I think this brief essay is worth reproducing here:
"I am optimistic that human intelligence can be increased, and can be increased dramatically in the near future. I see three avenues that will lead to this end.
First, the fruits of cognitive neuroscience and related fields have identified a host of distinct neural systems in the human brain. Different combinations of these systems are used in the service of accomplishing different tasks, and each system can be made more efficient by "targeted training." Such training involves having people perform tasks that are designed to exercise very specific abilities, which grow out of distinct neural networks. Just as a body builder can do curls to build up biceps and dips on parallel bars to build up triceps, we can design computer-game-like tasks that exercise specific parts of the brain—mental muscles, if you will. By exercising the right sets of systems, specific types of reasoning not only can be improved but—the holy grail of training studies—such improvement can generalize to new tasks that draw on those systems.
Second, people often grapple with problems in groups, be they formally designated teams or casual huddles around the water cooler. I am optimistic that understanding the nature of such group interactions will increase human intelligence. Just as a mechanical calculator can extend our mental capacities, other people help us extend our intelligence—both in a cognitive sense (as required to solve problems) and in an emotional sense (as required to detect and respond appropriately to emotions, ours and those of others). In this sense, other people can serve as "social prosthetic systems," as extensions of our own brains; a wooden leg can fill in for a missing limb, and others' brains can fill in for our cognitive and emotional limitations. To the extent that researchers come to understand how such social prosthetic systems arise and operate, they will understand how to increase human intelligence.
Third, the line between animate and inanimate information processing is becoming increasingly blurry as research in multiple fields proceeds apace. I expect that engineers will continue to press forward, designing increasingly powerful machines to help us extend our intelligence. For example, some people carry computers with them everywhere they go, and treat Google as an extension of their own knowledge bases. Or, in my case, my PDA extends my organizational ability enormously. We soon will have a wide variety of mechanical helpmates. The distinction between what goes on in the head and what relies on external devices is becoming more subtle and nuanced, and in so doing human intelligence is being extended.
Crucially, each of these three developments amplifies the effects of the others, producing synergies: As "brain exercises" enhance our personal intellectual abilities, we can learn how to make better use of mechanical aids and how to rely more effectively on other people. The confluence of all three types of developments will produce positive feedback loops, where the very act of interacting with others or working with smart devices will help us continue to develop our brains, and as our brains develop we will in turn be able to use increasingly sophisticated devices and rely on people in more complex and powerful ways.
With luck, such developments will produce news sorts of extended social links and highly integrated social networks, and a new kind of "smart society" will emerge. And, who knows, such a society may not only be smarter, but also wiser."