I suspect that when most people refer to critical thinking, and the need to improve critical thinking within schools, they are referring to the former definition of critical thinking as a general ability. However, most research on the transfer of skills suggests that the latter definition, critical thinking as a domain-specific ability, is more accurate (1). People’s ability to solve problems and make effective decisions depends on their level of expertise and experience within one area.

Does this mean that we can’t teach critical thinking as a domain general skill? Not necessarily. An excellent article by van Gelder (2005) summarizes some key lessons from cognitive psychology that can help guide instruction on critical thinking (2).

First, van Gelder notes that critical thinking is HARD. It is a higher-order skill that involves the mastery of low-level skills before you even begin to tackle the critical thinking part. For example, reading this blog post requires you to have mastered some basic reading comprehension and vocabulary skills. Before you can begin to think critically about what I am writing, you first need to be able to understand what I am writing.

Second, critical thinking takes practice just like everything else. Instruction on critical thinking needs to done explicitly and deliberately. I would argue further that it should be done in a way that encourages spaced practice and retrieval of those critical thinking skills. It’s unreasonable to expect that students will learn how to think critically just by being exposed to a topic area. If students are expected to critically evaluate an idea or theory, then they need practice and instruction on how to do that.

Third, transfering critical thinking is also hard and needs practice. As I mentioned above, the transfer of these skills is notoriously difficult. Just because we know how to solve problems in one area does not mean we will naturally transfer and apply those skills to another area (See this post on analogical transfer). So once again, instruction needs to be deliberate and explicit. For example, I teach students how to write literature reviews as part of my course on Statistics and Research Methods. This, as it turns out, is not as simple as teaching them how to cite papers and look up appropriate references. The hardest part about this assignment is their ability to write the literature review as a persuasive essay. Their ability to think critically about the literature they are reviewing. Now, I know that every student in classroom has not only gone through twelve years of primary and secondary education, during which time I can assume some exposure to essay writing, but that they have also taken a mandatory freshman writing course at my university. This writing course focuses on writing essays and constructing persuasive arguments. I know that my students know how to do this. I also know that they have no idea how to transfer those skills to my class. So every year I refine the assignment and build in more and more explicit instruction on how to write essays and make explicit references to what they have learned in their writing course. So far it seems to be helping.

Fourth, there is a difference between practice and theory and both are valuable. This point really drives at the distinction between critical thinking as a domain general versus a domain specific skill. Having a practical understanding and working knowledge of an area can help you think more critically about it. On the other hand, having a broader conceptual framework for critical thinking can also help you think critically about it. Van Gelder uses the example of learning about beer. A beer aficionado may have a deeper understanding, a richer vocabulary, and more experience with beer. In other words, they have a theory of beer. This also allows them to perceive more than a naive, inexperienced beer drinker. They may be able to tell you about the particular balance of malt and hops in a particular brew and recommend pairings. Van Gelder argues that the more domain general knowledge about how to form arguments and recognize logical fallacies would enhance this beer aficionado’s ability to think critically about beer and presumably win more bar arguments over appropriate pairings.

Fifth, mapping out arguments can facilitate critical thinking. Van Gelder argues that drawing argument maps can be helpful, particularly with complex ideas. His reasoning here sounds very much like dual coding and concrete examples. Mapping out arguments may help to make a very high-level and abstract concept, like a chain of logical arguments used in critical thinking, easier to follow and understand.