In a letter to Jean-Baptiste Leroy in 1789 Ben Franklin wrote, “In this world nothing can be said to be certain, except death and taxes.”

We’ve all heard the quote. But I want to add a third certainty: typos.

We all make them—at least anyone who writes does. Whatever your chosen profession, writing enters into the game at some point. It can be as simple as an email, as complex as an academic dissertation, or as routine as a company newsletter. Finding typos can make you feel smarter, and making them—let alone not catching them as you proofread—can make you feel like the biggest idiot on the planet. Everyone has found a typo in his or her own work at some point or another, even those who make a living off their words.

Twice in October, the New York Times dealt with backlash because of typos on their front page. In one case a front-page article contained no byline or subheading and the article began mid-sentence (Mon., Oct. 13). Then a week later, on Oct. 20, a front-page headline read, “Panic Were Ebola Risk Is Tiny; Stoicism Where It’s Real.”

The impression left on the reader when encountering a typo can be huge—a misspelled word can quickly transform into a world of criticism. Flashback to the typo the NYT printed in May that chastised Obama’s “Cautious Reponse to World Crises.” The social media buzz said nothing about Obama’s foreign policy choices and everyone became a pedantic editor, highlighting the missing s. Typos matter. But they don’t always indicate carelessness.

The truth is that there’s more to proofreading and editing than first meets the eye. In fact, the whole secret to why we make typos lies not in the eye, but in the brain.

When it comes to high-level brain function, generalization is key. Formulating words into sentences activates a different part of the brain than transforming sentences into complex thoughts and ideas. Martin Lotze, a radiologist at the University of Greifswald in Germany, published a study that attempts to explain the basis of creativity, isolating a part of the brain used by established writers that remains inactive in the minds of novice writers. In all this higher-level brain function, the parts of the brain that make us good spellers—yep, you guessed it—aren’t as active.

But what about proofreading and editing? Finding typos undermines all those high-level ideas we’ve worked so hard to convey. So we use spellcheck. We proofread our written work two to three times. We print out the page and look over it again. All clean. And then we hand it to a friend or an editor, and . . .

How did they find errors in that perfectly clean document we edited so carefully?!

In an interview with Wired magazine, psychologist Tom Stafford of the University of Sheffield in the UK admitted, “We don’t catch every detail; we’re not like computers or NSA databases. Rather, we take in sensory information and combine it with what we expect, and we extract meaning.” When we read other people’s work we are learning the words for the first time, so we catch things that stand out as different from our expectations. Proofreading our own work, we tend to skip over those same errors or omissions because what is on the page is competing with the narrative voice in our heads that expects the intended meaning to be there.

The key to proofreading is to trick the brain into thinking it is reading the piece for the first time, which in itself can often require some higher-brain function. Reading the words backwards, changing the font, or printing off the page and editing the hard copy are tricks commonly used by long-time writers. Or, of course, you can always hire a professional editor.

Crystal Atamian is a writer and editor for Eagle Eye editing. She loves hot tea, long hikes, and articles without typos.