Critical Thinking

Diane F Halpern & Patrick Williams. 21st Century Psychology: A Reference Handbook. Editor: Stephen F Davis & William Buskist. Volume 1. Thousand Oaks, CA: Sage Publications, 2008.

The National Center on Education and the Economy (2007) issued a report in which they envisioned the needs of the future workforce. They provide an educated prediction about how we will work and, as a consequence, how we will live during the next several decades. If you are embarking on your career or just planning on being alive for several more decades, it is important reading. The report, titled “Tough Choices or Tough Times,” depicts the prototypical industry in the next 10 years (if all goes well!) as resting on a base of routine work that is done by both people and machines, topped with creative work where critical thinking skills are essential. Some examples of high-level work, located at the peak of the pyramid-shaped depiction of the world of work, are research, development, design, marketing and sales, and global supply chain management. This list of high-level jobs that require critical thinking brings to mind a key question that was posed by Earl Hunt, a cognitive psychologist at the University of Washington. In his book on the future of the U.S. workforce, Hunt (1995) asked, quite simply, “Will We Be Smart Enough?” The answer to that question has significant repercussions for our society and for young people preparing for their future at a time in history when the ability to engage in high-level thinking skills will determine the quality of your work life, your income level, and the role you will play in the rapidly developing and technologically savvy world.

The good news is that creative and critical thinking skills can be taught and learned. All we need to do now in order to remain competitive (and we add cooperative) as a nation is persuade those people with the power to set curricular agendas and national imperatives to invest time, money, and energy into making critical-thinking instruction a national priority. Instruction in critical thinking can begin in elementary school and continue through graduate and professional education, with age-appropriate learning objectives and examples. The research literature on high-order learning has made it clear that both high- and low-achieving students benefit from explicit training and repeated practice in critical thinking. There are ample data to support our claim that critical-thinking skills can be learned and transferred to novel situations when students receive explicit instruction designed to foster transfer (Bangert-Drowns & Bankert, 1990; Halpern, 2003).

Instruction in critical thinking is for everybody. No society can prepare its workforce for the future if there is an underlying belief that the work that requires critical thought should be reserved for the educated elite. In our increasingly complex and technological world, critical-thinking skills are needed by a growing portion of the population. Manual labor is increasingly done by machines, and repetitious and unskilled jobs offer little or no opportunity for personal or financial growth. According to Browne and Keeley (2004), the rapid acceleration of the complexity of the world drives the need for more and better education in critical thinking and other high-level skills such as oral communication, writing, and technology. But what exactly is critical thinking, and how does one learn to think critically?

Defining Critical Thinking

Jones and colleagues (1995) surveyed 500 policy makers, employers, and educators and found a consensus for the meaning of critical thinking. It is a broad term described as reasoning in an open-ended manner that includes an unlimited number of solutions. It also involves constructing a reasoned argument with evidence and reasoning that supports the conclusion. Critical thinking should be self-directed and “fair-minded,” with clarity about the nature of a problem, the way generalizations are made, the way evidence is presented, and how conclusions are drawn.

Halpern (2003) proposed one of the most comprehensive definitions of critical thinking. She defined critical thinking as the appropriate use of cognitive skills that increase the probability of a desirable outcome. This definition includes the idea that critical thinking is not just “fair” or “reflective”; it also includes thinking in ways that are related to better outcomes. Halpern’s definition also entails the idea that critical thinking is purposeful, reasoned, and goal-directed. In other words, when people are engaged in critical thinking they are attempting to move toward a desired goal or outcome. It is the sort of thinking that is used when solving problems, formulating inferences, calculating likelihoods, and making decisions. Critical thinking also involves the conscious evaluation of thought processes used to achieve a desired goal (e.g., make a decision) as well as the outcome of those processes (e.g., how good the decision was or how well the problem was solved).

The act of evaluating one’s own thought processes is known as metacognition. More colloquially, metacognition is thinking about one’s own thinking. Costa (2001) offered a simple example to illustrate the usual findings that too often most people do not reflect on the “how” of their own thinking. He asked a large group of people “How much is one half of two plus two?” Quickly—what is your answer? How did you think about this question? Did you mentally take half of two and then add it to two, or did you sum two plus two and then take half? It is likely that you did not think about the way in which you solved this problem or even realized that alternative solution strategies would produce different answers. Costa’s point is that many people fail to think about the solution strategies they use and instead apply a ready-known strategy that is easily accessible in memory.

With proper training in critical thinking, people can understand better the multiple challenges of their environment and society at large. Some skills involved in critical thinking include, for example, evaluating the cause of an event or events; giving reasons that support a conclusion; recognizing and criticizing assumptions that are either implicit or explicit in an argument; and developing an orderly plan for comprehension of a complex topic such as prioritizing the order in which “pieces” of evidence or arguments are examined and rated for quality.

The use of analogy in problem solving is an example of a critical-thinking skill that often provides novel or creative responses. A concrete analogy can make an abstract concept easier to comprehend and remember. Halpern’s definition allows for creative and critical thinking to exist under the same rubric because creativity is conceptualized as a novel response that increases the probability of a desirable outcome. Thus, creative thinking is one type of critical thinking. Its sole distinction from other types of critical thinking is that the response is novel. In addition to creative thinking, a critical thinker should also understand basic research principles and be able to present a coherent and persuasive argument about a controversial topic. It is not a coincidence that these outcomes are the same outcomes that many colleges and universities list as desired outcomes for their graduates.

Assumptions for Critical-Thinking Instruction

The idea that critical-thinking skills can be taught is predicated on two assumptions: (a) Thinking skills are clearly definable and identifiable and can be taught and applied appropriately, and (b) students will be more effective thinkers if thinking skills are recognized and applied. It is clear that students can learn critical-thinking skills from both explicit classes on critical thinking as well as from critical-thinking skills instruction that is embedded within the curriculum of a class. The advantage of embedding critical thinking into course work is that this instructional approach does not require additional courses in an already over packed curriculum.

The disadvantage of this approach is that it is heavily reliant on the instructor in content-area classes (e.g., literature, history, psychology) to provide instruction in critical thinking in addition to “covering” the basic content of the course. Most instructors do not have the necessary background knowledge to teach broad critical-thinking skills in ways that would transfer across academic disciplines. As experts in a content area, teachers tend to focus instruction on the topic they are expected to teach. In fact, it would be difficult to argue that an emphasis on a teacher’s content area of expertise is not appropriate, given that is the way our curriculum is arranged. The problem with relying on imbedded instruction for critical-thinking skills is that the skills may never be taught and even those teachers who use critical thinking for understanding their content matter may not provide the necessary instruction in how to think critically.

When students learn critical-thinking skills within a specific discipline, those skills are less likely to transfer to other academic disciplines, or more important, to the real world. Sternberg (1997) recommended that to increase the chances of transferring critical-thinking skills from the classroom to everyday situations, instructors should use real-life issues when teaching problem-solving skills. Halpern advocated for critical-thinking instruction that uses multiple examples from different disciplines, so that students learn to focus on the critical-thinking skill that is being taught and so that they learn when it is appropriate to use that skill in many different contexts. Along similar lines, Staib (2003) suggested the use of real-life role-play, case studies, discussion, and student-instructor interaction as effective tools in critical-thinking instruction.

Although some elementary and high school teachers are familiar with critical thinking as its own content area and will teach critical thinking along with their usual course topics, it is most often the case that formal education in critical thinking does not begin until postsecondary education. A critical-thinking course is often included in undergraduate education, with opportunities to practice those skills in courses throughout the curriculum. If critical-thinking instruction occurs only at the college level, then many students, particularly those from poor or disadvantaged populations with low college-going rates, will not have the opportunity to learn the important critical-thinking skills they will need for their future employment and for managing the complexities of everyday life, such as determining which phone plan is best for a particular person or how to decide about the myriad complex issues that face them as voters. The inclusion of critical-thinking instruction is most urgent in high schools, surpassing the need in both middle and elementary schools. What high school students generally lack upon graduation, diploma or not, are the tools to deal with higher education and the real world. Thus, we are advocating for courses designed to teach critical-thinking skills in ways that facilitate transfer in all high schools and colleges.

Theoretical Perspectives

There are some naysayers who contend that the emphasis on critical-thinking instruction is just another educational fad that will go away if they wait long enough. It is likely to be a very long wait. The new fad of critical thinking can be traced back to the famous American educator, John Dewey. Dewey’s writing has been influential since the very early 1900s and continues to be so today. He advocated for a progressive education in the instruction of both skeptical and reflective inquiry. Reflection, skepticism, and inquiry are important components of what is now referred to as critical thinking. When students are taught how to solve problems, they learn that they must consider multiple types of evidence to understand the problem, which includes context, alternative assumptions, reasons, explanations, motives, and costs and benefits for alternative solutions. They must be able to tolerate ambiguity while they are working to reduce uncertainty (for example, gathering additional information). These basic ideas may be found in Dewey’s many books on learning (one such book, Democracy and Education, published in 1916, is available free online at He thought of schools as a sort of repair organ for society. Through what is now called critical thinking, schools can refocus on ways to provide students with necessary thinking skills so that they can live up to Dewey’s legacy and ultimately correct modern societal ailments. In this way, progressive education can lead to a society that can improve itself.

Halpern (1998) proposed a four-part model for teaching thinking skills so they will transfer across domains of knowledge. The component parts include (a) a dispositional or attitudinal component, (b) instruction in and practice with critical-thinking skills, (c) structure-training activities designed to facilitate transfer across contexts, and (d) a metacognitive component used to direct and assess thinking. Each of these components is grounded in theory and research in cognitive psychology.

The dispositional or attitudinal component of critical thinking is distinct from any of the performance or contemplative components. Some people have excellent critical-thinking skills and may recognize when the skills are needed, but they also may choose not to engage in the effortful process of using them. This situation exemplifies the distinction between what people can do and what they actually do in real-world contexts. People with dispositions that are not congruent with doing the difficult work of critical thinking appear content with giving “cursory” thought to complex issues. Such people are often sanguine when decisions have poor outcomes, resolving their low level of effort in the decision-making process and the poor outcome it produced by assuming that the additional effort of thinking critically would not have helped or that there is little they can do to increase the probability of desirable outcome. For example, consider a student who has to decide where to live. Instead of putting in the hard work of gathering information about alternatives and evaluating them, she picks an apartment that is too expensive, too far from transportation, or unsafe. When any of these problems becomes apparent (after moving in), she might justify the failure to use critical-thinking skills in her decision-making process by stating that she had few choices (but she never checked out other apartments) or that it is just impossible to live on the money she has (when she never considered less expensive living arrangements).

Instruction and practice in critical thinking are essential because learners need to know what critical thinking skills are available, how to use them, and to how to select the right skill for any given situation. For example, when listening to a political candidate speak about all of the great accomplishments that will follow from her election, it is not an automatic response to think about the cost of what has been promised, what won’t happen if we are paying for one desirable program and not funding others, or how the promised achievements will be accomplished. With practice in a variety of domains—the sciences, humanities, social sciences, and the popular media, for example—critical thinkers learn to recognize which critical thinking skills are appropriate for the situation.

The third part of Halpern’s (1998) four-part model focuses on structure training. Linguists talk about surface and deep structure when describing language. Deep structure is the meaning part of language; surface structure refers to the words used to convey the meaning. This distinction is useful in thinking about structure-training in critical thinking. Suppose that a student learns about the need to consider base rates when making judgments. If this critical-thinking skill is taught so that the learner understands that there is a need to think about base rates when making a judgment about a sample taken from a population with known characteristics, then he should be able to use this skill with a diverse array of topics that have this underlying structure, such as thinking about the number of people in a sample who are likely to be aggressive or likely to be Democrats (or both aggressive and Democrats) or the likelihood that your neighbor’s dog has fleas or rabies (or both). He will be able to see beyond the surface or topical level of the issue being considered to discern the structural similarities in these examples and consider ways that the sample might not be representative of the population from which it was drawn.

The fourth component in Halpern’s (1998) model is metacognition. In the example just provided, in which a learner sees that the need to think about base rates cuts across contexts as diverse as aggressive people and dogs with fleas, he will consciously consider how to make those judgments, and after considering base rates, he will consider if the answer is likely to be correct. Critical thinkers will also consider whether there are other skills that might be useful (e.g., is there anything in the context or the sample that might alter his decision to use base rates). Conscious reflections on the process that went into deciding on an answer and the quality of the answer are necessary components of being a critical thinker.

Sternberg (1997) offered a tripartite theory of successful thinking. His three broad groupings of thinking skills include analytical thinking skills, creative thinking skills, and practical thinking skills. According to Sternberg, students generally have a preference for one type of thinking skill over the other two, and there is evidence to show that when students are taught predominantly with the method that matches their preferred thinking skill, learning is increased. Sternberg recognized the problem with advocating that students be taught in three different ways, so ideally, these three thinking skills should work together to form what he calls “successful intelligence.” Analytical thinking skills are most valued in the school settings, the most heavily weighted on traditional standardized tests, and include analyzing, critiquing, judging, evaluating, comparing, contrasting, and assessing. Creative thinking skills include creating, discovering, inventing, imagining, supposing, and hypothesizing. Last, practical thinking skills include applying, using, and practicing the other thinking skills. Creative and practical skills are, for the most part, independent of the kind of skills that are assessed in traditional measures of intelligence.

In thinking critically, students should be able to evaluate what their preferred thinking skills are through metacognition. Metacognition is the ability to engage in self-correction through reflection upon thoughts and thought processes. Metacognition can be thought of as the executive “boss” function that acts as a guide to how someone uses different strategies and makes decisions on how best to allocate limited cognitive resources according to task demands. More simply, metacognition is the personal knowledge and understanding of one’s cognitive processes. Given this definition, a metacognitive understanding of their intellectual strengths and weaknesses should allow people to modify and strengthen weaknesses in their thinking while utilizing their own particularly strong thinking skills. In this way, a critical thinker can learn from mistakes because he or she is able to identify mistakes, which makes improvement more likely to occur.

Kruger and Dunning (1999) provided a good example of the power of metacognition. They showed that people who scored very low in ability within a particular content area (participants scored in the 12th percentile) judged themselves to be significantly higher (in the 62nd percentile). This research provides evidence that when people have little knowledge of a content area, they tend to consider themselves much more knowledgeable than they are. The implications of these findings are that some people will never learn from their mistakes because they simply cannot recognize the mistakes that they make. The inability to see one’s own errors is a clear barrier to improvement. Knowledge of competence in a given area, through metacognition, then leads to improvement of skill in that area.

Methods of Assessing Critical Thinking

A strong body of evidence exists to support the conclusion that specific instruction in critical-thinking skills will enhance critical thinking when the instruction includes a wide range of contexts. If critical thinking is taught for just a few select contexts, it is less likely that those skills will be learned at a deep level that will generalize to novel real-life situations. In creating a critical-thinking assessment that can determine if critical-thinking skills transfer to everyday situations, Halpern (2001) created an online assessment of critical thinking in which problems are posed in the context of everyday situations ( The Halpern critical-thinking assessment covers five broad categories of critical-thinking skills: verbal reasoning, argument analysis, hypothesis testing, likelihood and probability, and decision making and problem solving. It is a unique assessment in that each question begins with a common, everyday scenario. The first part of each question requires a constructed (written) response to a question about the scenario. The constructed response is followed by a similar question that is presented with a multiple-choice or multiple-rating format. The distinction between these two response types is based on the cognitive distinction between generating a response and recognizing a correct response. Everyone is more likely to respond correctly to any question when alternative answers are presented in a multiple-choice format than when the participant is required to construct a response without the benefit of seeing possible alternative answers. With two types of response formats, the test requires both the spontaneous application of critical thinking skills through constructed responses and the recognition of appropriate answers through a multiple-choice response format.

The Halpern critical-thinking assessment is ecologically valid, meaning that the scenarios are representative of examples found in newspapers and everyday discussions. The following is an example question from the online assessment that requires the construction of an appropriate response:

A recent report in a magazine for parents showed that adolescents who smoke cigarettes also tend to get low grades in school. As the number of cigarettes smoked each day increased, GPA decreased. One suggestion made in this report was that we could improve school achievement by preventing adolescents from smoking.

—Based on this information, would you support this idea as a way of improving the school achievement of adolescents who smoke?

—Type “yes” or “no” and explain why or why not.

After writing a response, the same question could be posed followed by a selection of responses of varying degrees of suitability. These responses could either be ranked by how appropriate they are or the one best choice could be chosen.

Nisbett (1993) and his coauthors compiled a book of readings in which each chapter is a different study of success in teaching and learning critical-thinking skills. In one of the studies he described, researchers phoned the homes of students after these students had completed a course that taught about regression to the mean—a difficult concept for many people to learn. The investigators phoned the students under the guise of conducting a survey. They posed questions that required students to apply their recently learned knowledge about regression to the mean to a novel example while they were in their home environment. The researchers found that the students spontaneously applied the critical-thinking principles they had learned in class. This finding is particularly significant because school-related cues about the appropriate responses were absent. In addition to this study, Nisbett’s edited book includes 16 chapters showing that rules of logic, statistics, causal deduction, and cost-benefit analysis can be taught in ways that will generalize to a variety of settings. He also found that logical and statistical errors, two common errors of inference, could be substantially reduced with only very brief training. Other independent reviewers came to a similar conclusion about the effects of courses designed to promote critical thinking. These examples demonstrate that it is not always difficult to help adults think more critically in ways that have long-lasting and cross-contextual effects.

Several studies of high schools found that most do not properly train students to deal with the real-world demands of work and higher education. Thus, an increased emphasis on critical-thinking instruction is important if American schools are to prepare their students for the rapidly changing world in which they will spend their adult life. For example, a 2005 report by the National Governor’s Association found that of 10,000 high school students, over one third rated their critical-thinking skills as fair-to-poor. Although almost everyone agreed that critical-thinking instruction is important at all educational levels, 83 percent of respondents to a national survey expressed that the need for reform is greatest at the high school level.

Moseley, Baumfield, and Elliott (2006) reviewed the vast literature on critical-thinking instruction and found that although most educators agree about the importance of critical-thinking instruction, they do not agree on the best method to teach it. Both explicit training of critical-thinking skills and critical-thinking skills training that is imbedded into already existing curriculum have been shown to lead to increases in critical thinking. However, there is robust evidence that explicit instruction of critical-thinking skills is the preferred method for high school students.

Current research by Marin-Burkhart and Halpern (unpublished) supports the hypothesis that explicit instruction in thinking strategies is more effective than imbedded instructions in that explicit instruction is more likely to lead to transfer of critical-thinking skills to challenges faced in everyday situations. They found significant gains from only a few weeks of instruction, so courses need not be lengthy as long as instruction is taught for transfer and there are opportunities to practice what is learned in their regular classes. They found that students can learn critical-thinking skills in a class designed as an afterschool program or during the day without seriously disrupting normal curricular operations. In a meta-analysis of explicit critical thinking skills, Bangert-Drowns and Bankert (1990) found that an intensive, practical skills orientation was most effective in generalizing skills to everyday situations.


Regarding the applications of critical thinking outside of the classroom, Moseley et al.’s (2006) review of 23 highly relevant studies whittled down from 6,500 chapters, articles, and papers found no negative effects of critical-thinking instruction on a range of noncurriculum measures. When students make the effort not only to learn critical-thinking skills but also to adopt a critical-thinking frame of mind, they learn to apply critical thinking to many everyday situations. A frame of mind for critical thinking requires a concern for accuracy and persistence, as opposed to what is familiar and comfortable. Often the hardest part of being a critical thinker is staying open to new ideas and suppressing immediate and easy responses.


Critical-thinking instruction is sometimes likened to courses that aim to increase intelligence because it seems logical to many people that if one becomes a better critical thinker, then intelligence must also increase. Much like intelligence, there has been disagreement as to whether critical thinking can be taught or improved throughout life, but unlike intelligence, few people believe that the ability to think critically is an inborn or innate skill that is relatively immune to educational practices or environmental effects. Fortunately, critical thinking does not carry all of the negative baggage associated with the concept of intelligence, thus, although they are similar concepts, there are also important differences in how people think about these related constructs.

Clearly, critical-thinking instruction should include a metacognitive function. Learning about learning and memory has a beneficial effect on all cognitive processes. If an instructor, for example, models his or her own thinking by thinking aloud or through other symbolic systems, a student can do the same until such habits become conscious, automatic, and most important, available for improvement.

Future Directions

Critical-thinking skills are increasingly included with traditional skills such as mathematics, writing, and oral communication as fundamental goals of education. It is interesting to note that very few people ever ask if writing skills transfer beyond writing courses or if mathematical skills transfer beyond mathematics courses, yet this question is often raised about critical-thinking courses, and we expect that much future research will examine the questions of how to make transfer more likely and how to assess critical thinking in natural contexts. Nothing in learning theory suggests that critical-thinking skills could not be learned or that they would not transfer, but these seem to be persisting questions in the literature. There is also little debate about the value of improving critical thinking. In the real world beyond the classroom, a lack of critical-thinking skills leaves one vulnerable and disempowered. To access resources in education and job training, the ability to think critically will only become increasingly important. Traditionally, kindergarten through twelfth grade curriculum has focused on pure didacticism, or memorization of content information. Too often, memorization is also stressed in typical standards-based assessments. To prepare future generations for an increasingly uncertain world, more focus must be shifted away from didacticism and toward more active participation by students in the learning process.

Although educators (almost) universally accept critical-thinking skills as an essential and central element of effective instruction, the task of fostering critical thinking is a daunting one. Educational standards at the state and national level describe critical thinking as integral to the learning process, yet it is largely recall for which students are tested on standards-based assessments. To foster greater critical thinking in the future, resources should be better allocated on teacher training to facilitate learning and applying and assessing critical thinking instead of primarily on student testing and on teacher assessment. A new approach would recognize the need for accountability and the important role of assessment while simultaneously recognizing the need to engage students in the learning process.

In traditional classrooms, students are treated as passive receptacles in which an instructor places knowledge for later recall. Contemporary research in cognitive psychology recognizes that learning is a constructive process whereby information is transmitted in pieces from an instructor to students; students must actively construct concepts, with the instructor acting as a cognitive guide. Constructivism has been influential in recent curriculum design to foster critical thinking. This theory of learning takes aim at educational tradition that treats learning as a one-way hierarchy, starting with content knowledge, moving through comprehension and application, and only in the end encompassing critical-thinking skills such as analysis, synthesis, and evaluation. As education continues to be reformed using knowledge about the way the mind works and curricular content continues to shift toward the goal of enhancing critical thinking, instruction in critical thinking will be regarded as an essential element of a whole education to prepare students for the problems faced in everyday situations.


In fields as diverse as ecology and political science, agriculture and warfare, biology and human development, our future as a country and the future of our planet depend on an educated populace who can think critically about issues of local and global concern. There is a large body of evidence showing that critical thinking can be taught and learned in ways that transfer across settings and time. Although there are multiple ways to help students improve their critical-thinking abilities, there is strong support for direct and conscious instruction in critical-thinking skills, using a wide variety of examples and helping learners think about the thinking process. The need for critical-thinking instruction at all levels of education is a fundamental concern because only a critically thinking workforce and citizenry can successfully tackle the problems of contemporary life.