Transposed letters

Like me, you may have received an e-mail asking if you can read this block of text:

Aoccdrnig to a rscheearch at Cmabrigde Uinervtisy, it deosn't mttaer in waht oredr the ltteers in a wrod are, the olny iprmoetnt tihng is taht the frist and lsat ltteer be at the rghit pclae. The rset can be a toatl mses and you can sitll raed it wouthit porbelm. Tihs is bcuseae the huamn mnid deos not raed ervey lteter by istlef, but the wrod as a wlohe.

This bit of linguistic trivia has been circulating since 2003, and references research at Cambridge University. This came as a surprise to Dr. Matt Davis at Cambridge's Cognition and Brain Sciences Unit: "If there's a new piece of research on reading that's been conducted in Cambridge, I thought I should have heard of it before....To my knowledge, there's no-one in Cambridge UK who is currently doing research on this topic. " He was able to trace the possible origin to Graham Rawlinson, whose 1976 Ph.D. dissertation at the University of Nottingham was entitled, "The Significance of Letter Position in Word Recognition."

The understandability of transposed words appears to be self-evident based on this example, but is actually an urban legend with an element of truth to it. Not all garbled texts are as easy to understand as the quote above. Davis clarifies the issues in detail here, and I summarize some of the main points below:

• Words of only 2 0r 3 letters can't be transposed and this includes most function words (the, be, you), so the preserved grammatical structure helps the reader.
• Transpositions of adjacent letters (porbelm for problem) are easier to read than more distant transpositions (pborlem).
• None of the words that have reordered letters create another word (as with salt and slat), which would introduce confusion and make the passage more difficult to read.
• Many of the transpositions that were used preserve the sound of the original word (toatl rather than ttaol for total), which helps with understanding because we often attend to the sound of the words even when reading for meaning.
• The text is reasonably predictable, which suggests that context is as important in understanding jumbled written text as in interpreting distorted speech.

The word coined to characterize the cognitive processes behind reading written text is "typoglycemia." The concept works very differently in semitic languages (Hebrew or Arabic) where vowels tend not to be written in text, agglutanative languages (Finnish or Turkish) where words are dramatically longer than in English, languages (like Thai) which do not conventionally put spaces between words, and logographic languages (Chinese) in which complex symbols represent a whole word or idea. But even in English, a sentence with words that have scrambled interior letters is not always a breeze to understand. Consider this:

The sprehas had ponits and patles.

This example has many possible interpretations, including "The sherpas had pitons and plates," "The shapers had points and pleats," and "The seraphs had pintos and petals."

Note: I have been unable to source the origin of the image above, so my apologies to the artist.