Researchers recruited expert typists—college students, of course—and showed them 600 five-letter words, one at a time. And they asked the students to type those words as quickly and accurately as possible. But sometimes, the researchers inserted typos in the word as it appeared on screen, when the students hadn’t made one. Other times they automatically corrected typos the students did make.
And the students tended to believe the screen. So if a typo had been added, they figured they must have messed up. If a typo had been corrected they thought they typed it right. But the hands didn't fall for it. When the fingers slipped up, they paused a split second longer than usual before typing the next letter. But they didn't pause when fake typos appeared on-screen only. So we apparently have two discrete mechanisms guarding against typing errors, one visual, the other tactile. To fox quick brown fixes. To fix quick brown foxes.、