This article has been reviewed according to Science X's editorial process and policies. Editors have highlighted the following attributes while ensuring the content's credibility: Bionic Reading is a method of bolding certain letters in words that is purported to facilitate reading speed and comprehension. The idea is that guiding the eyes to focus on highlighted initial letters lets the brain complete the word.
But does steering someone's gaze actually help them read? An eye-tracking experiment with 90 skilled adult readers found a revealing split: Bolding changed where their eyes landed on longer words but didn't make them read faster. The researchers from University College London report their findings in the journal Royal Society Open Science.
There is a plausible reason to emphasize word beginnings. Initial letters play an important role in recognizing words, so making them stand out might help readers identify words more efficiently. Yet an earlier eye-tracking study, published in Attention, Perception, & Psychophysics in 2025, found that bolding word beginnings hindered rather than helped reading.
The new experiment tested selective bolding in the beginning versus the middle of both short and long words in order to investigate the two parts of the Bionic Reading promise: Does it change where readers look and does it help them to process what they see? After two pilot studies, the researchers tested adults ages 18 to 40 without a history of reading disorders or neurodevelopmental or neurological conditions. Each participant read 90 sentences, presented individually on a screen in the font Courier New.
In some sentences, the text contained no bolded letters. For others, roughly the first half of target words were bolded. A third format bolded the same number of letters around the middle instead to test whether location mattered.
Readers had to answer a true-or-false question after each sentence. Within the sentences, the team tracked selected four- and eight-letter words that commonly occur in English and could describe a similar concept. For example, one sentence could include either a "doll" or a "princess." An eye tracker recorded where readers first looked within a word.
Extract — continue reading at the source.
