Eyes lock on different letters when reading

YORK (Reuters) - When we read our eyes lock on to different letters in the same word instead of scanning a page smoothly from left to right as previously thought, researchers said on Monday.

Using sophisticated eye tracking equipment, the team looked at letters within a word and found that people combined parts of a word that were on average two letters apart, said Simon Liversedge, a cognitive psychologist at the University of Southampton.

The findings could lead to better methods of teaching children to read and offer remedial treatments for those with reading disorders such as dyslexia, said Liversedge, who presented his work at a meeting organized by the British Association for the Advancement of Science.

"What I'm trying to understand is the relationship between the physiological processes that underpin human written language comprehension and their relationship with eye movements people make to read sentences," he said in a telephone interview.

Over the past 40 years scientists have studied eye movements and reading, with a general consensus that people look at the same letter within a word with both eyes, Liversedge said.

To test this, Liversedge and colleagues measured the reflections of a low-intensity infrared beam shone into a volunteer's eye when reading. This allowed the researchers to pinpoint exactly where the eye had fixated on a word.

Then they ran further tests to see why people did not have double vision from picking out individual letters and found that the brain fuses the two signals that come in from the different eyes into one clear image, Liversedge said.

"It had always been assumed that both eyes moved in perfect harmony and you looked at a word with just one fixation," he said. "Because of this assumption scientists looking at reading behavior have just measured one of the eyes because they assumed the eyes were doing the same thing."

The findings also add to a wealth of information about eye movements that scientists have built up over the years as they seek a better grasp of how we understand written language, Liversedge said.

They also help paint an overall picture of language comprehension that can one day benefit those with reading problems and disorders, he added.

"In order to fully understand what is going wrong in people with reading difficulties, we first need to understand what is involved in normal language comprehension," he said.