March 15, 2013
Why Can You Sltil Raed Tihs Haeldine?
Lee Rannals for redOrbit.com — Your Universe Online
The human brain has an amazing ability to decode letters on a page that have been all jumbled up. Sentences like "tihs is ofetn misseplled" can be read, despite all the misspellings of the words, and researchers in the UK set out to find out why.Readers need to identify the letters in words, as well as accurately code the positions of those letters in order to distinguish between words like CAT and ACT. However, readers are able to raed sectnenes in wihch not all teh leettrs aer in thier corerct psotiions.
"How the brain can make sense of some jumbled sequences of letters but not others is a key question psychologists need to answer to understand the code the brain uses when reading," says Professor Colin Davis of Royal Holloway, University of London, who led the research.
Researchers have used standard psychological tests to work out which sequences of letters in a word are important cues that the brain uses. However, this technique has limitations that made it impossible to probe more extreme rearrangements of sequences of letters.
For the latest study, the UK researchers used computer simulations to work out that a simple modification to the test could allow it to question these more complex changes to words. Increasing the test's sensitivity makes it more valuable for comparing different coding theories. They tested current theories of how readers decode words by developing a new, more sensitive test of theoretical models than the existing standard test.
"For example, if we take the word VACATION and change it to AVACITNO, previously the test would not tell us if the brain recognizes it as VACATION because other words such as AVOCADO or AVIATION might start popping into the person's head," says Professor Davis. "With our modification we can show that indeed the brain does relate AVACITNO to VACATION, and this starts to give us much more of an insight into the nature of the code that the brain is using — something that was not possible with the existing test."
Researchers can use the modified test to crack the code the brain uses to make sense of strings of letters, but also examine differences between individuals.
"These kinds of methods can be very sensitive to individual differences in reading ability and we are starting to get a better idea of some of the issues that underpin people's difficulty in reading," says Professor Davis.
He said ultimately the research could lead to new approaches to help people overcome reading problems, such as dyslexia, which is a reading disorder that occurs when the brain cannot properly recognize certain symbols.
Recently, researchers writing in The Journal of Neuroscience said they found a biological mechanism that appears to play an important role in the reading process.
“We discovered a systematic relationship between reading ability and the consistency with which the brain encodes sounds,” says Nina Kraus, Hugh Knowles Professor of Neurobiology, Physiology and Communication. “Our results suggest that good readers profit from a stable neural representation of sound, and that children with inconsistent neural responses are likely at a disadvantage when learning to read."
She said understanding the biological mechanisms of reading puts scientists in a better position to understand how normal reading works and to identify where it goes awry.