Teaching critical thinking most effective when tied to specific content, knowledge

iStock_000018618557XSmallCritical thinking is high on the list of what students should learn as they make their way from grades 1-12. But teaching critical thinking as a set of skills separate from any specific content or from a domain of knowledge is not an effective way to do it, writes a professor of cognitive psychology at the University of Virginia in a recent issue of American Educator.

“People who have sought to teach critical thinking have assumed that it is a skill, like riding a bicycle, and that, like other skills, once you learn it, you can apply it in any situation,” writes Daniel Willingham.

“Research from cognitive science shows that thinking is not that sort of skill. The processes of thinking are intertwined with the content of thought (that is, domain knowledge),” Willingham says.

Nested in subject matter

In recent years, many schools have taught critical thinking as a separate set of skills in across-the-curriculum programs, the author writes. But to be taught effectively, critical thinking needs to be “nested” in subject matter, he says. For example, if you teach students to look at an issue from multiple perspectives, they may not be able to put this into practice if they don’t have enough knowledge about an issue.

Telling students they should consider the source of information is difficult without adequate 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,” Willingham writes.

To think critically, students must penetrate beneath the surface structure of an issue or problem and work with its deep structure, he explains. Frequently this requires repeated exposure to bits of knowledge.

When a teacher gives students word problems to solve, for example, students already may have the mathematical formula they need to solve the problems, but they are too distracted by the surface structure of the word problem, he says.

For there to be a transfer of knowledge to a new problem, two things are needed, Willingham writes: Familiarity with a problem’s deep structure and the knowledge that one should look for a deep structure.

Because of their familiarity with the Hansel and Gretel story, when American college students were presented with the following problem, 75% of them came up with the solution while only 25% of Chinese students (who were not familiar with the story) did, notes Willingham.

A treasure hunter is going to explore a cave up on a hill near a beach. He is afraid he might get lost inside the cave. All he has with him are a flashlight and a bag. What can he do to make sure he does not get lost and can find his way out of the cave?

The solution, of course, is to carry some sand in the bag and leave a trail as you go so you can find your way out again, like Hansel and Gretel did with bread crumbs. While the surface structure of this problem was different, American students’ familiarity and repeated exposure to the Hansel and Gretel story enabled them to apply the bread-crumb-trail solution to a new situation.

“American subjects didn’t think of the problem in terms of sand, caves, and treasure; they thought of it in terms of finding something with which to leave a trail. The deep structure of the problem is so well represented in their memory, that they immediately saw that structure when they read the problem,” he writes.

Practicing strategies

Metacognitive strategies can take students only so far, he explains; they need practice in implementing those strategies, which often requires domain knowledge.

If students are told not to accept the first reasonable-sounding solution to a problem, that doesn’t mean they know how to come up with alternative solutions or judge how reasonable each one is.

That doesn’t mean critical thinking is just for older, more advanced students, Willingham says. Because of the nature of critical thinking, sometimes a three-year-old will have enough knowledge to be able to see a solution to a problem that a professional scientist will miss. Student experiences can offer entrĂ©e to complex concepts.

To demonstrate that correlation is not the same as causation, for example, students could be told that the number of crimes committed on a given day is correlated to the amount of ice cream consumed.

“With a little prodding,” Willingham writes, “students soon realize that ice cream consumption doesn’t cause crime, but high temperatures might cause increases in both.”

Everyday experiences

A committee of prominent science educators organized by the National Research Council recently recommended that scientific reasoning be taught in the context of rich subject matter, the author points out. The committee concluded that background knowledge is necessary to engage in scientific thinking. Knowing that an experiment should have a control group, for example, is not the same as being able to create one, and to do that you need to know the subject matter.

“This understanding that critical thinking is not a skill is vital,” the author writes. “It tells us that teaching students to think critically probably lies in small part in showing them new ways of thinking, and in large part in enabling them to deploy the right type of thinking at the right time.”

“Critical Thinking Why Is It So Hard to Teach?” by Daniel Willingham. American Educator, Summer 2007 pp. 8-18.

Published in ERN October 2007 Volume 20 Number 7

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