This is the second article in a three-part series on teaching critical thinking: Part I | Part II | Part III

"Critical thinking is not a set of skills that can be deployed at any time, in any context. It is a type of thought that even 3-year-olds can engage in — and even trained scientists can fail in" — Dan Willingham, psychology professor at the University of Virginia

Being able think critically in a variety of contexts is undoubtedly a valuable life skill. The benefits of knowing how to read between the lines, see the full picture of a situation, assess the validity of a claim, make a judgement and realize when you need more information clearly extend far beyond classroom study.

Yet the classroom can serve as an incubator for students to begin to develop and practice the tools that facilitate such thought processes.

Critical thinking is generally associated with cognitive skills like synthesis, analysis, evaluation and interpretation represented in the higher levels of Bloom's Taxonomy. While this is certainly true, it's only part of the picture.

Critical thinking also comprises certain dispositions or habits of mind, such as fair-mindedness, inquisitiveness, flexibility, creativity, a desire to be well informed and a respect for and willingness to consider various distinct viewpoints. In this context, it can be considered the contrary of closed-minded, irrational or undisciplined thought.

Why is critical thinking so complicated to teach?

The first article in this series explored ways teachers can prepare students to think critically. But when it comes to teaching the real thing, questions arise as to whether it's really possible and if so, how?

To begin with, critical thinking is difficult to teach because it is difficult to do. This applies to everyone — not just students.

It involves self-direction on the part of the thinker versus the mere deference to authority as much of our cultural conditioning is geared toward. In essence, we are surrounded by influences pulling us in the opposite direction. Sadly, certain methods of education fit into this category.

Next, we need to consider our human tendency to look for quick solutions, to see things as good or evil, right or wrong, or to trust our personal experience over thorough scientific research. "Dr. Diane Halpern argues that human beings are programmed to look for patterns, particularly in the form of cause-and-effect relationships, even when none exist," writes Emily Lai in a Pearson research report.

Such tendencies stem largely from how our brains function. Surprisingly, the brain is not built for thinking, it is wired to memorize and recognize and match patterns. Consequently, we shouldn't expect critical thinking to come naturally — it must be learned and practiced.

This automatic seeing of patterns and making associations can actually complicate problem solving. In his article, "Teaching Critical Thinking," Willingham, a professor of cognitive psychology, gives the obvious example that a person reading about the illegal copying of films would not associate the word "piracy" with pirates sailing ships in the 1700s.

"The cognitive system gambles that the incoming information will be related to what you've just been thinking about," he explains. "Thus, it significantly narrows the scope of possible interpretations of words, sentences and ideas."

Such automatic editing facilitates rapid comprehension of a conversation or an article, yet makes it more difficult to see past the superficial scenario presented in a math story problem to recognize the actual math problem or what would be considered its deep structure.

How can critical thinking be taught?

Although the phrase "critical thinking skills" is commonly used, it is not a set of skills that can be taught then automatically applied at any time or in any context. But characteristic strategies — examine things from another perspective, do not automatically go with the first possible outcome, investigate your sources of information, etc. — can be instilled in students.

In the case above, they can be instructed on how to look past the surface for the deep structure and reminded to do so when encountering problems. However, just knowing these strategies isn't enough. If students intend to solve a real math or history problem, for example, they need to have knowledge and practice related to that subject matter.

"Thought processes are intertwined with what is being thought about," Willingham says.

Critical thinking strategies shouldn't be introduced as global generalizations. Instead, they need to be explicit and practiced in the context of the subject matter being taught.

The ideal age for learning critical thinking

While critical thinking instruction is best assimilated and practiced within context, that doesn't necessarily mean a traditional school subject.

For young students or perhaps language learners, experiences from their own lives can be used to explore concepts involving critical thinking. Actual or role-played interactions between classmates provide excellent teaching opportunities and practice as they entail or mirror the emotionally-loaded nature of real-world encounters.

For example, a lesson may demonstrate:

• the importance of understanding an issue, claim or statement before agreeing or disagreeing
• the need to distinguish facts from interpretations, opinions or theories
• recognizing contradictions

Thorough explanations for such examples are offered in the Critical Thinking Handbook, a compilation of 35 principles with instructional strategies designed especially for the K-3 classroom. Along with fairmindedness, effective strategies covered include intellectual perseverance, suspending judgement as well as exploring thoughts underlying feelings and feelings underlying thoughts.

Critical thinking isn't necessarily a linear process, nor is there an optimal age to teach it. Research over the past 30 years provides evidence that children as young as 3 engage in many of the same cognitive processes that adults do. They've been shown to recognize conditional probabilities and differentiate the credibility of various sources of information.

In one study, 4-year-old preschoolers demonstrated greater trust toward unfamiliar adult participants with a track record of being correct than known teachers who were purposefully inaccurate in identifying familiar objects.

Along the same lines, there's no upper age limit, so the development of critical thinking need not stop when we finish our schooling. As educators, taking on the challenge to become more agile in our critical thinking — remembering both the cognitive and dispositional aspects — will improve our abilities to plan, teach and administrate.

As importantly, our learners may recognize that we practice what we teach.