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Why is critical thinking so hard?

…and how we can teach it.

Hello! Welcome to the 8th edition of Things in Education, the fortnightly newsletter through which we hope to share the latest in education research and developments in the form of accessible summaries and stories to help you in the classroom and at home.

Let’s be frank. Thinking critically is hard. It’s so hard that most adults struggle to think critically. Take the example of the millions who are convinced that world leaders and award-winning actors are actually power-hungry aliens, or that the COVID-19 vaccines contain microchips so that the government can track every second of our every day…

And so, education boards all over the world have made the teaching of critical thinking skills compulsory in school. But if learning how to think critically is hard, teaching it is a hundred times harder. After all, there is no set definition of critical thinking. And unlike the steps of long division, there is no set process to teach critical thinking either.

Though all is not lost. With some understanding of how the mind likes to think and what thinking critically really requires, we can begin to build these skills in ourselves and in our students. What better day to begin than today?

Surface Structure and Deep Structure

So let’s begin by exercising our own critical thinking skills.

In 1980, researchers Mary Gick and Keith Holyoke conducted an experiment. In this experiment, they gave some college students a story to read:

The students were asked to memorise this story. Then, they were asked to solve a problem:

Here’s the solution: Just like the army general broke up his soldiers into small groups to converge on the fortress at the same time, the doctor can send several low-intensity rays towards the tumour. These rays won’t destroy healthy tissue, but when they all converge on the tumour, their intensity will be high enough to destroy it.

In the experiment, only 20% of the students were able to solve the problem, in spite of memorising the first story. Why do you think most of them were not able to see the similarities in the structures of the two problems?

Here’s why: Our mind tends to prefer the surface structure of new information – the specific, concrete details and particulars. In this case, these concrete details were the fortress and the general and the roads in the first problem, and the tumour and the tissue and the rays in the second problem.

In order to think critically, we must also understand the deep structure of new information – the general underlying principle. In this case, the underlying principle was “the dispersal and regathering of strength” – of the soldiers and of the rays!

So what does this look like in the classroom? Let’s take an example from English. Ask your middle- or high-school students the following question: Why will Grade 7 students not enjoy the story of the lion and the mouse as much as a mystery set on Mars?

Source: WikiCommons

Students will most likely begin by thinking about the surface structures of the stories: Mars is more exciting; lions and mice cannot talk; and so on. However, students have not thought critically in giving these responses – they have not gone down to the deep structure.

Thinking about the deep structure in this case begins with thinking about the genres of the two stories – one is a fable, and the other is science fiction. Fables are written keeping the developmental stage of young children in mind; science fiction is for teenagers and young adults. Fables have simple storylines; the plotline of science fiction is much more complicated. Fables present everything as black and white, good and bad; while science fiction usually poses moral dilemmas that teenagers are beginning to grapple with… The deep structures of stories give us a much more critical understanding of the question posed!

Background Knowledge

Here’s another task for you: Do you agree with the following tweet by Web3 Coin? Support your opinion with 2 pieces of evidence.

Here were my thoughts when I first read this: 543 retweets? And 525 people liked this tweet? I don’t even know what it means… What is web3 in the first place? Is web3 something we can “have”? Huh? What does it have to do with crypto? I’m not intelligent enough for this…

Does this mean that I have no critical thinking skills? Absolutely not. What it does mean is that background knowledge is the first and most important requirement for critical thinking. I can’t think critically about something I don’t know enough about. A doctor can think critically about the oxygen requirements of her patients, but that does not mean that she can think critically about the construction of an oxygen cylinder. A lawyer can think critically about the legal nuances of a mental harassment lawsuit, but that does not mean that she can think critically about the medical requirements of mental health. Background knowledge is the foundation of critical thinking.

So what does this mean for the classroom? One of the best ways to build students’ background knowledge is to adopt a multi-disciplinary approach. A multi-disciplinary approach analyses a concept or a topic through the lens of various disciplines. For example:

Such an approach would require teachers of different subjects to plan well in advance and collaborate on the progress of the curriculum. At the same time, individual subject teachers can also implement the multi-disciplinary approach in simpler ways by incorporating one other subject into their curriculum, like asking students to use their knowledge of language to break down and understand new scientific terms, or having students research the history of the place in which a famous author lived. Slowly but surely, teachers will see students begin to think critically in these subjects.


There is no set definition of critical thinking because different areas of life and different problems require different types of thinking skills. “Critical thinking skills” is an umbrella term for many different skills. What we do know, however, is that going beyond the surface structure of information and to the deep structure as well as building background knowledge are important steps towards developing critical thinking skills. Let’s start there!


Useful Links:

  • Multi-disciplinary learning: In this blog, we explain how multi-disciplinary learning leads to deep understanding by increasing and strengthening connections in the brain.

  • Critical thinking: In this periodical, cognitive psychologist Daniel Willingham explains why critical thinking is so hard to teach.


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Edition: 1.8

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