By Marc Chao, adapted from Michael Ireland

Critical thinking is the disciplined process of actively and skilfully conceptualising, applying, analysing, synthesising, and evaluating information gathered from observation, experience, reflection, reasoning, or communication. It is a cornerstone of psychological inquiry and practice, enabling us to navigate the complexities of human behaviour and mental processes with clarity and precision.

At its core, critical thinking involves questioning assumptions, evaluating evidence, and considering alternative perspectives. This process is not merely an academic exercise but a vital skill that empowers individuals to make informed decisions, solve problems effectively, and understand the world more deeply.

One of the most challenging aspects of critical thinking is overcoming our inherent biases. Bias refers to a systematic deviation from rationality in judgement or decision-making. It occurs when individuals’ perceptions and interpretations are influenced by their pre-existing beliefs, preferences, or experiences, leading to skewed or partial viewpoints. In psychology, biases can manifest in various forms, such as cognitive biases, which affect how we process information, and affective biases, which are influenced by our emotions. Recognising and mitigating biases is crucial for critical thinking, as it allows for more objective and balanced analysis of information.

Humans are naturally inclined to accept information that aligns with their pre-existing beliefs and to reject information that contradicts them. This cognitive bias, known as confirmation bias, can significantly hinder our ability to think critically. When we encounter information that supports our beliefs, we tend to accept it without much scrutiny. Conversely, when we face information that challenges our beliefs, we often become defensive and dismissive.

This defensiveness is a natural human response, often rooted in our desire to protect our sense of identity and coherence. Our beliefs are not just abstract ideas; they are integral to how we understand ourselves and the world around us. When these beliefs are questioned, it can feel like a personal attack, triggering an emotional reaction. Emotions like anger, frustration, and fear can take over, making it difficult to engage with the new information objectively. Instead of considering the evidence on its merits, we might focus on discrediting the source or finding flaws in the argument. This emotional reaction can create a barrier to understanding, preventing us from seeing the potential value in the information being presented.

For example, consider a person who strongly believes in a particular political ideology. When presented with evidence that supports their views, they are likely to accept it readily. However, when confronted with evidence that contradicts their beliefs, they may question the credibility of the source or the validity of the data. This defensiveness is a natural response, rooted in our desire to maintain a consistent and coherent worldview.

Moreover, when we are defensive, we are more likely to shut out information that might be useful. This is particularly problematic in an age where misinformation and disinformation are rampant, because defensiveness does not just filter out poor-quality information. Instead, it can lead us to dismiss high-quality evidence simply because it challenges our existing beliefs. At a time when reliable information can be harder to identify, overlooking such evidence is especially harmful to our understanding and decision-making. Misinformation refers to false or inaccurate information shared without the intent to deceive, while disinformation is deliberately false information spread with the intent to mislead. By dismissing information that contradicts our beliefs, we may miss out on important insights and opportunities for growth. This tendency to reject challenging information can reinforce our existing biases and limit our ability to learn and adapt.

Psychologist Daniel Kahneman offers a helpful framework to understand why these biases are so pervasive. In his book Thinking, Fast and Slow, he describes two modes of thinking: System 1 and System 2. System 1 is fast, intuitive, and automatic. It enables quick judgements but is also prone to errors and biases. System 2 is slow, deliberate, and analytical, requiring effort to engage. Most of our daily thinking relies on System 1, which is efficient but often irrational. Critical thinking requires us to consciously override our automatic System 1 responses and activate System 2, enabling us to evaluate evidence more carefully and make more reasoned decisions.

Therefore, critical thinking requires us to recognise these biases and actively work to mitigate their influence. It involves being open to new information, even when it is uncomfortable or challenging. This openness is not about abandoning our beliefs but about being willing to re-evaluate them in light of new evidence. It is about fostering a mindset of curiosity and scepticism, where we are constantly questioning and refining our understanding of the world.

Moreover, critical thinking is not a solitary endeavour. It thrives in environments where diverse perspectives are valued and where dialogue and debate are encouraged. Engaging with others who hold different viewpoints can help us to see our own biases more clearly and to develop a more nuanced understanding of complex issues. In this way, critical thinking is both a personal and a collective practice, essential for the advancement of knowledge and the betterment of society.

In the field of psychology, critical thinking is particularly crucial. Psychologists must navigate a vast array of theories, research findings, and clinical practices, each with its own set of assumptions and evidence. By applying critical thinking, psychologists can discern which theories and practices are most supported by evidence, which are most effective in different contexts, and how best to integrate new findings into their work.

As we delve deeper into the principles and practices of critical thinking in psychology, we will explore various strategies and tools that can help us to think more critically. From understanding logical fallacies to developing better questioning techniques, this journey will equip us with the skills needed to navigate the complexities of human thought and behaviour with greater insight and effectiveness.

Here is a brief video by Macat that explains the concept of critical thinking [2:30]:

Critical Thinking and Common Sense

Critical thinking is often misconstrued as common sense, leading many to dismiss it as unnecessary to learn or develop. This misconception arises from the belief that common sense, which is generally understood as sound practical judgement, is sufficient for navigating complex issues and making decisions. However, critical thinking and common sense are fundamentally different in several important ways.

Common sense is based on everyday experiences and intuitive judgements that seem obvious to most people. While it can be useful in routine situations, common sense is inherently influenced by personal biases, cultural norms, and subjective perceptions. These factors can cloud objective thinking and lead to errors in judgement. For example, common sense might suggest that a correlation (correlation is also known as a relationship) between two events implies causation, but critical thinking teaches us to scrutinise such assumptions and consider alternative explanations.

Critical thinking, on the other hand, is a disciplined and systematic approach to evaluating information and arguments. It involves skills such as interpreting, analysing, evaluating, and inferring, which go beyond the surface-level understanding that common sense provides. Critical thinking requires us to question assumptions, seek out evidence, and consider multiple perspectives before drawing conclusions. This rigorous process helps to mitigate the influence of biases and ensures that our judgements are based on sound reasoning and reliable evidence.

Moreover, common sense often relies on heuristics, or mental shortcuts, that can lead to cognitive biases. These biases, such as confirmation bias and availability heuristic, can distort our perception of reality and hinder our ability to think critically. For instance, confirmation bias leads us to favour information that confirms our pre-existing beliefs and ignore information that contradicts them. For example, if someone believes that left-handed people are more creative, they might pay more attention to instances where left-handed individuals display creativity and overlook instances where right-handed individuals do the same.

Similarly, the availability heuristic causes us to overestimate the likelihood of events based on how easily examples come to mind. For instance, after seeing news reports about aeroplane accidents, a person might overestimate the danger of flying, despite statistics showing that air travel is safer than car travel. Critical thinking, by contrast, encourages us to be aware of these biases and actively work to counteract them.

Another key difference is that common sense is typically reactive, responding to situations as they arise, whereas critical thinking is proactive. Critical thinkers anticipate potential problems, gather relevant information, and plan their actions accordingly. For example, a person relying on common sense might assume that a “low-fat” processed food is healthy because the label suggests it, whereas a critical thinker would read the nutritional information, investigate ingredients, and make decisions based on evidence rather than marketing claims. This proactive approach enables them to make more informed and effective decisions, even in complex and uncertain situations. Similarly, in a work setting, a common-sense approach might involve dealing with conflicts as they occur, while a critical thinker would establish clear communication channels and conflict resolution strategies in advance to handle potential disputes more effectively.

Hence, while common sense can be helpful in everyday situations, it is not a substitute for critical thinking. Critical thinking provides a more robust and reliable framework for evaluating information and making decisions. By recognising the limitations of common sense and embracing the principles of critical thinking, we can enhance our ability to navigate the complexities of the modern world with greater clarity and insight.

Critical Thinking in Contemporary Society

In today’s fast-paced, media-saturated, and increasingly politicised world, critical thinking skills are more essential than ever. We are inundated with an overwhelming amount of information, news, opinions, and ideas at an unprecedented speed. This deluge can feel inescapable, making it crucial to develop sharp, refined thinking skills to navigate this environment effectively. The rapid changes in our information landscape are set to continue accelerating, presenting us with more information than we can possibly absorb and process. Consequently, we must make daily decisions about which sources to trust and which to ignore. It is vital to avoid confining ourselves to sources that only reinforce our pre-existing beliefs, such as worldviews and political beliefs.

Historically, this is a relatively new challenge. In the span of about 80 years, the global population has transitioned from being largely illiterate to becoming active users of the internet, the most extensive information source ever created. This dramatic shift means that while the majority of adults today are active internet users, we are also living in what has been termed a ‘post-truth era’.

The consequences of this post-truth era are severe. We face numerous social, economic, and environmental issues exacerbated by a lack of critical thinking. For instance, unvaccinated populations contribute to the resurgence of previously eradicated diseases, and misinformation spreads so widely that NASA has had to debunk absurd claims like Mars being a secret child labour colony. Similarly, during the COVID-19 pandemic, misinformation about the virus and vaccines spread widely on social media, leading to vaccine hesitancy and resistance. This misinformation had severe public health consequences, including increased infection rates and deaths. In another example, the August 2024 riots in the UK were fuelled by misinformation following a tragic incident in Southport, where false claims about the identity of the attacker spread rapidly online. This misinformation incited violence and unrest, particularly targeting mosques and asylum-seeker accommodations.

We are bombarded with a constant stream of information and ideas, making it more urgent than ever to practice skilled and active interpretation and evaluation of observations, communications, information, and arguments. In simpler terms, critical thinking helps us filter useful signals from the overwhelming noise. Without it, we cannot reliably determine the accuracy and usefulness of the information we encounter.

While this challenge is not entirely new, it has become more pressing as the volume of information and rhetoric grows daily. In the twenty-first century, your attention is a valuable commodity, with countless corporations and interests competing for your engagement. This ‘attention economy’ has led media companies to employ cognitive scientists, social scientists, and statisticians to design platforms that exploit human vulnerabilities, primarily through emotional manipulation, to keep you engaged. This is addiction science weaponised to turn your attention into a commodity for sale. Be mindful that the information you consume is often heavily processed, much like processed food, and can be just as harmful to your mental health.

In the broader commercial context, information is a major commodity in the twenty-first-century global economy, hence the term ‘Information Age’. We are entering the ‘Fourth Industrial Revolution’, characterised by information and information technologies. As a result, employers increasingly recognise the importance of critical thinking among their employees. Many businesses now have dedicated manuals and guides to adopt critical thinking approaches, and it is considered one of the primary skill sets for success in various industries.

Recently, global employers ranked the top ten skills, with half directly related to critical thinking. The top three skills—complex problem-solving, critical thinking, and creativity—are core components of critical thinking. Other critical thinking-related skills include judgement and decision-making, and cognitive flexibility.

Here are the top 10 skills identified by the World Economic Forum:

1. Complex problem-solving
2. Critical thinking
3. Creativity
4. People management
5. Coordinating with others
6. Emotional intelligence
7. Judgement and decision-making
8. Service orientation
9. Negotiation
10. Cognitive flexibility.

The question ‘Who should study critical thinking?’ closely intertwines with ‘Why study critical thinking?’. The benefits of studying critical thinking are numerous and there are genuinely no downsides to developing a critical thinking skillset.

Here is a video by Bart Millar that explains why critical thinking is important [15:24]:

References

Kahneman, D. (2011). Thinking, fast and slow. Farrar, Straus and Giroux.