How to teach critical thinking

In a 2025 survey of faculty members by the American Association of Colleges and Universities, 90% suspected that generative AI would lower students’ critical-thinking skills.

This concern also comes up in conversations with educators in the GPTZero community. In our own poll, critical thinking was the skill educators most often said was at risk, while the two biggest barriers to teaching it effectively were students wanting quick or definitive answers (35%) and overreliance on search engines or AI tools (31%).

It’s no longer enough for students to hand in confident-sounding assignments: what’s more crucial these days is students being able to explain how they reached their conclusions, so that educators can assess how much students have actually learned. Critical thinking has always been important, but it’s becoming even more so in the age of AI. 

In this guide, we’ll cover what critical thinking actually is, and how to teach it effectively. By the end, you’ll have strategies for knowing how to encourage critical thinking in the classroom, and practical ways to help students recognize what a necessary skill it is.  

TLDR

Critical thinking needs to be taught explicitly, as students benefit from seeing what good reasoning looks like instead of just being instructed to “think critically.” Subject knowledge matters, as students need enough background knowledge to judge evidence and apply reasoning effectively. Questions, reflection, source evaluation, and revision can make students’ thinking more visible, and fundamentally, critical-thinking skills develop through repeated practice across different tasks and contexts.

What Is Critical Thinking?

Critical thinking is fundamentally about actively judging information instead of passively accepting it, and it’s never been more important in the age of AI. It is about examining evidence and coming to a conclusion that you can explain and reconsider, noticing your own assumptions and recognizing other potential other explanations. 

Robert H. Ennis, Emeritus Professor from the University of Illinois, argues that “Critical thinking is reasonable and reflective thinking focused on deciding what to believe or do.” He argues that an ideal critical thinker can be defined by 12 dispositions and 18 abilities. These have evolved over time, but the crucial elements have not changed, and include being able to:

• Identify or formulate a question, along with criteria for judging possible answers
• Analyze arguments, including their structure and conclusions
• Ask and answer questions of clarification and/or challenge
• Judge the credibility of a source, including a lack of conflict of interest and use of established procedures
• Make and judge value judgments, including background facts and alternatives 
• Define terms and judge definitions
• Consider and reason from premises, reasons, assumptions, positions, and other propositions with which they disagree or about which they are in doubt. 

In the classroom, this means that students should ideally be able to explain the evidence they used, identify assumptions, consider alternatives, and show why their conclusion follows. 

What the Research Says About Teaching Critical Thinking

A key takeaway from the research around critical thinking is to make the reasoning task explicit. In other words, if you want students to evaluate an argument, you need to show them what they should examine and how to do it, as asking them to just “think critically” will leave far too much open to interpretation.

For example, in Anat Zohar and Flora Nemet's study, students were taught argumentation explicitly through dilemmas in human genetics. Their arguments improved, and they scored higher on genetics knowledge than a comparison group, and teaching reasoning supported their understanding of the material, too. Even though this is a subject-specific study, it shows how reasoning can be taught. 

Then again, being able to reason well is only one aspect of critical thinking, and psychologist Diane Halpern also talks about the willingness to make the effort, known as disposition. She says, “It is of no value to teach students the skills of critical thinking if they do not use them.”

Domain knowledge is also essential. Professor of Psychology at the University of Virginia Daniel Willingham explains how students need relevant knowledge to apply reasoning strategies, and success in one context doesn't guarantee success elsewhere. For example, they might be able to evaluate a historical source but struggle to assess a scientific experiment..

This is why critical thinking requires repeated practice over time, across lessons and years, with teachers ideally helping students to see when a familiar approach applies. As Willingham declares, “The way the mind works, shallow is what you get first. Deep, critical thinking is hard-won.”

How to Teach Critical Thinking: 12 Strategies

Teaching critical thinking in the classroom comes down to asking open-ended questions, encouraging problem-solving, and having students analyze and justify their reasoning instead of just memorizing facts. 

The strategies below can be worked into existing lessons, and don’t have to be used all at once: choose one or two that fit what you’re teaching. 

Identify what critical thinking looks like in each domain

Willingham recommends starting with specific tasks that demonstrate critical thinking in a subject. In history, for example, that might mean interpreting a document in light of who wrote it, why and for whom.

Make this into a learning goal, where students should be able to explain how a source’s purpose affects what it can tell us. Then model the task and use those same criteria when giving feedback – which makes the expectation a lot more concrete than just asking students to produce a “critical” response.

Use Socratic Questioning

As Stacy E Walker outlines here: “Socratic questioning is defined as a type of questioning that deeply probes or explores the meaning, justification, or logical strength of a claim, position, or line of reasoning.”

When it comes to applying this in the classroom, you might ask a student, after they’ve offered a conclusion: What evidence supports that? What would we need to know before accepting that explanation? What might change your mind?

Make sure to give students time to think, then ask a classmate to summarize the reasoning before adding their own response: this gives you a way to check understanding while keeping the discussion focused on how the conclusion was reached.

Create space in the schedule for metacognitive reflection 

“Create space for students to both reflect on their ideas and discuss the power of doing so,” says educator Nicholas Provenzano, who recommends making time for students to examine their own thinking and assumptions. This is ultimately what metacognitive reflection involves: noticing how you approached a task and whether that approach helped

One way he suggests doing this is with a short written reflection at the end of a lesson, where you ask students to identify an assumption they made, evidence that changed their view and a question they still cannot answer. Use those reflections to decide what needs more explanation in the next lesson.

Include open-ended questions

An open-ended question gives students room to reach different conclusions while still requiring them to explain their reasoning, and Provenzano also recommends journalling before discussion to give students time to arrange their ideas before speaking.

For example, you might ask a class to propose how the school could reduce food waste, but before choosing an approach, go over the following: what information would they need? Who would they consult? How would they judge whether it worked? There could be multiple reasonable proposals, but students still need to show why theirs is workable, and this gives the discussion a purpose beyond collecting opinions.

Model your thinking process

Instead of just giving students the answer to an issue, let students hear you walk through it. When you’re examining a claim, stop to explain to them how you're checking its source or looking for a missing comparison, and make sure to include moments when you're unsure, so they can see how you work through uncertainty.

For example, you might come across an article that mentions research but doesn’t link to it. Show students how you look for the original study before accepting the claim. Talk through what remains uncertain if you cannot find it, or how you would narrow your conclusion if the study supports less than the headline suggests.

Encourage students to challenge their own bias and ideology 

Imperial College’s study guide shares the importance of challenging bias and ideology. It explains that our upbringing and environment can influence how we interpret information, and encourages learners to examine those assumptions.

This can be translated into the classroom by getting students to list which assumptions they may have automatically brought to a topic, what evidence might challenge those assumptions, and how somebody with a different perspective might interpret the same information. This shows them to recognize how assumptions can influence reasoning.

Teach Students to Evaluate Sources

When judging sources, students need to know how to ask who produced the information, what evidence supports it, and what perspective or incentive might shape it.

A repeatable checklist can help with this: Who created this? What evidence do they provide? Can I find the original source? What do other credible sources say? Is there information here that I cannot independently verify?

This becomes particularly important online, where even information that is not based on facts can have a polished and professional-seeming presentation.

Get students to practice lateral thinking

Put two accounts of the same issue side by side. Ask who produced each, what evidence they use, and where they disagree. For unfamiliar websites, teach lateral reading: leave the page and investigate what other sources say about its publisher.

Instead of judging credibility from a single page, students learn to open new tabs, investigate the source, and compare its claims with independent evidence. This mirrors the approach used by professional fact-checkers and gives students a practical routine they can use outside the classroom. 

 Teach students to read while questioning

Cambridge’s free lesson plan, “Self-evaluating Critical Thinking skills for reading”, asks teenage learners to reflect on how they read and evaluate arguments. This can be turned into a regular reading routine, where you get students to identify the author’s main claim, the evidence offered for it and an assumption that needs checking, then have them mark the passage that informed each answer.

This helps learners critically reflect on their critical reading skills, and as the guide says, “These guiding questions can be useful to help learners self-evaluate reading practices and identify where they need to improve their Critical Thinking”.

Make disagreement useful

Ask students to explain a classmate’s argument fairly before responding to it. Then compare the evidence, including where one position is better supported.

Abrami's 2015 review found positive effects from dialogue, authentic problems, and mentoring; simply putting students into groups isn't the whole lesson.

Ideally, you give the discussion a concrete outcome: each student should identify one point they would keep, revise or investigate further, and explain why, giving you something to assess beyond how confidently they spoke.

Look for a counterexample

Invite students to test a broad claim such as “Group work always improves learning.” Can they describe a situation where it might not? Have them revise the claim to make it more precise, explaining which conditions now matter.

The important step is the revision, as students should be able to explain how their counterexample changes the claim, rather than stopping at finding an exception. This video talks about exploring other viewpoints, and how that allows a student to look at alternatives, evaluating their own choices in the meantime and ultimately leading to more informed decisions. 

Ask students to explain their revisions

Build in a draft and revision stage. Where permitted, a grammar checker or an AI tool for writers can offer feedback. 

Ask students to explain which suggestions they accepted, adapted or rejected, and why. Did an edit improve the wording, or change the meaning? What did they check before deciding?

Accepting every edit without reviewing it skips that decision. A short revision note can make the process visible: what changed, why it changed and how the student judged whether it improved their work.

Teaching Critical Thinking in the Age of AI

There are two aspects to teaching critical thinking in the age of AI. The first is taking a broader perspective of emphasizing to students the difference between repeating information, and taking time to actually absorb and create their own arguments, and thinking for themselves. It has never been more important to question the quality of the information we are being told. 

The other is imparting a more specific form of AI literacy. Making sure that students know to evaluate AI content, instead of assuming that whatever chatbots produce is fact. 

One useful classroom exercise is to give students an AI-generated response and ask them to audit it. Which claims can they verify? Which sources can they trace? What information is missing? Where does the response sound certain despite weak evidence? The objective is to turn AI output into material for critical analysis rather than an answer students automatically accept.

Tools can support parts of this process, provided students understand what each one checks: GPTZero's hallucination detector can help flag citations or claims needing closer review, and an online plagiarism checker looks for matches with existing text.

Encourage independent thinking: students need to understand what each tool checks, alongside how to avoid plagiarism by keeping accurate notes and crediting sources. GPTZero's AI detector extension also has a Writing Replay and a Writing Report for reviewing how Google Docs developed. 

Teach students that an AI detector provides a signal about possible AI-generated writing, not proof of misconduct. Our guide for students falsely accused of AI cheating explains why that wider context matters.

FAQs

How do you develop critical thinking skills in students?

There are multiple skills associated with critical thinking, but choose one specific skill, model it, and give students repeated practice. Ask students to explain their decisions and apply what they've learned to another example, with enough background knowledge to do so.

How can you assess critical thinking?

This starts with looking at how students select evidence, justify the connections, evaluate alternatives, and back up their own conclusions. Compare their work over time to see how their ability to reason evolves.

Does using AI stop students from thinking critically?

It depends on how they use AI, and AI literacy is in fact part of developing critical thinking in the 21st century. Make sure to include assignment tasks that need to be completed independently of AI. 

What are examples of critical thinking activities?

Source comparisons, Socratic questioning, counterexample exercises, argument mapping, lateral reading, reflective journals, and revision notes can all make students practice critical thinking. In short, the strongest activities require students to explain why they reached a conclusion rather than simply choosing an answer.

Why does critical thinking matter these days? 

AI makes it easier to generate plausible-sounding information quickly, which makes evaluating information more important rather than less. Students need to be able to check claims, investigate sources, identify weak evidence, and decide whether an AI-generated response deserves to be trusted.