The more I think about it, the less I believe there is really such a thing as a "learning disability."* At least, not in the sense that a "learning disability" is a brain disorder or disease.
Learning disabilities are currently treated as a combination of handicap and disease in the U.S.* The very name "learning disability" implies a handicap. Like the blind and deaf, people with learning disabilities get special accomodations, such as extra time on tests. Like people with a disease, people with learning disabilities are medicated and given special therapy and even diets. I think so-called "learning disabilities" are neither a handicap nor a disease. They are a mismatch between a person's capabilities and the current requirements of his or her life situation and culture.
The idea of learning disability as mismatch suggests fluidity rather than fate. A person's abilities might be perfectly adequate to the demands of home, but not school; or of high school, but not college. Or a person who struggled at school and work might suddenly find a niche as a successful Silicon Valley entrepreneur.
Not only do the demands of a person's current life situation change continuously, but so do the opportunities and demands of the culture as a whole. Would today's computer whizzes have been seen as having any special talent if, with the same neurological profile, they were born into an illiterate tribe in Borneo, or a noble family in the Middle Ages? The modern world opens up so many opportunities for individual's cognitive profiles to be transformed into talent (i.e., some sort of product valued by the culture). But the more opportunities there are to display talent, the more opportunities there are to display...the reverse. If there can be computer "whizzes," there can also be computer "dunces." Thus, the more opportunities the culture offers, the more "disabilities" will appear: that is, people who are significantly below average in some ability and thus unable to handle some area, large or small, of life in that culture. By necessity, the more cultural activities there are in the world--the more arts and sciences, the more crafts, the more jobs--the more opportunities for mismatch there will be and the more "disabilities" we will find.
This minor change in perspective has profound implications for how people with "learning disabilities" live their lives and for how others treat them. If a learning disability is a disease or a handicap, then the person is permanently flawed. Any problems they encounter in work, school or home because of their area of weakness are just their fault; there's no need to ask whether they are in the wrong school, the wrong job, or the wrong relationship. If their school or job does adapt, it merely makes cosmetic adjustments--give a student extra time, for instance. It will rarely change any fundamental procedures that might actually help, but might be inconvenient to alter. For instance, a school will give a student with ADHD extra time rather than designing work so that it attracts the student's attention and keeps him involved, even though the latter would eliminate much of the student's distractibility.
As a result, children and adults with learning disabilities are likely to feel continually inferior ("something is wrong with me; I have this burden, this handicap that no one else does"). They do not see that they are simply on the low end of the same continuum of abilities everyone else is on. It never occurs to them that maybe everyone else has the same problem they do, but to a lesser degree, or can deal with it better. Maybe all children are fidgety and distractible in school when they're bored and don't have the chance to move around, but some express this in more acceptable ways. Maybe all people have lowered performance while doing multiple things at once, and people with learning disabilities experience this to a greater degree.
A "learning disability" treated as disease or handicap can distract people from real problems in their lives: a bad teacher or insufficiently challenging classroom; a dead-end job that doesn't fit one's passions; or an over-filled, overly-busy life. The distractible child's parents do nothing to deal with the bad teacher or insufficiently challenging classroom because it's the learning disability that's the problem.* The worker in the dead-end job doesn't try to switch careers or find her passion because it's her learning disability that's responsible for her low performance. The overworked Blackberry-juggler who forgets everything thinks these demands are perfectly reasonable, but he simply can't handle them because of his learning disability. The end result is children and adults are dissatisfied with themselves (because they are "disabled") and their lives (because they have not found work, school, and life situations that truly fulfill them).
The pattern is obvious: a diagnosis of "learning disability" abdicates people (or their parents) from responsibility for achieving the right fit between themselves and the circumstances of their lives.
It's easy to go to the other extreme, assuming that only the environment needs to change, not the person with a "learning disability." Authors who write about the "gift" of ADHD or dyslexia often do this. They say that if we had more stimulating schools or work that used our entire brains, ADHD and dyslexia would simply disappear. These authors are right that these learning disabilities are unique cognitive profiles that, in different environments, would not be problematic (and might even be positive). But they also say that the answer to learning disabilities is just to change school and work so it fits the needs of people diagnosed with a learning disability. There's an obvious problem with that. Maybe no one would present with ADHD symptoms if they were given a more stimulating environment, but the rest of us might be distracted and overstimulated. School and work must fit everyone's needs, to the greatest degree possible. The only way this can happen is if people and environment both adjust to accomodate each other. That means that, yes, school and work need to adjust their expectations to something humans can realistically handle, but it also means that people with learning disabilities have to develop coping skills and learn to adapt to what they can't change. This is the full implication of the idea that learning disabilities are a mismatch between a person and his or her environment.
*I don't mean that bright, motivated people don't sometimes struggle and fail where everyone else succeeds with little effort, for no apparent reason. I've seen these people and I've been one of them. The experience that gives rise to the idea of a "learning disability" is all too real.
*They may or may not be treated the same way in other cultures. I'm not uniquely criticizing the U.S., I simply lack knowledge of what other cultures do.
* It's no wonder that teachers often push to have problem students diagnosed with ADHD and other learning disabilities--it takes the onus off them to teach differently and better.