If you have ever done any proofreading, you know how easy it is to miss a typo. No matter how carefully you read a passage, somehow you still missed some very obvious typos. But why? This may be the answer:
Aoccdrnig to a rscheearch at Cmabrigde Uinervtisy, it deso’nt 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 wihtuot porbelm. Tihs is bcuseae the huamn mnid deos not raed ervey ltteer by istlef, but the wrod as a wlohe.