Cognitive Biases: The Invisible Enemy Sabotaging Your Trail Running Performance

Hi trail enthusiasts! This is Anthony. I still remember that ultra a few years ago. I was in dazzling shape, my legs felt great, my cardio was on top. On paper, everything was perfect. Yet, at kilometer 80, I blew up. Completely. Hit the wall, the real one. Analyzing my race afterward, I realized the problem wasn't in my legs, but between my ears. I had followed a group that started at too fast a pace, telling myself, “If they can do it, I can do it.” I had ignored the first signs of overheating, convinced my great shape would save me. In short, I was the perfect victim of a silent and formidable enemy: cognitive biases.

We talk a lot about VO2 max, nutrition, gear... But we often forget that our brain is the true conductor of the orchestra. And sometimes, this conductor plays us a funny tune. It takes shortcuts, misinterprets information, and pushes us to make completely irrational decisions that can ruin months of preparation. These shortcuts are cognitive biases. They are invisible, but their consequences on the trail are very real: poor pace management, neglected nutrition, unjustified DNFs... The list is long.

In this guide, we're going to dive together into the intricacies of our runner's psychology. We'll unmask these mental saboteurs one by one. No indigestible scientific jargon, I promise! Just lived experience, concrete examples from my own struggles and those I observe in races, and above all, practical strategies to regain control. Because understanding how your brain traps you is already halfway to becoming a smarter, more resilient, and ultimately, a better-performing runner. Ready for the challenge?

Unmasking the invisible enemy: your brain is playing tricks on you

Before going on the hunt, you need to know what you're looking for. We all tend to think our decisions are the result of logical and rational analysis. In reality, our brain is a bit lazy. To save energy, it constantly uses automatic thought patterns, mental shortcuts we call cognitive biases. This is a legacy from our ancestors, for whom making a quick decision (fight or flight?) was a matter of survival.

What is this 'cognitive bias' thing?

Imagine a trail you're used to taking. You know it by heart, you take it without even thinking. It's fast, efficient. A cognitive bias is a bit like that mental trail. It's a thought path your brain takes by default. The problem is, this path isn't always the most suitable for the situation. Sometimes, it leads you straight into a ditch, especially when fatigue and stress get involved.

It's not a character flaw or a lack of intelligence. It's simply the default operating mode of the human brain. Recognizing it isn't admitting weakness; on the contrary, it's a sign of great self-awareness. It's about going from being a passenger of your own thoughts to the conscious pilot of your machine.

Why trail running is a perfect playground for our biases

While these biases are present in our everyday lives, they find an ideal environment to thrive in the practice of trail running, and even more so in ultra-running. Why? Because our sport pushes us to our physical and mental limits.

• Extreme fatigue: When the body is exhausted, the rational brain (our prefrontal cortex) struggles to function correctly. It then gives free rein to our more instinctive reactions and our famous mental shortcuts.
• Stress and pressure: Whether it's the pressure of the finish line, the fear of not finishing, or simply the stress of a technical descent at night, these strong emotions encourage hasty and biased decisions.
• Uncertainty: The weather changes, the terrain surprises, a pain appears... Trail running is inherently unpredictable. Faced with the unknown, our brain tends to cling to what it thinks it knows, even if it's wrong.
• Information overload: Between bodily sensations, GPS watch data, trail markers, nutrition management... our brain has to process a huge amount of information. To simplify, it will filter, sort, and sometimes... throw crucial info in the trash.

Understanding this context means accepting that during a race, we are not always the most clear-headed version of ourselves. That's when the trap closes. But the good news is that we can learn to outsmart it. On the trail, nothing replaces experience, and this experience also comes from learning about our own mental flaws.

The Top 7 Mental Saboteurs on the Trails

Now that we've laid the groundwork, let's get down to business. I've identified 7 particularly common and devastating cognitive biases in our sport. For each one, I'll give you the explanation, a real-life example, and most importantly, the keys to avoid falling into the trap again.

1. Social Proof Bias: "If everyone's doing it..."

What is it? It's the tendency to consider an action more appropriate if we see other people doing it. It's the famous herd effect, the need to conform to the group to feel safe.

The classic trail example: The start of a race. The starting gun goes off, and it's a mad dash. Everyone takes off like a rocket. Your race plan, carefully thought out, told you to start cautiously. But your brain is screaming at you: "Look! Everyone is running fast! If you don't keep up, you'll be left behind. They must know what they're doing!" As a result, you settle into a pace that isn't yours, you burn your matches in the first few kilometers, and you pay for it dearly 50 kilometers later. This is exactly the trap I fell into during that ultra I told you about. The group seemed so comfortable, so confident... I let myself get sucked in, forgetting my own strategy, my own sensations. Big mistake.

How to counter it?

• Carve your plan in stone (almost): Before the race, precisely define your target paces, your nutrition and hydration strategy. This plan is YOUR anchor, YOUR beacon in the storm of the start.
• Run YOUR race: Repeat this phrase to yourself like a mantra. You have your own goals, your own physiology, your own preparation. Comparing is the best way to fail.
• Put on blinders: At the start, focus on your sensations, your heart rate, your breathing. Ignore the surrounding frenzy. If dozens of runners pass you, let them go. You'll catch up with many of them later, walking on the side of the trail. 😉
• Trust your watch: Use heart rate or pace alerts to force yourself to stick to your zones. The numbers are objective; they are not subject to social pressure.

2. Overconfidence Bias: "Today, anything goes!"

What is it? It's the tendency to overestimate one's own abilities, knowledge, and the accuracy of one's judgments. It's the first cousin of ego, and in ultra-running, ego is a very bad companion.

The classic trail example: You're coming off a perfect training block. Your times in training have never been better. You arrive at the starting line feeling invincible. The first few kilometers go wonderfully, you have "legs of fire." Overconfidence sets in: "I feel so good, I can skip this aid station, I'll eat later." Or: "The weather forecast calls for rain, but I'm not taking my rain jacket, it'll be fine." You feel stronger than your plan, stronger than the elements. And that's when the race humbly reminds you who's boss. A severe bonk or a case of hypothermia later, you're sitting in the sweep vehicle, full of regrets.

How to counter it?

• Respect the distance: No matter how fit you are, a 100k is still a 100k. Humility is the trail runner's greatest virtue. Every race is a new adventure with its share of surprises.
• Have plans A, B, and C: Goal A is your glory day. Goal B is a solid plan for average conditions. Goal C is simply to finish, even if you have to crawl. Having these scenarios in mind prevents you from falling apart if plan A doesn't work out.
• Doubt is your friend: A little doubt is healthy. It pushes you to check your gear, not to overlook a detail, to stay vigilant. Overconfidence leads to negligence.
• Listen to the veterans: Talk with more experienced runners. Their stories of struggles are the best vaccines against overconfidence.

3. Confirmation Bias: "I look for what suits me"

What is it? It's our tendency to search for, interpret, and remember information that confirms our pre-existing beliefs or hypotheses, while ignoring information that contradicts them.

The classic trail example: You've decided your new pair of shoes is revolutionary. During your race, you feel a little knee pain starting. Instead of thinking, "Damn, maybe these shoes aren't right for me," your confirmation bias will make you look for other explanations: "It's just fatigue," "It's because of that rock I tripped on." You'll focus on the great cushioning you feel on the downhills (the evidence that confirms your choice) and downplay the pain (the evidence that contradicts it). You keep going, the pain gets worse, and what could have been managed turns into a race-ending injury.

How to counter it?

• Play devil's advocate: Actively ask yourself: "What if I'm wrong?" What information could prove my hypothesis is false? If you think your hydration is good, look for signs that might indicate the opposite (dark urine, early cramps, dry mouth).
• Use objective checklists: Instead of relying on your feelings (which are subjective), use a checklist at each aid station. Did I drink 500ml since the last point? Did I eat my 200 calories? Did I take my salt? This is factual and limits interpretation.
• Be open to feedback: If your crew tells you that you look pale or that you're not drinking enough, listen to them! They have an outside perspective, unbiased by your current sensations.

4. Anchoring Bias: "Stuck on the first idea"

What is it? It's the difficulty of letting go of the first piece of information received. This first piece of information (the "anchor") serves as a reference point for all future decisions, even if it's completely arbitrary or no longer relevant.

The classic trail example: Six months ago, when you signed up for UTMB®, you set a goal of 30 hours. That's your anchor. On race day, it's scorching hot and a thunderstorm breaks out in the middle of the night, turning the trails into ice rinks. Logically, you should re-evaluate your goal. But the anchoring bias keeps you fixed on those "30 hours." You push the pace on runnable sections to make up for an imaginary delay, you take foolish risks on descents, you exhaust yourself... only to blow up or get injured. Your judgment was polluted by an anchor that was no longer adapted to the real conditions.

How to counter it?

• Focus on the process, not just the result: Rather than fixating on a final time, concentrate on present-moment indicators: running in the right heart rate zone, fueling properly, managing your effort on climbs. The final result will be the consequence of a well-executed process.
• Re-evaluate constantly: Each aid station is an opportunity to take stock. "Given the weather, my current condition, and the terrain ahead, what is a realistic goal for the next section?"
• Use RPE (Rate of Perceived Exertion): The perceived exertion scale (from 1 to 10) is an excellent tool. It's independent of external conditions. You can set a goal of not exceeding a 6/10 for the first 50 kilometers, no matter what your watch says.

5. Negativity Bias: "When one cloud hides the whole mountain"

What is it? It's our brain's tendency to give more importance and weight to negative experiences, information, and emotions than to positive ones. A single piece of bad news can spoil ten pieces of good news.

The classic trail example: You're at kilometer 70 of an ultra. You've just spent 8 hours feeling pretty good, enjoying the scenery, and fueling well. Then comes an endless, difficult climb. You hit a low point, a negative thought pops up: "I suck, I'm never going to make it." The negativity bias will do its work: this single thought will take over, eclipsing all the positive hours that came before. You forget you felt great 30 minutes ago. Everything turns dark. The downward spiral toward a DNF begins, fueled by this one difficult moment.

How to counter it?

• Prepare positive mantras: Have a few short, powerful phrases in mind to repeat over and over when things get tough. "I am stronger than this climb," "Every step brings me closer to the finish." It might sound simplistic, but it works!
• Practice gratitude: In difficult moments, force yourself to find something positive. "Okay, my legs hurt, but the scenery is magnificent," "This soup at the aid station is the best in the world." This helps break the fixation on the negative.
• The 15-minute rule: When a big wave of negativity washes over you, give yourself 15 minutes. Eat something, drink, walk, and tell yourself you'll make a decision after that time. Very often, simply refueling is enough to chase away the dark clouds.
• Smile! Even if it's forced, the physical act of smiling sends positive signals to your brain. Try it, you'll see!

6. The Dunning-Kruger Effect: "The beginner who knows everything, the expert who doubts"

What is it? This is a fascinating bias. The least qualified people in a field tend to overestimate their competence, while the most competent tend to underestimate it. Basically, it takes a certain level of competence to realize your own incompetence.

The classic trail example: The beginner runner who, after finishing their first 25k trail race, signs up for a 120k thinking it's "just a mental game." They have an overconfidence bias (bias #2) fueled by their incompetence in gauging the scale of the task: managing the night, cut-off times, temperature variations, long-distance nutrition... They radically underestimate the challenge. Conversely, you'll often see elite runners full of doubt before a race, because they are so expert that they are aware of the infinite number of parameters that can derail their performance.

How to counter it?

• Be an eternal apprentice: Adopt a posture of humility. Read, research, ask questions. The more you learn, the more you'll realize the extent of what you don't know.
• Listen to experienced runners: Don't just listen to their stories of glory. Ask them to tell you about their worst struggles. That's where the most valuable lessons are found.
• Progress in stages: Don't skip steps. Go from a 20k to a 40k, then to an 80k, before aiming for triple digits. Each distance is an essential learning experience for the next.
• Get a coach: An external and competent perspective is the best remedy for the Dunning-Kruger effect. A good coach will be able to objectively assess your strengths and weaknesses.

7. The Fundamental Attribution Error: "It's their fault, it's thanks to me"

What is it? It's our tendency to explain our own behaviors by external causes (the situation) and those of others by internal causes (their personality, their skills). We make excuses for ourselves, but we judge others.

The classic trail example: You DNF a race. Your explanation: "The course marking was terrible, I got lost" or "It was too hot, it was impossible." These are external causes. Now, imagine another runner DNFs. Your judgment (often subconscious): "He wasn't mentally prepared enough" or "He mismanaged his nutrition." An internal cause. Conversely, if you have a great performance, you'll attribute it to your mental fortitude and perfect preparation (internal). If someone else succeeds, you'll tend to think: "He got lucky with the weather" (external).

How to counter it?

• Be radically honest with yourself: After every race, whether successful or not, do an objective analysis. Ask yourself: "Regardless of external factors, what is MY share of responsibility? What could I have done differently?"
• Keep a race journal: Note your feelings, your mistakes, your successes. Rereading your own analyses with a cool head will help you identify your attribution patterns and become more objective.
• Show empathy: When you see a runner struggling, instead of judging them, tell yourself that you know nothing of their story, their preparation, or the problems they're facing. Kindness towards others helps you be fairer to yourself.

How to train your brain to stop sabotaging you?

Identifying these biases is good. Training to outsmart them is better! Your brain is a muscle. The more you work it to recognize its own traps, the less it will fall into them. Here is a concrete toolbox to build your own mental "antivirus."

Upstream Preparation: The Key to Lucidity

Most mental battles are won long before the starting line. Good preparation is not just about accumulating kilometers; it's about reducing the number of decisions you'll have to make when you're tired and vulnerable.

1. Detailed Planning: Develop a race plan that is as precise as possible. Estimated arrival times at aid stations, a list of what you need to eat and drink each time, gear management strategy... The clearer your plan, the less you'll have to improvise in the heat of the moment. This meticulous planning is also your best weapon against Decision Fatigue in Ultra-Running: When the Brain Gives Up Before the Legs, another one of those invisible enemies lurking after hours of effort.
2. Visualization: This isn't some guru trick! Every week before your goal race, take 10 minutes to lie down quietly and visualize your race. Imagine yourself running, feeling good. But most importantly, imagine problem scenarios: a bonk, a blister, a heavy downpour. Visualize yourself handling the situation calmly and effectively. On race day, when the problem arises, your brain will already have a pre-programmed solution.
3. Self-Knowledge: Your training log is your best ally. Note not only your data (distance, elevation gain, HR), but also your feelings, your thoughts, your moments of doubt. By rereading it, you might identify patterns: "I always panic on technical descents at night" or "I tend to forget to drink when it's cool." Becoming aware of your own biases is the first step to correcting them.

During the Race: Rituals and Mental Checklists

On race day, despite the best preparation in the world, chaos can set in. Here's how to stay on course.

• The Regular "Body Scan": Every hour, do a complete head-to-toe check-up. Force yourself to do it. Head: how am I feeling mentally? Neck: any tension? Stomach: hungry? Gurgling? Legs: heavy? Starting to cramp? Feet: any chafing? This ritual forces you to gather objective data about your condition and act before small issues become big problems.
• Strategic Chunking: Never think about the total distance. That's the best way to feel overwhelmed. Your only goal is to reach the next aid station. That's it. Once at the aid station, your goal becomes the next one. Breaking down a huge problem into a series of small, achievable tasks is the best technique to outsmart negativity bias.
• Using "If... Then..." Statements: Anticipate the triggers for your bad habits. For example: "If I see a group pass me and I'm tempted to follow them, then I will look at my watch to check my HR and focus on my breathing for 2 minutes." Having these action plans ready will prevent you from making a biased decision in the heat of the moment.

Post-Race: The Honest Debrief

The race is over, but the work continues. Now is when you can consolidate your learnings for next time.

A few days after the race, once the euphoria or disappointment has subsided, take a moment to debrief. Do it in writing. Be brutally honest. What worked perfectly? What was a disaster? Try to connect these events to your decisions. At what point did you deviate from your plan? Why? Is there one of the biases we've discussed that could explain that decision? This cold analysis is a gold mine. It's by understanding your past mistakes that you build your future successes.

To each their own adventure... and their own brain!

There you have it, we've taken a good tour of these little demons hiding in our skulls. I hope this journey has enlightened you and, above all, given you concrete tools. The goal isn't to become a robot that makes perfect decisions every time. That's impossible and would take away some of the thrill of the adventure. Trail running is also about instinct, adaptation, and emotion.

The real goal is to become a more conscious runner. A runner who knows when their brain is playing tricks on them and who has the weapons to take back control. It's this self-awareness that makes the difference between someone who is a victim of their race and someone who pilots it, even in the storm. It's what turns a potential struggle into a learning experience and an avoidable DNF into a victory over oneself.

So, the next time you pin on a race bib, remember that your greatest opponent and your best ally is yourself. Get to know yourself, train your body and your mind with the same rigor. The path is long, but exciting. To each their own adventure, and to each their own journey to tame the fascinating machine that is their own brain.