Our brains are equipped with functions that are required for learning such as listening, reading (looking), speaking (listening), writing, calculating, reasoning, and thinking. They are organized so that each has its own particular neuronal network system which is operated by what we might call a program of the mind. We could say that learning happens when information received visually, aurally and otherwise through sensory organs switches on these programs, which then drives the neuronal network systems and each of their functions. This is also what takes place when children learn at school.
But studying at school can become difficult if these programs are not functioning properly or the neuronal networks are defective. Schools and pediatric medicine have increasingly turned their attention to this problem of learning disabilities in recent years.
Although children with learning disabilities manifest poor scholastic performance, they do not immediately appear to be any different from other children, and some are even endowed with special talents. They differ from children with mental retardation and its greater degree of cognitive disability. The causes being unknown, learning disabilities were referred to as “minimal brain damage” during the 1950-60s when one of the authors studied medicine. Research technology at the time was unable to discover abnormalities in the brain, and so these disabilities were considered to be slight defects that were barely detectable.
In Japan, 2 to 4% of children and students in Japan are reported to have dyslexia, with the incidence seven times higher in boys than in girls. Dyslexia accounts for 80% of learning disabilities, which also includes dyscalculia or math disability and dysgraphia or writing disability.
The causes of dyslexia remain unknown, but difficulty with reading would tend to suggest visual impairment. This is the view taken by the authors of the article that we have chosen to introduce here: Schneps, M. H., Todd Rose S. L., and Fischer K.W., the members of a Harvard University research team, in “Visual Learning and the Brain: Implications for Dyslexia” in Mind, Brain, and Education (MBE), Vol.1. No.3 pp 128-139.
The human visual system is organized in concentric cones around the fovea centralis of the retina. Visual information received in the visual center and periphery is processed separately and then, as we all know, integrated somewhere in the brain. Central vision provides sharp visual detail, but has a limited visual field. On the other hand, while the resolution of peripheral vision is approximately one-tenth that of central vision, its visual field is three times greater.
A number of experiments indicate that the speed with which objects are compared increases in proportion to the distance from the visual center and that contemporaneous comparison is optimal in the periphery. The visual center is optimized for information that requires sequential search while the periphery well suited for rapid contemporaneous analysis over a wide field. Information processing in the center and periphery shows individual variance and also varies according to age, experience, brightness, degree of visual attention, focus of visual attention, etc. The ratio at which the peripheral visual field is used can be measured and quantified, resulting in a parameter of periphery-to-center ratio (PCR). In this respect, it would be interesting to measure the PCR of Ichiro Suzuki, the Japanese baseball player active in the U.S., who is known for hitting super-fast balls.
According to this article, dyslexics have a slight abnormality in the processing of visual information. They indicate a high PCR value, and many show a peripheral bias, that is, they tend to rely on the peripheral visual field over the center. While dyslexics have trouble identifying words with their visual center, the ability to discriminate between colors ranges from good to poor.
Many dyslexics have succeeded in fields related to visual processing of information such as science and the arts, which has led to the inference that they are endowed with a talent for spatio-visual processing. They are also adept at discriminating between shapes and performing tasks that require quick analysis of the peripheral visual field. This brings to mind a prominent immunologist who was somewhat dyslexic although it was not immediately obvious to people who came into contact with him. Immunology requires frequent observation of a wide range of reactions both with the naked eye and microscope; furthermore, immune cell reactions and interactions can be said to rely on image recognition. This one example seems to corroborate the visual abilities that have been found in dyslexics.
The article states that it is important to study whether dyslexics are proficient at learning that requires comparison of multiple factors arranged spatially in one material and less adept at learning that requires sequential searching in order to clarify the pedagogical implications of the relation between dyslexia and visual learning.
However, as the authors of the article note, much remains unknown about the causes of the dyslexia and it is unwise to simply consider it a disability in visual information processing. That is, we must keep in mind that human beings link and synthesize disparate pieces of the information when they learn. While further study is required, there is no doubt that the research findings introduced in this article provide important insights for the development of improved educational technology.
- Noboru Kobayashi, M.D., Pediatrician, Director, Child Research Net
Hirotaka Kataoka, Researcher, Benesse Educational Research and Development Center, Benesse Corporation
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