Cognitive enhancers: leveling the playing field?

A hot topic in neuroethics surrounds the use of drugs to enhance human intelligence.  Outside of the two most obvious issues (‘do they work?’ and ‘are they safe?’), ethicists have expressed concern over the possible unequal distribution of enhancers. Consider this statement from the President’s Council for Bioethics’ report on human enhancement (“scare quotes” are original):
“The issue of distributive justice is more important than the issue of unfairness in competitive activities, especially if there are systemic disparities between those who will and those who won't have access to the powers of biotechnical "improvement." Should these capabilities arrive, we may face severe aggravations of existing "unfairnesses" in the "game of life," especially if people who need certain agents to treat serious illness cannot get them while other people can enjoy them for less urgent or even dubious purposes. If, as is now often the case with expensive medical care, only the wealthy and privileged will be able to gain easy access to costly enhancing technologies, we might expect to see an ever-widening gap between "the best and the brightest" and the rest. The emergence of a biotechnologically improved "aristocracy"-augmenting the already cognitively stratified structure of American society-is indeed a worrisome possibility, and there is nothing in our current way of doing business that works against it.”
Is this a realistic worry? One counter to this argument, as pointed out by Anjan Chatterjee is that distributive justice is only a problem for cases where there are clear winners and losers (i.e. in a zero-sum game situation). Performance enhancing drugs are a big deal in sports because there is one winner and one loser. In other cases, enhancement of some can benefit more than just the enhanced individual, such as the case of subtle anti-theft devices such as LoJack: fewer cars are stolen in neighborhoods where LoJack use is higher because would-be thieves cannot tell which cars have the system, and will therefore look in LoJack free neighborhoods for victims.

Beyond the question of whether our current economic environment spawns competitive, zero-sum situations, we need to ask whether putative cognitive enhancing drugs provide the same effect size in all those that try them. Interestingly, a study by Mehta and colleagues in 2000 demonstrated that the degree of cognitive improvement with Ritalin in a spatial working memory task was negatively correlated with baseline working memory capacity at r = -0.78! This means that over 60% of the variance in the enhancing abilities of Ritalin could be explained by the subjects’ working memory capacities: those with lower working memories got more benefit than those with higher capacities. Similar results have been found in other studies using dextroamphetamine, and bromocriptine (a drug used to treat pituitary tumors and Parkinson’s disease).

Why is this effect not being mentioned in the ethical debate over cognitive enhancements? Partially, it is because many experiments are designed not to show the effect. The “lab rat” for most academic research is the undergraduate student. Although researchers assume that samples from this population are representative of all people, we know that they are young, educated, and have self-selected to be in universities with people of similar interests and backgrounds. Given this, it is perhaps not surprising that some studies of cognitive enhancers have not found this relationship: in a mostly homogenous population, the degree of enhancement would be similar.

Of course, the ethical debate we should be having in light of this data surrounds how we would deal with a more intellectually leveled playing field. Of course, there would be a great number of benefits to society as more people might be doing more important work, and developing new solutions at a more rapid rate. However, we should also ask how we would evaluate people for a job or academic position if all had the same intellect. Would we then put more emphasis on other traits such as creativity or cooperativeness? How would we deal with issues of nepotism, sexism and racism if there were no plausible arguments against the candidate’s intellect?