Have you ever typed an email, only to return to it and discover, to your mounting horror, that you’ve referred to your boss as “Don” instead of “Dan?” Or that you told him you would order a necessary “fart” instead of a “part?”

There’s a good reason why we’re so terrible at catching these typing errors, and it has to do with our brains being a little too efficient.

In a piece for Wired, author Nick Stockton explains that typos are the result of conveying meaning our brains already understand. Speaking with Tom Stafford, a psychologist with the University of Sheffield, Stockton illustrates the point by stating that a simple task like writing takes up less real estate in the brain than the more complex mission of organizing our ideas. In other words, our brains focus more on communication—saying what we want to say, how we want to say it—than the act of typing. This process is referred to as generalization.

When we read our own work back, we already know what we wanted to say, and that existing knowledge fills in “gaps” in the writing that go unnoticed. You might not catch “hte” because your brain fills in “the” for you. You expect to see it. It’s similar to how we go through automatic processes like driving to a familiar place.

That’s why proofreaders—people other than yourself—can more easily spot mistakes. Their brains don’t have a map to follow, and so typos become glaring.

Does this mean catching errors in your own work is a lost cause? Not really. The trick is to take the familiarity out of the equation. If you’ve written something on a device, print it out or change the font. Do something to make it look a little strange to your eyes so it won’t look so strange to someone else.

[h/t Wired]