least!). I’ve summarised here some of the points that he made (and I apologise if I’ve misunderstood or misrepresented them).

Key Characteristics

Threshold Concepts have some key characteristics, including:

They’re transformative: they induce a change in the learner and the way they understand something or see the world. You can think of them as a portal to new (or changed) understanding.

They’re integrative: like a jigsaw piece that, once put in place, pulls others around it into place, too. It makes it clear how other pieces fit into the overall picture.

Threshold Concepts make ideas accessible that were previously outside your realm of understanding. This makes Threshold Concepts troublesome (another key characteristic): letting go of old views can feel uncomfortable. You can enter into a space of uncertainty, which highlights another key characteristic of Threshold Concepts: they’re irreversible. They change the way you talk about things, and the ideas are internalised. For example, once you’ve encountered the theory of evolution, there’s no return to the way you viewed the world before, and you have to let go of these previous ideas.

They’re not “big ideas” (or misconceptions)

Threshold Concpets aren’t just ‘key concepts’ or ‘tricky concpts’ or even ‘big ideas’, because they transform understanding, rather then just helping you to make predictions. For example, centre of gravity is a key concept, but gravity itself is transformative (and is a Threshold Concept in Physics).

This is something that (I think) makes them quite tricky to identify in the first place. As teachers, we’ve often forgotten the transformative leaps in understanding that we made on the journey from naivety to expertise. I also think that they are very few and far between, and there can be a temptation to identify a wide range of tricky ideas and misconceptions as Threshold Concepts, when they’re not.

Threshold Concepts are troublesome, but this can be a good thing!

Threshold Concepts aren’t specific to Science. In fact, they originated in the Social Sciences. Opportunity cost is a Threshold Concept from Economics: understanding about choice influencing decisions brings other concepts into view. And their “troublesome” nature needn’t have negative connotations: the ability to unsettle someone enough that they leave their prevailing views behind is a positive thing. But they can be hard to assimilate; they can be difficult to know how to deal with (eg. the concept of infinity) or counterintuitive (eg. imaginary numbers), and you need to let go of your previous frame of reference, which can be uncomfortable. They can also become inert if they’re not used enough. For example, you might have been taught some ways of using data, but you might not have much opportunity to practise using them. It’s then only when you start to use them that they start to really make sense and they ideas fall into place.

So, when a student is stuck, we need to ask ourselves what the reason might be. Dewey described how on of the most comfortable places in learning is “a mental rut already made” and it “takes troublesome work to get out”. Sometimes we can become ‘defended learners‘: we don’t want to mess up our current way of thinking and move into an uncertain, liminal space.


Liminality is an idea that originates in social anthropology: a space of transformation, a rite of passage, for example moving from boyhood to adulthood; moving through adolescence requires letting go of previous way of being, and generally involves a degree of oscillation: sometimes you behave like a child, then at other times, more like an adult. Bereavement is another example: you think you’re through it, but then you discover you’re not actually quite there yet.

As they enter this liminal state, students have to let go of old ideas. But they can get stuck and fail to see a way forward. As teachers, we know that these ideas will crystallise eventually, but students need supporting and to be helped through the process. We need to recognise and help stave off the emotions that can accompany the liminal state: anger, despair, feeling inadequate, exhausted.

We also need to be mindful that students might not want us to know that they don’t understand something, and they may resort to mimicry; in other words, they’ll piece together the information they have assimilated, and present an answer that they think will please us, without having fully understood and integrated the concepts. This is not always a bad thing: it can be a route to understanding. But it means we need to listen carefully for misunderstanding and misconceptions.

We need to teach students to be patient, to be resilient, and be hopeful.

We also need to help students recognise that, although this new way of thinking will feel challenging at the times, that’s all part of the learning process, and it’s also why it can feel so rewarding when you finally understand something.

Students might find it less threatening to seek help from peers, so find ways of encouraging them to do so. Furthermore, a peer who has just understood something themselves might be more able to explain something in a way that is understandable, as they’re not “cursed by expertise”.

Further reading

Ray Land recommends this collection of links from Dr Mick Flanagan at UCL on Threshold Concepts, and there is certainly a lot there! But I think it can be a little daunting… This page is less daunting, and also excellent.

I’d recommend beginning with this beautiful, readable paper from Glynis Cousin, then this seminal paper from Meyer and Land and this readable paper.

Also, you might want to read the posts I wrote from my ResearchEd talk on Threshold Concepts or this article in Education in Chemistry.

Posted on 4 December 2017
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