Critical Thinking: Why Is It So Hard to Teach?
Author: Daniel T. Willingham
"Students can learn certain metacognitive strategies that will cue them to think (critically). But,…, the metacognitive strategies only tell the students what they should do - they do not provide the knowledge that students need to actually do it."
An Overview
In this article the author argues that Critical Thinking is not a skill like many other skills, such as riding a bike. The author summarises this as "Critical thinking does not have certain characteristics normally associated with skills - in particular, being able to use that skill at any time". The author goes further to say that we need to explicitly teach critical thinking in terms of a specific topic.
"…if you remind a student to 'look at an issue from multiple perspectives' often enough, he will learn that he ought to do so, but if he doesn't know much about an issue, he can't think about it from multiple perspectives."
The focus of this article is then on two separate, but intertwined, ideas linked to the teaching of critical thinking skills.
1. "familiarity with a problem's deep structure"
This relates to the fact that any problem is made up of two parts: the surface structure (the scenario in which the problem is stated); the deep structure (the underlying useful subject matter). "The difficulty is that the knowledge that seems relevant relates to the surface structure".
The author gives several examples taken from various pieces of research, and I know that I have seen this phenomenon in my own classroom, and have fallen to it myself on regular occasions too. An example from maths would be looking at these two problems: my sister is half my age, and in five years time she will be 10 years younger than me; in my garden there are ten more tomato plants than there are carrot plants, but 5 weeks ago there were twice as many tomato plants, and I plant one more of each plant each week. The surface structure of these is very different (age and vegetable plants) but the underlying deep structure is the same (in fact they are identical, with a solution given at the bottom of the page for those interested).
Some people may have spotted the connection here very quickly. Others may not. As Willingham states, "When one is very familiar with a problem's deep-structure, knowledge about how to solve it transfers well" or put another way "the ability to think critically depends on having adequate content knowledge".
"Knowing that a letter was written by a Confederate private to his wife in New Orleans just after the Battle of Vicksburg won't help the student interpret the letter - unless he knows something of Civil War history."
The author's final point around the importance of subject knowledge with regards to the deep structure is that students need to practice a particular type of problem a lot in order to "…know it well enough to immediately recognize its deep structure…".
This suggests that we can only teach critical thinking with respect to our own subject, but more than that, we can only teach it with respect to each individual topic within our subject, and that these skills will not be transferable until students have developed a better knowledge of the subject first. So we, as teachers, should focus on ensuring the students have the required knowledge first.
This links to my previous post about direct instruction vs minimally guided instruction in that minimally guided approaches usually require strong critical thinking skills, but this article suggests that these cannot be developed until the knowledge is in place.
2. "the knowledge that one should look for a deep structure"
This is what is formally known as metacognition, and is the ability to think about what you are thinking about. This covers the idea of teaching students mantras to help them remember what they need to do. You can remind students to "look for the deep structure" or "consider both sides of an argument" and these will help remind students of what they need to do.
But, as already mentioned, as useful as these metacognitive strategies are, they do not provide the underlying knowledge needed to actually follow them.
"The difficulty lies not in thinking critically, but in recognizing when to do so, and in knowing enough to do so successfully."
My Takeaways
Obviously developing critical thinking skills has been a school aim for a few years now, and this article sheds some light on why we have been finding it difficult to actually do this. Some of the key points I have taken from this article are: "thinking critically should be taught in the context of subject matter"; "to teach critical thinking strategies, make them explicit and practice them"; and that critical thinking actually looks very different in different subjects.
My initial thoughts are to spend some time towards the end of each topic (when students hopefully have the required knowledge) working through problems. This is nothing new to my teaching, but what I will spend more time focusing on is giving them a mixture of problems with very similar deep structures, and very different surface structures. This should provide them with opportunities to practice spotting the deep structure and hopefully embed it a little.
I am also wondering about the usefulness of looking at this the other way. Providing problems with very similar surface structures but very different deep structures. This should hopefully make it more clear to students that these two structures exist.
I am also considering how I can make these strategies more explicit in my teaching. I have already put more of a focus on worked examples in my teaching to great effect, so my thoughts are to incorporate examples of me showing how to solve problems first, rather than expecting students to try it with little guidance.
Problem Solutions
If my sisters age is n, then my age is 2n.
In 5 years time my sisters age is n + 5, and my age is 2n + 5.
But in 5 years I am 10 years older than my sister, so we get the equation:
2n + 5 = n + 5 + 10
2n = n + 10
n = 10
So my sister is 10 and I am 20. In 5 years time, my sister is 15 and I am 25.
If I have x carrot plants, then I have x + 10 tomato plants.
5 weeks ago I had x - 5 carrot plants, and x + 10 - 5 tomato plants.
But 5 weeks ago I had twice as many tomato plants, so we get the equation:
2(x - 5) = x + 10 - 5
2x - 10 = x + 5
x = 15
So I have 15 carrot plants and 25 tomato plants. 5 weeks ago I had 10 carrot plants and 20 tomato plants
Notice the similarities between the answers. Both problems could have been solved in exactly the same way if we rearranged the order like so for the second problem:
If I had k carrots 5 weeks ago, then I had 2k tomato plants.
Today I have k + 5 carrot plants, and 2k + 5 tomato plants.
But today I have 10 more tomato plants than carrot plants, so we get the equation:
2k + 5 = k + 5 + 10
2k = k + 10
k = 10
So five weeks ago I had 10 carrots and 20 tomato plants. Today I have 15 carrots and 25 tomato plants.