The Proofreader's Illusion
The proofreader's illusion refers to our tendency to overlook errors when reading typed material. It seems no one is immune to this mischievous trick of the mind—not even professional proofreaders, whose job is to catch such mistakes! In fact, this phenomenon was so prevalent that it inspired renowned proofreader Annie Smith to write a poem on the subject, titled Proof-Reader's Lament, published in 1871. Here are the first two verses.
What news is this falls on my ear? What next will to my sight appear? My brain doth whirl, my heart doth quake Oh, that egregious mistake! "Too bad! too bad!!" I hear them cry, "You might have seen with half an eye! Strange! passing strange!! how could you make So plain, so blunderous a mistake!
Research into misreading the printed word has a long history in psychology. For instance, in his book An Introductory Study of the Structure and Function of Human Consciousness (1904), James Rowland Angell notes that misreading printed words is among the most frequent illusions. He adds:
We sometimes read the words put before us as we have reason to suppose they ought to be, not as they are. Thus, if we come across the word mispirnt, many of us will read it in all good faith as misprint and never notice the difference.
The term proofreader's illusion has been present in psychological literature for well over a hundred years, as seen in the following citations:
Pierce, A. H. (1915). Imagery illusions: The non-visual character of the proofreader's illusion. Psychological Bulletin, 12(1), 1-9.
Downey, J. E. (1918). The Proof-Reader's Illusion and General Intelligence. The Journal of Philosophy, Psychology and Scientific Methods, 15(2), 44-47.
Due to enduring interest in the proofreader's illusion, it’s a topic that can be employed to explore a range of perceptual and cognitive processes, such as top-down processing and perceptual set. It also provides an opportunity for students to reflect on how factors like habit formation and familiarity influence how we perceive and construct the world around us.
Teaching Ideas
The proofreader's illusion offers an excellent way to teach students about the experimental method in psychology. For instance, many professional proofreaders claim that reading text out loud helps you spot errors that you would otherwise miss when reading silently in your head.
This is just one of many proofreader's illusion hypotheses that you could have your students test through a simple experiment. Even better, you could ask your students to devise and test their own hypotheses by designing an experiment as part of a formal activity or assessment.
A Final Test
Now that you know all about the proofreader's illusion, I'm sure you won't have any trouble spotting the error below! You might want to let your family and friends have a go, as you'll be amazed at how long it can take some of them to spot it.
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