All thinking involves connections between ideas. Critical thinking involves making sure those connections meet certain standards.
Argument mapping helps us visualise the connections between our ideas and makes them clear to both student and teacher.
It requires students literally connect the dots of their thinking. That's why it is so powerful.
And while argument mapping is usually found in a philosophy or critical reasoning class, there is no reason that it can't be used in any discipline to help students think critically about their subject domain.
Connecting the dots
Most students get very little exposure to critical thinking throughout their education - even at university.
Because of this, the criteria that they use to evaluate their thinking is usually limited to associative coherence. If two ideas gel together, if they can make a coherent story out of them, then those ideas 'make sense'.
But critical thinking requires much more than just association between thoughts and ideas - it requires directed connections with particular qualities.
The ‘direction’ of the connections goes from statements that we think are, or might be, true to statements that we think follow from them. We call this process inferring, and connections which have this quality are inferential connections.
So one of the first activities I like students to try is designed to help them focus on the shape and direction of the inferential connections between claims.
I like to start easy with what I call the "Because Test". Very simply, students are required to show which idea justifies the other by dragging supporting reasons onto a claim.
It should then be possible to state the inference as "A because B".
Sometimes, the answer is obvious. Other times, the answer can stimulate a great deal of classroom debate.
To increase student reflection on the inferential structure, I find it best to initially make the content less contentious. This way, students focus more on how some claims justify others and less on whether those claims are true or false.
Filling in the blanks
Once students are comfortable connecting ideas together in a way that adequately represents the inferential structure of an argument, another useful activity is to fill in the blanks of an argument map.
Beginning with the obvious, where the missing reason must make argument valid ...
And progressing to more "nuanced" arguments ...
Discussions as well as doing
There's a great deal of pedagogical value in argument mapping that is derived from simply having students do these exercises in order to see their own thinking and reflect on it.
Yet there is so much more that can be derived from using argument mapping as the focal point of classroom discussion.
Reasoning is far better understood as a social competence rather than as an individual faculty.
So when we explicitly depict our thinking in visual form, we create a shared representation of our reasoning. We can literally point to our claims, our reasons for them, and how these reasons connect with each other.
This shared artifact allows students to discuss and collaborate, to develop the norms of effective thinking, and engage in social cognition.
And that's exactly what we want in a critical thinking pedagogy - to have our students think about and evaluate their thinking.