A reading method that bolds the opening letters of words guides the eye to exactly where it claims to, and produces no measurable improvement in reading speed or comprehension, researchers at University College London have found.
Bionic Reading bolds selected letters, usually the first part of a word, on the theory that drawing the eye to the highlighted opening lets a reader take in the rest more quickly.
The study, published in Royal Society Open Science, involved 90 skilled adult readers aged 18 to 40 with no reading disorders or neurodevelopmental conditions. They read 90 sentences, presented individually on a screen in the font Courier New.
Three conditions were compared: no bolded letters, the first half of the target word bolded, and the middle section bolded. Target words were four and eight letters long.
On eye movements, the method did what it says. Bolding the beginning "shifted readers' initial gaze toward the start of eight-letter words more than it did for four-letter words".
On speed, it did not. "Neither bold initial letters nor bold middle letters reduced the time spent reading target words or whole sentences."
Participants answered about 95 per cent of the comprehension questions correctly overall, leaving little room for improvement, and there was no reliable comprehension benefit from bolding. Nor was there any reliable change in how often words were skipped altogether.
The authors' summary is that the manipulation redirected the eyes towards the important part of the word, and that this was not enough to make the words quicker to read or the text easier to understand.
It is worth being exact about what was demonstrated. The method proposes to move the eye to the start of the word. The eye moved to the start of the word. On its own terms, Bionic Reading works.
Reading speed is a separate claim, which the study tested separately and found nothing to support. The Department of Unnecessary Research therefore treats the two as independent products, of which one has now been validated under laboratory conditions.
Comprehension is a harder case for the critics. Readers were already answering 95 per cent of questions correctly, which the authors themselves note leaves little room for improvement. A method cannot fairly be blamed for a ceiling it did not build.
Our analysts accordingly record the result as the strongest evidence yet assembled that bolding the first half of a word tells the reader where the word begins.
Skilled readers, it turns out, already knew.