5 Mental Exercises to Defeat Cognitive Bias and Make Smarter Decisions

Let’s be honest. If your brain came with an owner’s manual, the first chapter would be titled “Warning: This Device Is Not As Rational As It Appears.” We navigate our days with a deep-seated faith in our own judgment, a quiet confidence that we see the world clearly and make decisions logically. Yet, science has shown us, time and again, that our minds are riddled with cognitive biases—systematic glitches in our thinking that cause us to make questionable decisions and hold stubbornly to flawed beliefs.

Acknowledging these biases is one thing. We can read about Confirmation Bias and the Sunk Cost Fallacy and nod sagely, recognizing these foibles in our friends, family, and political adversaries. But knowing is not the same as doing. It’s like reading a book about weightlifting and expecting your muscles to grow. To truly improve our thinking, we need to move from passive awareness to active practice. We need a mental workout plan.

That’s precisely what this is. Forget abstract theory. We’re rolling up our sleeves and getting practical. What follows are five powerful, research-backed “debiasing” exercises. Think of them as push-ups for your prefrontal cortex. These aren’t one-time fixes but mental habits you can integrate into your daily life—at work, at home, and in your own head—to counteract your brain’s laziest tendencies. They are designed to be a little uncomfortable, just like a good workout. But the payoff—clearer thinking, better decisions, and a more accurate view of reality—is well worth the effort.

Exercise 1: The Pre-Mortem—Your Crystal Ball for Failure

We are, by nature, a ridiculously optimistic species. When we embark on a new project—be it launching a business, planning a wedding, or starting a new diet—we are infected by a potent cocktail of enthusiasm and overconfidence. We focus on all the ways it will succeed. This rosy outlook is driven by the Optimism Bias, our tendency to overestimate the likelihood of positive outcomes. It’s a great motivator, but a terrible project manager.

To fight this, we need to inject a dose of productive pessimism. Enter the Pre-Mortem. Coined by psychologist Gary Klein, this technique is as simple as it is profound. Right before you commit to a major decision, you gather your team (or just yourself) and imagine a different future.

How to Conduct a Pre-Mortem

1. Set the Scene: The decision has been made. The plan is finalized. Before you pop the champagne, announce to the group: “I have a crystal ball. I’m looking one year into the future, and I see that this project has failed. It’s been a complete and utter disaster. A catastrophe.”
2. Generate the Reasons: Give everyone five to ten minutes to independently write down every single reason they can think of for why this failure occurred. The key is that it has failed; this isn’t a “what-if” exercise. This framing liberates people from the social pressure of appearing negative or disloyal. They aren’t criticizing the plan; they are performing a factual historical analysis of a future event.
3. Share and Consolidate: Go around the room and have each person share one reason from their list, continuing until all unique reasons have been shared. Record them on a whiteboard for all to see. You’ll hear things you never would have heard otherwise: “Marketing didn’t get the funding they needed because we were too optimistic about early revenue,” or “The key engineer we depended on quit because she felt her concerns about the timeline were ignored.”
4. Strengthen the Plan: Now, with this list of potential pitfalls and vulnerabilities exposed, you can systematically address them. How can you mitigate these risks? How can you strengthen the plan to prevent this litany of disasters from coming true?

The Pre-Mortem works because it shatters the illusion of inevitable success. It bypasses the conformity and overconfidence that often doom projects from the start. It gives a voice to silent doubts and transforms vague anxieties into a concrete list of problems you can actually solve. It is the single best way to find the fatal flaws in a plan before they become fatal.

Exercise 2: The Designated Dissenter—Your Weapon Against Groupthink

Humans are social creatures. We crave belonging and harmony. In a group setting, this instinct can manifest as Groupthink, a psychological phenomenon where the desire for consensus overrides a realistic appraisal of alternatives. People self-censor their dissenting opinions to avoid “rocking the boat,” leading to a collective illusion of unanimity and, often, terrible decisions. The Bay of Pigs invasion and the Space Shuttle Challenger disaster are textbook examples of Groupthink in action at the highest levels.

To combat this, you need to institutionalize dissent. You need to formally appoint a Designated Dissenter, also known as a devil’s advocate.

How to Use a Designated Dissenter

1. The Formal Appointment: In any important group discussion or decision-making meeting, explicitly assign one person the role of the dissenter. Their job is not just to be difficult; it is to actively critique the prevailing opinion, question assumptions, and build the strongest possible case against the proposed course of action.
2. Rotate the Role: This shouldn’t be the same person every time. That person would quickly become branded as “the negative one.” The role should be rotated among team members. This accomplishes two things: First, it ensures that everyone gets practice in the skill of critical thinking. Second, it depersonalizes the criticism. When Jane is the Designated Dissenter this week, everyone knows she’s playing a role. Her critiques aren’t seen as a personal attack but as a fulfillment of her assigned duty.
3. Reward the Dissent: The group leader must actively protect and reward the dissenter. When they raise a valid point, the leader should say, “That’s an excellent point, Jane. Let’s explore that. What does everyone else think about that risk?” This signals to the entire group that dissent is not just tolerated; it is valued.

The Designated Dissenter gives “permission” for critical thought. It creates a safe space for doubt and forces the group to confront uncomfortable truths and unexamined assumptions. It ensures that the most popular option isn’t automatically crowned the best option, thereby inoculating the team against the seductive and dangerous allure of consensus.

Exercise 3: Prospective Hindsight—Talking to Your Future Self

Why do we continue to pour money into a failing investment, stay in a dead-end job, or finish a terrible movie? The answer is often the Sunk Cost Fallacy. This is our tendency to follow through on an endeavor if we have already invested time, effort, or money in it, whether or not the current costs outweigh the benefits. We hate the feeling of having wasted our resources, so we waste even more in a futile attempt to justify the initial investment.

One of the most effective ways to escape this trap is a technique called Prospective Hindsight. It’s about bridging the gap between your present self and your future self. We often treat our future self like a stranger, someone who will magically have more time, energy, and willpower than we do now. Prospective Hindsight forces us to see our future self as a direct consequence of our present actions.

How to Practice Prospective Hindsight

This is a personal mental exercise. When facing a decision where sunk costs are a factor, take a moment and vividly imagine two futures:

1. Future A (Continue the Course): Imagine it is one year from now. You have continued to pour resources into this project/job/investment. What does your life look like? What are you feeling? Be specific. Are you still stressed about the same problems? Are you lamenting the additional time and money you’ve spent? Feel the frustration and regret of that future self. Let them “speak” to you.
2. Future B (Cut Your Losses): Now, imagine it is one year from now, but you decided to cut your losses today. It was painful at first. You felt the sting of “wasting” what you had already put in. But what does your life look like now? What new opportunities have you been able to pursue with the resources you saved? Feel the sense of relief and freedom that comes from being unburdened by a failing endeavor.

By making these future states tangible and emotional, you change the calculation in your head. The pain of the sunk cost (which is in the past and cannot be recovered) is weighed against the potential future pain of continuing down the wrong path. More often than not, this exercise makes it glaringly obvious that the wisest course of action is to stop digging.

Exercise 4: Considering the Opposite—The Antidote to Being Right

Here’s the mother of all biases: Confirmation Bias. It is our natural, deeply ingrained tendency to seek out, interpret, and remember information that confirms our existing beliefs, while simultaneously avoiding or dismissing information that contradicts them. It’s why we click on headlines we agree with and unfriend people we don’t. It feels good to be right, and our brain is addicted to that feeling.

This bias is the engine of polarization and the enemy of learning. To fight it, you must engage in an exercise that feels profoundly unnatural: Considering the Opposite.

How to Consider the Opposite

This technique, championed by social psychologist Charles Lord and his colleagues, is beautifully simple. Before you solidify a strong opinion on any topic—be it political, personal, or professional—force yourself to perform these two steps:

1. Pause and Assume You’re Wrong: Take a moment and operate under the assumption that your initial belief is incorrect.
2. Articulate the “Other Side”: Then, build the best, most intellectually honest, and most persuasive argument you can for the opposite point of view. This isn’t about creating a flimsy “straw man” that’s easy to knock down. It’s about “steel-manning” the opposition. What are their most rational points? What evidence do they find most compelling? What values underpin their position?

If you’re pro-nuclear energy, what is the most intelligent argument against it, focusing on waste disposal and safety concerns? If you’re convinced a certain marketing strategy is the way to go, what is the most compelling case for the alternative strategy your colleague proposed?

Doing this does a couple of remarkable things. First, it can reveal legitimate weaknesses in your own position you were blind to. Second, even if you don’t change your mind, you will understand the issue with far greater depth and nuance. You’ll be able to say, “I understand why they believe X, and I respect that position, but I still believe Y because of Z.” This transforms you from a dogmatic believer into a thoughtful advocate.

Exercise 5: The Information Diet—Breaking Out of the Echo Chamber

Have you ever noticed that after you search for a product online, ads for it seem to follow you everywhere? Your digital world is a meticulously curated space, designed to show you more of what you already like. This creates an Echo Chamber, where your own beliefs are amplified and repeated back to you, and it’s supercharged by the Availability Heuristic—our tendency to judge the importance of things by how easily they come to mind. When all you see are stories about crime in your city, you’ll believe crime is skyrocketing, even if the data shows otherwise.

To get a clearer picture of the world, you need to go on an Information Diet. This isn’t about consuming less information, but about consuming it more consciously and critically.

How to Go on an Information Diet

1. Conduct an Audit: For one week, keep a log of your information sources. Where do you get your news? Which social media accounts do you follow? Which podcasts do you listen to? Be honest. At the end of the week, look at the list. How much of it simply confirms your existing worldview?
2. Diversify Your Sources: Intentionally add sources to your diet that challenge you. Follow a few thoughtful people on social media who you disagree with. Subscribe to a newsletter from a different political perspective. If you only read news from your home country, make a point to read an international source like the BBC, Al Jazeera, or Reuters. The goal isn’t to be converted, but to see how the same event can be framed in vastly different ways.
3. Prioritize Data Over Anecdote: Our brains are wired for stories, not statistics. A single, emotional story about someone winning the lottery (anecdote) has a bigger impact on us than the statistical reality of the astronomical odds against winning (data). When you see a compelling story, train yourself to ask, “Is this a single data point or a representation of a larger trend? What does the broader data say?” Seek out primary sources and statistical reports, not just commentary on them.

An information diet breaks the feedback loop of confirmation and availability. It replaces a passive, algorithm-driven firehose of information with a deliberate, curated, and more balanced consumption of knowledge. It is the essential final step in taking control of the inputs that shape your thoughts.

The journey to clearer thinking is a marathon, not a sprint. These five exercises—the Pre-Mortem, the Designated Dissenter, Prospective Hindsight, Considering the Opposite, and the Information Diet—are your training plan. They won’t make you infallible, but they will make you more thoughtful, more flexible, and far less likely to be duped by the slick, fast-talking con artist that is your own biased brain.

Sorry! This part of content is hidden behind this box because it requires a higher contribution level ($5) at Patreon. Why not take this chance to increase your contribution?

Unlock A World of Learning by Becoming a Patron