Typing test reveals two processes in error detection

December, 2010

A study involving skilled typists shows how the part of a person that does the thinking relies on different feedback than the part that does the doing.

There are a number of ways experts think differently from novices (in their area of expertise). A new study involving 72 college-age typists with about 12 years of typing experience and typing speeds comparable to professional typists indicates that our idea that highly skilled activities operate at an unconscious level is a little more complex than we thought.

In three experiments, these skilled typists typed single words shown to them one at a time on a computer screen, while occasionally the researchers inserted errors in the words they typed, or corrected errors they made. When asked to report errors, typists took credit for corrected errors and accepted blame for inserted errors, claiming authorship for the appearance of the screen. Not surprising in the first experiment, when the typists weren’t told what the researchers were doing. But even in the later experiments, when they knew some of the errors and some of the corrections weren’t theirs, they still tended to take responsibility for what they saw.

Nevertheless, regardless of what they saw and what they thought, their typing rate wasn’t affected by inserted errors. Only when the typists themselves made errors, regardless of whether or not the researchers corrected them, did their fingers slow down.

In other words, it wasn’t the feedback of the look of the word on the screen that triggered the finger slow-down, but the ‘knowledge’ the fingers had as to what they had done.

But it was the appearance of the words on the screen that governed the typists’ reporting of errors, leading the researchers to propose two error detection processes: an outer loop that supports conscious reports and an inner loop process that slows keystrokes after errors.


Logan, G.D. & Crump, M.J.C. 2010. Cognitive Illusions of Authorship Reveal Hierarchical Error Detection in Skilled Typists. Science, 330 (6004), 683-686. http://www.sciencemag.org/content/330/6004/683.abstract?sid=140a96b9-ef5...