In our pocket, on the computer screen, on the TV in the living room or in the conversation in the lift: words, data and opinions flow all the time. Never in the history of mankind has it been so easy to access information… nor so difficult to know what to trust. Between alarmist headlines, social media threads and viral WhatsApp audios, the 21st century citizen lives in an incessant stream where truths are mixed with half-truths, biased interpretations or outright fabrications.
The problem is that an overabundance of information does not automatically translate into knowledge. On the contrary: it hinders it. We know that, faced with a surfeit of contradictory messages, people tend to cling to what confirms their previous beliefs, regardless of the strength of the evidence. This phenomenon, which psychologists call confirmation bias, is the perfect fuel for misinformation.
In this context, critical thinking is one of the most important competences, on the same level, of course, as empathy or mindfulness. And at the same level as mathematics or reading and writing. The IDB defines it as the ability to objectively assess the quality of information, identify one’s own and others’ assumptions and consider alternative perspectives before reaching a conclusion. Most importantly, research shows that it can be taught, measured and reinforced, with tangible benefits in academic achievement and civic participation.
If in previous articles in this series we have explored how mindfulness helps us to slow down and think or how self-control and empathy allow us to act with restraint and humanity, in this post we address the skill that gives meaning to this process: learning to think well before deciding.
What is it and why is it important
How to distinguish between a fact and an opinion when both are “dressed” with the same words and figures? And what is the point of having access to all the information if we cannot separate the ruth from the lie? In its review A Review of Life Skills and Their Measurability, Malleability, and Meaningfulness, the Inter-American Development Bank (IDB) defines critical thinking as the ability to “evaluate and infer from information, whether it comes from observation, experience, reflection or reasoning, or from external sources”, with particular emphasis on analysing the credibility of those sources and questioning one’s own and others’ assumptions.
It is not a matter of criticising for the sake of criticising, nor of adopting an absolute scepticism towards everything. It is about applying a methodical process to distinguish the true from the false, the relevant from the ancillary, and the proven from the merely speculative. It is the difference between replicating a claim because it “sounds logical” or checking it against data, verifying the source and analysing whether it fits with the available body of evidence.
The IDB groups its key skills into three broad domains: relational, self-management and intellectual. Critical thinking belongs to the latter, along with competences such as problem solving. And, of course, it meets the three criteria that, according to the IDB study, determine whether a skill deserves to be prioritised in education:
- Measurable: there are reliable tools adapted to young people, such as the Cornell Critical Thinking Test Level X, available in Spanish, which assesses induction, deduction, source credibility and identification of hidden assumptions.
- Malleable: A meta-analysis of 117 studies, cited by the IDB, shows that programmes designed to strengthen critical thinking achieve significant improvements (one third of a standard deviation), especially if they combine general instruction with practical application in subjects.
- Significant: although longitudinal studies for adolescents are lacking, according to the IDB study, in adults it has been linked to better academic outcomes, job performance and complex problem-solving skills.
On the IDB scale, critical thinking scores an aggregate score of 15 out of 22, a high result, thanks to its development potential and the availability of validated measurement instruments.
The importance of this skill is not theoretical: it affects (very much) our daily lives. A critically thinking citizen is less vulnerable to falling for hoaxes, more capable of interpreting an election poll, assessing the implications of public policy or making informed health decisions. Disinformation does not succeed because it is credible, but because we do not know how to think better.
Critical thinking is not born: it is made
One of the most important findings of the Inter-American Development Bank review is that critical thinking is neither a fixed trait nor an innate talent reserved for a few people. It is a skill that can be developed through deliberate practice, and the data supports this.
The meta-analysis mentioned in the previous section revealed that programmes designed to strengthen critical thinking produce improvements equivalent to one third of a standard deviation. This means that participants not only learn more than the control group, but also maintain some of those gains over time. The effects are particularly noticeable when teaching combines explicit instruction on what critical thinking is with opportunities to apply it in real-life contexts, such as a science subject, a debate or a case study.
Factors that make the difference
- The evidence points to several common ingredients in the most effective programmes:
- Specific teacher training: Teachers who receive advanced training in teaching critical thinking make greater improvements in their students.
- Cross-cutting application: it is not limited to one subject; it is integrated into different subjects so that the student practices the analysis and evaluation of arguments in multiple contexts.
- Ongoing assessment: using instruments such as the aforementioned Cornell Critical Thinking Test Level X allows you to adjust your teaching and measure progress.
- Active learning: discussions, collaborative projects, media analysis and open problem solving promote the transfer of skills to real situations.
An inspiring example: Biology Critical Thinking Project
In this programme, developed in Israel, trainers reviewed the biology syllabus looking for points where they could introduce critical skills: recognising logical fallacies, distinguishing between findings and conclusions, identifying implicit assumptions, isolating variables or testing hypotheses. Although it did not include general pre-training, the participating students obtained differences of up to two standard deviations from the control group.
Real-life impact and current urgency
Critical thinking is not just an academic skill; it is a practical resource that influences the quality of our decisions and, by extension, our lives. The scientific literature (although more abundant in the adult population than in adolescents) has documented its relationship with better academic performance, greater employability and the ability to solve complex problems. In work environments, it is associated with more consistent performance, as practitioners tend to assess risks, detect inconsistencies and propose better- informed solutions.
At the personal level, this competence reduces vulnerability to misinformation. Think of the flood of messages received during a health crisis: contradictory recommendations, misinterpreted preliminary studies or hoaxes designed to generate alarm. A critically thinking citizen not only consults more than one source, but assesses its credibility and the quality of the evidence before acting.
This filter can make the difference between making the right health decision or falling into potentially dangerous practices. The absence of critical thinking also has a collective cost. In a saturated media ecosystem, polarising narratives thrive when audiences do not question assumptions or recognise biases. This erodes social trust and hinders basic consensus to address common problems, from climate change to public security.
The pressing need to reinforce this skill is growing in parallel with the technological challenges. Generative artificial intelligence, deepfakes and digital manipulation techniques facilitate the creation of increasingly plausible fake content. According to recent warnings from international bodies, traditional verification capabilities are becoming insufficient. In this context, critical thinking becomes a first line of defence.
It also integrates naturally with other skills already covered in this series. Mindfulness helps to slow down before reacting, self-control avoids impulsive responses and empathy allows other perspectives to be considered. Critical thinking acts as a catalyst for all of these, ensuring that the final decision is not
only rational, but also informed and ethical. It is therefore no exaggeration to say that, in today’s society, critical thinking is as vital as being able to read or write. And, as the IDB warns, its systematic teaching should be an educational and social priority.
An investment in the future
Critical thinking is much more than a school skill: it is, above all, an advocacy. A defence against unsubstantiated opinions, misrepresented facts and lies. Evidence from the Inter-American Development Bank confirms that it can be measured, that it can be taught and that it has a real impact on academic performance, employability and civic participation. We don’t need more data, we need more judgement.
That is why we must make it a priority in the education of our students. Because without critical thinking, reading, listening or watching ceases to be an act of comprehension and becomes mere consumption. And a citizen who only consumes information, without digesting it, does not decide: he obeys.
