In our last post we provided an analysis of Dewey’s definition of “critical thinking.” Generally, critical thinking is the process by which one defines a problem and then formulates and evaluates possible solutions to that problem. An essential addition that we made to Dewey’s definition is the requirement that students open their minds to other perspectives and experiences when collecting potential solutions so that they can more readily find the most effective solution to the given problem. 

 Critical thinking is an essential skill for all academic disciplines, whether it be the humanities and social sciences, or math and science. Thus, educators in every discipline should be concerned about how exactly they can best develop critical thinking skills within their classrooms. In our first article in the series on critical thinking we worked to define, in a concrete way, what the skill of critical thinking entailed. In this article, I will argue that one of the most effective strategies to encourage critical thinking amongst students (8th through 12th grade) is to help them become familiar with the process of argument mapping. Generally, the reason why argument mapping, as a pedagogical tool, increases critical thinking skills amongst students is that it involves students actively constructing and evaluating prose-style arguments in a visual way. 

First, it would be helpful to outline exactly what argument mapping is. Mapping is the process of creating a visual representation of a logically structured argument. The map visually recreates the structure that is normally hidden within a prose argument. The main claim goes at the top, and boxes containing the premises go underneath, with arrows connecting the boxes to indicate the inferential relationships between claims. 

Consider the following example of a prose style argument: 

It is raining outside: I walked outside my front door this morning and I immediately got soaked by the rain. Every time it rains puddles form everywhere on the ground. Therefore, there must be puddles everywhere outside. 

A simple argument map, which can construct this argument in a visual way may look like the following:

Notice that the argument map looks like an upside down tree. The main claim, “There must be puddles everywhere outside” is positioned at the top of the map. The premises “It is raining outside” and “Every time it rains puddles form everywhere on the ground” work together to provide support for the idea that there must be puddles everywhere. Moreover, the observation that when the author walked outside she got wet, acts as evidence for the claim that it is raining outside. 

Argument maps can also visually enhance a student’s analysis of the argument under consideration. For example, you can change the color of a box to indicate whether you think it is true or false, and lines between boxes can be made thicker or thinner to visually indicate the strength of inferences. Objections to the argument can also be added to the map (usually with a red line, as opposed to green). In this way, a map can not only help students understand an argument as it is written on the page, but to evaluate the quality of the argument and identify any weaknesses in its reasoning.

Charles Twardy conducted a study looking at students’ gains in critical thinking after an intensive, one-semester argument mapping course. According to Twardy’s research, students who underwent argument mapping training showed gains in critical thinking that were almost triple the gains of students who did not receive argument mapping training. Moreover, the gains in critical thinking that students of argument mapping experienced over a single semester surpassed those of students who were not trained after three years of university education. 

Ultimately, Twardy argues that argument mapping improves students’ critical thinking skills because it assists students when they need to evaluate arguments “in the wild” or when they come across them in real life (either verbal or written). Because argument mapping can be applied to any kind of argument, it’s clear that the skills that students gain through such study are flexible and easily applied. Given that argument evaluation is an essential component of critical thinking (see the previous post), as argument mapping improves evaluative skills it also increases critical thinking. 

Furthermore, argument mapping improves critical thinking skills because it reduces cognitive load (the amount of information that one must hold in one’s working memory). As cognitive load is decreased, students are freed up to use higher-order reasoning to evaluate the argument at hand. This gives students the ability to practice employing their critical thinking skills because they need not devote working memory to keeping the whole argument in view at any one moment. There are two distinct ways in which argument maps reduce cognitive load.  

First, while arguments in prose are primarily represented linearly, argument maps are able to organize an argument’s structure both vertically and horizontally. This makes the hierarchy of premises both more obvious and easily analyzed. Prose arguments often struggle to organize their premises in ways that make their relationships clear. Because argument mapping allows students to place premises both next to as well as on top of each other (like a chain), it is easier to represent the flow of the argument and makes more obvious the levels of the argument, in other words, which premises are meant to be supporting which premises. This allows students to better identify logical chains of reasoning or inferential relationships between premises and to notice if there are hidden assumptions or missing premises that would be needed in order to complete the chain. This makes it much less complicated to analyze the overall argument, particularly given that its structure inherently makes argumentative flaws more obvious. 

Consider the following prose-style argument:

Some people claim that we should not let immigrants enter the United States. This is because if immigrants are allowed to enter the U.S. they will take jobs away from U.S. citizens. There are only so many jobs available within the United States and the more people are available to fill the jobs, the steeper the competition for work will be. An objection to the idea that immigrants take jobs from U.S. residents is that there is a demonstrable increase in economic growth that comes with immigration. Thus immigration can actually create jobs for native-born citizens as opposed to taking them away. 

An argument map constructed from this argument may look like the following:

This argument map not only shows the logic of how the author constructed her argument but where the objection (marked with a red inference line) responds to her claims and even makes obvious some essential missing premises. The missing premises are outlined with a dotted line instead of a solid one. 

In all of these ways, argument maps can decrease cognitive load by presenting a large amount of information at a glance, saving students from having to collate and analyze the information like they would have to do if they were reading an argument in prose.  As cognitive load is decreased, students have more of an opportunity to encode the information into their long-term memory and engage in higher-order reasoning, like critical thinking.  

Beyond decreasing cognitive load and increasing critical thinking, argument maps are useful pedagogical tools to use within the classroom for two reasons:

1. Assigning the activity of creating an argument map provides educators and students with multiple opportunities for targeted feedback. As students create the maps, educators gain important information regarding their students’ current level of understanding of the content of the argument and how they are thinking of its logical structure or organization. In this way, educators can then more easily provide feedback to their students that is tailored to correct for a misunderstanding of specific content or a lack of clarity regarding how particular parts of the argument are structured. 
2. Argument mapping activities can stimulate deep and careful classroom discussion. Once students gain a more complete idea of how an argument is structured they are better able to understand both where they disagree and where they agree. Then, in discussion, participation can be more pointed and specific. That is, participants will be better able to understand how their co-deliberators are responding to the argument in question and if there are points of similarity between their positions. In this way, thinking critically about argument structure through the use of mapping can dramatically improve the quality of discussion that students engage in or even their written work.

This is particularly important because participating in better discussions can help students develop empathy for their fellow deliberators, a quality that is important to have when one lives within a cooperative community. In our next post, we will consider why empathy is important and how critical thinking can lead to more empathy. Generally, empathy and critical thinking are interconnected abilities because both require a person to consider viewpoints and experiences outside of their own. Thus, as students practice evaluating possible solutions to problems (critical thinking) including those solutions provided by others, they are working to shift their viewpoints, which is an essential component of developing empathic concern for others.

Referred Resources:

1. Dwyer, Christopher. “Improving Critical Thinking Through Argument Mapping” Psychology Today, Nov. 9, 2018, https://www.psychologytoday.com/us/blog/thoughts-thinking/201811/improving-critical-thinking-through-argument-mapping Date accessed: 5/26/21
2. Harrell, Maralee. “Assessing the Efficacy of Argument Diagramming To Teach Critical Thinking Skills in Introduction to Philosophy” Inquiry: Critical Thinking Across Disciplines, vol. 27, no. 2, Summer 2021, pp. 31-39
3. Rider, Yanna and Neil Thomason. (2008) Cognitive and Pedagogical Benefits of Argument Mapping: L.A.M.P. Guides the Way to Better Thinking.
4. Twardy, Charles. “Argument Maps Improve Critical Thinking” Teaching Philosophy, vol. 27, no. 2, June 2004, pp. 95-116
5. Van Gelder, Tim. (2015) “Using Argument Mapping to Improve Critical Thinking Skills” In: Davies, M., Barnett R. (eds) The Palgrave Handbook of Critical Thinking in Higher Education. Palgrave Macmillan, New York.