We know checking for understanding is an essential part of instruction and effective practice. Without it, we cannot accurately assess where pupils are now and where to go next. Understanding can falter easily when pupils have a lack of prior knowledge or fail to attend to the necessary information. While factors like these can be outside of our control, we can control when and how we check for understanding. We know the best teachers spend more time questioning and that they use a variety of methods for doing so: cold calling, probing deeper, getting pupils to emulate what has been shown and so on, but what is the best method for doing so?
I believe the best method for checking understanding is ‘getting it wrong’. What I mean by this is the teacher getting it intentionally wrong, presenting a contrasting example with what has just been taught. In maths, this is often referred to as a ‘non-example’.
Put simply, a non-example is something that is not an example of what has been taught, and therefore seeks to secure understanding through direct contrast. It is proof by contradiction. By saying what isn’t, we can say what is. Aristotle once intimated that, “A real definition will give you the necessary and sufficient conditions for an object to be an instance of the concept”. Without those conditions, we have a non-example.
Imagine children have just been taught what a square is. The teacher then presents the children with a picture of a triangle. “So, is this a square?” the teacher asks. The same could be done with democracy, photosynthesis, singing in harmony – as long as something has a definition or necessary conditions, this method can be used.
Presenting something that contrasts provokes the learner into thought: ‘Is this the same as what I have just been taught? Yes or no? If not, what makes it different?’
This cognitive conflict is something we should seek to embed within our instruction. It helps the learner to clarify their understanding and present it in a coherent manner – “This isn’t….. because……”. Pupils sometimes find it easier to define what something isn’t, rather than what something is.
Non-examples intentionally lack certain characteristics and this is what helps to clarify the boundaries for the learner.
So, ‘getting it wrong’ helps the learner to secure their understanding and it helps the teacher to ascertain what, and if, the learner has understood.