In addition to improving a kid's ability to focus, by increasing the release of dopamine, Ritalin also improves learning, by increasing brain plasticity, by releasing another type of dopamine. This is based on rats learning that sugar water followed a flash of light and a sound. Rats given Ritalin (in doses relatively the same as those give human kids) learned that faster than rats not given Ritalin. If researchers blocked D1 (for dopamine) receptors, Ritalin no longer helped learning; if they blocked D2 receptors, Ritalin didn't improve focus.
Some of the neat part of this is just learning more about the brain. The best part is the speculation it brings on. Suppose they find a drug that only enhances D1 release and (or some other drug that enhances the ability to learn), and even suppose we know it not to have any harmful side effects. Would we want to give it to all kids to generally improve their ability to learn? I don't mean requiring it, like vaccinations, just making it legally available to everyone without a social stigma, like steroids for the brain.
I'd be all for it. But imagine a high-school brain bowl where some kids are juiced and some are not. Is it fair to the non-drugged kids that the drugged kids all know more because they've been on super-Ritalin since kindergarten? Is this like steroids in baseball and track and field? Logically they are the same: taking a drug to increase your ability to learn or to increase your ability to train hard. Maybe the reason they feel different to me is that it's now my ox being gored. I would take a pill to learn better but not to train harder.
And I would see it less as a way for people who already learn well to learn even better, but even more as a public health measure, like adding folic acid to bread to prevent spinal bifida, only this would increase the percentage of people who can read car repair manuals or rental agreements.
I wonder if there are any foods (not food supplements) with nutrients that increase the release of D1. Google will know.