Why We Make Mistakes

“Why do we keep making the same errors? Understanding how our brains work can help us avoid them in the future.”

1. Our perception of the world is limited by biology and psychology

Our ability to accurately perceive the world around us is inherently limited. Our field of vision spans only 180 degrees, meaning we always miss about half of what’s out there. The immense amount of information in our environment overwhelms us, and we often fail to notice what’s right in front of us.

Psychologically, our expectations narrow our focus. We tend to see what we predict will be there or what aligns with our experiences. This is why airport baggage screeners, who almost never find a gun, often miss real ones during their training exams. They simply don’t expect to see one.

This limited view also shifts depending on whom we identify with. When witnessing a man steal a woman’s purse, men often focus on the thief while women may focus on the victim. Essentially, our mental filters shape our understanding of every situation, often leading to unnoticed details and mistakes.

Examples

• Burt Reynolds punched a harasser without realizing the man had no legs – his focus on broad shoulders led him to miss key details.
• Baggage screeners miss around 25% of firearms due to their rarity, skewing expectations.
• Observation experiments show men and women fixate on different parts of the same scene depending on their gender-related identification.

2. We remember meaningful information better than random data

The brain stores meaningful data more effectively than abstract or random information. We’re naturally wired to give importance to connections and context, helping us retain details more thoroughly.

A study demonstrated this by having participants memorize biographical information. People remembered occupations more than names because jobs often connect to familiar imagery or personal experiences. Similarly, meaningful sequences stick better – for example, historical dates like 1492 are easier to recall than random numbers.

This wiring is why we struggle with arbitrary data like phone numbers, often forgetting them if they lack context or association. By breaking down random information into meaningful groups, like memorable dates or patterns, we can transform pointless data into something easier to recall.

Examples

• A quarter of people in a survey couldn’t recall their own phone numbers.
• “1492-1776-1945” is easier to recall because they are important historical years.
• Biographical data studies show people remember roles (e.g., “baker”) better than unrelated facts like age or name.

3. Quick judgments lead to blind spots

Our survival instincts make us rely on snap judgments, a trait shaped by evolution. While this helps us react quickly, it sometimes results in errors due to biases. For instance, we unconsciously judge people based on their clothing, facial features, or even the color of their belongings.

Color influences these judgments. Studies revealed sports teams wearing black uniforms face harsher penalties from referees, as black is associated with aggression. Similarly, people often make decisions based on facial traits they interpret, like assuming a broad nose signals dominance.

Outward perceptions also control how we act unconsciously. Subtle cues, such as scents in a store, change our behaviors, like how differing fragrances affected men’s spending habits in tests. These unrecognized factors shape our split-second reactions more than we realize.

Examples

• Black uniforms increased penalty rates for hockey teams like the Pittsburgh Penguins.
• People judged political candidates' competence in one-second glances of their photos.
• Men spent more money in retail stores when tempted by masculine fragrances.

4. Simplification leads to distorted memories and decisions

We simplify information to make complex ideas manageable, but this often leads to distorted conclusions. Our brains straighten crooked lines, smooth uneven details, and remove contradictions to keep things simple.

Maps frequently illustrate this phenomenon. When Parisians were asked to draw their city’s layout from memory, nearly all “straightened” the winding River Seine. Similarly, when retelling events, we naturally delete details that don’t fit the story or make sense to us.

This mental shortcut stems from our limited capacity to process and hold complex information. While it’s practical, it can mislead us, causing oversights or inaccurate recollections of events, places, and experiences.

Examples

• Experiments showed people chose incorrect maps because they matched simplified mental versions.
• A friend’s funny but complex story about losing pants and finding a pearl is likely retold with edits.
• Rivers or street maps are mentally "flattened" for ease when recollecting or traveling.

5. Our minds find patterns, even when they’re not there

Rather than absorbing individual details, we scan for patterns, which speeds up many tasks but can also mislead us. Experts in any field, from linguistics to music, rely on conventions and predictability to quickly process information.

For example, interpreters don’t listen word-for-word but instead anticipate phrases based on context. Musicians do something similar: they focus on patterns in sheet music rather than each note. However, this efficiency can create errors. A misprint in a Brahms score went unnoticed for decades because musicians played by context, not by checking every detail.

In everyday life, this tendency to look for patterns comes with similar risks. It makes repetitive work faster but often blinds us to anomalies when we’ve trained our minds to expect something else.

Examples

• Interpreters rely on early clues to rapidly process dialogue.
• A misprinted note in Brahms’ sheet music remained uncorrected for years until a beginner played it directly.
• Reading comprehension speeds up by scanning initial letters rather than analyzing each one.

6. We revise the past to make ourselves look better

Our memories are malleable, and we often edit them to align with favorable outcomes. This phenomenon explains why people say they “knew it all along” after events occur, even when their earlier predictions were off.

For instance, experiments in the 1970s showed students misremembering their predictions about Nixon’s diplomatic visits, revising them to align with real outcomes. Similarly, people exaggerate their achievements, such as students inflating their old high school grades.

Despite being unconscious, this self-marketing tool aligns memories with societal expectations. Men and women revise the number of romantic partners they’ve had to fit social norms, viewing themselves through the lens of cultural stereotypes.

Examples

• Students recalled their past predictions about global events inaccurately to boost their accuracy.
• High school grades were exaggerated when students were asked to report their marks from memory.
• Gender stereotypes shaped responses about lifetime romantic partners in surveys.

7. Multitasking is less efficient than we think

Contrary to popular belief, multitasking doesn’t save time; it just divides our focus, leading to reduced productivity. Our brains can only make one decision at a time, so multitasking reduces efficiency because we’re actually switching attention between tasks.

Switching focus includes a hidden cost – time lost to adjustment. For example, responding to emails while working on taxes disrupts our concentration, adding mental friction. Studies even show that the brain slows down when juggling competing tasks.

In worst-case scenarios, multitasking can create hazards. Tasks that demand full attention, like driving, leave little room for distractions. With 78% of road accidents caused by inattention, trying to concentrate on multiple things at once can have dire consequences.

Examples

• Drivers experience danger even when inputting simple GPS commands while maneuvering.
• Switching from reading an article to texting a friend slows overall processing.
• Research suggests attention-switching is detrimental when handling heavy cognition tasks like accounting.

8. Overconfidence skews our self-perception

We tend to overestimate our abilities, believing we’re better than average in most situations. This overconfidence makes us set unrealistic expectations or take unnecessary risks, such as assuming we’ll use that costly gym membership more than we actually will.

Men especially inflate their self-image. Research shows they perceive themselves as more capable, attractive, and intelligent than women, leading them to make bold predictions about success. But confidence doesn’t always correlate with skill – female students tend to achieve higher academic grades, despite men’s greater certainty of their abilities.

This mindset can bias decision-making, whether it’s overestimating dieting success or trusting hunches about random outcomes, like tossing a coin.

Examples

• Gym memberships often cost more due to overestimating attendance.
• Male subjects overestimated their test performances, even when incorrect statistically.
• Studies showed men believed they could predict coin-toss results after false validation early on.

9. Better design and manageable data improve decision-making

Many mistakes stem from unclear communication, confusion, or overwhelming information. Simple tweaks to designs and how we process information can drastically reduce errors and improve outcomes.

For instance, marking surgery sites prevents wrong incisions, while clear labels and color coding for medicine avoid dangerous mix-ups. Similarly, simplifying data presentation helps us focus on what matters instead of drowning in facts, as seen with novice investors overwhelmed by countless stock options.

Restricting and organizing information benefits decision-making, enabling careful, informed action instead of rushed choices caused by data overload.

Examples

• American hospitals reduced dosing errors by redesigning vial labels.
• Operating rooms cut mistakes by marking body parts for surgery.
• Reducing financial strategy complexity for beginners helps them avoid poor decisions.

Takeaways

1. Use checklists for complex tasks to avoid omissions – small details matter more than we think.
2. Limit how much information you research before deciding. Too much data overwhelms the brain.
3. Reflect on and write down past predictions to assess their accuracy and improve future decisions.