There is often a greater number of dyslexics in English-speaking countries compared to countries like China, Japan, and even Spain and Italy. Why do we see this difference across countries?
The answer can be found by looking at one cause of dyslexia: a difficulty in processing and remembering the sounds of phonemes. English is a particularly complex language and one that has been described as ‘orthographically nontransparent’. This means that the phonemes do not always have the same sounds. Languages like English that are not ‘transparent’ give rise to greater difficulties in reading.
In contrast, other language such as Spanish and Italian are orthographically transparent and it is easy to match the letter with the correct sound. Languages, such as Chinese or Japanese (Kanji), that use characters require greater use of visual memory, rather than verbal memory skills.
Brain imaging studies have found dyslexics in different languages (English, French and Italian) all showed the same brain deficits involving difficulty in processing verbal information.
Some might suggest that the differences in the education system across countries lead to higher rates of dyslexia in some countries. However, studies that have looked at bilingual children have found that they can struggle in reading in one language (usually English), yet be excellent readers in another language (such as Chinese or Spanish).
You may remember the 1968 movie, the Planet of the Apes. Charlton Heston played an astronaut, Taylor, who crash-landed on an alien planet of super-smart apes. He was imprisoned by the apes and, after escaping, he sees the Statue of Liberty, fallen to the ground. That’s when he realises, the alien planet was Earth all along! The super-smart apes have taken over the world.
This sounds far-fetched, right? Apes will never be smarter than humans . . . right? Well, in fact, they are already smarter than us. In a study by Japanese researchers*, five-year-old chimpanzees were able to correctly recall the location and sequence of numbers on a computer screen, and even outperformed university students!
What gives the chimps the edge on this working memory task? A couple of things: Biology and Age.
Biology: Chimps have an amazing photographic memory—an ability to quickly look at a very complex scene and retain an accurate image of it. They use this ability in the wild to quickly asses any potential dangers. Humans don’t have this ability, but it is not necessarily a bad thing. Scientists believe that humans gave up this skill to make room in the brain for developing complex language skills.
Age: This visual memory has been found in some human children but this ability fades as we get older. This aging effect is found even in chimps as the older chimps did worse on the task than the university students. So, the five-year-old chimps had the advantage of age compared to the college students.
*S. Inoue & T. Matsuzawa (2007). Current Biology
