Cognitive enhancement - of adults - is definitely one of the most promising innovations of biotechnology we have to expect. Obviously it is going to change society. I wondered what you think it's social influence will be. If cognition enhancers will be affordable to the masses, I can imagine, that it will help people with lower abilities to climb up the social ladder more easily by allowing them to take up professions which today require high IQ's. This in turn bolsters up competition and thereby benefits economy in a twofold way. Since the high IQ professions of today are the ones which have the most economical importance and the ones which confer the most power and the highest status to their holders society as a whole and the members of all social classes would benefit because to chance of everyone to make it to the top would be almost equal(and not dependent on your genetics). On the other hand I'm not sure whether todays "cognitive elite"(do we even have something like an organized elite???) will support technologies that flood the market with tons of highly trainable and willing workers, who dispute the elites leadership position in society by breaking its monopoly on cognitive abilities.
However, if cognition enhancers are going to be specialized tools, which will only be useful in certain workplace settings or which are going to have a price, which is not affordable to a single person, I fear, that powerful organizations like the government of a country or a powerful corporate group will be able to create their own league of "brainworkers", who then will dominate society economically and politically. It would be pretty much be like in soviet Russia, where only faithful communists were allowed to enter universities but with the difference, that "normal" people would not be able to overthrow such a government anymore, since they'd be totally dependent on it's knowledge and skills and would not even understand its decissions.
I worry too, that jobs which require cognitive enhancement( which would be a common thing I guess, since enhanced employees confer advantages in productivity, which forces companies with a non enhanced staff out of business) could have the character of mob work. Once you get in you can never leave again. Since the company paid for your brains new tricks, you will have to stay there until you earned it its investment back( or forever if the enhancement can't be removed anymore and the other employers have different technical standards).
Furthermore I wonder, what happens if technologie moves on and there are people who can't be upgraded. Will they be the new underclass or will they have the status handicapped people have today?